Anaerobic Co-Digestion of Sewage Sludge and Concentrated Soluble Wastewaters

The anaerobic treatment of sewage sludges (primary and secondary) mixed to concentrated soluble wastes (olive mill effluents, cheese whey and landfill leacheate) in conventional once-through and anaerobic contact digesters, has been investigated in laboratory scale reactors. Experimental results indicate that it is possible to increase appreciably (100 %) the volumetric loading rate of sludge digesters (anaerobic contact) by addition of soluble substrates and keep stable operating conditions. The proposed treatment is economically very attractive if the load due to high strength wastewaters is of the same magnitude as the sludge load, as it does not require additional reactor volume.