Development of a Batch Type Bio-Digester
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Date
2014
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Publisher
EUROPIAN SOciety of Agricultural Engineers, Zurich, Switzerland
Abstract
A bio-digester was designed, constructed and tested for the production of biogas. The
digester was designed and constructed using a 32 liter – digester tank, an 18.5 liter water
displacement tank and a 20liter temporary storage tank of 16 liter. Biogas was produced by
charging the slurry into the digester through the inlet channel and then closing the inlet
channel and a hose was used to connect the digester and the water displacement tank
which was already filled with water to the bream, a second hose was also used to connect
the water displacement tank to the temporary storage tank were the displaced water is
channeled to and the volume of water displaced was measured and recorded daily for the
two type of slurry. A digital thermometer was used to take the ambient temperature of the
digester. The digester was tested with two types of slurry that is made up of poultry litters
and water at the ratio of 1: 4 and 1: 2, one poultry litter was mixed with water in the ratio of
five liter to twenty liters respectively and the other in the ratio of five liters to ten liters. On the
first and second day after loading there was no significant production of gas. The third day a
gas production of 1.53ml was noted and the volume continued to increase until the eight day
with 7.52ml and the reduction continued from 7.34, 7.09, and 6.41 on the 9th, 10th, 11th day
respectively. However with the reduction observed on the 8th day in which the average
temperature was 33oC. The reduction in the volume of gas can be linked to the decrease in
the amount of organic matter present in the slurry. The volume of the slurry retained in the
digester tank was about nineteen liters which means that about five liters of slurry were
converted to biogas. Change in the color of slurry evacuated was noticed with non offensive
odour. From the result it can be deduced that the concentration of the slurry is directly
proportional to the rate of gas production and also the ambient temperature of the digester is
directly proportional to the production of biogas.
Description
Keywords
Batch type bio-digester, biogas, slurry, ambient temperature