title: A hybrid process of biofiltration of secondary effluent followed by ozonation and short soil aquifer treatment for water reuse.
abstract: The Shafdan reclamation project facility (Tel Aviv, Israel) practices soil aquifer treatment (SAT) of secondary effluent with hydraulic retention times (HRTs) of a few months to a year for unrestricted agricultural irrigation. During the SAT, the high oxygen demand (>40 mg L(-1)) of the infiltrated effluent causes anoxic conditions and mobilization of dissolved manganese from the soil. An additional emerging problem is the occurrence of persistent trace organic compounds (TrOCs) in reclaimed water that should be removed prior to reuse. An innovative hybrid process based on biofiltration, ozonation and short SAT with ∼22 d HRT is proposed for treatment of the Shafdan secondary effluent to overcome limitations of the existing system and to reduce the SAT's physical footprint. Besides efficient removal of particulate matter to minimize clogging, coagulation/flocculation and filtration (5-6 m h(-1)) operated with the addition of hydrogen peroxide as an oxygen source efficiently removed dissolved organic carbon (DOC, to 17-22%), ammonium and nitrite. This resulted in reduced effluent oxygen demand during infiltration and oxidant (ozone) demand during ozonation by 23 mg L(-1) and 1.5 mg L(-1), respectively. Ozonation (1.0-1.2 mg O3 mg DOC(-1)) efficiently reduced concentrations of persistent TrOCs and supplied sufficient dissolved oxygen (>30 mg L(-1)) for fully oxic operation of the short SAT with negligible Mn(2+) mobilization (<50 μg L(-1)). Overall, the examined hybrid process provided DOC reduction of 88% to a value of 1.2 mg L(-1), similar to conventional SAT, while improving the removal of TrOCs and efficiently preventing manganese dissolution.
authors.affiliation: School of Mechanical Engineering, Tel Aviv University, Tel Aviv, 69978, Israel; Hydrochemistry, Geography and the Environment, Tel Aviv University, Tel Aviv, 69978, Israel.
authors.forename: I
authors.initials: I
authors.lastname: Zucker
authors.affiliation: School of Mechanical Engineering, Tel Aviv University, Tel Aviv, 69978, Israel.
authors.forename: H
authors.initials: H
authors.lastname: Mamane
authors.affiliation: Environmental Engineering Services, Tel Aviv, Israel.
authors.forename: H
authors.initials: H
authors.lastname: Cikurel
authors.affiliation: Technical University of Berlin, Chair of Water Quality Control, Strasse des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Jekel
authors.affiliation: Technical University of Munich, Urban Water Systems Engineering, Am Coulombwall, 85748, Garching, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Hübner
authors.affiliation: Hydrochemistry, Geography and the Environment, Tel Aviv University, Tel Aviv, 69978, Israel. Electronic address: droravi@post.tau.ac.il.
authors.forename: D
authors.initials: D
authors.lastname: Avisar
mesh_terms: D005374:Filtration; D009930:Organic Chemicals / Q000378:metabolism*; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
chemical_list: D009930:Organic Chemicals; D014874:Water Pollutants, Chemical
keywords: Biodegradation; Biofilter; Nitrification; Reclaimed water; Tertiary effluent; Trace organic compound