Design of a sand mound sewage disposal system : case study : Kimbilio primary school-Tororo.

Abstract

The rural communities in Tororo are not served by public Sewer facilities and the majorly existing excreta disposal facilities in these areas include simple pit Latrines, Ventilated Improved Pit (VIP) latrines and a few institutions in the area use systems that require water for their operation such as flush toilets (TDLG; 2013). Kimbilio Primary school is located in the rural areas of Tororo district on a site with Shallow soil depth over underlying bedrock making it difficult to use conventional subsurface soil absorption systems for. waste water disposal. This inappropriate disposal of sewage makes the school and the entire community more susceptible to water borne diseases. The main objective of this project was to design a Sand Mound Sewage disposal system for Kimbilio Primary School. The project involved a review of several literature pertaining sewage disposal systems, geophysical study of the site, characterizing and quantifying the waste water composition, designing the various components of the sand mound sewage disposal system and finally economic analysis of the project was done. The study was yery successful in achieving its objective of designing a Sand Mound Sewage disposal system for the school. The geophysical investigations of the site indicated a clay loam soil of average percolation rate 31.3 sec/mm and a site slope of 2%. A 20m3/daysand mound sewage disposal system Was designed to meet a projected population of 500 people in 25 years. The economic evaluation of the designed. sand mound sewage disposal system indicated a cost benefit ratio of 1.81 hence making the project viable. This design once constructed will provide a method of final treatment and discharging of partially treated wastewater to the soil environment where it receives final treatment by the natural soils prior to contact with the groundwater. In order to ensure success of the project, the designed sand mound sewage disposal system should be fenced to prevent traffic and compaction of the absorption site a diversion ditch should be constructed Uphill of the mound to prevent surface water and an additional useable area of 50. percent should be set. aside for future expansion.