The effect of transient loading, pH and temperature shocks on anaerobic filters and fluidised beds

Abstract

Two anaerobic filters, two fluidised beds and a two phase anaerobic system consisting of a CSTR acidogenic phase and a fluidised bed methanogenic phase, operating at mesophilic temperatures on an influent of ice‐cream factory production waste, were subjected to quantitative increases in COD loading under varying conditions for 8 hour periods. Methane production and effluent SS, TVA and alkalinity levels increased but % COD removals decreased during the shock periods. However most operational parameters had returned to pre‐shock levels by 24 h. Variations in operating temperature and COD/influent pH were also applied. Eight hour reductions to ambient temperature were tolerated well in both filters and fluidised beds but low influent pH levels coupled with increased loading produced a permanent shift in reactor operational parameters and were considered inadvisable.