title: Technologies for reducing sludge production in wastewater treatment plants: State of the art.
abstract: This review presents the state-of-the-art sludge reduction technologies applied in both wastewater and sludge treatment lines. They include chemical, mechanical, thermal, electrical treatment, addition of chemical un-coupler, and predation of protozoa/metazoa in wastewater treatment line, and physical, chemical and biological pretreatment in sludge treatment line. Emphasis was put on their effect on sludge reduction performance, with 10% sludge reduction to zero sludge production in wastewater treatment line and enhanced TS (total solids) or volatile solids removal of 5-40% in sludge treatment line. Free nitrous acid (FNA) technology seems good in wastewater treatment line but it is only under the lab-scale trial. In sludge treatment line, thermal, ultrasonic (<4400kJ/kg TS), FNA pretreatment and temperature-phased anaerobic digestion (TPAD) are promising if pathogen inactivation is not a concern. However, thermal pretreatment and TPAD are superior to other pretreatment technologies when pathogen inactivation is required. The new wastewater treatment processes including SANI®, high-rate activated sludge coupled autotrophic nitrogen removal and anaerobic membrane bioreactor coupled autotrophic nitrogen removal also have a great potential to reduce sludge production. In the future, an effort should be put on the effect of sludge reduction technologies on the removal of organic micropollutants and heavy metals.
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, QLD 4072, Australia; Griffith School of Engineering, Griffith University, Nathan Campus, QLD 4111, Australia. Electronic address: qilin.wang@griffith.edu.au.
authors.forename: Qilin
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, QLD 4072, Australia.
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.affiliation: School of Environment, Guangzhou Key Laboratory of Environmental Exposure and Health, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Gong
authors.affiliation: Griffith School of Engineering, Griffith University, Nathan Campus, QLD 4111, Australia.
authors.forename: Qiming
authors.initials: Q
authors.lastname: Yu
authors.affiliation: Griffith School of Engineering, Griffith University, Nathan Campus, QLD 4111, Australia; Queensland Miro- and Nanotechnology Centre, Griffith University, Nathan Campus, QLD 4111, Australia.
authors.forename: Qin
authors.initials: Q
authors.lastname: Li
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, QLD 4072, Australia.
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, QLD 4072, Australia.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Yuan
keywords: Anaerobic digestion; Methane; Pretreatment; Sludge reduction; Waste activated sludge; Wastewater treatment plants