Mechanical pretreatment of waste activated sludge for anaerobic digestion process

This research investigated the effect of mechanical pretreatment of waste a ctivated sludge (WAS) to a pilot scale (2000 1) anaerobic digestion process . Mechanical pretreatment of WAS by jetting and colliding to a collision-pl ate at 30 bar made the sludge solubilized, as examining some parameters bef ore and after mechanical pretreatment of waste-activated sludge; for exampl e, Suspended Solid (SS), Soluble Chemical Oxygen Demand (SCOD), Soluble Tot al Organic Carbon (STOC), particle size, protein. ammonia-nitrogen (NH3-N), total phosphorus (T-P), and alkalinity. This research showed that solubili zation of WAS is effective to the digester performance through measuring th e unit gas production, volatile fatty acids (VFA), pH, and volatile mass re duction efficiency. WAS pretreatment allowed a decrease in the digester SRT from 13 to 6 days, without major effects on process efficiency and on effl uent quality. It enhanced volatile mass reduction and unit gas production. (C) 2000 Elsevier Science Ltd. All rights reserved.