Temperature anaerobic digestion

Masse DI, Croteau F, Masse L (2007) The fate of crop nutrients during the low temperature anaerobic digestion of swine manure slurries in sequencing batch reactors. Bioresour Technol 98 2819-2823... 

Sludge is destroyed by microorganisms and the kinetics of their life processes is temperature dependent. Short anaerobic digestion detention times are obtained at 35°C. Even shorter detention times are possible at 52—54°C, but detention in this range is costly. An increase in detention time occurs at 35—43°C and then a progressive decrease takes place until 52—54°C. This variation is caused by a change in character of the dominant process organisms. 

Anaerobic digestion, like pyrolysis, occurs in the absence of air. But, the decomposition is caused by bacterial action rather than high temperatures. This process takes place in most biological materials, but it is accelerated by warm, wet and airless conditions. It occurs naturally in decaying vegetation in ponds, producing the type of marsh gas that can catch fire. 

After aeration for 3-5 days, flooding with heated excess liquid the charge will be heated to 55-60°C. The feeding orifice then will hermetically be closed and the anaerob digestion lasting 3-4 weeks will be started. During this process the temperature of the biomass will be reduced daily by 1-1°C, while at the end of digestion it will reach 30-... 

The monitoring scheme carried out on 5 Mi-scale plants, 4 demonstrative ones and an experimental one, shows high biogas yield (m3.Kg VS.d ). The anaerobic digestion process is shown to be stable, even when there are falls in digestion temperature, or breaks in the mixing and feeding process. Considerable problems were noted, however,... 

Maharaj, I., Elefsiniotis, P. (2001). The role ofHRT and low temperature on the acid-phase anaerobic digestion of municipal and industrial wastewaters. Bioresource Technology 76 191-197. 

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