title: Pre-treatment optimisation studies for secondary effluent reclamation with reverse osmosis.
abstract: Physical-chemical pre-treatment was used for the reverse osmosis unit for reclamation of secondary effluents. The pilot plant was equipped with a variety of tertiary treatment units to prevent fouling and biofouling of the cellulose-acetate reverse osmosis membranes used. The optimisation of pre-treatment involved application of various concentrations of lime to raise the pH to 10.3-12.1, and to stabilise the sludge generated, as well as different dosages of ferric chloride (15, 20, and 25 mg/L) for the coagulation and solid-liquid separation. Sodium hypochlorite (8 mg/L) and UV disinfection are used for microbiological control. The water quality obtained, under the optimum conditions (pH=10.5; FeCl(3): 25 mg/L; anionic flocculant: 0.5 mg/L; sodium hypochlorite: 8 mg/L) was high, showing an average conductivity of 66 microS/cm and low COD values 4 mg O(2)/L. The product water is suitable for injection into a groundwater aquifer to counteract seawater intrusion.
authors.affiliation: Faculty of Marine and Environmental Sciences, Department of Chemical Engineering, Food Technology and Environment Technologies, University of Cádiz, Polígono Río San Pedro, s/n. 11510, Puerto Real, Cádiz, Spain. juanantonio.lopez@uca.es
authors.forename: J A
authors.initials: JA
authors.lastname: López-Ramírez
authors.forename: S
authors.initials: S
authors.lastname: Sahuquillo
authors.forename: D
authors.initials: D
authors.lastname: Sales
authors.forename: J M
authors.initials: JM
authors.lastname: Quiroga
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D003247:Conservation of Natural Resources; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D009995:Osmosis; D010100:Oxygen; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid / Q000379:methods*; D014871:Water Microbiology
chemical_list: D001672:Biocompatible Materials; D008567:Membranes, Artificial; C005062:acetylcellulose; D002482:Cellulose; D010100:Oxygen