Physicochemical evaluation of wastewater from the main sewer in Abidjan City

Abstract

In many parts of the world, health problems have often been caused by untreated wastewater. The objective of this study was to determine the pollution level of wastewater in Abidjan city and to evaluate their impact on marine environment. Thus, wastewater samples were collected and analyzed according to French Association of Standardization (FANOR). The results showed that the values of these parameters are ranged on average between 14500 and 18500 mg/L for Biological Oxygen Demand (BOD 5), between 36000 and 41800 mg/L for Carbon Oxygen Demand (COD) and between 75 and 145.5 mg/L for Suspended Matters (SM). All these values are beyond World Health Organization recommendations for wastewater discharge. However, the analysis of the ratios between the COD and BOD 5 of the different effluents showed that it is ranged on average between 1.44 and 2.60. That means that wastewaters have a domestic character and are therefore easily biodegradable. So, the government should build a sewage treatment plant in Abidjan city to minimize health and environmental risks.