The activity of anaerobic biomass in thermophilic and mesophilic digesters at different loading rates

Abstract

The thermophilic anaerobic process brings an acceleration of biochemical reactions and higher efficiency in the degradation of organic matter in comparison with the mesophilic process. The methanogenic activity of the thermophilic and mesophilic digested sludge was examined during the adaptation of full-scale digesters to an increasing temperature from 38 to 55°C. The results proved a higher activity of the thermophilic sludge after the addition of glucose, acetate and propionate in comparison with the mesophilic sludge; the maximum methane production rates and the methane yield of the raw sludge were always higher under thermophilic conditions; the stability of the degradation process at an increased substrate load was also better. After the adaptation of anaerobic biomass to the temperature of 55°C, the responses of this culture to addition of simple substrates substantially changed, especially in favor of acetate and propionate degradation rates.