Extraction and precipitation of phosphorus from effluent out of a sewage treatment plant to reduce eutrophication of surface water: a case of Lubigi Wastewater Treatment Plant

Abstract

The removal of phosphorus (P) from domestic wastewater was investigated primarily to reduce the potential for eutrophication in receiving waters. Phosphorus was extracted from domestic wastewater collected from Lubigi Wastewater Treatment Plant. Phosphorus, being a fundamental element for growth and metabolism of living organisms, yet problematic to water quality, is an irreplaceable component. Application of enhanced biological phosphorus removal (EBPR) technology was used in the removal and recovery of this component. Several control tests were carried out to monitor amount of phosphorus before and after biological treatment. Total Phosphorus Standard Test and Standard Orthophosphate Test were used to monitor changes in Phosphorus concentrations while keeping physical parameters like Temperature constant. The potential for P extraction to reduce eutrophication and potential of this extraction to supplement Phosphorus Fertilizer industry were investigated as well as characterization of effluent from Lubigi Wastewater Treatment Plant. It was found that an average of 8mg/l of Phosphorus was extracted and recovered having carried out several EBPR processes with similar HRT. In the case of Lubigi Wastewater Treatment Plant, the results were extrapolated and P removal was found to have the potential to extract 42 kg per day of Phosphorus from sludge wasting daily from this Secondary Treatment as it was paramount to determine the amount of P that could be extracted from sludge wasting after Biological Treatment. If this treatment can be incorporated in all wastewater treatment plants, eutrophication in wastewater will greatly reduce. It is postulated that P extraction over a long period of time from Wastewater effluent at Lubigi WWTP will have a great effect on eutrophication in surface water in the Great Lakes region. This study found that Biological P extraction has potential of reducing P concentrations at Lubigi WWTP by 33% before the effluent is disposed into the environment.