Removal of waterborne bacteria from surface water and groundwater by cost-effective household water treatment systems (HWTS): A sustainable solution for improving water quality in rural communities of Africa

Mmb Momba,Bb Mamba,Jk Mwabi

doi:10.4314/wsa.v39i4.2

Abstract

In this study 5 household water-treatment devices/systems (HWTS) were constructed using inexpensive local materials (sand, gravel, zeolites and clays). They included the silver-impregnated porous pot filter (SIPP), the ceramic candle filter (CCF), the conventional biosand filter (BSF-S), a modified biosand filter with zeolites (BSF-Z), and a bucket filter (BF).Their ability to remove turbidity and pathogenic bacteria (Vibrio cholerae, Salmonella typhimurium and Shigella dysenteriae) from synthetic sterile water, groundwater and surface-water sources was evaluated. The flow rates ranged from 0.05 ℓ·h-1 to 2.49 ℓ·h-1 for SIPP; 1 ℓ·h-1 to 4 ℓ·h-1 for CCF; 0.81 ℓ·h-1 to 6.84 ℓ·h-1 for BSF-S; 1.74 ℓ·h-1 to 19.2 ℓ·h-1 for BSF-Z; and from 106.5 ℓ·h-1 to 160.5 ℓ·h-1 for BF. The highest (64% to 98% (0.74 to 1.08 NTU)) and lowest (14% to 76% (2.91 to 7.19 NTU)) average percentage turbidity removals were noted for SIPP and BF, respectively. The SIPP was the only device that consistently removed 100% of all target pathogens throughout the study. Its performance was found to be significantly superior (p<0.05) compared to that of the other four devices. Sixty (60%) to 100% bacterial removals were observed for BSF-S; 90% to 100% for BSF-Z; 90% to 100% for CCF; and 40% to 99.9% for BF. Based on the findings of this study the SIPP can be recommended for use by rural communities as it consistently produced high-quality water that complied with the SANS 241 turbidity and microbiological limits for drinking water.Keywords: safe drinking water, household water treatment, waterborne pathogens

Highlights

In 2008, the World Health Organisation reported the percentage of rural populations within some African countries still using unimproved water sources
The quantity of water produced by household water-treatment systems is important, as each of these systems must be able to produce the minimum quantity of potable water of 25 l·person-1·d-1 for basic human activities, as prescribed by the Regulations under Section 9 of the Water Services Act (No 108 of 1997) of South Africa; Norms and Standards for Quality Water Services (DWAF, 2002)
The average flow rates obtained ranged from 0.05 l·h-1 to 2.49 l·h-1 for silver-impregnated porous pot filter (SIPP); from 1 l·h-1 to 4 l·h-1 for ceramic candle filter (CCF); from 0.81 l·h-1 to 6.84 l·h-1 for Biosand filter-standard (BSF-S); from 1.74 l·h-1 to 19.2 l·h-1 for biosand filter with zeolites (BSF-Z); and from 106.5 l·h-1 to 160.5 l·h-1 for bucket filter (BF) (Fig. 5)

Summary

Introduction

In 2008, the World Health Organisation reported the percentage of rural populations within some African countries still using unimproved water sources. These were reported to be 72% for the Democratic Republic of Congo, 71% for Madagascar and Mozambique, 62% for Angola, 55% for Tanzania, 54% for Zambia, 28% for Zimbabwe, 23% for Malawi, 19% for Lesotho, 14% for Swaziland, 12% for Namibia and 10% for Botswana (WHO/UNICEF, 2010). A number of studies have suggested that the key to reducing or even eradicating the burden of waterborne disease is through appropriate sanitation facilities and piped water systems. These could take decades to be established, especially in impoverished rural communities of African countries. Due to the low cost of manufacturing the filters using locally available materials and the simplicity and ease of construction and maintenance, POU water-treatment systems enable users to have potable water available almost immediately after installation (Mol, 2001)

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Conclusion