Comprehensive assessment of industrial wastewater treatment systems at selected industries in Rwanda

Abstract

Developing countries are characterized by a fast growing in industrialization sector. This push them to heavily rely on water need because one the first industrial requirement is water. A worrisome problem, is the production of unplanned wastewater that is discarded in the environment without treatment or inadequately treated. This study aimed at comprehensive assessment on industrial wastewater treatment systems at Kigali special economic zone (KSEZ) and three more selected industries in Kigali and one secondary city. To achieve this assignment, the study targeted the comparison of treated and untreated wastewater effluents from those industries with national and international tolerance limits of industrial wastewater parameters that are allowed to be discarded off in the environment. Wastewater samples were collected at points before treatment, near the treatment sites after treatment and far from the treatment sites in the months of December, February and June,2020 for three industries. Questionnaires were used to assess the management of treatment systems during operation. Microsoft excel and a statistical package of social sciences (SPSS) were used in data analysis. Two of the four selected industries was found that it has no treatment plant and the treatment method employed was very poor. However, wastewater treatment in all of four selected industries was inadequate in removal of the parameters: pH, nutrients (TN, TP), COD, BOD, TSS, O&G, FC, and heavy metals. Industrial effluents that were discharged of in the environment contain some parameters that are not compliant with RSB and international tolerable limits. It was recommended to establish wastewater treatment plants at two industries and improve the management of treatment systems for all the selected industries.