Development and performance evaluation of low-cost wastewater treatment plant

A pilot-scale wastewater treatment plant was developed for the purpose of treating wastewaters in south-western Nigeria. The plant, mounted on a roller frame was divided into three sections, viz. wastewater holder, purification chamber and treated water collector. The purification chamber contained three sets of strainers with locally sourced materials which include Azolla pinnata fern, fine sand, chlorine pellets, alum cubes and palm kernel shell charcoal (PKSC). The performance of the treatment plant was evaluated using four different wastewater (WW) sources which were industrial (IW), municipal (MW), domestic (DW) and aquaculture (AW) wastewaters. Sixteen physicochemical parameters and ten metals were monitored in the four WW samples which included temperature, turbidity, electrical conductivity (EC), pH, total suspended solids (TSS), total dissolved solids (TDS), total solid (TS), acidity as CaCO3, total hardness, total phosphorus (TP), total nitrogen (TN), ammoniacal nitrogen, dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), fecal coliform, Escherichia coli and total coliform count. The metals were Na, K, Ca, Mg, Zn, Fe, Pb, Cu, Cd, and Mn. Water quality analysis was done using standard laboratory procedures and results obtained were subjected to statistical analysis. From the results, 100% removal efficiencies were obtained in some heavy metals such as cadmium (Cd) and manganese (Mn) and in parameters such as turbidity, TP, and TN after passing through the treatment plant. The presence of pathogens and microorganisms that were also reduced does not in any way affect its use for agricultural purposes. All other parameters reduced appreciably with results which were statistically significant at P < 0.05. This indicated the high efficiency of the treatment plant in the removal of the water pollutant and heavy metals from the four WW sources considered.