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.

Jocelyne K Mwabi,Bhekie B Mamba,Maggy N B Momba

doi:10.3390/ijerph9010139

Abstract

There is significant evidence that household water treatment devices/systems (HWTS) are capable of dramatically improving microbially contaminated water quality. The purpose of this study was to examine five filters [(biosand filter-standard (BSF-S); biosand filter-zeolite (BSF-Z); bucket filter (BF); ceramic candle filter (CCF); and silver-impregnated porous pot (SIPP)] and evaluate their ability to improve the quality of drinking water at the household level. These HWTS were manufactured in the workshop of the Tshwane University of Technology and evaluated for efficiency to remove turbidity, faecal coliforms and Escherichia coli from multiple water source samples, using standard methods. The flow rates ranged from 0.05 L/h to 2.49 L/h for SIPP, 1 L/h to 4 L/h for CCF, 0.81 L/h to 6.84 L/h for BSF-S, 1.74 L/h to 19.2 L/h and 106.5 L/h to 160.5 L/h for BF The turbidity of the raw water samples ranged between 2.17 and 40.4 NTU. The average turbidity obtained after filtration ranged from 0.6 to 8 NTU (BSF-S), 1 to 4 NTU (BSF-Z), 2 to 11 NTU (BF), and from 0.6 to 7 NTU (CCF) and 0.7 to 1 NTU for SIPP. The BSF-S, BSF-Z and CCF removed 2 to 4 log10 (99% to 100%) of coliform bacteria, while the BF removed 1 to 3 log (90% to 99.9%) of these bacteria. The performance of the SIPP in removing turbidity and indicator bacteria (>5 log10, 100%) was significantly higher compared to that of the other HWTS (p < 0.05). The findings of this study indicate that the SIPP can be an effective and sustainable HWTS for the Southern African Development Community (SADC) rural communities, as it removed the total concentration of bacteria from test water, can be manufactured using locally available materials, and is easy to operate and to maintain.

Highlights

Waterborne diseases have a negative impact on public health in developing countries where the drinking water is of a poor quality [1]
A device that improves water quality and removes turbidity and bacteria under various water source conditions will provide the rural communities with high-quality water regardless of the quality of the source water, as reported by Sobsey and co-authors [13]
The results from our study show that there is a direct relationship between turbidity and bacterial removal as strong positive correlations were observed between the removal of E. coli and turbidity from groundwater of low turbidity by the biosand filter (BSF)-S (r = 0.761) and biosand filter with zeolite (BSF-Z) (r = 0.780)

Summary

Introduction

Waterborne diseases have a negative impact on public health in developing countries where the drinking water is of a poor quality [1]. Because of the impact of drinking water of poor microbiological quality on the health of rural communities, and especially on immunocompromised people, children and elderly people [8], there is a great need to develop or identify alternative systems by means of which people in rural communities can obtain access to safe drinking water. Household Water Treatment and Safe Storage Options in Developing Countries: A Review of Current Implementation Practices; Water Supply &

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Conclusion