Authors : Ndala Mbavu Bavon; Mungwa Kalundu Gaylord; Keshijina Ndala Ernest

Volume/Issue : Volume 11 - 2026, Issue 1 - January

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DOI : https://doi.org/10.38124/ijisrt/26jan262

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Abstract : Context: Increasing climatic variability threatens the efficacy of conventional water treatment lines, particularly gravity filtration, a robust and economically accessible process in resource-limited contexts. Lake Kabongo, a major supply source, exhibits significant quality fluctuations (turbidity, organic matter, algal blooms) likely to alter filter performance.  Objective: To develop a hybrid (mechanistic–statistical) predictive model of gravity filtration performance (effluent turbidity, head loss, cycle duration) based on raw water quality, to shift from empirical operation to anticipatory management.  Methodology: A systematic meta-analysis of over twenty historical trials conducted between May and June 2025 on Lake Kabongo water was performed. A hybrid model combining fundamental equations of porous media filtration and multivariate polynomial regressions calibrated on experimental data was developed. Validation is based on data partitioning (70/30), comprehensive statistical analysis (coefficients with 95% CI, residual analysis) and simulation of extreme climatic scenarios.  Key Results: Initial turbidity, Total Organic Carbon (TOC) concentration and UV275 absorbance explain over 85% of the performance variance. The final model shows coefficients of determination of 0.89 for effluent turbidity, 0.86 for TOC and 0.83 for UV275. Sensitivity analysis identifies activated carbon height (Hc) as the second most influential parameter after initial turbidity. Simulations reveal critical thresholds (e.g., turbidity > 100 NTU) beyond which filtration efficiency drops sharply.  Conclusion / Scope: The developed tool allows for optimization of the future Katebi containerized plant operation by anticipating at-risk periods and adjusting operational parameters. This approach is transferable to other gravity filtration systems subject to hydro-climatic variability and contributes to securing drinking water production in a context of global change.

Keywords : Gravity Filtration; Performance Modeling; Tropical Surface Water; Water Quality Variability; Lake Kabongo; Artisanal Activated Carbon; Least Squares Method.

References :

1. Ndala Mbavu, B., & Mujinga, Z. (2025b). Performance and durability of a gravity charcoal filter for organic pollution. International Journal of Innovative Science and Research Technology, *10*(10), Article 25oct1442. https://doi.org/10.38124/ijisrt/25oct1442
2. Ndala Mbavu, B., Katshil, P. M., Kalundu, G. M., Kon-A-Kabey, T., & Mpanga, P. K. (2025). Assessment of the Water Quality of Lake Kabongo Before and After the Cessation of Anthropic Activities. International Journal of Innovative Science and Research Technology, *10*(9), Article 25sep003. https://doi.org/10.38124/ijisrt/25sep003
3. Sobsey, M. D., Stauber, C. E., Casanova, L. M., Brown, J. M., & Elliott, M. A. (2008). Point of use household drinking water filtration: A practical, effective solution for providing sustained access to safe drinking water in the developing world. Environmental Science & Technology, *42*(12), 4261–4267.
4. World Health Organization. (2022). Guidelines for drinking-water quality (4th ed.). WHO Press.
5. Burch, J. D., & Thomas, K. E. (1998). Water disinfection for developing countries and potential for solar thermal pasteurization. Solar Energy, *64*(1–3), 87–97.
6. Clasen, T., Nadakatti, S., & Menon, S. (2006). Microbiological performance of a water treatment unit designed for household use in developing countries. Tropical Medicine & International Health, *11*(9), 1399–1405.
7. Elliott, M. A., Stauber, C. E., Koksal, F., DiGiano, F. A., & Sobsey, M. D. (2008). Reductions of E. coli, echovirus type 12 and bacteriophages in an intermittently operated household-scale slow sand filter. Water Research, *42*(10–11), 2662–2670.
8. Fewtrell, L., & Colford, J. M. (2005). Water, sanitation and hygiene in developing countries: interventions and diarrhoea—a review. Water Science and Technology, *52*(8), 133–142.
9. Gundry, S. W., Wright, J. A., & Conroy, R. M. (2004). A systematic review of the health outcomes related to household water quality in developing countries. Journal of Water and Health, *2*(1), 1–13.
10. Hasan, H. A., Abdullah, S. R. S., Kamarudin, S. K., & Kofli, N. T. (2012). Response surface methodology for optimization of simultaneous COD, NH4+-N and Mn2+ removal from drinking water by biological aerated filter. Desalination, *302*, 1–9.
11. Hijnen, W. A. M., Beerendonk, E. F., & Medema, G. J. (2006). Inactivation credit of UV radiation for viruses, bacteria and protozoan (oo)cysts in water: A review. Water Research, *40*(1), 3–22.
12. Hutton, G., & Haller, L. (2004). Evaluation of the costs and benefits of water and sanitation improvements at the global level. World Health Organization.
13. Jagals, P., & Grabow, W. O. K. (1996). An evaluation of the effect of an experimental container on the microbiological quality of drinking water. Water SA, *22*(4), 319–324.
14. Karanis, P., Kourenti, C., & Smith, H. (2007). Waterborne transmission of protozoan parasites: A worldwide review of outbreaks and lessons learnt. Journal of Water and Health, *5*(1), 1–38.
15. LeChevallier, M. W., & Au, K. K. (2004). Water treatment and pathogen control: Process efficiency in achieving safe drinking water. IWA Publishing.
16. Mintz, E. D., Bartram, J., Lochery, P., & Wegelin, M. (2001). Not just a drop in the bucket: expanding access to point-of-use water treatment systems. American Journal of Public Health, *91*(10), 1565–1570.
17. Peter-Varbanets, M., Zurbrugg, C., Swartz, C., & Pronk, W. (2009). Decentralized systems for potable water and the potential of membrane technology. Water Research, *43*(2), 245–265.
18. Schwab, K. J., Gibson, K. E., Williams, D. L., Kulbicki, K. M., Lo, C. P., & Mihalic, J. N. (2014). Microbial and chemical assessment of regionally diverse household drinking water filters. Water Research, *48*, 100–114.
19. Shannon, M. A., Bohn, P. W., Elimelech, M., Georgiadis, J. G., & Marinas, B. J. (2008). Science and technology for water purification in the coming decades. Nature, *452*(7185), 301–310.
20. Tiwari, S. S., Schmidt, W. P., Darby, J., Kariuki, Z. G., & Jenkins, M. W. (2009). Intermittent slow sand filtration for preventing diarrhoea among children in Kenyan households using unimproved water sources: randomized controlled trial. Tropical Medicine & International Health, *14*(11), 1374–1382.
21. Vinnerås, B., Hedenkvist, M., Nordin, A., & Wilhelmson, A. (2009). Peepoo bag: self-sanitising single use biodegradable toilet. Water Science and Technology, *59*(9), 1743–1749.
22. WHO/UNICEF. (2021). Progress on household drinking water, sanitation and hygiene 2000–2020: Five years into the SDGs. World Health Organization.
23. Wright, J., Gundry, S., & Conroy, R. (2004). Household drinking water in developing countries: a systematic review of microbiological contamination between source and point-of-use. Tropical Medicine & International Health, *9*(1), 106–117.
24. Zhang, Y., & Love, N. (2009). Activated carbon filtration in drinking water treatment: A review. Critical Reviews in Environmental Science and Technology, *39*(12), 1035–1073.
25. Zwane, A. P., & Kremer, M. (2007). What works in fighting diarrheal diseases in developing countries? A critical review. The World Bank Research Observer, *22*(1), 1–24.
26. Chowdhury, S., Champagne, P., & McLellan, P. J. (2009). Models for predicting disinfection byproduct (DBP) formation in drinking water: A comparative study. Science of the Total Environment, 407(13), 4189-4197.
27. Korshin, G. V., Li, C. W., & Benjamin, M. M. (1997). Monitoring the properties of natural organic matter through UV spectroscopy: A consistent theory. Water Research, 31(7), 1787-1795.
28. Matilainen, A., Vepsäläinen, M., & Sillanpää, M. (2010). Natural organic matter removal by coagulation during drinking water treatment: A review. Advances in Colloid and Interface Science, 159(2), 189-197.
29. Sharp, E. L., Parsons, S. A., & Jefferson, B. (2006). The impact of seasonal variations in DOC arising from a moorland peat catchment on coagulation with iron and aluminium salts. Environmental Pollution, 140(3), 436-443.
30. Weishaar, J. L., Aiken, G. R., Bergamaschi, B. A., Fram, M. S., Fujii, R., & Mopper, K. (2003). Evaluation of specific ultraviolet absorbance as an indicator of the chemical composition and reactivity of dissolved organic carbon. Environmental Science & Technology, 37(20), 4702-4708.