The intensification method of anaerobic methane fermentation of sludges, based on the stimulation activity of cell lysate, was studied. The effect of lysate is caused by the still remaining activity of released enzymes and by the stimulating properties of other compounds that are present inside the cells. The anaerobic cell lysate was prepared by a thermal treatment of anaerobic sludge and the aerobic cell lysate by a partial mechanical destruction of cells of the excess activated sludge by a special adapted thickening centrifuge.
The use of cell lysate as a stimulating agent was examined in the laboratory experiments of anaerobic degradation of simple organic compounds (glucose, acetate, formate and propionate) and of complex substrates as municipal raw sludge, excess activated sludge and some pharmaceutical organic wastes. The results show a significant improvement of the removal rates of substrates and the enhancement of methane production in all cases of lysate addition. In the fermentation of raw sludges and pharmaceutical wastes with anaerobic lysate, the increment of the methane yield ranges from 38.2–61.8% and 20.2–36.7% respectively. The aerobic lysate increased the methane yield of excess activated sludge and of its mixture with primary sludge at the range of 17.1–86.4% and 24% respectively.