JOURNAL OF THE GHANA SCIENCE ASSOCIATION

Abstract: Hospital wastewater in Ghana is frequently treated using waste stabilization ponds (WSPs); however, their treatment efficiency and reuse potential remain poorly characterized. This study conducted a six-month assessment of the Cape Coast Teaching Hospital WSP using an integrated framework that combined physicochemical, microbial, hydrochemical, and heavy metal analyses with predictive modeling and reuse suitability indices. The system achieved notable reductions in suspended solids (54.5%) and heavy metals, including Pb (0.001 mg/L) and Cr (0.002 mg/L), which complied with WHO (2006) discharge standards. Fecal coliform concentrations decreased by 21.7%, yet remained above acceptable thresholds for direct reuse. In contrast, salinity and nutrient levels accumulated, with electrical conductivity reaching 1565 μS/cm, ammonia rising to 59.4 mg/L, and nitrate and phosphate concentrations indicating elevated eutrophication risk. Corrosivity indices (LSI −98; RSI >200) suggested strong potential for metal corrosion, while sodium hazard (SAR up to 155.9) and Kelly’s ratio (>9) rendered the effluent unsuitable for irrigation without dilution or tertiary treatment. This study introduces a novel integrated framework that combines pollutant attenuation assessment with reuse potential analysis, offering a comprehensive approach rarely applied in hospital-based waste stabilization pond systems. The findings demonstrate that, although the effluent contains nutrients beneficial for crops, its high salinity and sodium hazard necessitate controlled reuse strategies and post-treatment interventions to prevent soil degradation, thereby informing sustainable wastewater management and reuse planning.

Keywords: Hospital wastewater, Waste stabilization ponds, Predictive modelling, Effluent reuse, Corrosion indices, tropical wastewater treatment

Abstract: Ground settlement is a major issue in geotechnical engineering since it may cause significant structural damage and financial losses. The study evaluates ground settlement at Wassa Agona in the Western Region of Ghana using field investigation, laboratory testing and numerical methods. Five trial pits were investigated, from which soil samples were obtained for geotechnical characterisation and settlement assessment. Detailed data were gathered through fieldwork and laboratory testing, which provided the basis for empirical analysis and numerical modelling using Settle3D and Plaxis 3D software. The numerical settlement analysis was conducted under a foundation pressure of 125 kN/m² at 1.0 m embedment depth. Results from the laboratory and field tests revealed that the soil is mainly silt-dominated with low plasticity and specific gravity values indicating quartz-rich mineralogical setting. Oedometer consolidation test results indicated primary consolidation settlement values of 21.3 mm, 20.9 mm and 19.5 mm for Pit 1-Layer 3, Pit 2-Layer 3 and Pit 5-Layer 3, respectively. Settle3D predicted maximum staged settlement values of 34.1 mm, 30.4 mm and 36.1 mm, while Plaxis 3D predicted 10-year downward displacement values of 0.77 mm, 0.71 mm and 0.52 mm for the same pits, respectively. The results show that Settle3D is more responsive to one-dimensional compressibility and staged consolidation settlement, while Plaxis 3D provides a complementary three-dimensional finite element check on relative vertical displacement. The findings indicate that settlement serviceability checks should be included in foundation design at Wassa Agona, particularly where predicted staged settlements exceed acceptable limits.

Keywords: Ground settlement, Consolidation settlement, Oedometer Test, Numerical modelling, Tropical soils