Efficiency of oxidation ponds in wastewater treatment



A research was conducted at Kauma oxidation ponds, a Sewage water treatment plant found in Lilongwe, Malawi with an aim of establishing the efficiency of these sewage treatment ponds in treating sewage wastewater. Water samples from the effluent discharging points in the maturation ponds were collected and analysed in the labouratory for, BOD, Coliform bacteria, Total Nitrogen (TN), Phosphorous and Chlorophyll-a. Other parameters like Temperature, DO, and pH were measured on site. It was found out that FCB, TP, TN, Chlorophyll a and BOD were 4.59x103CFU, 1.94x103μg/L, 1.78x103μg/L, 2.68x103μg/L and 10.6mg/L, way above the WHO guidelines for drinking, swimming and bathing waters for which uses is the Lilongwe river to which this effluent is discharged. The presence of FCB, BOD, P, chlorophyll-a, in large quantities indicates the inefficiency of the oxidation ponds. Furthermore, the presence of high concentration of chlorophyll-a indicated a heavy loading of the river with organic matter found in phytoplankton demanding a tertiary treatment to have a clean water discharged into the river system.