Assessment of a microalgae pond for post-treatment of the effluent from an anaerobic fixed bed reactor treating distillery wastewater.

An evaluation of the performance of a laboratory-scale microalgae pond treating effluent from an anaerobic fixed bed reactor digesting distillery wastewater was carried out. The microalgae pond operated with an effluent recycling (R) of 10:1 with respect to the influent and at surface organic loading rates of 418 kg COD ha(-1) day(-1) and 92 kg BOD5 ha(-1) day(-1). During the experiment total chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total solids (TS), total suspended solids (TSS), volatile suspended solids (VSS), total nitrogen, ammonia, total phosphorus, orthophosphate, total chlorophyll (CT) and chlorophyll a (Ca) concentrations were monitored. Overall COD and BOD5 removal efficiencies of 98.2% and 98.8% were obtained. The global solids removal efficiencies were of 93.2%, 92.6% and 97.6% for TS, TSS and VSS, respectively. The removal efficiencies obtained for organic nitrogen and ammonia were 90.2% and 84.1%, respectively. Finally, the removals for total phosphorus and orthophosphate were 85.5% and 87.3%, respectively. It was demonstrated that microalgae grew in this waste by determination of the total chlorophyll and chlorophyll a in the effluent.