Evaluation of Reliability Engineering Practices in Water Treatment Plant Equipment in Enugu State

Water treatment plant equipment reliability has a direct bearing on the ability of urban water utilities to meet population demand, and in Nigerian cities where infrastructure maintenance has historically been underfunded, equipment failures translate into prolonged service interruptions affecting public health outcomes. This study evaluates the reliability engineering practices applied to mechanical equipment at the Oji River water treatment plant in Enugu State, which serves as the principal water supply facility for Enugu metropolis. The research combines analysis of equipment failure records spanning five years, direct condition assessment of pumping sets, filter media, chemical dosing units, and sluice gates, and interviews with plant engineers and maintenance officers. Reliability metrics including equipment availability, mean time between failures, and failure rate were computed for major equipment categories. Reliability block diagrams for the critical supply path from intake to distribution were developed to quantify system-level availability. Results indicated that raw water pump availability averaged 78 percent, below the recommended minimum of 90 percent for continuous supply infrastructure. Filter media replacement intervals exceeded manufacturers' recommendations by an average of 18 months, contributing to reduced filtration efficiency and increased backwash frequency. The study recommends implementation of a documented reliability programme based on reliability-centred maintenance principles, systematic spare pump capacity provision, and regular condition-based overhaul scheduling. Keywords: reliability engineering, water treatment plant, equipment availability, reliability-centred maintenance, Enugu State.