Treatment of potato-processing waste water by an anaerobic lagoon–filter system

An anaerobic lagoon–filter system was operated in the laboratory to treat potato-processing waste water at 20 °C and pH 7 under three loading rates varying from 0.149 to 0.719 kg BOD∙m−3 ∙day−1. The overall removals of biochemical oxygen demand (BOD) and suspended solids (SS) were high, in the ranges of 97–98 and 89–97%, respectively. The system was consistently stable in effluent quality despite periods of shock loads and zero input.The optimum loading rates to the lagoon and the filter were 0.3 and 0.4 kg BOD∙m−3∙day−1, respectively. Most of the BOD and SS removals occurred in the bottom portion of the reactors. A base had to be added to the waste water to maintain the pH at 7 for good performance. No lagoon desludging is expected for full-scale operation. Filter clogging is also unlikely under the optimum loading rates.