title: Sewage pre-concentration for maximum recovery and reuse at decentralized level.
abstract: Pre-concentration of municipal wastewater by chemically enhanced primary treatment (CEPT) was studied under controlled laboratory conditions. Both iron and aluminium-based coagulants were examined at gradually increasing concentrations (0.23, 0.35, 0.70 and 1.05 mmol/L). The CEPT sludge generated from different coagulation experiments was digested in batch anaerobic reactors, while the supernatant was tested in a dead-end microfiltration setup. The results of the study show that biogas yield was dramatically decreased (from 0.40 to 0.10 m(3)/kg chemical oxygen demand of influent) with increasing coagulant dose. In contrast, supernatant filterability was improved. Based on the laboratory results, a conceptual design was produced for a community of 2000 inhabitant equivalents (IE), using CEPT technology (at low coagulant dose) with anaerobic digestion of the concentrates. According to this, the capital and operational costs were 0.11 and 0.09 €/m(3), respectively. The biogas generated is used for digester heating and the overall process is energy self-sufficient. At a small-scale and in private applications, CEPT technology is preferably operated at higher coagulant dose, followed by membrane filtration for water reuse. Accordingly, sewage purification and reuse is possible without implementing aerobic biological processes.
authors.affiliation: Laboratory of Wastewater Management and Treatment Technologies, Department of Environmental Engineering, Democritus University of Thrace, Greece. bdiamant@env.duth.gr
authors.forename: V
authors.initials: V
authors.lastname: Diamantis
authors.forename: W
authors.initials: W
authors.lastname: Verstraete
authors.forename: A
authors.initials: A
authors.lastname: Eftaxias
authors.forename: B
authors.initials: B
authors.lastname: Bundervoet
authors.forename: V
authors.initials: V
authors.lastname: Siegfried
authors.forename: P
authors.initials: P
authors.lastname: Melidis
authors.forename: A
authors.initials: A
authors.lastname: Aivasidis
mesh_terms: D059027:Recycling; D012722:Sewage; D018505:Waste Management
chemical_list: D012722:Sewage