Physicochemical assessment of urban wastewater of Cotonou (Benin)

• Published in: Water science and technology Vol. 83; no. 6; pp. 1499 - 1510
• Main Authors: Daouda, Mohamed M Arêmou, Hounkpè, S Peace, Djihouessi, M Belfrid, Akowanou, A V Onesime, Aïna, Martin Pépin, Drogui, Patrick
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01.03.2021
• Subjects: Benin; Biochemical oxygen demand; Biodegradability; Biodegradation; Biological Oxygen Demand Analysis; Blackwater; Chemical oxygen demand; Cities; Design; Design parameters; Developing countries; Effluents; Electrical conductivity; Electrical resistivity; Gap analysis; Greywater; Households; Industrial pollution; Industrial wastes; Industrial wastewater; Laundry; LDCs; Medical wastes; Organic loading; organic pollution parameter; Oxygen requirement; Parameters; Pharmaceutical industry wastes; Pharmaceuticals; Phosphorus; Physicochemical processes; Physicochemical properties; Plant design; Pollutants; Sanitation; Sewage disposal; Sludge; Statistical analysis; Statistical methods; Total oxygen demand; urban wastewater; uv absorbance 254; Variance analysis; Waste Disposal, Fluid; Waste Water; Wastewater treatment; Wastewater treatment plants; Water Pollutants, Chemical - analysis; Water reuse; Water treatment; Benin; Cities; Africa
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2021.073

The present study aims to fill the data gap analysis in urban wastewaters characteristics in Benin and its statistical analysis. Physicochemical parameters such as pH, electrical conductivity (EC), Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD ), Total Kjeldahl Nitrogen (TKN), Total Phosphorus (TP) and UV Absorbance at 254 nm, were determined on domestic (greywater and blackwater) and industrial (hospital, pharmaceutical and commercial laundry) wastewater in Cotonou city. Analysis of variance showed a strong significant difference in the physico-chemistry of the various effluents. The pharmaceutical wastewater has the highest concentration of organic pollution (COD = 5,912 ± 1,026 mg/L, Abs.UV254 = 2.667 ± 0.327 cm ). The organic load of blackwater is mainly in particulate and biodegradable form. Besides, the correlation study showed the limits of pH and EC as an indicator of organic load. Furthermore, the choice of COD or BOD as the main design parameter would be limited to blackwater treatment. Abs.UV254 was found to be the parameter having a strong relationship with other parameters of all effluents except blackwater. It then takes priority over COD for the treatment of greywater and industrial wastewater. For future wastewater treatment plant design, we recommend to consider Abs.UV254 as an important parameter.