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Humus farming: from a sceptic 

to a pioneer P. 6 

The VOA / TIC value put 

to the test P. 28 

Denmark totally committed to 

organic residues P. 42 

Humus: 

keep the 

edaphon 

alive! 

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Editorial 

Keep the 

edaphon alive! 

Dear Readers, 

In this issue of the Biogas Journal, among other topics, 

we address the subject of humus management in agriculture. 

The farm businesses with biogas plants introduced 

here are trying out management methods, some 

of which are unconventional, to increase humus content 

and thereby enhance overall soil fertility. Why deal with 

this topic? Well, in Europe, recent years have shown that 

when long periods without precipitation occur together 

with high temperatures, soil moisture levels are quickly 

depleted – depending on the type of soil and its humus 

content. On the other hand, plants grown in soil with a 

humus content of two percent or more or plants growing 

in plaggen soil reach a ripened or prematurely ripened 

stage later. 

One percent more humus in the soil means an additional 

saving of about 400,000 litres of water per hectare. Humus 

particles store twenty times their weight in water 

and up to 95 percent of soil nitrogen. This means that 

building up humus is worthwhile in order to increase 

the usable water holding capacity with regard to the water 

available in the soil. Also significant, though, is that 

with each additional tonne of carbon in the soil biomass, 

which is equivalent to about two tonnes of humus, 3.67 

tonnes of CO 2 

are removed from the atmosphere. We 

don’t have enough space here to list all of the many other 

benefits. This is why we should pay more attention to 

humus formation because, in the future, not only must 

our business activities be CO 2 

neutral, but we must also 

remove a considerable portion of the previously emitted 

CO 2 

from the atmosphere. 

From a purely scientific perspective, humus is made up 

of the total dead organic substance of the soil mixed 

together with the mineral soil. A central component is 

the so-called edaphon, which Raoul H. Francé was already 

investigating 100 years ago. Edaphon refers to the 

totality of living organisms, such as bacteria, archaea, 

fungi, viruses, protozoans, nematodes, spiders, insects 

and earthworms. The greater the amount of species and 

the amount of individuals per species, the more active 

and fertile the soil. This activity depends on soil temperature 

and soil water content, and therefore, also on 

the seasons. 

According to Australian soil scientist Dr. Christine Jones, 

however, it is even more important for plants that perform 

photosynthesis to be growing at the soil’s surface 

for as much of the year as possible. The edaphon, just 

as humus, is not produced by organic fertilisation alone, 

but instead due to root excretions (exudate). Among 

other items, these include amino acids and easily degradable 

sugars, which feed bacteria and fungi. In this way, 

the living plants pump large quantities of liquid carbon 

into the soil, which feeds the edaphon organisms. 

In a process akin to bartering, the microorganisms give 

the plants the nutrients they need from the soil. The 

so-called mycorrhizal fungi are particularly important in 

this interaction. U.S. soil scientist Dr. Elaine Ingham 

also talks about the “soil food web”, which refers to the 

process by which the edaphon organisms provide each 

other with nutrients; but they also form a nutrient chain 

based on the principle of “eat and be eaten” in which 

every dead organic substance is always recycled. 

We must become aware of natural connections and interactions 

and align our agricultural practices accordingly. 

Essentially, our lives depend on just the top few centimetres 

of topsoil. Everything that debilitates humus and 

inhibits the edaphon should be reduced to a minimum. 

I wish everyone success in increasing humus, boosting 

soil fertility and developing “ripe” soil. 

Best regards, 

Martin Bensmann, 

Editor, Biogas Journal 

German Biogas Association 

3

English Issue 



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4

Biogas Journal | Spring_2021 English Issue 

Editorial 

3 Keep the edaphon alive! 

By Martin Bensmann, Editor, Biogas Journal 


4 Imprint 

Germany 

6 From a sceptic to a pioneer 

By Christian Dany 

14 Feeding soil life with organic matter 

By Dipl.-Journ. Wolfgang Rudolph 

22 Biogas can improve the soil 

By Dierk Jensen 

28 The VOA / TIC value put to the test 

By Prof. Dr. Paul Scherer, Martin Pydde, Dipl.-Ing. Sebastian 

Antonczyk and Dr. Niclas Krakat 

6 

34 NuTriSep: Nutrient extraction and peat substitute 

from digestates 

By Dipl.-Ing. Heinz Wraneschitz 

38 Seven biogas plants supply one gas feed-in plant 

By Marie-Luise Schaller, EUR ING 

Country reports 

42 Denmark 

Denmark totally committed to organic residues 

By Thomas Gaul 

46 South Korea 

Mandarin orange juice production – residues 

used to produce biogas 

By Achim Kaiser 

48 Philippines 

Converting pineapple waste into biogas 

By Medina Berbic 

coverphoto: Silke Goes photos: Christian Dany, Dierk Jensen, LIPP GMBH 

22 

48 

5

English Issue 



From a sceptic to a pioneer 

Hans Grötzinger is a passionate crop, biogas and organic farmer. He discovered renewable 

agriculture while searching for better soil fertility and stability in view of the climate 

change. He applies some of the measures mentioned under this term, but not all of them. 

He focuses on humification, a well-balanced supply of nutrients and organic fertilization. 

By Christian Dany 

Hilling in the Lower Bavarian district of 

Landshut: Hans Grötzinger sticks a spade 

into the soil of his field. “The chunks in the 

soil are good,” he explained. “They maintain 

the soil structure so that the soil won’t 

become too muddy when it rains. Below the chunks is 

the fine soil.” He then digs more than 30 centimeters 

below the surface. There is no visible cultivated layer, 

which is no wonder, as the organic farmer Grötzinger 

stopped using a plough three years ago. 

Another interesting factor is the test with a one meter 

long soil probe: It can easily be pushed into the soil as 

far as it will go. 37-year old Grötzinger then inspects a 

field of five-week-old oat plants dispersed with buckwheat 

and goosegrass. “The buckwheat is from the 

previous catch crop and the goosegrass shows there is 

good nutrient availability,” he explains. We then see a 

demonstration of renewable agriculture live when his 

brother, Josef, works the remnants of a catch crop blend 

into the soil with a seedbed cultivator. 

Grötzinger’s father Josef switched to organic farming in 

the Naturland Association as early as 1989. “We were 

a mixed farm, with dairy cattle and bullock fattening,” 

said Grötzinger. The quadrangle-shaped farmhouse lies 

on the main street of the village, just like some of the 

other farms. But most of the approximately 500 inhabitants 

live in the adjacent residential area. There are 

some large industrial companies nearby. Employment 

opportunities have accelerated structural change. 

“The smaller farms closed down about 30 or 40 years 

ago.” Grötzinger himself also did not follow a predestined 

course of life. After his apprenticeship in agriculture, 

he no longer enjoyed working in that profession. 

“For five years, I worked as a paramedic. I wasn’t really 

interested in dairy cattle,” he said. 

But when the special permit for livestock breeding expired, 

he experienced a turnaround: “We would have 

needed more pasture, but were a little too penned between 

the road and the Bina River,” said Grötzinger. He 

enrolled in the organic agricultural college in Landshut- 

Schönbrunn and graduated as a master of agriculture. 

He later gave up livestock breeding and revolutionized 

the business: “We have a lot of clover grass in the crop 

rotation. That can be optimally utilized in the biogas 

photos: Christian Dany 

Josef Grötzinger, who is the operations 

manager’s brother, removes the 

stubbles with a seedbed cultivator. The 

picture also shows the tire pressure 

regulation system with the equalizing 

tank at the front. 

6


plant. I have good technical skills, which is 

just what we needed,” said Grötzinger, who 

has two sons. 

The biogas plant, which has an electric capacity 

of 210 kilowatts (kWel) was set up 

along the lines of the build-owner model 

in 2010 with connected load. A 100 kW el 

CHP unit for flexible operation was added 

in 2016. Grötzinger: “We operate a little 

according to the temperature.” That means 

full power, particularly in October 

“We have a lot of clover grass 

in the crop rotation. That can 

be optimally utilized in the 

biogas plant” 

Hans Grötzinger 

Grötzinger checks 

the soil moisture 

before continuing 

the processing. 

7

English Issue 



and November, when grain maize is being dried, and 

in winter to ensure a guaranteed supply of heat for the 

seven households connected to the heating grid. In 

return, power is reduced in mid-summer. Grötzinger 

wants his plant to run as much as possible on residues 

Picture of the farm of Hans Grötzinger 

Geographic location: 

Operational setup: 

Size of the farm: 

Soil type: 

Land use: 

Individual operating units: 

Bavarian Molasse Hills, height above sea level: 470 meters 

crop cultivation, renewable energies 

150 hectares 

+/– sandy loam, 47 to 75 ground points 

130 hectares , 20 ha Grassland 

Crop cultivation: cash crops and fodder as biogas feedstock 

Renewable energies: biogas and photovoltaics 

Biogas plant: 210 kW el 

rated output, 310 kW el 

installed capacity (100 kW el 

for flexible operation), 

Substrates: silage grass, deep sloped floor litter, 

small silage grass residues 

Family: Operations Manager Hans Grötzinger (37), 

wife Katrin, sons Julian and Johannes 

Employees: 

1 full-time Operations Manager, 80 % part-time employee 

Josef Sen., 20 % part-time employee wife, 20% part-time 

employee Josef (brother), one minor employee for the 

biogas plant 

which it does: The main component of the feedstock is 

grass silage made of grass clover and catch crops, 32 

to 35 percent of it consists of sloped floor deep litter 

manure, which he buys in addition. Only 15 percent of 

it is maize silage. 

Biogas plant as a nutrient supplier 

On the organic farm, the biogas plant fulfills the important 

function of a “nutrient plant”. In return for the 

manure he buys, Grötzinger partly returns digestate 

as fertilizer and partly receives a nutrient input. He 

also cooperates with other biogas plants, from which 

he gets grass clover in exchange for the digestate. The 

Lower Bavarian considers cooperation an important 

aspect at many levels: In a community of five farmers, 

he tests and develops the cultivation of linseed: “If it 

works, we’ll expand it.” He ventures into unusual farming 

methods in other ways, too: He cultivates spelt, 

oats, grain maize and even sweet maize, of which the 

cobs are picked and sold as barbecue maize. 

Grötzinger sells around two thirds of the field crops as 

cash crop, one third goes into the biogas plant. “Reallocation 

and consolidation of the farm holdings resulted 

in a great infrastructure,” he says. Most of the 

farm boundaries have been readjusted and 80 percent 

photo: Grötzinger 

Operating the rotary cultivator, viewed 

beyond the tip of the tractor: Here 

showing clover grass being milled 

before the winter crop. 

8


of the fields are less than 2.5 kilometers 

away. They have an average size of about 4 

hectares. And besides that, crop production 

benefits from the loess soils in this 

area. Crop and energy farmers also have 

about 20 hectares of grassland, many of 

which are wildflower meadows along the 

Bina River. Grötzinger farms a total of 150 

hectares, a large part of which is leased 

land. 

The basis of Grötzinger’s crop rotation is 

clover grass. He says that well-planned 

crop rotation will ensure a clean, healthy 

plant stock; for example, as a prevention 

against stone blight in wheat. Catch crops 

are planted after each primary crop to ensure 

that the soil is always covered. For example, 

he grows vetch rye or Landsberger 

mixture, which generally consists of vetches, 

scarlet clover and Italian ryegrass. 

This mixture regularly brings the organic 

farmer a harvest of more than 30 tons of 

fresh matter per hectare with about 28 percent 

of dry substance. “That’s about half a 

maize harvest and there is also a cash crop 

on top of that.” The additional 

revenue and the humification 

more than make up for all the 

work and the hours spent on 

the tractor. Grötzinger has his 

own seed blending unit with 

which he can also make individual 

mixtures. Besides that, 

he also puts in more undersown 

crops when he plants 

grain and maize: for example, 

white clover, rye-grass or grain 

legumes. 

Retting instead of 

ploughing 

So far, not so good. “Even 

with good yields and good agricultural 

practice, the problems 

did not decrease, they 

rather tended to increase,” 

said Grötzinger. The yields 

were not stable enough, especially 

during dry periods. 

So he took a closer look at 

new forms of agriculture and 

how to brace himself for the 

climate change. He considers 

the enrichment of humus 

as the most important task 

for the future because of its 

capability to retain water and 

nutrients. “We have been planting catch 

crops for a long time now. We also used 

to have solid manure. We had 2.8 to 3.5 

percent of humus, but did not manage 

to get more than that,” he said, looking 

back. He found solutions in principles that 

today are summed up as “renewable agriculture”. 

He changed the inversion and 

soil sampling methods and also organic 

fertilization. 

He has been tilling the soil without a 

plough for about 4 years now, as it did 

more to destroy the life and structure of the 

soil than enhance it: “Ploughing interferes 

with the development of bacteria. Further 

down, there are anaerobic bacteria that 

are brought to the surface, which you can 

smell.” Instead of doing that, Grötzinger 

removes the crop residue and puts it into 

the surface retting. Later, he stirs the soil 

with a cultivator at a depth of about 15 

centimeters and then compacts it with a 

Cambridge-type roller. 

“Anything that has a thick sward, like clover 

grass and Landsberger mixture, is cut 

right down to the roots,” he explained. The 

rotary tiller, that he leases, cuts to a depth 

of 3 to 5 centimeters. “If there are straw 

and maize stubbles, green rye and whole 

crop silage, we use a blade cultivator because 

it consumes less diesel.” The special 

hydraulic cultivator with adjustable 

depth can also cut plants to that depth. 

“That’s how I put organic material into the 

soil with maximum soil conservation,” said 

Grötzinger. He refrains from using retting 

control, like enzymes or the like: “It needs 

time. The material stays in there for three 

to ten days. The more there is, the longer 

it takes for the organic matter to be converted.” 

The chisel ploughing is followed 

by rolling. He says that is important to 

ensure that the CO 2 

is retained in the soil 

rather than being outgassed. And besides 

that, the soil retains its resistance to heavy 

loads much faster. 

“If left for a few weeks, the soil becomes 

porous and compaction is reduced. We 

hardly ever need a rotary harrow, even 

though our soil is heavy.” Although this 

kind of tillage requires several cycles, it 

uses up less diesel: “We only use between 

2 and 4 liters of diesel per hectare for each 

flat cultivating and rolling cycle.” The annual 

consumption is 28,000 liters, which 

is about 2,000 liters less than when he was 

still using a plough. 

9 

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English Issue 



“There’s no point fertilizing 

according to a pH level” 

Hans Grötzinger 

Round crumbly soil 

with good root density 

in a field of oats. 

Fertilization according to Albrecht/Kinsey 

The changing tillage methods go hand in hand with 

soil analyses according to the Albrecht/Kinsey method, 

which is applied to create a balanced proportion of nutrients 

in the soil and adequate levels of trace elements. 

Grötzinger explained the theory of “scarcity despite 

abundance”: “Today, you have to eat ten times more 

salad than after World War II to absorb the same amount 

of trace elements. This method will provide us with food 

items that are simply more nutritious.” The farmer, who 

comes from Hilling, works with the agricultural retailer 

Josef Hägler and with Geobüro Christophel, and supervises 

the soil samples of other operating farms in the 

region. 

The Albrecht/Kinsey method primarily focuses on the 

cation exchange capacity, which is a measure of the 

quantity of nutrient cations that occurs in interchangeable 

form and that is thus accessible to plants (for example 

C a2+ , Mg 2+ , K + ). It also used to examine the interaction 

of nutrient contents, for which there are special 

ratios, such as the carbon:nitrogen ratio: “Within two 

years, we adjusted the C:N ratio to 9:1 (10:1 would be 

ideal). We started off at 5:1,” said Grötzinger, “That’s 

too tight for most of the farms, no matter whether they 

have dairy cattle or biogas.” According to Grötzinger, 

another indication is the calcium:magnesium ratio: 

“Ideally, it would be 68:12. We had 75:11. Too much 

calcium prevents other nutrients from being absorbed.” 

Grötzinger also found that the pH level is not a decisive 

criteria: “There’s no point fertilizing according to a pH 

level.” In the past, too much calcium was often used in 

fertilization if the pH level was low. But he believes that 

if the nutrients are well-balanced, there will automatically 

be a good pH level of around 6.5. His farm was 

discovered to have a shortage of boron and sulphur. Sulphur 

deficiency is a widespread phenomenon, he said, 

but you need enough sulfur for nitrogen availability and 

to build up humus. 

Grötzinger recommends having soil analyses made during 

the soil dormancy period before the soil is fertilized – 

ideally in November. Repeated analyses should then 

be made on the same date after two or three years. He 

recommends taking samples from a very good and a 

very bad area and from two or three average areas. A 

standard analysis costs around 100 Euros. 

photo: Grötzinger 

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photo: Christian Dany 

Digestate treatment with Leonardite 

and In-wa Quartz 

Organic fertilization with organic manure from the biogas 

plant is of prime important on Grötzinger’s farm. 

He separates the thick part of the digestate and in that 

way, extracts around 500 tons of solid phase per year. 

Grötzinger processes the liquid phase with Leonardite 

and In-Wa Quartz, which are both approved in organic 

farming. “The high proportion of grass clover produces 

7 kilograms of nitrogen per cubic meter in the 

Catch crop of winter 

peas with triticale 

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undersown by grass. 

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English Issue 



Julian Grötzinger with 

a whole crop silage 

mixture of winter peas, 

barley, rye and Landsberger 

mixture. 

manure. Despite the high protein content, the digestate 

no longer smells after it has been processed. That 

works one hundred percent,” he says. The In-Wa Quartz 

makes the manure black, although only 0.5 liter of it is 

needed for every 100 cubic meters. The digestate goes 

into a rotting phase and that brings about a stimulating 

effect for self-protection. 

“In an experimental field, we treated organic rapeseed 

with In-Wa Quartz and lime,” said Grötzinger when talking 

about a particular incident. “The rapeseed had been 

completely infested with the rapeseed gloss beetle. The 

next day, there wasn’t a single beetle to be seen.” He 

says that Leonardite is a lignite precursor that results 

from the humification of plant matter. That makes it 

rich in humic acids (up to 90 percent). “The Leonardite 

binds the nitrogen and the plant gets it little by little, 

whenever it needs it, which means that there is no free 

nitrogen present in the soil.” This conditioning prevents 

nitrate from being leached out. “I have two digestate 

storages,” he said when explaining his nutrient management 

methods. “The digestate from the farms that 

supply me with clover grass is not treated, unless this 

is expressly requested. The treatment costs 1 Euro per 

cubic meter.” 

Composting digested, separated solids 

Grötzinger spreads liquid digestate with the trailing 

shoe method and makes sure it is distributed over cultivated 

fields. That can be achieved by cultivating catch 

crops and by splitting the individual applications. “We 

no longer have any fertilizer burn. Spreading manure 

over open soil would cause rotting,” he said. “You would 

‚encourage‘ weeds to grow.” Grötzinger has also produced 

“MC compost” from the solid phase. “To do that, 

the material is spread on a storage clamp and compacted. 

The nitrate and moisture content must be well-balanced. 

It takes eight weeks for compost that is rich in 

humic acid to form and that way there is less carbon 

loss than in usual compost,” he explains. According to 

the current fertilizer ordinance, MC compost may no 

longer be produced on open fields, although as it turns 

out, it is completely dry beneath the storage clamp and 

Nmin sampling has not shown considerable amounts of 

nitrogen. That is why Grötzinger stores the solid phase 

in a covered horizontal clamp and then distributes it 

like that. 

“The system needs time to warm up,” Grötzinger summarizes. 

He maintains that you cannot expect any 

miracles overnight. But the trend in the right direction 

became clear quite quickly. “We managed to produce 

between 0.2 and 0.5 percent of humus within three 

years – depending on the location,” he said. But he 

spends a lot of time on the plant production system, 

criticizing that the biggest problem of some of the farms 

nowadays is the lack of time. “Everyone is in a hurry, 

nobody wants to wait.” 

He criticizes the lack of patience and the fact that liquid 

manure or digestate is then spread on the fields in 

as early as March. “If you see how wet the soil is, you 

shouldn’t be driving over it with a total weight of 25 

tons.” He said that last year, he sowed maize as late as 

June 2 nd and then managed to shred 60 tons of fresh 

matter; and that is all grown organically with a supply of 

15 cubic meters of digestate. “I’ve never known anyone 

not to succeed because they did something too late, but 

rather because they did it too early. Just wait and keep 

cool,” he says. “If you take pleasure in the method and 

the soil, the rest will practically work by itself.” 

photo: Christian Dany 

Author 

Christian Dany 

Freelance Journalist 

Gablonzer Str. 21 · 86807 Buchloe 

00 49 82 41/911 403 

christian.dany@web.de 

12


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13

English Issue 



Rolf Schneider examines the 

crop development in a mixed 

crop of rapeseed and peas. He 

is one of the pioneers of no-till 

farming in Germany. 

Feeding soil life 

with organic matter 

Rolf Schneider, who is a farmer, has been cultivating 

his land with the no-till farming method for 30 years and 

builds up humus in the soil with fermented products. 

By Dipl.-Journ. Wolfgang Rudolph 

This year’s crop of rapeseed in Rolf Schneider`s 

field in Apolda, Thuringia, has bright yellow 

flowers and good branching. He sowed the crop 

with the no-tilling method in wheat stubble on 

September 8 th 2019 together with peas as a corollary 

plant. The legumes in the mixed crop collected nitrogen 

with their nodule bacteria until late fall. Once the peas 

were winter-killed, the rapeseed had sufficient nutrients 

in the spring. 

Schneider considers the no-till farming method which 

he also applies to all the other fields on his 300-hectare 

farm as the most natural form of agriculture. The concept 

of this system of cultivation has formed the basis 

of his farming strategy for the past 30 years. That makes 

Rolf Schneider one of the pioneers of no-till farming in 

Germany to which he is making a crucial contribution. 

He is more surprised than annoyed at the fact that the 

whole scene is relatively limited, as so many of the facts 

become obvious when you take a close look at them. 

And the generally good harvests he gets from his fields 

in such a dry area of the Weimar district would justify 

the results, as would the relatively low crop losses in the 

past two, very hot summers. The precipitation amounts 

in that period were considerably below the annual average 

of just under 500 mm. Only a few interested visitors 

came to inspect his fields and those of other notill 

farming enthusiasts in Germany from the vicinity. 

Instead, farmers from New Zealand or Australia came 

to exchange experience. Many of them were making 

repeated visits. 

“In any case, you can no longer rely on the experience 

you have in the area on weather development, not even 

if you take the wide fluctuation margin into account,” 

said Schneider. He added that only the relatively good 

water retention capacity is still as it was before. 

More than just non-inversion tillage 

“But the term no-till farming is a little unfortunate,” 

says 53-year-old Schneider. He says that it is more than 

just a matter of merely skipping some of the field work, 

particularly what he refers to as “continually rummaging 

through the field” to save machine power. He claims 

that is more the result of a strategy that focuses on field 

soil and soil life, meaning micro-organisms, bacteria 

and fungi. “The overall goal is to attain consistently 

loose, fertile soil that regenerates, forms humus and 

stores carbon in a cycle. To achieve that, the soil must 

be allowed to rest. This idea has inspired me back when 

I was still a young farmer,” says Schneider. 

He says you can see that, for example, in the forest or in 

permanent grassland. But in cultivated fields, the soil 

life has to be preserved and provided with organic material 

by doing without tillage, either through the root 

excretions of living plants or decomposition products 

of dead plant particles. “This is exactly what is best 

achieved by sowing the main crop into an established 

cover crop or stubble, intercropping and mixed seedphotos: 

Carmen Rudolph 

14


ing,” said the farmer when describing the basic idea of 

the cultivation system. He continued saying that applying 

the organic manure directly in the soil also promotes 

the formation of humus. 

The peas sown as corollary plants with the rapeseed 

show that this not only provides additional nitrogen, but 

a whole row of other effects achieved by non-inversion 

tillage. That includes better root penetration in the soil, 

suppression of flea beetles and other harmful insects 

with odors that are not typical for rapeseed, reducing 

the use of herbicides by ensuring faster soil coverage 

and, last but not least, the provision of food for soil 

organisms. 

In order to keep track of the effects of horticultural 

measures like that, Schneider inspects the nutrient 

status on each of his 18 fields in five-year intervals in 

addition to the legally prescribed soil samples by making 

a full soil analysis according to the Kinsey method. 

With this approach, the percentages of 13 nutrient elements 

are examined in a laboratory in the USA. “The 

balance of the individual micronutrients in relation to 

each other is decisive for the evaluation of the soil fertility 

derived from that,” Schneider explained. So, he 

injected the rapeseed field with a nutrient solution prepared 

according to the Kinsey recommendation. 

Before the farmer, who comes from the Westerwald in 

Hessen, acquired the former “Volkseigenes Gut” (German 

for People-Owned Property; abbreviated VEG) in 

Apolda in 1992, he had already gained experience 

with minimum tillage methods on his family’s farm. “It 

bothered me that vast quantities of energy were being 

consumed just to bring the field to heel with technology 

The dense population of earthworms in 

the field indicates diverse soil life. 

use,” said Schneider, thinking back. He also received 

fresh impulse from the ideas of the agricultural machinery 

manufacturer Horsch in the 1980`s. Schneider had 

bought one of the tillers with a sowing bar for broad 

seeding, the “sowing actuator”, which then was still 

mounted in the barn on the Sitzenhof farm in Schwandorf 

and used it for many years. The Horsch com- 

The digestates that 

come from the small 

liquid manure system are 

completely spread on the 

fields as fertilizer with a 

strip-tilling machine or a 

slurry injector. 

“It bothered me that vast quantities of 

energy were being consumed just to bring 

the field to heel with technology use” 

Rolf Schneider 

15

English Issue 



Rolf Schneider uses the Primera seed drill made 

by Amazone on his farm for the sowing. 

The equipment 

of the Primera 

seed drill made by 

Amazone includes 

coulter units for 

no-till farming. 

Digestate to supply nutrients and improve 

the soil is applied directly in the soil, for 

example with slurry injectors. 

The strip-till machine is often used before the 

corn is sown to deposit digestate as fertilizer. 

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English Issue 



The pea seeds added to the main crop of rapeseed assume a 

whole series of other tasks besides supplying nitrogen. 

The little nodules on 

the network of roots of 

the corollary plants of 

peas collect nitrogen 

for the main crop, 

which is rapeseed. 

The root crowns of the rapeseed plants had 

a diameter of almost 3 centimeters in just 

under eight weeks after the sowing. 

The mixed crops consisting of rapeseed and peas had already 

developed well by the end of October last year. 

pany then changed its approach and was no doubt very 

successful. But for Schneider, that meant too many 

compromises that he does not want to make. 

The aversion to soil-working power tractors met with 

economic constraints during the expansion of the farm 

in Apolda, where the staff includes his partner, Petra 

Stoll, and an employee. “We couldn’t afford a large 

fleet of machines to farm in the traditional way it’s done 

in this region,” Schneider remembered. Moreover, 

there were problems with erosion in the rugged terrain. 

So, he made a virtue out of necessity and adapted the 

technology to the fields, not the other way round. 

Digestates improve soil fertility 

Today, the machinery at the farm in Apolda includes 

the robust Brazilian airseeder Semeato and the Ama- 

18


zone Primera equipped 

with coulter units for 

no-till farming with a 

working width of 6 meters 

for sowing in drills. 

The Semeato has a dead 

weight of 3.5 tons. That 

enables the twin discs 

to penetrate the ground 

in order to sow the seed 

because the soil is partly 

clayey and is hard during 

the dry periods. 

Schneider is planning to 

technically upgrade the 

seeders to plant the crop 

in specific areas. All the 

machines are equipped 

with an automatic tire 

pressure control system 

to protect the soil. 

The fertilizer spreader is only used selectively, 

for example, for targeted application 

of nutrients based on the Kinsey recommendations. 

Otherwise, nitrogen fertilization, 

apart from farm manure, is only performed 

based on ammonium, mainly by 

injection using the Cultan method. Schneider 

gave up milk production with the 

400 cows that were initially part of the 

farm in 2018. Instead of that, he now has 

an average of 700 heifers that are reared 

for a large dairy farm in a region otherwise 

dominated by arable farming. 

Manure and dung out of the livestock production 

are fermented in 900 cubic meter 

(m³) fermenters in the small 75 kW liquid 

manure system that was put into operation 

in 2012. The annual yield of 8,000 

to 9,000 m³ of digestate is applied to the 

fields as grain top fertilization by slurry 

injectors in the spring, or by means of a 

strip-tilling unit, which creates a nutrient 

depot under the subsequently sown row of 

corn. This work is done by contractors. “I’m 

currently looking for a service provider who 

can apply liquid manure with a tube wagon, 

that is, by means of pipes from the biogas 

plant to the field. That would be feasible 

on the fields near the farm, which take up 

about half of the farm surface, and would 

also be another way of reducing soil pollution,” 

he says. 

A sensitive issue of no-till farming is the use 

of total herbicides. “The problem is not so 

much the weeds,” says Schneider. He says 

that he can handle that, as the absence of 

tillage would significantly reduce the activation 

of weed seeds. And a few things 

could be done about the crop rotation. But 

in order to plant cereals or maize in catch 

crops, which are typical for no-till farming, 

Glyphosate is indispensable for killing the 

plant cover. He sees neither other means 

that have a comparable effect, nor a practical 

alternative procedure. 

Crop rotation adapted to weather 

conditions and the market 

Schneider says that since he took over the 

farm, he has been focusing on “returning 

the soils to their natural balanced states 

with the no-tilling farming system and restoring 

the original biology”. His target is 

to attain a permanent humus content of 

5 percent. Although he has only achieved 

this on part of his cultivated area, soil life 

has considerably increased everywhere. 

The now more biologically active limestone 

weathered soils with loess overlays, that 

have an average acreage of 50 but a range 

of 20 to 100, would show more stress tolerance 

and the yield variability would be 

lower. On average, he gets 92 decitonnes 

per hectare of wheat, 38 dt/ha of rapeseed, 

90 dt/ha of winter barley and 45 tonnes 

of fresh matter per hectare of silage maize 

from the field. Compared with the harvests 

in the region, that is in the upper fifth, with 

lower operating costs. 

“At any rate, you can`t rely on experience 

gained in the area on weather development 

anymore, not even if you take the large variations 

into account,” says Schneider. He 

says that only the capacity of the soil to 

retain water is still effective, though this 

is only of limited use during lengthy dry 

periods. 

Since no-till farming eliminates the need 

for preparatory soil cultivation and the arable 

land can often be driven over, even 

in wet weather, Schneider can adapt the 

crop rotation system to the weather and 

the expected feeding requirements. He describes 

the possible variations, using vetch 

grown with rye –which is a mixture of winter 

rye and fodder vetch – as an example: “If 

the spring is very dry, I don’t harvest the 

vetch grown with rye when it’s green before 

the ears emerge in early May as is usually 

done. I leave it untouched until June. The 

established plants absorb the little water 

that is available very effectively with their 

extensive root systems and then 

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English Issue 



The farmer Rolf Schneider has been farming his land with the no-till farming method for thirty years. 

His particularly focuses his crop management on improving the fertility of the soil. 

There is an abundance of earthworm castles like 

that in the arable land tilled with no-till farming 

methods. 

yield plenty of fresh matter, even as whole crop silage”. 

Sorghum, which worked well last year, or leguminous 

grain mixtures could be considered as drought stresstolerant 

fodder plants for possible successive crops. If 

the weather changes and a wet period is expected, Schneider 

says he could sow clover grass. The harvest in the 

fall is then followed by winter grain. Corn only grows in 

a two-crop system after vetch grown with rye or Landsberg 

mix is harvested while it is still green. Instead of 

corn, these crops can be followed by a summer crop 

as an alternative, such as a mixture of oats and peas. 

Current example: In late May this year, Schneider used 

the Amazone direct seeding machine to sow Landsberg 

mix on a 50-hectare field. After it was cut and taken to 

the silo, Schneider planted corn on the field over the 

next few days without cultivating the field any further. 

Stop destroying the dwellings of the 

diligent little helpers 

In a field of small young wheat plants, Schneider points 

to numerous mounds on ducts leading downwards, the 

so-called earthworm castles. “That’s were my most important 

workers operate,” he says. The earthworms are 

a true indicator of life as they work tirelessly to loosen 

and vent the earth beneath our feet and draw organic 

materials and thus nutrients into lower soil layers. “We 

should stop continually using applicator tools that destroy 

the dwellings of diligent little helpers like that, who 

reinforce the soil against adverse weather and make it fit 

for the climate change,” says Schneider. 

On his farm, Rolf Schneider breeds young cattle for a dairy farm. The dung and manure he gets 

from the heifers is fermented in the biogas plant and the digestate is applied to the fields as 

fertilizer to improve the soil. 

Author 

Dipl.-Journ. Wolfgang Rudolph 

Freelance Specialized Journalist 

Rudolph Reportagen – Agriculture, 

Environment, Renewable Energies 

Kirchweg 10 · 04651 Bad Lausick 

00 49 3 43 45/26 90 40 

info@rudolph-reportagen.de 

www.rudolph-reportagen.de 

20


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21

English Issue 



Biogas can improve the soil 

Healthy soil can be a guarantee for a good harvest. But impoverished soil causes major 

problems: Nutrients are thrown out of balance, water retention capacity will decrease and 

the share of humus will diminish. New considerations when confronted with “the soil 

factor” in times of climate change. 

By Dierk Jensen 

The earthworm is one 

of the most important 

living organisms of 

soil life. 

The world is small. Of course, he is familiar 

with Johann Düker, said Uwe Schmidt. 

“Anyone who deals with agricultural issues 

in the Elbe-Weser region is familiar 

with the biogas pioneer from Basdahl,” he 

said on the phone. And as chance would have it, the 

dairy cattle consultant Uwe Schmidt has a current 

newspaper with a reader’s letter by Düker lying on 

the desk at his office in Hipstedt on the very day of 

our visit. 

“We have always known that plants can only subsist 

on their haustoria. I found practical examples of that 

in as early as 1952/52: My father fertilized the fields 

every few years with compost; nitrogen was not used 

as a fertilizer. If there was not enough compost, a few 

barrels of liquid manure were spread on the fields. 

What interesting is that the fields fertilized with liquid 

manure were greener than the composted fields after 

just a couple of weeks,” said Düker in his reports in the 

Bremervörder newspaper. 

Furthermore: “In the second harvest at the end of 

August, it was the other way round. In the years that 

followed, the crop on the composted fields improved 

more and more.” And at the end of his extensive plea 

for greater sustainability in agriculture and society, 

Düker wrote that “We need to be aware that all life in 

God’s creation is absorbed into our food cycle through 

the fine roots of our plants.” 

photo: Silke Goes 

22


Paying more attention to the soil 

That brings us to the center of the issue. “Unfortunately, 

a lot of farmers don’t realize the consequences of 

their methods of cultivation and the damage they do to 

the soil until a lot later,” Schmidt complains. “The situation 

on some of the farms is deteriorating year by year, 

the crop yields are declining and cows in the stables 

are becoming increasingly ill.” Often, by the time he is 

consulted as an expert on animal health and nutrition 

at the consultancy firm “mmb”, it is too late. 

Uwe Schmidt and his employees have been traveling 

to dairy farms throughout Germany, the Baltic states 

and other places for the last twenty years to revitalize 

the performance and health of farm animals. Schmidt 

feels noticeably enthusiastic about healthy livestock; 

he himself kept a small herd of suckler cows on his own 

land for many years. He feels that the vitality of the cattle 

essentially shows whether the agricultural system on 

the farms is still working. 

That is why a holistic approach to animals, health, 

nutrition, excretions, dung, liquid manure, fermented 

manure and ultimately soil and plant growth are so extremely 

important to sixty-five year old Schmidt. “I’ve 

seen so many stables in my consultancy work. I usually 

see at first glance what is going wrong,” said Schmidt. 

“I can even smell it. If it smells bad, something is out 

of balance.” 

He has no doubt that humification is important for soil 

life and soil structure – not to mention the integration 

of climate-friendly carbon. That is why he regrets that 

a large percentage of farmers still do not care enough 

about it. “They still regard liquid manure as something 

like waste. They are not aware of the fact that their liquid 

manure is very valuable,” he emphasized. “In the 

end, we could fertilize our fields adequately with farm 

manure without using any mineral fertilizers.” 

He continued by saying that this can only be done 

through biological diversity on the fields and in the 

soil. Which is why he uses a special herb biology to 

“In the end, we could fertilize our fields 

adequately with farm manure without 

using any mineral fertilizers” 

Uwe Schmidt 

reactivate the biology in dairy feed that has a favorable 

impact on the health of the cows’ liver, on their hooves 

and ultimately on the (rotting) liquid manure. “But if 

everything is biologically dead, we shouldn’t be surprised 

if the soil is ultimately dead, too,” says Schmidt, 

with a warning against the stubborn continuation of 

conventional agriculture that always lags too much behind 

quantitative reasoning. 

It is not surprising that Uwe Schmidt works with Dr. 

Sonja Dreymann. The soil expert, who lives in Kiel, 

pursues similar approaches as those of Schmidt. 

Maize treated with plant 

biology compared with 

untreated crop. 

23

English Issue 



Dr. Sonja Dreymann making a pH test (a rapid test using a Hellige 

model pH meter) to determine the pH level and to find out if the silted 

topsoil is caused by acidification or whether acidification can be ruled out. 

Dr. Sonja Dreymann using a pipette 

to trickle hydrochloric acid onto a soil 

sample for the so-called carbonate test. 

Dr. Sonja Dreymann 

during advisory work 

on the Szarvasi and 

grain stock. 

She thinks in terms of cycles, analyzes agriculture 

as a whole, with special focus on 

the soil and on soil life. Her customers are 

farmers seeking advice on how to breathe 

more life and more humus into their arable 

land once more. 

“If the yield isn´t good, then it was the 

weather,” remarked Dreymann about the 

Szarvasi stock produced by the biogas producer 

Kalle Rave in Ausacker in Schleswig- 

Holstein south of Flensburg. A dozen farmers 

and biogas producers stand around her, 

listening closely to her comments on a soil 

sample. “You can see that the root density 

in the lower part is quite good, but further 

up, right under the surface, there is a narrow 

soil horizon that is condensed,” she explains, 

breaking the piece of topsoil. 

Mentally combining the soil 

condition and nutrient supply 

“As the panicle likes this compaction, it 

gratefully spreads and increasingly forces 

out the energy grass.” “Well, under wet conditions 

up to the beginning of March and 

then only dryness,” a participant interjects. 

“How can you change that?” “Yes, sure. The 

weather conditions this year most certainly 

increased this condition, but the silting up 

may be a sign that there is not enough calcium 

on the surface because of a high potassium 

level, so that not enough oxygen can 

get into the upper layer,” Dr. Dreymann answers. 

To check her assumption, she makes 

the so-called carbonate test, for which she 

trickles diluted hydrochloric acid onto the 

photos: Dierk Jensen 

24

Triple Lifetime and 

Easiest Maintenance 


soil horizon.“There is no formation of vapor 

bubbles, so there is obviously not enough 

calcium carbonate,” Dreymann states. She 

advises the biogas producer Rave to do liming 

in the spring and to work the field with a 

grass rejuvenator (a kind of harrow) before 

the first cut – it will gently slit open the soil 

so that air can get in.” 

Dr. Dreymann and the farmers speak at eye 

level. Her aim is not to discuss the topic in 

a monolog, but rather to find constructive 

solutions to the dilemma that crop yields 

have significantly declined at so many arable 

farms in recent years. Maize harvests of 

50 tons of fresh matter per hectare are now 

a thing of the past in a lot of areas. Many 

of the farmers at Dreymann’s practical soil 

seminar agree, some of them even mention 

up to 20 percent less harvest yields. It 

shows that something is going wrong. 

The climate change reveals 

management errors 

“Success in the field ultimately always 

depends on the method of cultivation,” 

Dreymann notes unmistakable. “The climate 

change and extreme weather conditions 

in recent years have exacerbated or 

confirmed this fact.” But this does not 

mean that there are no strategic solutions 

to these growing challenges. Quite the contrary. 

But Dreymann also said that farmers 

have to rethink the way they are treating the 

soil and that they have to realize that plants 

Uwe Schmidt in 

his own laboratory 

with fermentation 

specimens. 

and the soil form a close symbiosis which 

must be observed. 

For that purpose, what they knew in the 

past and what is still generally being circulated 

by the chambers of agriculture is 

no longer adequate. Classical soil analyses 

with mere NPK values do not provide the 

answers to important questions. Knowing 

more about the soil, about research on 

humic substances and about soil microbiology 

therefore requires a new transfer of 

the knowledge which Dreymann actively 

mediates. 

Humification plays a key role here, but it 

will not work if the nutrients in the soil fall 

out of balance. The high phosphate levels 

on many farms, for example, prevent the 

build-up of humus. According to Dreymann, 

if fermented manure is used appropriately, 

it could contribute to humification 

which has a high level of binding capacity 

for nitrogen. 

Promoting bacteria that fix 

nitrogen in the air 

Soil experts assume that about 2,500 kilograms 

of nitrogen fixation per hectare are 

required to increase humus in the soil by 

one percent. Dreymann knows that this 

cannot be done merely by fertilizing, but 

rather through the fixation of free nitrogen 

from the air by micro-organisms that also 

live around the roots of non-leguminous 

matter. 

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with more diversity and greater root 

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English Issue 



carbon and nitrogen in the soil for a long 

period. Neither carbon nor nitrogen will be 

bound in the soil without energy. “The close 

relationship that exists between nitrogen 

and carbon is often misunderstood in climate 

discussions,” Dreymann said. 

“My aim is to achieve a five-percent humus 

level on my fields in the long term,” says 

Kalle Rave to the group of seminar participants. 

That is an ambitious goal, as right 

now his fields have a humus level of two 

percent. But he is confident that he and his 

successor Ole Dietz will succeed. They plan 

to finance the additional costs required to 

store more carbon in the fields with a bonus 

from regional commercial enterprises in 

which they have their CO 2 

emissions compensated 

for by targeted humification. 

That will give crop plants and mixed crops, 

that normally do not achieve sufficient revenues 

on the agricultural markets, a new significance, 

as they will revive local diversity, 

contribute to reducing their share of CO 2 

and also help to generate heat, electricity 

and fuel. Dreymann and the biogas farmers 

Kalle Rave (second from the 

right) explains to his colleagues 

which characteristics have to be 

taken into account when cultivating 

the cup plant Silphium 

perfoliatum. 

Humification on Kalle Rave’s farm 

Kalle Rave’s farm comprises pig fattening, 270 hectares of arable land and a 

biogas plant with an output of almost one megawatt. Rave wants to achieve 

humification with a crop rotation range of wheat, rye, triticale, silage maize, 

Szarvasi grass, beets and mixed winter grain consisting of rye, triticale, Welsh 

grazing grass, vetches and clover. 

Although it is getting increasingly dry in other regions, Rave can hardly complain 

about a lack of rainfall in his area. Quite the contrary: Precipitation levels 

in Ausacker have even risen from formerly 850 millimeters to 980 millimeters 

per square meter and year in the past 30 years. 

He fertilizes his crops with manure and fermented manure, if available – the 

rest is fertilized “on a mineral basis”. He used the so-called SOBAC system 

this year for the first time. He hopes, that will enable him to reduce fertilization 

costs in the future. He still uses a plough for the spring crops and only has to 

use “relatively small amounts of herbicide”. 

The northern latitude makes Schleswig-Holstein a border region for maize; the 

soil in that federal state between the seas warms up later and more slowly after 

the winter compared to other regions in Germany. Rave knows that this is one 

more reason why the maize needs well loosened soil that optimally enhances the 

development of the roots. So far, non-inversion tillage has not been an issue in 

northern Schleswig-Holstein. “That can only be done from a humus content of 

five percent upwards,” said Rave. 

Although he does not use any biological supplements like compost tea or enzymes, 

he is nevertheless open to these approaches. In the past, he added 

sauerkraut juice to the manure and the digestates to improve their treatment. 

Meanwhile, venting the manure on his farm has proven to be difficult because 

the manure is in a closed container and is only pumped into the open container 

shortly before it is distributed on the fields. But Rave consistently uses 

vegetable carbon in the fermenter. That binds the nitrogen in the fermented 

manure and minimizes both the amount that is leached in the soil and what is 

discharged into the atmosphere when it is applied to the fields. 

26


Pumps- and Agitators 

Classical tillage under scrutiny: Can tilling be done without a plough? 

from Ausacker agree that that will not work 

with classical-conventional arable farming 

with classical cash crops, like rapeseed, 

wheat and barley. 

Rave is not alone in times of climate 

change. He is a member of the Boben Op 

association that is aiming to promote a local 

energy transition and is actively tackling 

new approaches to CO 2 

sequestration. 

By now, about a dozen famers are participating 

in Boben Op with the aim of obtaining 

revenues of 1,500 euros per hectare 

within a period of five years by means of 

climate-friendly humification. 

There is a comparable project in the 

metropolitan area of Munich in southern 

Germany, where the participants of the 

“Himmelserde” project are pursuing similar 

goals. Even if they are still in the early 

stages, these concepts encompass new opportunities 

that the biogas industry should 

definitely take advantage of in times of deteriorating 

weather and soil conditions. 

Author 

Dierk Jensen 


Bundestr. 76 · 20144 Hamburg 

00 49 40/40 18 68 89 

dierk.jensen@gmx.de 

www.dierkjensen.de 

27 

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English Issue 



The FOS/TAC (VOA/TIC) value 

put to the test 

Together with the research and development department at MT Energy Service GmbH, 

scientists at the HAW Hamburg compared and tested the classical VOA/TIC method of 

biogas process monitoring according to Nordmann with an alternative calibrateable 

method for the first time over an extensive period of time. The VOA/TIC value describes 

the proportion of volatile organic acids to the buffer capacity. The buffer capacity is 

measured by total inorganic carbonate. 

By Prof. Dr. Paul Scherer, Martin Pydde, Dipl.-Ing. Sebastian Antonczyk and Dr. Niclas Krakat 

The VOA/TIC value according to Nordmann, 

which is calculated by means of double titration, 

has come to play a significant role 

in the process monitoring of biogas reactors 

since it was published by Weiland and 

Rieger in the Biogas Journal 4_2006 (Scherer 2007). 

Depending on the balance between the formation of 

acid and methane, acid metabolites occur that, at high 

concentrations, can inhibit the methane formation or 

even completely acidify the anaerobic process of decomposition, 

which is why it has to be assessed very 

carefully. We want to present an alternative procedure 

as a comparison to the VOA/TIC value. It is based on an 

Diagram 1: Diagram of the new GC-VOA value that was tested in 

recent years by HAW Hamburg and the MT Energy Service GmbH 

(MTES) with or without reference to the TIC buffer value 

New 

combination 

Previous 

combination 

VOA 

TIC 

TIC 

VOA 

Is more relevant. 

Is more accurate. 

Stability rating biogas plant 

The new GC-VOA value provides an accurate total value in acetic acid equivalents 

to control the process or the acetic acid-propionic acid ratio, the AA/PA ratio. 

accurate, calibrateable analysis of short-chained fatty 

acid metabolites in the biogas process using gas chromatography 

(GC). This accurate analysis of the fatty 

acid metabolites alone is sufficient to rate the stability 

of biogas plants, but can also refer to the TIC value, 

meaning the pH buffer capacity (see diagram 1). 

Particular acceptability of the conventional VOA/TIC 

method is the result of double titration of a biogas 

reactor sample with 50 millimolar (mM) of sulpuric 

acid that can be carried out quickly with comparatively 

compact equipment. This method that was once 

established to monitor sewage sludge digestion, was 

published in a paper by Nordmann in the Verbandszeitschrift 

Korrespondenz Abwasser journal (KA, 1977) 

as a “Staff supplement” with an exact replica of 

McGhee from 1968. At that time, there was no modern 

analytical equipment available, such as GC or HPLC 

(High Pressure Liquid Performance) with operating 

routines and PC connection. 

In double titration according to Nordmann or McGhee, 

the TIC value (“Total Inorganic Carbonate”), the socalled 

buffer capacity, is determined in the first phase, 

and the “VOA” value, the sum of organic fatty acid 

metabolites, is determined in the second. For basic 

pH buffers, a weak base or a salt of this weak base, 

for example hydrocarbonate/carbonate, should be able 

to delay or “buffer” the pH drop in the titration, also 

called pH buffer, if small amounts of a strong acid (for 

example bivalent sulphuric acid, H 2 

SO 4 

) are added. 

At a pH value of 6.5, the carbonate buffer is 50 percent 

hydrocarbonate and 50 percent carbonate (see Diagram 

2). This fifty percent value is also called the pK 

value and this is the area where buffering is strongest. 

This value is 4.8 for short-chain, weak organic acids 

(VOA) that are also buffered in a pH range of 3.0 to 

6.5. When using manure and renewable raw materials, 

a role is also played by the alkaline ammonium buffer 

(pK value 9.24) and the phosphate buffer (three pK 

values: 2.15, 6.8 and 12.3). 

28


Diagram 2: Diagram of the two main buffer areas in the microbial biogas 

process, the acid buffer of the short-chain organic fatty acid metabolites (VOA) 

and the alkalinity/”lime reserve” (TIC) of the hydrocarbonate buffer 

VOA I TIC [mg Hac-Equ L -1 ] 

VOA buffer 

GC-VOA method 

VOA / TIC alkalinity 

Previous VOA/TIC method 

Hydrogen carbonate buffer 

buffer 

buffer 

Unrecorded fatty acids 

(previous VOA / TIC method) 

Besides the VOA and TIC diagram, there is the phosphate buffer with a pK value of 6.8, the ammonium 

buffer with a pK value of 9.24 is more or less outside of that. In the final titration values 

of 4.4, 5.0 and 5.75, fatty acids are “cut off” and are not detected, which is something that 

cannot happen in the GC-VOA method which is separately calibrated for each fatty acid. 

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Digester contents are a mixture of 

buffer solutions 

Thus, biogas digesters are basically a mixture 

of buffer solutions that can normally 

be titrated with sulphuric acid in order to 

obtain a rough estimate of the buffer quantities 

of short-chain organic acids (C 1 

-C 6 

) 

and also of the carbonate buffer (TIC value) 

they contain by means of the titration 

amount changed in that way (see Diagram 

2). Incidentally, the carbonate buffer is 

also an essential component of physiologically 

important blood buffer. 

The titration end points usual for the VOA/ 

TIC value are shown in Diagram 2. The TIC 

value according to Nordmann (titration up 

to a pH value of 5.0) is converted and given 

as a calcium carbonate equivalent or “calcium 

reserve” in CaCO 3 

milligrams (mg) 

per liter. The VOA value (titration of pH 5.0 

to 4.4) states the acetic acid equivalents 

in mg/l or ppm (parts per million). Half a 

dozen variations can be found in literature, 

for example, Ripley 1086 (=APHA 1992) 

titrates from pH 5.75 to 5.0 instead of 

from pH 5.0 to 4.4 (see Diagram 2). 

In the Biogas Journal published in 2006, 

Rieger and Weiland were the first to compare 

the VOA/TIC values according to Nordmann 

(or McGhee) with concentrations of 

short-chain organic acid metabolites determined 

by titration by using an HPLC 

analysis method that could be validated 

and they found that the values correlate. At 

the same time, GC and HPLC analytics are 

of equal value, each fatty acid is calibrated 

individually. 

The VOA titration values of 500 to 5,000 

acidic acid equivalents (mg/kg), however, 

were more a point cloud with a mean value 

of 2,000 that was not forced to the zero 

point, while the values determined very accurately 

according to the concentration via 

HPLC lay on a straight line that was forced 

to the zero point. It is important to keep 

in mind that in a titration from an alkaline 

range (pH ≈ 8.0) to 5.75 or 5.0, a part of 

the TIC and also the VOA buffer is not recorded 

(see Diagram 2). Thus, the resulting 

TIC value in the second titration from 

pH = 5.0 to 4.4 according to Nordmann 

(McGhee) or in Ripley from pH = 5.75 to 

5.0 is added to the VAO value. 

Thus, an excessively high erroneous VOA/ 

TIC initial value is suggested, particularly 

in greatly buffered liquid manure biogas 

systems with low fatty acid values, that is 

not forced to the zero point, such as in digestion 

towers. As a result, it usually only 

starts at 0.2 with Nordmann, although the 

parallel concentration of fatty acids is still 

within an acceptable range. 

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29

English Issue 



Diagram 3: Process monitoring at an agricultural large-scale biogas plant (2.5 MW el, install 

) over a ten-month period 

VOA / TIC Nordm.; VOA Eq-GC/TIC + 0,3 

VOA / TIC Nordm. 

VOA Eq-GC/TIC 

TIC 

TIC 

Test days 

Comparison between the VOA Nordmann/TIC Nordmann (red) 

and the new VOA Equ GC value/TIC (green) 

and also the TIC value (blue). 

Diagram 4: Process monitoring of the agricultural biogas plant in diagram 3 shown over a period of 10 months, the VOA/TIC ratio according 

to Nordmann (red) is shown in turn as a reference, and also the acetic acid reference values (VOA Equ GC) shown alone without the TIC value 

as a ratio (dotted, grey), moreover the new propionic acid / acetic acid value shown as a ratio (PA/AA, green) in the modified mode 

VOA / TIC Nordm. 

PA/AA modified 

VOA Eq-GC 

VOA / TIC; PS/ES mod 

VOA Eq-GC [mg/I] 

Test days 

Handling samples accurately 

As recently as 2014, Purser at al. modeled a modified 

mathematical correction factor for the VOA/TIC value 

according to Nordmann and Ripley, so that it then 

forced to the zero point. However, the previous titration 

points were still considered feasible for both methods 

and were not questioned. In the meantime, there have 

been publications by Hinken, Voß, Weichgrebe and 

Rosenwinkel about titration according to Nordmann 

(for example in Biogas Journal 6_2012) which emphasize 

accurate pre-treatment of samples by filtration or 

centrifugation. In addition, the measurement result is 

greatly affected by the age of the sample (CO 2 

outgases 

and changes the carbonate buffer) and by representative 

sampling from the reactor. 

A comparably large variance of the measurement according 

to Nordmann that depends on the laboratory 

is also reflected in an interlaboratory comparison made 

by the Bavarian State Research Center for Agriculture 

(Köcker and Henkelsmann, Biogas Journal 1_2011). 

Thus, in an extreme case, a measurement of same 

sample led to VOA/TIC values of between 0.11 and 

0.88, resulting in an averaging range of between 0.3 

and 0.45. This disastrous divergence among the laboratories 

shows that a comparison between the different 

laboratories with VOA/TIC Nordmann can only be done 

with great uncertainty. 

Rieger and Weiland cautiously write “… Even if a limit 

value of ≤ 0.3 is considered as relatively certain for 

a stable process, this value is still mainly significant 

30



English Issue 

for the observation of its long-term development…” (2006). 

They also point out that a mere pH check in a well-buffered 

renewable raw materials biogas plant with or without liquid manure 

(TIC>7,000) is insufficient because the pH value hardly 

changes. 

There is no universal validated reference to estimate the VOA/ 

TIC ratio for a safe biogas process. Our own experience shows 

that the slurry-corn biogas plants (TIC value between 9,000 and 

25,000) such as those of Rieger and Weiland with an acceptable 

range with a VOA/TIC value of

English Issue 



ergy, 2013) on “Process Monitoring in Bio gas Plants”, 

however one that is commercially available with freely 

adjustable titration points. The VOA equivalent GC value 

determined in the test should in no case be smaller 

than the buffer capacity (usually the latter should be 

four times greater), as the biogas reactor would acidify. 

Diagrams 3 and 4 show process monitoring at a typical 

agricultural biogas plant (2.5 MW el, install 

) with 70 percent 

maize, 30 percent liquid manure, dung and grain 

waste over a period of ten months. They show that the 

VOA Nordmann/TIC Nordmann (red) never falls below 

0.25, and partly rise from 0.4 to 0.5 due to imbalances. 

The VOA Equ GC values (converted to total acetic acid 

equivalents) react parallel to that. To make the curves 

lie directly above each other for better comparison, the 

VOA Equ GC/TIC was added by 0.3. The pH merely value 

fluctuated between 7.75 and 8.0, and the TIC value 

moved from 15,000 to 25,000 mg CaCO 3 

equivalent 

per liter (see Diagram 3). 

The quantitative fatty acid pattern through gas chromatography 

would supply even more information for the 

biology, in this case particularly the propionic acid or 

the ratio of propionic acid to acetic acid (PA/AA) as a 

marker (see Diagram 4). Butyric acid, that can be split 

into two acetic acid molecules, occurs comparatively 

seldom, like valerian acid (C 5 

) or caproic acid (C 6 

) and 

is thus not shown. A high acetic acid level with low propionic 

acid AA/PA = between 5 and 10 to 1 (AA>1,000 

mg/l) may indicate a deficiency in micronutrients. However, 

biogas plants are particularly at risk from propionic 

acid, which is difficult to degrade. Therefore the 

PA/AA ratio was selected here. 

To make sure that the PA/AA ratio provides useful, unambiguous 

results, it is important to take into account 

that a division by zero is not mathematically defined. 

That means that the concentration of acetic acid has 

to be greater than zero [AA]>0. Furthermore, a visually 

more balanced interpretation of the measurement results 

in the diagrams is shown if the low concentrations 

are hidden, so that the following applies: 

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33

English Issue 



NuTriSep: Nutrient extraction and 

peat substitute from digestates 

When the pilot project began two years ago, it was small enough to fit into one container on 

the farm in the Kupferzell district of Füßbach. But now a fully operable treatment facility 

for digestates on the operating area of the Agro Energie Hohenlohe GmbH & Co. KG fills the 

entire building, which was formerly used to keep pigs. 

By Dipl.-Ing. Heinz Wraneschitz 

Fabian Geltz calls the nutrient recycling system 

a “nutrient production plant” and seems to be 

very pleased with it. “Besides phosphorous, 

other nutrients and peat substitutes are recovered 

systematically in high-quality separate 

fractions,” explains the process engineer, who is the 

junior manager and executive assistant of Geltz Umwelttechnologie 

GmbH in Mühlacker, which is a town 

in northwestern Baden-Wuerttemberg. 

Phosphorous: About 40 million tonnes of it are applied 

as phosphate fertilizer to fields and gardens all over the 

world. That is about more than 80 percent of the mineral 

wealth of white phosphate minerals extracted from 

the earth per annum, usually in Africa, China and North 

America. But scientists around the world agree that 

there will only be enough reserves of phosphate rock 

for a few more decades. That is why a whole series of 

research projects are underway for the recovery of used 

phosphate. A lot of experiments are being made with a 

variety of liquids. Even in Germany: Experts are trying 

to make this recovery in the large municipal sewage 

plants. Or on the biogas plant in Kupferzell-Füßbach. 

The Agro Energie Hohenlohe power plant, with its rated 

output of 700 kilowatts electric (kW el 

), has been in 

photos: Heinz Wraneschitz 

34



English Issue 

Thomas Karle explaining 

the plant for the recovery of 

phosphorous (phosphate) 

and other substances. 

operation since 2001. The gas 

tank has been enlarged several 

times, peak power has doubled. 

The plant has a total of three 

combined heat and power plants 

(CHP plants). An ORC turbine to 

convert the heat of exhaust gas 

into electricity was installed in 

the largest CHP in 2019 to increase 

efficiency. 

The purchase of heat from the 

CHP plant has been fully secured 

for years, says the director 

Thomas Karle. Füßbach itself is 

a real bioenergy village and has 

been obtaining most of its energy, 

electricity and heat from 

its biogas plant. There is also a 

hall on the company premises in 

which grain and other substances 

can be dehumidified for a fee. 

NADU with a positive life 

cycle assessment 

Last but not least, the digestates 

from the plant are dried there. 

The product Agro Energie Hohenlohe 

advertises in the Internet 

is called “NADU Natural Fertilizer”: 

“An innovative fertilizer 

from Baden-Wuerttemberg that 

is not only good for your plants, 

but also for the environment.” 

Because of its “positive life cycle 

assessment, NADU has received 

several sustainability awards! It 

is produced by a controlled fermentation 

process and is made exclusively out of raw 

materials and products.” 

The biogas plant in Füßbach differs from many others 

when it comes to substrate material for the fermenter. 

“Various fractions of animal manure – from cows, 

pigs and horses. And added to that, mainly vegetable 

by-products, such as grape marc or vegetable waste,” 

Karle adds. The bulk of animal manure is provided by 

full-time farmers from the small village and from a radius 

of three kilometers, the plant remains come from 

no more than 17 kilometers of the surrounding area. 

Thomas Karle has been promoting the concept of getting 

nutrients from land cultivation for a long time now. 

“Where does it make sense to place the nutrients outside 

of agricultural application?” So far, he has mainly 

been trying to respond to this question by using the 

NADU gained from the digestate. His involvement may 

also be due to the fact that he is the honorary chairman 

of Gütegemeinschaft Gärprodukte e.V. (GGG), 

which cooperates closely with Fachverband Biogas e.V. 

“The problem with the nutrients is exacerbated even 

further by the fertilizer ordinance,” says Karle. And 

while elsewhere digestate dewatering “usually only 

reduces the volume, here something is filtered out, individual 

tradable substances,” says the biogas plant 

operator enthusiastically. And he points to the huge 

plant with numerous containers and machines in what 

used to be a pigsty. 

NuTriSep – Technology on an industrial 

scale 

Basically, this system, which was developed by Geltz 

and set up in 2019, is an upscaling of the container 

prototypes that have already been tested here on an 

industrial scale. But there is a small catch: The largescale 

plant could process 70,000 tonnes (t) of liquid 

per year, but the Agro Energie Biogas plant only has an 

annual flow rate of 18,000 tonnes. 

In 2019, the VR Banks in Baden-Wuerttemberg awarded 

Geltz first prize at the Innovations Awards for the Nu- 

TriSep development and the step towards the versatile 

industrial scale, which was an achievement for the test 

facility that was already in operation in Füßbach at the 

time. Since January 2020, Isabella Maier, who works 

for Geltz as a product engineer with a master’s degree 

in environmental protection engineering, has been able 

to demonstrate in real terms on tours of the plant that 

the anticipated award was obviously justified. Even if 

visitors do not really know straight away what there is to 

see. The former pigsty has exactly 30 single units that 

are consecutively numbered. Geltz describes this as 

follows: “A sequence of several filtration, solution and 

precipitation steps to extract nutrients from digestates 

and gain uncontaminated residual water with- 

Isabella Maier from Geltz Umwelttechnologie holding 

various forms of phosphate sludge. 

35

English Issue 



Overview of the NuTriSep process 

Biogas plant of Agro Energie 

Hohenlohe GmbH & Co. KG. 

The process starts with the separation of organic solids: 

The phosphate and the ammonium nitrogen dissolve 

when sulphuric acid is added; the solid matter 

is also freed of it. The (gaseous) ammonia converts to 

liquid ammonium when the pH value is lowered, thus 

preventing it from escaping. 

The sulphuric acid that is used does not endanger 

plant growth. That is important, as after the hygienization, 

the solid matter that accrues should be able 

to be used as a peat substitute in horticulture. This 

material is valued at more than 10 Euros per cubic 

meter and more than 40 Euros per tonne. 

“Phosphate is precipitated from the remaining liquid. 

The phosphate salts that result are of mineral quality 

and can either act as fertilizer instead of apatite fluoride 

or be used in the chemical industry,” says Geltz 

describing the next process step. The phosphate salt 

costs about 80 Euros per tonne. 

The liquid that is now free of phosphate is stripped of 

ammonia in a closed stripping unit – by raising the pH 

value and the temperature. According to Geltz, “in this 

process, the ammonium is changed back to ammonia 

and advances to the gas phase in the stripping unit. 

It is freed of ammonia in an acid gas scrubber, which 

produces an ammonium sulphate solution, briefly referred 

to as ASL.” With a nitrogen content of 8 percent, 

ASL is a common commercial product. Value: about 25 

Euros per tonne. After this process step, the residual 

water is free of solids, phosphate and ammonium. 

It can be used to irrigate the fields. 

WRA 

Irrigation on 

arable land 

Separation of 

organic matter 

Phosphate 

precipitation 

Ammonia 

stripping 

Physical 

separation 

Direct 

discharge 

Organic 

solids 

Phosphate 

salts 

Nitrogen 

solution 

out a fertilization effect to create valuable, 

marketable products.” 

Development of digestate 

The digestate is pumped over from the biogas 

plant via a pipeline. A new supply shaft 

was constructed specially for that. On its 

way through the units in the former pigsty, 

the liquid always has to flow through 

increasingly finer filters and a number of 

chemicals are added during the process. At 

the beginning of the process chain, there 

are two identical storage tanks, T1 and T2. 

“The addition of sulfuric acid dissolves 

phosphorus from the solid and it passes 

into the liquid phase. The coarse organic 

solids are separated,” says Maier. 

Thomas Karle describes the solids and fibres 

that are filtered out as a “loose product 

that is very similar to peat”. Agro Energie 

sells this peat substitute “to a certain industrial 

customer, who uses it to make 

composites for riding arenas or for the production 

of turf.” The liquids essentially go 

through three steps: A screw press sorts the 

fibres. Then even smaller solids are sifted 

out in a vacuum separator, also called a vacuum 

spiral filter. The final micro-filtration 

then removes the entire suspended matter 

residues that are above 0.2 micro-meters 

(µm). “After that, the digestate looks like 

apple juice,” says Isabelle Maier, holding 

up a glass of that liquid. The salts and other 

nutrients that are still dissolved in it are extracted 

later. 

Recovery of phosphate salts and 

ammonium sulphate 

“Phosphate is taken out by adding caustic 

soda. The phosphate salts become phosphate 

sludge and in the end, after the drying, 

there are phosphate plates that can be 

granulated,” Maier and the plant operator 

Karle explain together. The nitrogen in turn 

is separated from the liquid as “ammonium 

sulphate”. During the so-called “ammonia 

stripping”, the liquid is heated to 50 

degrees Celsius, the pH value rises, the 

ammonia becomes gaseous and escapes. 

Energy is later extracted again from the 

heated liquid through heat recovery. “The 

packing of the stripping unit enlarges the 

Dosage of sulphuric acid: When sulphuric acid is 

added, the phosphorous is dissolved from the solid 

matter and goes into the liquid phase. 

36


surface of the liquid through which the ammonia is 

emitted,” Maier explains pointing to an enclosure covered 

by Plexiglas with two redundant systems. That is 

where the ammonia gas is filtered in an “acid scrubber” 

and combined with sulphuric acid to form the ammonium 

sulphate solution ASL. “The procedure is finished 

when the pH value is 7, meaning that it is neutral,” says 

Maier. An ASL produces about 200 liters per hour. 

The fourth separation step is in the 

testing phase 

But the development of NuTriSep is still continuing: 

Geltz Umwelttechnologie is currently trying to treat residual 

waters by means of reverse osmosis so that it 

can be discharged into watercourses. “After the process 

preceding it, the reverse osmosis is extremely efficient. 

The concentrate of the reverse osmosis is rich in potassium 

and can be used as a potash fertilizer.” So, will the 

digestate from the biogas plant of Agro Energie Hohenlohe, 

that is often considered a “taboo issue” (Thomas 

Karle), soon be producing a fourth viable product besides 

peat substitute, phosphate and an ammonium 

sulphate solution? 

Solid content is separated by the vacuum separator. 

Author 

Dipl.-Ing. Heinz Wraneschitz 

Feld-am-See-Ring 15a 

91452 Wilhermsdorf 

00 49 91 02/31 81 62 

heinz.wraneschitz@t-online.de 

www.bildtext.de · www.wran.de 

Original image at the gas leak detection at the biogas plant 

Hands free and best light in the danger area with 

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www.acculux.de 

37

English Issue 



Seven biogas plants 

supply one gas 

feed-in plant 

A majority of the biogas plants in the state of Rhineland- 

Palatinate are located in the Bitburg-Prüm district (Eifel 

region). Most of them were commissioned in the period 

from 2009 to 2011, but some as early as 2001. Now the 

operators are asking themselves how things will continue 

when the funding by the Renewable Energy Sources Act 

(EEG) expires. 

By Marie-Luise Schaller, EUR ING 

Wolfgang Francois 

and Jürgen Neuß in 

front of the raw gas 

storage unit of the 

treatment plant. 

The regional energy provider, the Stadtwerke 

Trier (SWT) public utility, is working on 

incorporating the proven potential of the 

regional biogas producers into the future 

energy supply strategy. In the “Regional 

Interconnection System Western Eifel”, [Regionales 

Verbundsystem Westeifel] the Eifel municipal networks 

(Kommunale Netze Eifel (KNE), established in 2009 

by the Bitburg-Prüm district (Eifel region) and the SWT) 

connect the long-term security of the drinking water 

supply with the improvement of the structures for expanding 

renewable energies. 

The core component of this infrastructure project, the 

only one of its kind in the country, is an 80 kilometre long 

pipeline route for drinking water, electricity and broadband 

lines as well as biogas and natural gas pipelines. 

It runs from the boundary with the state of North Rhine- 

Westphalia in the north to the region around Trier in the 

south. To Arndt Müller, technical management director 

of the SWT, it is important to make the best possible 

use of the existing, abundant renewable energies by constructing 

a flexible system in connection with biogas. 

As a result, he became one of the primary initiators 

of another cooperative solution which supports the repowering 

of the biogas plants. H. Berg & Partner, an 

engineering firm based in Aachen, provided guidance 

for design and planning for the initial feasibility analyses 

produced in 2013, which examined the idea of 

connecting several operations to one biogas collection 

pipeline in order to treat the biogas on a large scale in 

a central plant and then to feed it into the new natural 

gas interconnected grid system. 

The participants founded their own company, Biogaspartner 

Bitburg GmbH, for this purpose. Company 

partners are the Stadtwerke Trier (SWT), the private disposal 

business Luzia Francois and the Landwerke Eifel 

AöR public utility. In turn, the following are partners 

in the Landwerke Eifel AöR: the Eifel municipal networks 

(KNE), the Bitburg-Prüm district (Eifel region), 

the Bitburg public utility and the collective municipality 

Bitburger Land, the community of Speicher, the 

Südeifelwerke AöR public utility and the water works 

associations Trier-Land and Kylltal. 

A gas collection pipeline 42 kilometres long 

The idea didn’t stop here. The 42 kilometre long biogas 

collection pipeline was laid in an east-to-west direction, 

seven biogas plants were connected and in February 

2020, start-up operation began for the central gas 

treatment after a construction period of just six months. 

Wolfgang Francois, managing director of Biogaspartner 

Bitburg GmbH, remembers the challenging time during 

which he and his partners were developing the project: 

“The complexity and size of the project required numerous, 

intense discussions in order to convince the 

farmers to connect their plants to the collection pipephoto: 

Marie-Luise Schaller 

38


photo: ETW Energietechnik GmbH 

line. They are experienced experts in biogas production, 

which is their contribution to the project. Their 

participation in the project offers them prospects for 

the period after which the EEG funding expires. The 

banks also needed specific clarification in view of the 

tremendous dimensions of the project so that project 

financing could be secured.” 

In addition, he continues, the amendments to the EEG 

always generated new challenges with regard to costeffectiveness, 

which continually forced the partners to 

develop new strategies. “In general, we focus on reducing 

costs to a competitive level and on developing 

business models that don’t rely on EEG funding and 

that contribute to the success of the energy transition 

by producing green gas.” 

And in this sense, the contribution of this large project 

is quite impressive. Jürgen Neuß, managing director at 

the H. Berg & Partner engineering firm, notes that in 

the future, about 40 percent of the natural gas used by 

Bitburg will be replaced by the infeed of biogas from the 

treatment plant of Biogaspartner Bitburg GmbH. That 

is almost exactly equivalent to the amount required by 

the Bitburger brewery, one of the largest and most distinguished 

private breweries. 

As a partner, the Stadtwerke Trier public utility plays a 

key role because it takes care of the regional and transregional 

distribution of the biomethane, which keeps 

the value in the region. Wolfgang Francois explains: “A 

significant future issue for us and our partners is that 

we will soon begin marketing biogas as fuel for the public 

transport of the SWT and for heavy cargo traffic. The 

division responsible for the public transport of SWT and 

the location at the middle of the industrial park at the 

Bitburg airport play a helpful role here.” 

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39 

Knowledge in motion

English Issue 



Distribution of biogas plants, route of the raw gas pipeline and location of the biogas treatment 

and feed-in plant in the Bitburg region and key project data 

Raw gas pipe – approx. 42 km long 

Biogas plant 

Biogas treatment plant 

Key project data 

Biogas suppliers 

Biogas collection pipeline 

There are currently seven biogas plants with up to 900 nm³/h raw gas volume 

DN 125 … 250, 42 km long 

Biogas storage capacity 5,300 m 3 

Treatment technology 

Treatment capacity 

Pressure swing adsorption (PSA) 

1,800 nm 3 /h raw gas – 1,000 nm 3 /h biomethane 

ETW Energietechnik GmbH, located in Moers, is the 

treatment supplier. Their convincing response to the 

functional tender of the H. Berg & Partner engineering 

firm, which was open to all types of technology, offered 

the lowest energy costs. Dr. Oliver Jende, sales engineer 

at ETW, emphasises that the ETW SmartCycle ® PSA 

gas treatment method also features a simple process 

and high availability (reference plants with 99 percent 

availability) and it handles changing raw gas qualities 

and amounts well. 

“A significant future issue for us and 

our partners is that we will soon begin 

marketing biogas as fuel for the public 

transport of the SWT and for heavy 

cargo traffic” 

Wolfgang Francois 

Jürgen Neuß notes that the main challenge of the planning 

contract was to optimise the transportation of 

the raw gas through the 42 kilometre long collection 

pipeline both technically and with regard to power. The 

biogas producers deliver the biogas up to this point. 

Biogaspartner Bitburg GmbH has already begun with 

the construction and operation of the feed-in plants. At 

the plant site at the Bitburg airport, the raw biogas is 

first collected from the gas tank with a capacity of up to 

5,300 cubic metres. 

It consists of about 53 percent methane (CH 4 

) and 

about 46 percent carbon dioxide (CO 2 

). In addition, it 

contains low concentrations of oxygen, hydrogen sulphide, 

nitrogen, etc. To remove pollutants, particularly 

hydrogen sulphide, an activated carbon filter is located 

upstream of the biogas treatment plant. This treatment 

removes primarily CO 2 

from the raw biogas. This process 

is performed in six containers filled with a special 

activated carbon and subject to pressure in alternation 

(adsorbers). 

Pure gas with 98 percent methane content 

In the first phase, the containers are filled with the raw 

biogas at a pressure of about 3 bar. The CO 2 

molecules 

in the activated carbon are adsorbed at this pressure. 

The raw gas flow is removed at a methane content of 

about 98 percent and transferred to the feed-in station 

on the natural gas grid. When the pressure then 

decreases in the second phase of the pressure swing 

adsorption process, the separated CO 2 

is discharged 

from the adsorbers. 

The plant is designed to process 1,800 nm³ of raw gas 

per hour; it is currently running at about half of that 

load. The plan is to connect up to three more biogas 

plants to the existing group. Altogether, the biogas from 

up to 48 biogas plants in the region could be used in 

a central treatment process. In order to do so, more 

transport and treatment systems must be constructed. 

According to information provided by Wolfgang Francois, 

the initial operating experiences of Biogaspartner 

Bitburg GmbH have been consistently positive. Currently, 

fine-tuning is underway. In a few months, the 

40


valuable insights gained from practice will be available. 

Some of this knowledge will be transferrable to other 

sites and will become the basis for further project developments. 

photo: Stadtwerke Trier Versorgungs-GmbH 

Flexible utilisation of biogas possible 

Participating farmers have two options for utilising 

their biogas. One possibility is feeding in the maximum 

amount, which increases the total amount of green 

gas produced regionally. Another possibility, however, 

is that they can still use their CHP system for on-site 

conversion of the biogas to electricity. This way, they 

can profit from market developments if less energy can 

be produced with the fluctuating renewable sources of 

wind and solar power. This makes them an important 

component of the regional energy network that the SWT 

public utility is building. 

The Stadtwerke Trier public utility is creating the distribution 

and sales structures so that profitable business 

models can be created, and in turn, so that the region 

generates added value and establishes a secure, inexpensive 

energy supply. The ideas that regional energy 

provider SWT will realise in the future also include integrating 

the production of green hydrogen. This will 

make SWT a pioneer in the implementation of regional 

interconnection concepts for expanding renewable energies. 

That`s why it`s no wonder that the minister of 

the environment for the state of Rhineland-Palatinate, 

Ulrike Höfken, did not hesitate to attend the official 

commissioning ceremony on 24 August 2020. 

Author 

Marie-Luise Schaller, EUR ING 

ML Schaller Consulting 

mls@mlschaller.com 

www.mlschaller.com 

Official commissioning 

of the Bitburg biogas 

feed-in plant on 

August 24, 2020. 

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FIELD 

SILO 

FERMENTER 

ENERGY 

41

English Issue 



Denmark totally 

committed to 

organic residues 

Copenhagen 

Only residues such as 

stable manure, stover 

and potato peelings 

are used at the plant 

in Ringe. 

Denmark is among the growing markets for biogas. In the period from 2012 to 2020, the biogas production of 

our neighbours to the north increased more than threefold, currently reaching about 4.1 billion kilowatt hours. 

Biogas is primarily used to generate electricity; however, it is expected that the percentage that is treated and 

fed into the gas grid will increase. The ambitious goals that Denmark has set for 2035 also include a complete 

shift away from fossil fuel sources and the decarbonisation of 70 percent of the gas grid. Notably, in addition 

to agricultural biogas plants, there are quite a few very large plants at industrial scale. 

By Thomas Gaul 

In terms of biogas production, Denmark 

has always followed its own path. 

For example, energy crops have never 

played the same role as substrate as 

they have here up to now. Instead, from 

the very beginning, Denmark committed 

to using residues and made the circular 

economy a priority. This demonstrates that 

cattle manure and pig slurry can serve as a 

source of nutrients for the bacteria in the 

digester, even on a large scale. 

Up to now, substrate in Danish biogas 

plants was still allowed to contain up to 25 

percent maize, but this figure has now been 

reduced to 12 percent. In future, the plants 

will have to manage with just six percent 

maize. The Nature Energy Midtfyn biogas 

plant in Ringe demonstrates how this looks 

in practice. In three digesters, each with a 

volume of 8,500 cubic metres, 360,000 

tonnes of biomass are processed annually. 

Previously, this also included a percentage 

of maize silage and grain meal. 

Stable manure, stover and the like 

instead of maize 

But now only alternative biomass such as 

stable manure, stover or potato peelings is 

used. The amount of agricultural residues 

totals 75 percent; 25 percent is biowaste 

from households, restaurants and cafeterias. 

To prevent unpleasant smells, collection 

takes place in a closed hall. After the 

residues are unloaded into an underground 

container, a crane with a gripper is used to 

feed the biomass into the chopping process 

because it is important to open up the cell 

walls of the material before fermentation. 

The treatment is performed with a hammer 

mill in a drum in which heavy steel chains 

rotate and chop the material. Together with 

slurry from animal husbandry, the material 

is pumped into the first digester. After 

a retention time of 20 days, the substrate 

is pumped into the second digester, where 

it remains for another ten days. The process 

takes place at a temperature of 52 

degrees Celsius in the digesters. The lorries 

that pick up the slurry from the agricultural 

operations take the liquid fermentation 

residues back with them as return freight. 

The biogas is processed and fed into the 

gas grid. They have also discovered an application 

for the CO 2 

removed during biogas 

treatment: It is used to produce beer. 

Biogas from fish residues 

In a recently expanded plant in Herning, 

after pasteurisation they also ferment 

slaughterhouse waste and fish residues 

that arrive from Norway by ship. In addition, 

650 tonnes of slurry flow daily into the 

four digester towers of Herning Bioenergi 

A/S where it is transformed into biogas. Two 

of the towers have a volume of 3,500 cubic 

metres each and the other two 8,000 cubic 

metres each. 

In Herning, gas is not converted to electricity 

in combined gas and heat power plants. 

Neither is the biogas specially treated in 

photos: Thomas Gaul 

42


order to feed it into the natural gas grid. 

Instead, Herning Bioenergi has two large, 

direct customers – and they belong to Arla 

Foods, a global dairy company with cooperative 

ownership including over 13,500 

dairy farmers from Sweden, Denmark, Germany, 

Great Britain, Belgium, Luxembourg 

and the Netherlands. 

A 21 kilometre long gas pipeline connects 

the biogas plant in Herning to the first farm 

in Naviro. From there, another 6 kilometre 

long pipeline runs to the Arla production 

site in Videbæk. Only when it reaches these 

two production sites the biogas is burned in 

a total of three combined heat and power 

plants (CHP). The electrical power generated 

is used on site for the base load supply 

as well as for heat. 

But even though all three CHP plants 

achieve an output of about three megawatts 

with cogeneration, the demand for 

the two milk processing operations is many 

times greater. “Because the base load is so 

high and we only contribute only a small 

percentage of it, we can be sure that the 

biogas is really used,” explains Olav Hald, 

plant manager of the biogas plants in Herning. 

This offtake security creates a basis 

for continuous operation with optimum 

biological processes. 

Lots of cows and a grit washer 

Torben Pedersen currently has 2,000 cows 

in Holsted. From a small operation at the 

beginning, the farm has grown continuously 

over the years. Each cow produces 

an average of 40 litres of milk per day. The 

yields of 800 hectares of forage maize, 

400 hectares of grass and 200 hectares 

of grain are used to feed the cattle. When 

they are in their stalls, the cows stand on a 

bed of sand. “Since then I haven’t had to 

deal with hoof problems anymore,” Torben 

Pedersen reports. 

The disadvantage here, though, due to the 

herd size, is the huge demand for sand. 

“Per week I need 160 tonnes,” says Pedersen. 

This not only poses a logistics problem, 

but it is also a cost issue. In 2016, in 

order to separate the sand from the slurry, 

Pedersen invested in an innovative grit 

washer. He uses it to reprocess the sand 

so that it can be used in the stalls again. 

The separated slurry is delivered to a biogas 

plant. By regulating the dry matter and 

flow meter, the grit washer is continuously 

supplied with the slurry-sand mixture. A 

cyclone separator divides the slurry from 

the sand. The sand settles out in the grit 

washer, where it is rinsed with clean water 

and removed by the screw conveyor. 

After it is dried, the sand can be reused. 

The desanded slurry flows from the grit 

washer through a drum screen, where it is 

separated into a liquid portion and a solid 

phase. About 10 to 12 cubic metres of raw 

slurry can be pumped into the grit washer 

per hour. 

Slurry acidification is quite 

common 

An important issue for our neighbours 

to the north is the acidification of slurry. 

There are various practical methods for 

adding sulphuric acid to slurry. The goal 

is to decrease the outgassing of ammonia 

by reducing the pH value. This eliminates 

the need to immediately incorporate it into 

the soil. In general, the pH value is set at 

6 if the slurry will be distributed within the 

next 24 hours. 

The pH value setting is reduced to 5.5 if 

the slurry will be distributed within a period 

of up to three months. The addition of the 

sulphuric acid is carried out in the storage 

container. Reportedly, the acidified slurry 

does not damage the concrete. But the acid 

can also be added directly before distribution, 

either when the container is filled or 

directly during the spreading process. To 

do so, the front tractor hydraulics are used 

to pick up the acid tank, usually an IBC 

container, and the acid is dosed continuously 

as the slurry is spread. 

Johan Solmer, a farmer with an operation 

near Sonderborg in southern Denmark, decided 

to add acid to the slurry while it is 

still in the tank. “That gives me more flexibility 

during spreading in the spring,” he 

says, explaining his decision. The slurry is 

used to fertilise 250 hectares of grain and 

rapeseed. All of the field work is done with 

his own machines. Only the slurry transport 

and a few other small tasks are performed 

by a contractor. The slurry is produced by 

750 breeding sows. The piglets remain on 

the farm until they reach a weight of 30 

kilogrammes and then they are exported. 

Johan Solmer doesn`t need to handle the 

96% sulphuric acid solution himself. A 

service provider delivers it in a tank lorry. A 

hose connection is used to supply the acid 

to an agitator. The agitator is mounted on 

a high-performance tractor and can 

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43

English Issue 



The sulphuric acid is added directly at the agitator. 

Tall digesters are typical at large plants in Denmark. 

The residues delivered in Ringe are stored temporarily in a 

collection hall in a container equipped with grippers. 

High-performance tractors are used together with large 

agitators for stirring and acidification. 

A special washing system separates the sand, a 

bedding material, from the organic matter, which is 

fermented in the digester. 

Slurry is transported to the plants in large tank lorries. 

44


agitate containers with volumes starting at 500 cubic metres. The 

acid is dosed through a nozzle located directly above the agitator 

paddles. The amount is set based on results provided by a pH 

measuring instrument. Foam is produced when the slurry is agitated 

vigorously as the sulphuric acid is added. For this reason, the 

agitator operator must constantly watch the contents of the slurry 

container in order to prevent it from overflowing. When the desired 

pH value is reached, the acidification process is stopped. When the 

tank lorry has left the farm, there is no longer any risk of danger. 

Currently, 26 percent of the farm fertiliser is fermented in Danish 

biogas plants, of which there are more than 90. The increase is 

notable because in 2012 it was just four to five percent. However, 

imported biomass such as molasses or olive stones also play a role 

in biogas production. “Danish farmers also consider maize to be an 

energy crop after animals have eaten it,” says Jin Mi Triolo at the 

University of Southern Denmark (USD) in Odense. 

Professor Triolo, who researches alternative biomass for biogas 

plants, thinks that more slaughterhouse waste will end up in the 

digesters of Danish biogas plants in the future. She thinks a share 

of 25 percent of the substrate input is conceivable. Hog operations 

represent an important sector of Danish agriculture, which 

is export oriented. 

Biogas has a future 

In the highly advanced laboratories at SDU, scientists work on 

the future for biogas. This energy source could play an important 

role in the hydrogen economy. Algae can also be produced in the 

digester of a biogas plant. But in Odense they are also researching 

material applications, such as harvesting high-quality oils from 

cherry stones. 

In the context of the EU Interreg project BIOCAS (BIOmass CAScade), 

they share their work with German colleagues. The project 

brings together 18 partners from four EU countries to cooperate in 

the area of the sustainable transformation of biomass streams by 

using new technologies, process sequences and business models. 

Furthermore, they are working together with other local partners. 

The German partners include the Heidekreis district, the 3N Competence 

Centre and the University of Oldenburg. 

In the meantime, Denmark is developing into a significant market 

for German manufacturers in the biogas area. For the planned 

construction of a mega biogas plant in Hojslev, near Viborg in the 

central Jutland region, Stallkamp is producing and erecting all 

of the digesters and equipping the plant with pump and agitator 

technology. Lundsby Biogas ApS, located in Denmark, is the ordering 

client for the large-scale project, but assembly will be executed 

by the Danish sales representative Biogas Teknik A/S. The biogas 

plant is designed for a total of 14 containers. The three tall digesters 

will be assembled with stainless steel roofs and the remaining 

11 will be equipped with gas-tight, double membrane roofs. 

Author 

Thomas Gaul 


Im Wehrfeld 19a · 30989 Gehrden 

00 49 1 72/512 71 71 

gaul-gehrden@t-online.de 

45

English Issue 



South Korea 

Seoul 

Mandarin orange juice production – 

residues used to produce biogas 

At the centre of Jeju, by far the largest of South Korea’s islands, the German in East Württemberg-based 

company Lipp was able to participate in an impressive project to figure out a system for the environmentally 

sustainable use of residues from the manufacture of mandarin orange juice. In just ten months this system 

became a reality. 

By Achim Kaiser 

Jeju is a subtropical, volcanic 

island located 100 kilometres 

south of the Korean peninsula. It 

is about half the size of Majorca 

and, due to its mild climate, it 

offers optimum conditions for cultivating 

citrus plants. Moreover, thanks to its lush 

and diversified natural setting and its expansive 

beaches, it is a popular port of call 

on cruises through East Asia. 

With a market share of 55 percent, China is 

by far the world’s largest producer of mandarin 

oranges. South Korea, where cultivation 

is limited to Jeju, is in tenth place, with 

a production total of just about two percent. 

Due to the mild climate, more than 40 different 

varieties thrive on this island. On 

Jeju, the mandarin orange harvest takes 

place from October through February. Because 

of its high content of vitamins A and 

C, calcium and potassium, this well-known 

winter fruit is also a very healthy food. But 

primarily due to strict regulations, which 

stipulate that mandarin orange juice must 

consist of 100 percent fruit, the oranges 

are seldom processed into juice. 

The only production site for mandarin orange 

juice in Korea is located on Jeju. Its 

production capacity has increased steadily 

in recent years. The pressing residues accumulated 

from juice production are processed 

further in a dewatering system. The 

press cakes produced in this way are used 

in cattle feed and the thin, liquid phase is 

used to feed the biogas plant. 

Because the requirements for the quality 

of fresh water and processing water are 

high in the beverage industry, the increase 

in juice production pushed the cleaning 

performance of the aerobically operated 

wastewater treatment plant to its limits. 

Consequently, treating the water such that 

its quality is sufficient for discharge into 

receiving waters has become more complex 

and expensive in recent years. The 

reason was that at 165 grammes per litre, 

the biochemical oxygen demand (BOD), 

which represents the amount of oxygen required 

by bacteria for the biological decomposition 

of the organic compounds in the 

wastewater, was significantly higher than 

the permissible limit value. On the island 

of Jeju, the state’s environmental requirements 

are high. Compliance necessitated 

that solutions be found. 

Plant construction and operating 

experience 

Mandarin orange juice is not produced all 

year long; instead, it is a seasonal business 

that starts at the beginning of the harvest 

and lasts somewhat longer than half a year. 

For this reason, to ensure uniform operating 

performance for the biogas plant to be 

constructed, four vertical containers with 

a total storage capacity of 20,000 cubic 

metres were required to store the mandarin 

orange residue. To achieve maximum leak 

tightness, these containers, as well as all 

of the others supplied by the Lipp company, 

were manufactured with the patented 

double-seam system using a stainless steel 

composite material. 

The other containers include a universal digester 

(850 cubic metre) for the anaerobic 

treatment of the highly polluted wastewater 

before further aerobic treatment in the municipal 

wastewater treatment plant as well 

as a mixing tank and a buffer tank. Each of 

these tanks has a volume of 100 cubic metres. 

The biogas produced in the digester 

is used for heat generation for the wastewater 

treatment plant and the production 

site. The entire plant was commissioned 

in 2019. Since then it has been operating 

successfully and achieves very good BOD 

values of less than 3 grammes per litre for 

the wastewater. 

Author 

Achim Kaiser 

Managing Director of FnBB e.V. 

and Project Engineer at IBBK 

Fachgruppe Biogas GmbH 

kaiser@fnbb.de 

Photo: LIPP GMBH 

46


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the dates! 

7 – 9 December 2021, Nuremberg, Germany 

International biogas exhibition 

Programme and information: 

www.biogas-convention.com 

47

English Issue 



Manila 

Philippines 

Converting pineapple waste 

into biogas 

The Philippines is an archipelago located in Southeast Asia comprised of more than 7,000 

islands dotting the Pacific Ocean. With a long total coastline, the Philippines is blessed 

with stretches of pristine white sand beaches at the edge of crystal-clear waters. The 

warmth and hospitality of the Filipinos increase the potential of Philippines to become one 

of the top destinations for holiday and exotic travel with budget friendly options. But the 

Philippines also has other unseen potential, hidden in form of energy. 

By Medina Berbic 

Biogas technology was introduced in the Philippines 

in 1965 by Dr. Felix D. Maramba, 

an agricultural and mechanical engineer 

who is still well known there as an important 

scientist and developer of biogas applications. 

At the time it was introduced, biogas technology 

did not receive social or economic support as a 

method of energy production because fuel was cheap 

and readily available. It would take a few decades for 

the technology to gain environmental and commercial 

significance. 

The oil crisis of 1973 affected the Philippines in a way 

similar to the largest oil spill incident in the country’s 

history. After the crisis, more attention was paid to renewable 

energy, with a focus on the development and 

utilisation of hydropower, geothermal and solar energy. 

The biogas industry, with its complex technology, really 

got started much later, early in 21st century (2000), 

after carrying out various studies and analysing the potential 

of biomass. Up to this time, practical applications 

included just small biogas plants for home use 

because large-scale plants were not economically feasible 

due to the ubiquity of coal for power generation. 

After the Philippines joined the Paris Climate Accord 

in 2017, when the country committed to reduce greenhouse 

gas emissions by 70% and to increase renewable 

energy sources to 35% by 2030, biogas technology 

started to play a larger role in reaching this goal. 

The great potential of the Philippines, as an agricultural 

country, lies in the large quantities of biowaste, 

a problem with which the Philippine government is 

struggling. 

Photos: LIPP GMBH 

48



English Issue 

4,700 MW could be produced by using 

all organic waste 

The waste management system is still not established 

in practice and the collected biowaste is unsorted, 

mixed with plastic and another waste. Further potential 

lies in municipal waste, animal manure – pork production 

is one of most important industries in the Philippines 

fish waste and waste from exotic fruits. For example, 

a study by the U.S. Energy Association, carried 

out in 2015, indicates that 4,700 megawatts (MW) of 

energy could be generated if all of the organic waste in 

the Philippines were utilised. 

Despite this high potential, biogas technology and its 

implementation is not yet widespread in the Philippines. 

There is not enough social and economic support 

to make up for the lack of information and experience 

and to help manufacturers and developers of biogas 

technology succeed. 

A few large biogas plants, with an average capacity of 

1 MW have been built, but most of the potential is still 

unused. At the same time, the country still depends 

heavily on coal for power generation and has the highest 

energy costs in comparison with other ASEAN countries. 

This affects not only the Filipino population, but 

also the country’s global competitiveness. 

How was the project started? 

Mindanao, the second-largest island in the Philippines 

(after Luzon), is located in the southern region of the 

archipelago. The largest pineapple canning facility in 

the Philippines, Dole Philippines, Inc., is located here. 

The company has two operating sites, Surallah and Polomolok, 

and processes fruit juices and canned fruits 

from pineapple as well as from smaller amounts of other 

exotic fruits such as bananas and mangos. Dole Philippines, 

Inc. is part of the Dole company, an international 

market leader with an extensive range of high-quality 

exotic fruits and products made from them. Their products 

can be found in every supermarket in Germany. 

Dole Philippines, Inc. produced more than 180,000 

metric tonnes of organic waste (pineapple peels) in 

2018 (based on the company’s statistical data), and 

the amount is expected to grow in the coming years. 

The unprocessed pineapple residue was field-composted, 

releasing methane into the atmosphere during the 

process. Using the unprocessed pineapple residue in 

this way, however, called attention to the high methane 

emissions and the insufficient consumption of the rich 

nutrients in the fertiliser. This resulted in the identification 

of ways to improve the waste management system 

with an eye toward reducing greenhouse gas emissions 

and increasing the quality of fertiliser. 

It was found that capturing the methane produced from 

the anaerobic digestion of pineapple peel waste can reduce 

CO 2 

emissions by about 50,000 t per year. In turn, 

this methane can be used instead of fossil fuels to generate 

power and steam in the factory. These significant 

findings and CO 2 

compensation played an important 

role in the decision to install an industrial biogas plant 

with a total capacity of 7.9 MW. This plant consists of 

two biogas plants, one at Surallah, with a capacity of 

2.9 MW and one at Polomolok, with a capacity of 5 MW. 

The estimated costs for realising this project totaled 

one billion Philippine pesos (16.7 million euros). 

With the support of the Joint Crediting Mechanism 

(JCM), a progamme introduced by the Government of 

Japan, it was possible to secure co-financing to implement 

this idea. The JMC programme supports the 

reduction of global greenhouse gas emissions by promoting 

advanced low carbon technologies and systems 

and so on in developing countries. This financing programme 

supports 172 projects in 17 different developing 

countries. This biogas project in the Philippines is 

titled “Biogas Power Generation and Fuel Conversion”. 

How did LIPP become part of the project? 

The German company Lipp GmbH is well-known on the 

international biogas market with their unique “Double- 

Seam System” construction technique and tanks produced 

from Verinox ® material. Thanks to many years of 

experience and expert technology, the company offered 

competitive solutions for meeting the challenges of realising 

this large biogas plant and processing pineapple 

residue, a feedstock that has not been adequately 

researched. In addition, this German biogas technology 

was considered a suitable technology for meet- 

49

English Issue 



ing the high requirements for a 

JCM grant to ensure the longterm, 

reliable operation of the 

biogas plant and equipment. 

Lipp was commissioned by Met- 

Power Venture Partners, the official 

contractor of the project, 

to develop and build two biogas 

plants to be integrated into 

Dole’s Surallah and Polomolok 

canning facilities (South Cotabato, 

Philippines). The first 

draft of pre-feasibility studies 

for these two large-scale plants 

was started in 2017. Two years 

were needed to complete the 

final plans and obtain all of the 

necessary permits and required 

contracts. 

The biogas plant complex in 

Surallah consists of the following 

LIPP components: two LIPP 

ECO Digesters, each with a volume 

of 5,000 m 3 ,with an additional 

8,300 m 3 gas storage 

membrane, one LIPP buffer 

tank with a volume of 2,500 m 3 

and another LIPP buffer tank 

with a volume of 900 m 3 . The 

biogas plant complex in Polomolok 

consists of the following 

LIPP components: three LIPP 

ECO Digesters, each with a volume 

of 6,000 m 3 , with an additional 

8,300 m 3 gas storage 

membrane, one LIPP buffer 

tank with a volume of 5,000 m 3 

and another LIPP buffer tank 

with a volume of 1,300 m 3 . 

The construction of the first biogas plant in Surallah 

started in 2019, but due to the impact of covid-19 in 

2020, building was postponed for a few months. Additional 

difficulties with international travel restrictions 

and quarantine protocols have strongly affected the 

continuing work on site. Thanks to good cooperation 

and organization among all participants, however, work 

has been completed up to commissioning phase. Hopefully 

the plant will be in full operation in the next few 

months. The construction of the second biogas plant 

in Polomolok, with a planned start in 2020, had to be 

postponed due to the covid-19 pandemic. Despite the 

current situation, the Lipp team arrived in the Philippines 

some time ago and continues to work on site. 

Once fully operational, the two plants will utilise 100% 

of the pineapple waste designated for disposal to produce 

renewable energy and contribute to reducing 

greenhouse gases and air pollutant emissions along 

with lowering electricity costs for Dole. Once the biogas 

power plant is operational, the digestate, which is much 

more potent and environmentally sustainable, will be 

used. This project will certainly be among the best references 

for all of the participants, but it also represents 

one more successful milestone among the challenging 

projects in which Lipp has participated. 

Educational project for Filipinos – biogas 

training 

“Can I smell methane?” “Doesn’t it smell bad?” “What 

can I do with biogas?” These questions illustrate the 

lack of information about and experience with the biogas 

industry in this country. For this reason, the LIPP 

company carried out an additional promotion project 

in the Philippines with educational content. As part of 

a develoPPP.de project programme, experienced German 

biogas experts, the team of the German Biogas 

Association (GBA) and the LIPP team, supported by a 

local partner, the German-Philippine Chamber of Commerce 

and Industry (AHK Philippines), will provide 

biogas training and a biogas laboratory. This project 

incorporates not only high-quality technology, but also 

the transfer of technical know-how as well as thorough 

and comprehensive theoretical and practical training, 

including safety training. 

Due to the covid-19 pandemic, the experts from GBA 

could not travel to the Philippines to conduct the first 

training on site, but a virtual training programme was 

organized. Designed with six blocks of three hours 

each, the training was performed in March 2021 with 

70 participants. Filipinos participated in interactive 

activities and showed interest in continuing education, 

which provides positive feedback regarding the overall 

feasibility of the project. Spots are available in the three 

additional training sessions which will be organised in 

the near future. 

The develoPPP.de project was co-financed by the German 

Investment Corporation (DEG) with public funds 

from the German Federal Ministry for Economic Cooperation 

and Development (BMZ, www.developpp.de). 

BMZ can support your company’s innovative projects 

and commercial investments in developing and emerging 

countries provided that they offer long-term benefits 

for the local population. 

Author 

Medina Berbic 

Lipp GmbH 

m.berbic@lipp-system.de 

50


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Spring 2021 EN

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