title: Wash water in waterworks: contaminants and process options for reclamation.
abstract: Reclamation of clean water from filter backwash water was studied through pilot-scale experiments. The pilot plant consisted of clarification, sand-filtration, and ultrafiltration modules in sequence, with a provision to bypass the sand filter. Clean water that conformed to World Health Organization (WHO) guidelines on Potable Quality was reclaimed. Turbidity, aluminum and iron were found to be critical contaminants in process selection and design. Clarification, followed by sand filtration, was found to be the minimum requirement for recycling filter backwash. However, membrane filtration would enhance reclaimed water quality as the membrane acts as an additional barrier against Giardia and Cryptosporidium.
authors.affiliation: Centre for Advanced Water Technology, Singapore Utilities International Pte Ltd., 82 Toh Guan Road East # C4-03, Singapore 608575. cbcraj@cawt.sui.com.sg
authors.forename: C B Chidambara
authors.initials: CB
authors.lastname: Raj
authors.forename: Tan Ee
authors.initials: TE
authors.lastname: Kwong
authors.forename: Wong Wai
authors.initials: WW
authors.lastname: Cheng
authors.forename: Lee Mun
authors.initials: LM
authors.lastname: Fong
authors.forename: Soh Hoo
authors.initials: SH
authors.lastname: Tiong
authors.forename: Paul Stefan
authors.initials: PS
authors.lastname: Klose
mesh_terms: D000535:Aluminum / Q000302:isolation & purification; D002244:Carbon / Q000032:analysis; D015169:Colony Count, Microbial; D003116:Color; D003247:Conservation of Natural Resources / Q000379:methods*; D004755:Enterobacteriaceae / Q000302:isolation & purification; D005459:Fluorides / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000302:isolation & purification; D008345:Manganese / Q000302:isolation & purification; D009391:Nephelometry and Turbidimetry; D009566:Nitrates / Q000032:analysis; D010710:Phosphates / Q000032:analysis; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification
chemical_list: D009566:Nitrates; D010710:Phosphates; D014874:Water Pollutants, Chemical; D008345:Manganese; D002244:Carbon; D000535:Aluminum; D007501:Iron; D005459:Fluorides