Toxicity assays to determine the start-up strategy for an anaerobic sequencing batch reactor (anSBR)

Addition of glucose as the co-substrate and the use of a water-based polymer to enhance granulation were studied with the aim of shortening the start-up period of an anSBR (anerobic sequencing batch reactor) for high-strength industrial wastewater treatment. An initial start-up feed composition consisting of 70% sucrose and 30% industrial wastewater was favorable to reduce the start-up time. Increase in the average particle size and reduction in settled supernatant turbidity was observed with increased water-based polymer addition up to a concentration of 0.1 m/L. Polymer dosages above 0.1 ml/L were undesirable as big and "flaky" flocs were formed which prevented the flocs from settling quickly. Addition of 0.005 ml/L to 0.1 ml/L polymer to the mixed liquor had no observable adverse effects on the anaerobic biomass metabolism. Instead, the addition of the polymer appeared to improve biogas production and had an overall positive effect on anSBR performance treating the industrial wastewater.