Effect of additives on anaerobic methane production

Anaerobic digestion is widely known as a method of treatment of wastewater. Present technology, however, is able to achieve only partial degradation of waste. Increases in the cost of sludge disposal, and in the treatment process itself, has motivated many researchers to look for ways to improve the efficiency of the treatment process. Biocatalysts or other commercial additives are compounds that are capable of altering the rate of reactions of some microbial systems. Use of these compounds is a new innovation in wastewater treatment technology. Five commercial additives were added to anaerobic reactors containing primary municipal wastewater sludge loaded with 3% volatile solids. The additives were added in duplicate reactors and two reactors were maintained as control reactors. The effect of each of the additives on the treatment process was studied by the analysis of various biological and chemical parameters.

It was found that only two additives made a statistically significant difference (p<0.05) to the treatment process. The addition of Biocope™ caused an increase of 7% in the volatile solids destruction, while the addition of MPC caused a decrease of 8% in the volatile soHds destruction as compared to the control. The volatile solids reduction achieved by the remaining three additives was not significantly different from the control. It was also found that all the additives, except Medina, resuhed in a decrease in biogas production. The volume of biogas produced due to the addition of Medina was not significantly different from the control. The addition of Biocope™ and Aiken resuUed in a 74% decrease in the volume of biogas produced as compared to the control.