Biogas technology poses many challenges. Biogas production of mesophilic and thermophilic range
is well understood, conditions which can be applied in most developing countries (Kashyap et al. 2003;
Alvarez et al. 2006). The development of technology in making available biogas as energy for
cooking and heating in the colder areas of any country in the winter season is a matter of great
concern. The major reason for their failure seems to be the climatic conditions (temperature) in
these areas.
A number of researchers are engaged in studies on biomethanation, but very little work has
been done regarding the production of biogas at psychrophilic temperatures. Singh et al.( 1995)
have studied the effect of HRT on production of biogas from night soil under psychrophilic
temperature. At 20 day HRT, propionate concentration has been reported to be about three
times higher than that of acetate, whereas at higher HRT acetate and propionate maintained at
almost equal concentrations. From the above study it is concluded that anaerobic digestion of
night soil can be carried out at 10°C using adapted inoculums. Meher et al., (1994) indicate the
night soil under psychrophilic condition, he mention below 200
C methane production observed
with the addition of temperature adopted inoculums. Results of Zeeman (1991) showed a stable
digestion process at digesting cow manure at a process temperature of 15 0
C and an HRT of
100 and 150 days. The COD reductions were 14 and 18 percent respectively. Even at 150 days
HRT the gas production was lower as compare to that at 30 0
C and 20 days HRT.
Safely and Westerman(1994) evaluated the performance of lagoon anaerobic digesters under
low temperature ,that shows digestion is feasible at a minimum digester temperature of 100
C
with minimum hydraulic retention time of 50 days at the maximum loading rate of 0.12 kg
VS/m3
/day and this could be adjusted upward for higher temperatures. Sutter and Wellinger
(1988) indicate that the gross biogas production by a digester operating at 200
C and retention
time of 40-50 days is comparable to a digester operating at mesophilic temperature but at half
the retention time.