Two-stage cyclic operation of anaerobic filters

Abstract

Over the past few years, the need to pretreat industrial wastes has generated considerable interest in development and application of anaerobic treatment systems. This interest is due, in part, to recent research that has introduced new anaerobic process applications. Other reasons include the attractive features of anaerobic reactions such as methane gas production and low sludge yields. While many desired results may be sought when treating low to medium strength industrial waste streams, the ultimate pretreatment goal is to economically achieve an effluent that has organic concentrations reduced to below levels that can be discharged to municipal wastewater systems. Only in the past few years have researchers and process engineers demonstrated that anaerobic systems can achieve this goal, specifically using fixed-film processes such as the anaerobic filter. Recent studies have shown the impressive performance of a new anaerobic treatment process variation. This process, two-stage cyclic operation has shown considerable improvement in anaerobic filter treatment capabilities, especially in the levels to which soluble effluent chemical oxygen demand (COD) can be reduced. Research objectives were to compare the performance of two-stage cyclic anaerobic filters to that of single-stage units operated at equal volumetric organic loadings, and to evaluate the individual response ofmore » the two reactor stages immediately following stage reversals.« less