| || Fatty Acids Profile during Anaerobic Digestion of Night Soil-Effect of temperature, Calcium Carbonate and Selectively-enriched Inoculum
Author : Maurya, M.S. ;Singh, L.;Alam, S.I.
Source : Defence Science Journal ; Vol:46(1) ; 1996 ; pp 21-26
Subject : 57 Biological Sciences ;577 Biochemistry
Keywords : Sulphate reducing ;Volatile fatty acids;Anaerobic biodegradation
Abstract : Anaerobic biodegradation of night soil was carried out at 5-30 degree centigrade with 1.8-10.62 per cent volatile solids (VS). Biogas production increased with the temperature and VS up to 6.2 per cent. Further increase in VS caused higher Volatile fatty acids (VFA) accumulation resulting in decreased gas production. Acetate and propionate accounted for 62-83 per cent of total VFA. Butyrate to isobutyrate ratio increased with VS. Calcium Carbonate promoted VS degradation, biogas production and VFA degradation. The increased methanogenic and decreased sulphate-reducing bacteria caused proportional changes in CH4 and H2S gases. Enrichment with H2 oxidising methanogenic consortium is beneficial by enhancing VFA utilisation by two to three fold.
| || Effect of Fluctuating temperature Regime on Psychrophilic Anaerobic Digestion of Nightsoil
Author : Ramana, K.V. ;Alam, S.I.;Singh, Lokandra
Source : Defence Science Journal ; Vol:49(2) ; 1999 ; pp 135-140
Subject : 61 Medical Sciences;612 Physiology
Keywords : Hydrogenotrophic methanogens ;Volatile fatty acids;Anaerobic digestion
Abstract : "The effect of temperature fluctuation on anaerobic digestion of nightsoil using 10 °C adapted inoculum was studied. The digester was subjected to repeated temperature cycling of 10 °C and 30 °C. The total biogas, CH/sub 4/ and H/sub 2/S content, volatile fatty acids and microbial counts were compared with control digesters. No significant deleterious effect was noticed during initial temperature shock of one week. However, repeated exposures reduced the counts of hydrogenotrophic methanogens. There was no effect on the content of CH/sub 4/ and H/sub 2/S in the biogas."