Development of an optimized operation and maintenance framework for waste stabilization ponds in resource-constrained settings: A case study of MWAUWASA Butuja facility, Mwanza, Tanzania

ABSTRACT Waste stabilization ponds (WSPs) are the dominant low-cost wastewater treatment technology across Sub-Saharan Africa. This study developed and validated an integrated Operation and Maintenance (O&M) framework for the MWAUWASA Butuja WSP facility in Mwanza, Tanzania, through a mixed-methods approach, multiple linear regression, principal component analysis, one-way ANOVA, and key informant interviews. The facility achieved mean BOD5 and COD removals of 91.7 and 91.1%, meeting TBS 860:2022 limits, but exhibited near-complete microbiological failure: effluent faecal coliform concentration exceeded the regulatory limit by a factor of 2,870. Regression analysis (R2 ≈ 0) confirmed that effluent quality is governed by internal operational variables rather than influent loading, with sludge accumulation reducing anaerobic pond hydraulic retention time from the design 5.0 to 2.3 days. The resulting O&M framework specifies, stage-specific desludging frequencies, a cost-optimised monitoring protocol supported by statistically validated proxy indicators, inlet flow management interventions, and a competency-based operator training curriculum with measurable performance targets.