BACKGROUND To understand the intrinsic role of hydrolytic enzymes in sludge treatment, particularly their effect on the digestibility and dewaterability of sludge, activated sludge flocs were disintegrated using various techniques that included different enzymes (amylase, cellulase, proteinase, DNase, and polygalacturonase), pH adjustment, and temperature adjustment. The effectiveness of each e...

key dissimilarities between thermophilic and mesophilic anaerobic digestion of waste activated sludge (was) were experimentally studied in this research. typical was with total solids (ts) concentrations of 30 and 60 g/l were digested anaerobically in a batch digester at mesophilic and thermophilic temperatures. solids reduction, total cod changes, the production of different volatile fatty ...

This study applied a filter press for dewatering that uses pressure to reduce the water content of sludge generated in sewage treatment plants and evaluated improvement dewaterability under various coagulation conditions according type coagulants, amounts, pH conditions. The was by measurement time (TTF), change zeta potential, cake after dewatering. It found conditions, inorganic coagulants we...

This work deals with the effect of combined microwave-ultrasonic pretreatment on the anaerobic biodegradability of primary, excess activated and mixed sludge. The characteristics, biodegradability and anaerobic digester performance for untreated primary, excess activated and mixed sludge were compared to combined microwave-ultrasonic pretreated primary, excess activated and mixed sludge. All sl...

The performance of an anaerobic digestion fed with waste activated sludge (WAS) pretreated with NaOH was examined. The sludge was periodically collected from a municipal wastewater-treatment plant. The laboratory work was run in four 1-1 semi-continuous anaerobic digestion reactors. Reactor A was fed with untreated WAS at 1% total solids (TS). The other three reactors, B, C and D, were respecti...

Sludge management is a major issue for water utilities globally. Poor digestibility and dewaterability are the main factors determining the cost for sludge management, whereas pathogen and toxic metal concentrations limit beneficial reuse. In this study, the effects of low level nitrite addition to acidified sludge to simultaneously enhance digestibility, toxic metal removal, dewaterability and...

Conditioning of an alum-based water treatment sludge by single and dual polymers was investigated in this study. Capillary suction time (CST), specific resistance to filtration (SRF) and settling rate of conditioned sludge were used to evaluate the sludge dewatering characteristics. Sludge dewaterability resulting from single and dual polymer conditioning were compared for the purpose of explor...