Abstract
Turbidity is an important physical characteristic of water that is often due to high sediment flow, making it a critical factor in municipal water treatment. If not adequately reduced, turbidity causes treated water to have an unattractive cloudy appearance. The aim of the study was to assess the design and processes of Nzoia Water Services Company Limited (NZOWASCO) in Bungoma County, Kenya, to identify system weaknesses and recommend optimal methods for mitigating the adverse effects of high turbidity in the river. The study examined the flow characteristics of River Kuywa, the water source for Matisi Municipal Water Treatment Works, and the sediment load present during extreme conditions. It assessed water quality during these periods and evaluated the efficiency of the infrastructure of the Plant. Plant visits, data collection through sampling, laboratory testing, and a plant design assessment were conducted to identify significant weaknesses that need to be addressed to optimize turbidity removal processes. It was found that during extreme rainfall periods, the abstraction weir, which helps in sediment settling, is ineffective, as depicted by elevated raw water turbidity of 6961.67 NTU compared to 179 NTU measured during normal river flows. It was also deduced that flooding in River Kuywa causes increased turbulence, leading to a sediment-water mixture that flows into the sump where pumps are located. Finally, it was concluded that the absence of a pretreatment facility, essential for reducing sediment load in the water, is a significant issue.
References
Barbier, E. B. (2004). Water and economic growth. Economic Record, 80(248), 1–16. https://doi.org/10.1111/j.1475-4932.2004.00121.x
Bonton, A., Bouchard, C., Barbeau, B., & Jedrzejak, S. (2012). Comparative life cycle assessment of water treatment plants. Desalination, 284, 42–54. https://doi.org/10.1016/j.desal.2011.08.035
Chescattie, E. (n.d.). Filter plant performance evaluations (FPPEs)—What to expect and how to prepare.
Davies-Colley, R. J., & Smith, D. G. (2001). Turbidity, suspended sediment, and water clarity: A review. JAWRA Journal of the American Water Resources Association, 37(5), 1085–1101. https://doi.org/10.1111/j.1752-1688.2001.tb03624.x
Desye, B., Belete, B., Asfaw Gebrezgi, Z., & Terefe Reda, T. (2021). Efficiency of treatment plant and drinking water quality assessment from source to household, Gondar City, Northwest Ethiopia. Journal of Environmental and Public Health, 2021(1), 9974064. https://doi.org/10.1155/2021/9974064
Drinking-water quality guidelines. (n.d.). Retrieved June 22, 2024, from https://www.who.int/teams/environment-climate-change-and-health/water-sanitation-and-health/water-safety-and-quality/drinking-water-quality-guidelines
Fresenius, W., Quentin, K. E., & Schneider, W. (Eds.). (1988). Water analysis. Springer. https://doi.org/10.1007/978-3-642-72610-1
Government of Canada, Public Safety and Preparedness Canada. (2002, July 1). Guidance for safe drinking water in Canada: From intake to tap. https://publications.gc.ca/site/eng/9.817552/publication.html
Gregory, J. (1998). Turbidity and beyond. Filtration and Separation, 35(1), 63–67. https://doi.org/10.1016/S0015-1882(97)83117-5
Grigg, N. S. (1992). Urban water infrastructure: Planning, management, and operations. Krieger Publishing Company.
Hespanhol, I., & Prost, A. M. E. (1994). WHO guidelines and national standards for reuse and water quality. Water Research, 28(1), 119–124. https://doi.org/10.1016/0043-1354(94)90125-2
Hrdinka, T., Novický, O., Hanslík, E., & Rieder, M. (2012). Possible impacts of floods and droughts on water quality. Journal of Hydro-Environment Research, 6(2), 145–150. https://doi.org/10.1016/j.jher.2012.01.008
Kitchener, B. G., Wainwright, J., & Parsons, A. J. (2017). A review of the principles of turbidity measurement. Progress in Physical Geography: Earth and Environment, 41(5), 620–642. https://doi.org/10.1177/0309133317726540
Lambrou, T. P., Anastasiou, C. C., & Panayiotou, C. G. (2010). A nephelometric turbidity system for monitoring residential drinking water quality. In N. Komninos (Ed.), Sensor applications, experimentation, and logistics (pp. 43–55). Springer. https://doi.org/10.1007/978-3-642-11870-8_4
Lee, C.-S., Lee, Y.-C., & Chiang, H.-M. (2016). Abrupt state change of river water quality (turbidity): Effect of extreme rainfalls and typhoons. Science of the Total Environment, 557–558, 91–101. https://doi.org/10.1016/j.scitotenv.2016.02.213
Matos, T., Martins, M. S., Henriques, R., & Goncalves, L. M. (2024). A review of methods and instruments to monitor turbidity and suspended sediment concentration. Journal of Water Process Engineering, 64, 105624. https://doi.org/10.1016/j.jwpe.2024.105624
Mustapha, M., Sridhar, M., & Coker, A. O. (2021). Assessment of water supply system from catchment to consumers as framed in WHO water safety plans: A study from Maiduguri water treatment plant, North East Nigeria. Sustainable Environment, 7(1), 1901389. https://doi.org/10.1080/27658511.2021.1901389
Muthuraman, G., & Sasikala, S. (2014). Removal of turbidity from drinking water using natural coagulants. Journal of Industrial and Engineering Chemistry, 20(4), 1727–1731. https://doi.org/10.1016/j.jiec.2013.08.023
Mwabi, J. K., Mamba, B. B., & Momba, M. N. B. (2012). Removal of Escherichia coli and faecal coliforms from surface water and groundwater by household water treatment devices/systems: A sustainable solution for improving water quality in rural communities of the Southern African Development Community region. International Journal of Environmental Research and Public Health, 9(1). https://doi.org/10.3390/ijerph9010139
Services, B. C. M. of H. (2002). Action plan for safe drinking water in British Columbia. Office of the Premier.
Sigdel, B. (2017). Water quality measuring station: pH, turbidity and temperature measurement [Bachelor's thesis, Metropolia Ammattikorkeakoulu]. Theseus. http://www.theseus.fi/handle/10024/129380
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 and Technology, 42(12), 4261–4267. https://doi.org/10.1021/es702746n
Street, M. (n.d.). NSW Ministry of Health.
Summary of drinking water quality standards by KEBS and WHO. (n.d.). ResearchGate. Retrieved June 22, 2024, from https://www.researchgate.net/figure/Summary-of-drinking-water-quality-standards-by-KEBS-and-WHO_tbl2_373173857
Tassinari, B., Conaghan, S., Freeland, B., & Marison, I. W. (2015). Application of turbidity meters for the quantitative analysis of flocculation in a jar test apparatus. Journal of Environmental Engineering, 141(9), 04015015. https://doi.org/10.1061/(ASCE)EE.1943-7870.0000940
Zainal-Abideen, M., Aris, A., Yusof, F., Abdul-Majid, Z., Selamat, A., & Omar, S. I. (2012). Optimizing the coagulation process in a drinking water treatment plant – comparison between traditional and statistical experimental design jar tests. Water Science and Technology, 65(3), 496–503. https://doi.org/10.2166/wst.2012.561
Zezulka, Š., Maršálek, B., Maršálková, E., Odehnalová, K., Pavlíková, M., & Lamaczová, A. (2024). Suspended particles in water and energetically sustainable solutions of their removal—A review. Processes, 12(12), 2627. https://doi.org/10.3390/pr12122627
This work is licensed under a Creative Commons Attribution 4.0 International License.