Investigating the correlation of nitrates and phosphates to the effective removal of Fats, Oils, and Grease in Two Mangaung Municipal Wastewater Treatment Plants

Abstract

This study is about the effectiveness of wastewater treatment technologies in two treatment plants at Mangaung Municipality in South Africa. The removal of FOG, nitrogen and phosphorus is an important component of wastewater treatment. Therefore, the study aims at investigating the effectiveness of the two treatment technologies (biological trickling filter and activated sludge) in the wastewater treatment plants studied. Grab samples of the influent and effluent of the North East Wastewater Treatment Plant (NEWTP) and the Bloemspruit Wastewater Treatment Plant (BWTP) were collected per week over a period of five months. The laboratory analysis of FOG followed the description of the Environmental Protection Agency (EPA) 1664B. Hexane extraction and gravimetry-PBM method was used in the analysis. Nitrates were analysed using a SOP Chem 005 Spectroquant Nitrate test while phosphates were analysed using a Spectroquant Prove spectrophotometer in the laboratory. The results showed that the trickling filter from BWTP removed FOG by 61.36% while the activated sludge from NEWTP removed FOG by 52.81% which showed that the both of the two treatment technologies work the same and are ineffective in the removal of FOG. However, the nitrates and phosphates present in the effluent were found to be within the effluent discharge standards.