Improved Design of Sanitary System at the Nigerian College of Aviation Technology (NCAT), Zaria

Sanitation is a basic human requirement with the primary aim of separating human waste from settlements to prevent the spread of diseases. This study presents a preliminary design of a centralized sewerage collection, transportation, treatment, and final disposal system for the Nigerian College of Aviation Technology (NCAT) Zaria, Kaduna State (Site 1). The results of physico-chemical analysis of samples showed concentrations of Nitrates (2,550mg/l) and total suspended solids T.S.S. (1,778mg/l) were above the acceptable standard limits. The concentrations of Zinc (5.31mg/l) and Lead (2.78mg/l) were also above the acceptable limits. A sewerage system which comprised of 18 manholes, 22 junction chambers and 39 sewers covering a distance of 2,816m was designed for the college. The results of the design showed that 3 facultative and 3 maturation ponds were required. The capital cost for implementing the proposed sewerage system and WSPs for the college was determined to be ₦14,649,855.75 with an annual cost of operation and maintenance of ₦3,030,000.00. A comparison of the proposed sewerage and WSPs system with the existing septic tank and soak-away system revealed that the proposed sewerage and WSPs system had a higher cost-benefit ratio (0.94), longer lifespan (30 years), lower cost of annual desludging (₦30,000.00), and lower risks of groundwater contamination.