Phosporus Treatment Using Alum Residual: an Alternative Technology for Small Scale Wastewaterapplications

Phosphorus removal for small-scale wastewaterapplications were investigated using adsorption andcoagulation. Alum sludge, a waste residual generatedin water treatment utilities, was used for treatmentof orthophosphate. Bench scale experiments weredesigned to evaluate the effectiveness for phosphorusremoval. Tests were conducted on both deionized waterspiked with orthophosphate and wastewater (secondarymunicipal effluent, effluent from biofiltrationprocess and aquaculture process water) using ovendried alum sludge (ODS). Surface characterization wasdone to understand the adsorption process. The ODSwas effective in adsorbing orthophosphate, and wascomparable to otherconventional and emerging adsorbents oforthophosphates. Alum sludge was also effective inremoving phosphorus from smallscale wastewaters, evenbetter than that of deionized water. Coagulationprocess tested for phosphorus removal fromsmall-scale wastewaters was found to be ineffective. Surface characterization indicated thepossibility of OH- ion being replaced byorthophosphate ions. The waste residual generatedfrom the treatment process were found to reducealuminum leachability.