Abstract

Waterborne diseases are a significant health concern in Kenya, particularly for children under the age of five. This is primarily due to inadequate and affordable infrastructure for water treatment. A large portion of the water in Kenya does not meet the drinking water standards set by Kenya Bureau of Standards and World Health Organization, which poses a considerable risk for waterborne diseases. In light of this, the study aimed to develop a low-cost, activated-sand-based water treatment system for households in rural and informal settlements in Kenya, where access to clean water is limited. The research was motivated by the pressing need for an affordable and efficient water treatment solution in these areas with a focus on removal of physicochemical contaminants from water. The hypothesis proposed was that an activated-sand filter system, enhanced with silver for additional purification, could serve as an effective point-of-use water treatment option that is both cost-efficient and sustainable. To test this hypothesis, the study utilized a range of methods. The physical and chemical properties of the filter materials were characterized using X-ray fluorescence (XRF), Particle size analysis, and Fourier transform infrared spectroscopy (FTIR). The researchers also designed and fabricated a prototype activated-sand filter and conducted performance tests on river water. A 2^k factorial design was employed to optimize the filter's effectiveness, focusing on factors such as sand grain size, flow rate, residence time, sand concentration, and loading rate. The results of the study showed that the multi-layered filter design effectively removed a variety of contaminants. Removal efficiencies for various pollutants included 35.1% and 28.1% for nitrate, 66.7% and 39.9% for lead, 55.6% and 73.3% for copper, 77% and 70.5% for total iron, and 85.3% and 86.4% for turbidity in two different filter cartridges. While there were slight increases in certain water parameters like sulfate, alkalinity, and calcium, these changes remained within acceptable limits according to Kenya Bureau of Standards [1] and World Health Organization [2] standards. In conclusion, the silver-activated sand filter system proved to be a viable and cost-effective solution for improving water quality in rural and informal settlements in Kenya. It demonstrated significant pollutant removal and complied with health standards, making it a sustainable option for enhancing water safety and public health in areas where clean water access is a major challenge.