Biosand Filter as a Point-of-Use Water Treatment Technology: Influence of Turbidity on Microorganism Removal Efficiency

Daniela A Duran Romero,Maria Cristina De Almeida Silva,Antônio D Benetti,Beni J M Chaúque

doi:10.3390/w12082302

Daniela A Duran Romero, Maria Cristina De Almeida Silva + Show 2 more

Open Access

https://doi.org/10.3390/w12082302

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Journal: Water	Publication Date: Aug 17, 2020
Citations: 8	License type: CC BY 4.0

Affiliation: Universidade Federal do Rio Grande do Sul

Abstract

The number of people living without access to clean water can be reduced by the implementation of point-of-use (POU) water treatment. Among POU treatment systems, the domestic biosand filter (BSF) stands out as a viable technology. However, the performance of the BSF varies with the inflow water quality characteristics, especially turbidity. In some locations, people have no choice but to treat raw water that has turbidity above recommended levels for the technology. This study aimed to measure the efficiency with which the BSF removes microorganisms from well water and from fecal-contaminated water with turbidity levels of 3, 25, and 50 NTU. Turbidity was controlled by the addition of kaolin to water. Turbidity removal varied from 88% to 99%. Reductions in total coliform (TC) and Escherichia coli ranged from 0.54–2.01 and 1.2–2.2 log removal values (LRV), respectively. The BSF that received water with a higher level of turbidity showed the greatest reduction in the concentration of microorganisms. Additional testing with water contaminated with four bacterial pure cultures showed reductions between 2.7 and 3.6 LRV. A higher reduction in microorganisms was achieved after 30–35 days in operation. Despite the filter’s high efficiency, the filtrates still had some microorganisms, and a disinfection POU treatment could be added to increase water safety.

Highlights

IntroductionAbout 2.1 billion people in the world still consume drinking water from sources contaminated with feces [1], and about 2.3 billion people still lack basic health infrastructure
Despite numerous investments, about 2.1 billion people in the world still consume drinking water from sources contaminated with feces [1], and about 2.3 billion people still lack basic health infrastructure.some 159 million people, mainly from rural areas and principally in developing countries, still drink water collected directly from surface sources and shallow, unsafe wells [1,2]
These results showed that the biosand filter (BSF) worked better from day 35 onwards

Summary

Introduction

About 2.1 billion people in the world still consume drinking water from sources contaminated with feces [1], and about 2.3 billion people still lack basic health infrastructure. Some 159 million people, mainly from rural areas and principally in developing countries, still drink water collected directly from surface sources and shallow, unsafe wells [1,2]. There are high rates of gastrointestinal and parasitic diseases, as well as malnutrition associated with the consumption of water contaminated by microbial pathogens [3,4]. 2.2 million deaths per year [5], with diarrhea being responsible for 1.5 million deaths [6]. Most cases occur in developing countries and affect children under five years of age [3]. Point-of-use (POU) water treatment technologies have been recommended as an effective solution for the provision of safe water in places where families do not have access to conventional systems for the treatment and supply of drinking water [7]

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Conclusion