Assessment of the efficiency of the wastewater treatment plant: a case of Gacuriro Vision City

Abstract

Wastewater is the liquid waste generated after being used for different purposes. It has a great impact on the environment when discharged untreated or partially treated. The poor management of wastewater at Gacuriro wastewater plant leads to the discharge of subsequently untreated and partially treated wastes. Therefore, the research focused on the assessment of the efficiency of Gacuriro wastewater treatment plant. Samples of wastewater were collected at the inlet and outlet of the treatment plant for laboratory analysis. Parameters tested include pH, Temperature, Total Suspended Solids (TSS), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Coliform (TC), Oil and Grease, and Total Phosphorus (TP). Inlet and outlet results are 112.5-364.5 mg/l, 60-190.2 mg/l for BOD; 447-820 mg/l, 46.6-300 mg/l for COD, 19-24 mg/l, 12-18 mg/l for TSS; 6.8-9.05 mg/l, 6.4-5.75 mg/l for TP, 2419.6-50000 counts/100 ml, 1730-30000 counts/100 ml for TC, and 1.012-1.079 mg/l, 0.75-0.923 mg/l for Oil and Grease. Their percentage reduction of efficiency were in the range of TSS (62.50-75%), COD (63.05-78.74%), BOD5 (69.97-83.70%), Oil and Grease (48.67-62.19%), TP (49.26-60.82%), TC (57.14-64.00%) while average inflow and outflow discharge are 2.5 l/s and 1.5 l/s, respectively. The effluent from the treatment plant needs improvement in disinfection systems to remove bacteria out of discharged effluent.