Assessment of Wastewater Management Practices in Kigali City, Rwanda

ABSTRACT

This study aimed to assess the current wastewater management practices in the City of Kigali (CoK). It focused on the quantification of household wastewater production, estimation of its quality, and the development of practical strategies for sustainably managing the wastewater, now and into the future. It is based on data on population, water supply and on data from questionnaire surveys carried out which are used to assess and derive figures on water consumption, unit wastewater production by the three different residential categories according to dwelling type and household income; these are high, medium and low standings. Three samplings runs were conducted in order to assess the quality of wastewater. The average water consumption was found to be 184 l/ca.d for high standing, 57 l/ca.d for medium standing, and 20 l/cap.d for low standing dwellings. The respective return flows (or wastewater discharge coefficients) were found to be 0.52, 0.68 and 0.75. For the monitored main parameters of pH, conductivity, Dissolved Oxygen, Total Dissolved Solids, Chemical Oxygen Demand, Total Nitrogen, and Total Phosphorous, the effluent quality far exceeded the limits for effluents discharged into sensitive waters. It is recommended that all concerned institutions and key stakeholders should work together in formulating an appropriate wastewater management strategy, with special emphasis on decentralized sanitation, reuse of wastewater components wherever possible, and cleaner production in industries.

Keywords:

City of Kigali, water consumption, wastewater generation, wastewater management strategies, urban wastewater management, wastewater reuse.