Evaluating the resilience of a full-scale down-flow hanging sponge reactor to shock-loadings

The effect of shock-loading on the performance of a full-scale down-flow hanging sponge (DHS), used to treat effluent from an up-flow anaerobic sludge blanket treating municipal sewage, was evaluated. This full-scale DHS reactor comprises a polyurethane sponge that retains the sludge. It has a capacity of 500 m(3)/day and, at the time of this study, had been operating at a sewage treatment plant in India for more than 1,300 days. The DHS reactor was exposed to shock-loadings of organics at double the normal rate for 400 min under summer and winter conditions. The results showed that the DHS reactor maintained stable operation under the organic shock-loading and that it returned to a steady state soon after restart, confirming that the reactor was resilient to organic shock-loadings.