Physicochemical assessment of urban wastewater of Cotonou (Benin).

Mohamed M. Arêmou Daouda,Martin Pépin Aïna,S. Peace Hounkpè,Patrick Drogui,A. V. Onesime Akowanou,M. Belfrid Djihouessi

doi:10.2166/wst.2021.073

Abstract

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 (BOD5), 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-1). 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 BOD5 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.

Highlights

Urbanization is one of the major causes of the growing demand for energy and water
This low-load can be explained by the fact that in most of the households surveyed, the collection system of domestic wastewater excluding an important part of kitchen and laundry
The physicochemical parameters of five various urban wastewater in the Cotonou city were assessed to serve as a decision-making tool for integrated wastewater management in Benin republic

Summary

Introduction

Urbanization is one of the major causes of the growing demand for energy and water. Accelerating urbanization requires new approaches to wastewater. While its quantitative assessment can be deduced from the volume of water consumed (Tchobanoglous et al ; Matos et al ), the quality of wastewater deserves careful study because it varies depending on the country, source and practices (Kulabako et al ; Popa et al ; Antonopoulou et al ; Edwin et al ; Boutin et al ). Daouda et al | Physicochemical assessment of urban wastewater of Cotonou (Benin)

Methods

Results

Conclusion