Keywords: low cost treatment, phosphate removal, bittern, coated media, wastewater treatment, water treatment, seawater flocculation, adsorption, filtration, coagulation, iron, aluminium, raw dolomite
Low cost processes for the removal of phosphates in water and wastewater
This paper presents a synopsis of various low-cost techniques employed for the removal of phosphates from water and treated wastewater. Techniques employed include seawater flocculation and coagulation/flocculation using bittern, adsorption on fluidised raw dolomite bed, and filtration through iron and aluminium coated filter media. Seawater flocculation at a seawater concentration of 10% exhibited highly efficient (>90%) removal of Total Phosphorus (TP) from alkaline oxidation pond effluents. For experiments employing fluidised raw dolomite bed, varying degrees of phosphate adsorption capacities were observed for the different test influents used. Finally, laboratory experiments conducted to determine the efficacy of iron and aluminium coated media in removing low concentrations of phosphates indicated very effective phosphate removals (>90%) when applied to Distilled Water (DW) and synthetic groundwater, and less success when applied to Tap Water (TW) (<80%) and treated wastewater effluents (<70%).