A bench scale analysis of twelve 4-liter anaerobic digesters with a 3-liter working volume was operated to examine the effects of five commercial additives on the degradation of primary municipal sludge. The reactors were loaded with 150 ml per day of 3% volatile-solid content waste collected from the Lubbock Municipal Treatment Plant. Ten of the reactors were loaded with one of five commercial additives, in duplicate, with two reactors serving as the control. The primary objective of this research was to determine the feasibility of using commercially prepared products to enhance the degradation of wastewater. The influent and effluent from each reactor were analyzed for total volatile solids, volatile fatty acids, total solids, chemical oxygen demand, pH, and temperature within the reactors. The volatile fatty acids were analyzed by using gas chromatography.

The products used in this study were Biocope, Alken Clear-Flo 4100, MPC, Medina d-part, and Biosep. It was found that during steady state operation, the total volatile solids content of reactors receiving the Biocope additive were significantly lower (16.5%) than the control (P<0.05) receiving no additives, for an overall increase in volatile solids degradation of 8.2% (P< 0.05). Acetic and propionic acids were the only major volatile fatty acids present in the reactors receiving Biocope indicating the most complete degradation. The reactors receiving MPC, Alken Murray and Biosep produced considerable amounts of all six major fatty acids, thus indicating incomplete degradation of the wastewater. It was found that only Biocope affected the waste digestion process in a significant manner by causing the highest destruction of volatile solids.