Assessment on The Performance of AAWSA Controlled Sewerage System - The Case of Arada Sub city

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Addis Ababa University


Wastes originating from domestic, commercial, and industrial sources (often mixed with storm water) are collected, treated, and discharged back into the environment. The purpose of sanitary service is to prevent ground water pollution and minimize water borne diseases. The city of Addis Ababa provides sewerage service to its inhabitants by connecting their internal sewer lines to the sewerage network; however the level of service is still regarded as very low. This paper is therefore meant to assess the performance of the existing sewerage system both in technical and economic efficiency terms specifically in the Arada sub city, Addis Ababa. To achieve this, different evaluation methods were used. The methods comprise field visits (accompanied by capturing some pictures of the problem areas), cost analysis and comparison of the two common waste disposal techniques used in the city, Viz. vacuum truck and sewer line, gathering  from customers in order to identify the satisfaction level and finally evaluation of the sewerage network using sewer CAD version 4.3 to check and compare the existing hydraulic capacity and the future expectations. From the field visits different problems are identified which include manhole rising, manhole overflow, manhole loss and infrastructure problems. From cost analysis and , it was identified that there is lack of awareness and interest by the customers to connect their waste disposal point to the sewerage line. However, it was found out that sewer line is efficient than vacuum truck service considering cost and service efficiency. Finally the sewer cad analysis indicated that the existing sewer network can serve under capacity if the upstream area loads are excluded. However, the inclusion of the upstream area (Merkato site) to the Lideta existing sewerage system resulted in a complete system failure. The identified problems associated with sewerage system can therefore be overcome through having efficient operation and maintenance services in cooperation with other infrastructure agencies and through awareness creation.



Controlled Sewerage System, Performance, AAWSA