title: Effect of coagulation on treatment of municipal wastewater reverse osmosis concentrate by UVC/H2O2.
abstract: Disposal of reverse osmosis concentrate (ROC) is a growing concern due to potential health and ecological risks. Alum coagulation was investigated as pre-treatment for the UVC/H2O2 treatment of two high salinity ROC samples (ROC A and B) of comparable organic and inorganic content. Coagulation removed a greater fraction of the organic content for ROC B (29%) than ROC A (16%) which correlated well with the reductions of colour and A254. Although the total reductions after 60 min UVC/H2O2 treatment with and without coagulation were comparable, large differences in the trends of reduction were observed which were attributed to the different nature of the organic content (humic-like) of the samples as indicated by the LC-OCD analyses and different initial (5% and 16%) biodegradability. Coagulation and UVC/H2O2 treatment preferentially removed humic-like compounds which resulted in low reaction rates after UVC/H2O2 treatment of the coagulated samples. The improvement in biodegradability was greater (2-3-fold) during UVC/H2O2 treatment of the pre-treated samples than without pre-treatment. The target DOC residual (≤ 15 mg/L) was obtained after 30 and 20 min irradiation of pre-treated ROC A and ROC B with downstream biological treatment, corresponding to reductions of 55% and 62%, respectively.
authors.affiliation: School of Civil, Environmental and Chemical Engineering, RMIT University, GPO Box 2476, Melbourne, 3001 Victoria, Australia.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Umar
authors.affiliation: School of Civil, Environmental and Chemical Engineering, RMIT University, GPO Box 2476, Melbourne, 3001 Victoria, Australia. Electronic address: felicity.roddick@rmit.edu.au.
authors.forename: Felicity
authors.initials: F
authors.lastname: Roddick
authors.affiliation: School of Civil, Environmental and Chemical Engineering, RMIT University, GPO Box 2476, Melbourne, 3001 Victoria, Australia.
authors.forename: Linhua
authors.initials: L
authors.lastname: Fan
mesh_terms: D000534:Alum Compounds / Q000737:chemistry*; D005427:Flocculation; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009995:Osmosis; D062611:Solid Waste; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D000534:Alum Compounds; D062611:Solid Waste; C041524:aluminum sulfate; D006861:Hydrogen Peroxide
keywords: Alum; Biodegradability; Coagulation; Reverse osmosis concentrate; UVC/H(2)O(2)