Digestate as Fertilizer

Significance of digestate in developing countries
Cabbage: High crop yields using digestate as fertilizer
Currently, there is no clear legal framework regarding
the production and/or use of digestate in place in Uganda.
However, the following regulations are in place:
The National Environment (Standards for
Discharge of Effluent into Water or on Land)
Regulations, 1999 (S.I. No 5/1999);
The National Environment (Waste Management)
Regulations, 1999 (S.I. No 52/1999);
The National Water Act, Cap. 152;
The National Environmental Act,
Cap 153. (1995).
With a tax rate of 10% on imported goods in addition
to the Value Added Tax (VAT), this higher taxation applies
to imported mineral fertilizer. This is one reason
for the increasing use of organic fertilizer like digestate,
compost, manure, etc.
Digestate production
The high costs for mineral fertilizer in Uganda have
made digestate or bio-slurry applicable and attractive.
In some areas, use of mineral fertilizer in the past
proved harmful to soil. Agricultural policies greatly encouraged
the use of digestate; the majority of farmers
operating a biogas plant focus on digestate as a source
of organic fertilizer rather than on biogas as an energy
source. Digestate is also seen as a superior fertilizer for
producing seedlings (e.g. coffee, tea), a high caloric
feed for breeding poultry and feeding pigs and cattle –
and even in fish farming (e.g. Nile perch, a high-grade
and popular food fish) where it is used to fertilize fish
ponds. The liquid phase of digestate is furthermore
used as insecticide when sprayed on leaves.
Apart from promoting power generation, upgradation
and the bottling of biogas, UNBA plans to support efforts
to produce dried and packaged digestate as well
as bio-cake for livestock feeding. These products will
be sold to farming and fishing enterprises as well as
to the public. The marketing of filtered bio-slurry has
increased profitability and economics of the technology
within the country. Furthermore, the sale of dried and
packaged fertilizer from digestate will enhance crossborder
trade between Rwanda and Kenya and may even
encourage the use of digestate in Eastern Africa.
Supported by UNBA, private sector stakeholders are
piloting the upgrading of digestate and promoting the
use of this digestate together with the National Agricultural
Organisation. It is expected that this market will
increase in significance in the near future.
Facts & figures:
Domestic biogas plants (3-30 m³ digester volume):
approx. 10,000 plants
Institutional biogas plants (30-300 m³
digester volume), e.g. schools, universities:
approx. 100 plants
Industrial / commercial biogas plants
(20-100 kWh): approx. 10-20 plants
Further Information:
Uganda National Biogas Alliance www.unreeea.org/members/unba
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