European Bio-Energy Projects

3A-BIOGAS
Objectives
The project aims to develop the 3A process
to prototype size and the series production
of a modular batch system for dry
fermentation with percolation (DM 30-70%)
in the smaller capacity range.
The batch system provides three process
phases (aerobic; anaerobic; aerobic = 3A)
in one reactor. Adequate pore volumes of
the organic input substrate and the proper
use of closed-circuit process water avoids
wastewater and enables 3A-biogas to work
without material conveyance during the
whole process.
The main advantage of the 3A-biogas
process is the production of biogas during
the second phase. Sanitation takes place
within the first step, while maturation of
the end product is reached at the third
step. Top-quality compost for soil
improvement and fertilisation is the
valuable end product.
An optimised low-cost control system
guarantees process stability.
Three-step fermentation
of solid state biowaste for
biogas production
and sanitation
Challenges
Energy has to be added to the process (moving
the material) for treating organic substrates in
normal aerobic composting plants. On the other
hand, it is not possible to use the accruing
energy in any way. High volumes of water are
necessary for treatment in conventional
anaerobic liquid biogas plants, and subsequently
this remains as wastewater. As a consequence,
in relation to the quantities of feed material,
high plant and process energy costs are incurred
for material conveyance and maintaining
temperatures.
The 3A-biogas process aims to combine the
positive aspects (producing biogas and topquality
compost directly from solid state input
material) of these two possible treatments and
to avoid the disadvantages.
Project structure
The project consortium consists of six small
and medium-sized enterprises (SMEs) and three
research and technology developers (RTD).
This combination allows for the market-orientated
research and development of the 3A-process. In
a first step, the participating SME partners set
up end-user requirements for the possible
implementation of the technology at the end of
the project. Conclusions have been drawn for the
development of the process. The optimised
process will be developed using the experience
of the partners and a detailed work distribution.
For this purpose, intensive investigation on
substrate composition, sanitation requirements,
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and cause-effects of the key parameters will
be carried out in close co-operation with SMEs
and RTDs. Furthermore, a simulation tool will
be developed.
Approaching the detailed planning and an
operating control system, two prototype units will
be manufactured. During the project’s second
year, the 3A-biogas prototypes will be tested at
two project partner sites in Austria and Spain.
In addition, a socio-economic assessment,
dissemination, and preparation for exploitation
are integrated parts of the project.
Expected impact and exploitation
3A-biogas mainly addresses the communal and
agricultural waste-treatment industry where both
biodegradable wastes and organic residues are
available for the production of biogas. Often,
conventional liquid biogas plants are already
set up with an existing utilisation for the biogas
produced. The additional installation of a
3A-biogas system as a second treatment line
for dry input substrates will lead to several
synergies for end-users, and optimal completion.
The potential for biogas plants in the agriculture
and food sector, for example in Germany, was
estimated by Weiland to be 30,000 – 40,000
plants in total with an annual increase of
150-200. In the year 2000, just 1,000 plants had
been installed, although their number is
increasing significantly. The estimated potential
of energy produced is 753 PJ on the basis of
biogas for all EU Member States. Only a small
amount of this potential is currently being used.