TY - JOUR
T1 - Household slow sand filters in continuous and intermittent flows and their efficiency in microorganism’s removal from river water
AU - Nasser Fava, Natália de Melo
AU - Terin, Ulisses Costa
AU - Freitas, Bárbara Luíza Souza
AU - Sabogal-Paz, Lyda Patricia
AU - Fernandez-Ibañez, Pilar
AU - Anthony Byrne, John
N1 - Publisher Copyright:
© 2020 Informa UK Limited, trading as Taylor & Francis Group.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/11/11
Y1 - 2020/11/11
N2 - This study aimed to evaluate the efficiency of four household slow sand filter (HSSF) models for the removal of microorganisms from river water throughout the development of their biological layers (schmutzdecke). Two models were designed to be operated continuously (HSSF-CC and HSSF-CT) and two intermittently (HSSF-ID and HSSF-IF). Filters were fed daily with 48 L pre-treated river water (24 h sedimentation followed by filtration through a non-woven synthetic blanket). Water samples were quantified by coliform group bacteria and analysed by bright field microscopy to visualize the microorganisms. Total coliform reduction was between 1.42 ± 0.59 log and 2.96 ± 0.58 log, with continuous models showing a better performance (p-values < 0.004). Escherichia coli reduction varied from 1.49 ± 0.58 log to 2.09 ± 0.66 log and HSSF-IF, HSSF-CC and HSSF-CT presented a similar performance (p-values > 0.06), slightly better than the one presented by HSSF-ID (p-value=0.04). Microorganisms, such as algae, protozoa and helminths were detected by microscopy in raw water and pre-treated water. Algae were the most significant group in these samples, although they were not visualized by bright field microscopy in the filtered water. Results showed the potential of HSSF in microbiological risk reduction from river water, which increases the range of point-of-use water treatments in rural communities. However, additional studies of the HSSF biological layer must be performed.
AB - This study aimed to evaluate the efficiency of four household slow sand filter (HSSF) models for the removal of microorganisms from river water throughout the development of their biological layers (schmutzdecke). Two models were designed to be operated continuously (HSSF-CC and HSSF-CT) and two intermittently (HSSF-ID and HSSF-IF). Filters were fed daily with 48 L pre-treated river water (24 h sedimentation followed by filtration through a non-woven synthetic blanket). Water samples were quantified by coliform group bacteria and analysed by bright field microscopy to visualize the microorganisms. Total coliform reduction was between 1.42 ± 0.59 log and 2.96 ± 0.58 log, with continuous models showing a better performance (p-values < 0.004). Escherichia coli reduction varied from 1.49 ± 0.58 log to 2.09 ± 0.66 log and HSSF-IF, HSSF-CC and HSSF-CT presented a similar performance (p-values > 0.06), slightly better than the one presented by HSSF-ID (p-value=0.04). Microorganisms, such as algae, protozoa and helminths were detected by microscopy in raw water and pre-treated water. Algae were the most significant group in these samples, although they were not visualized by bright field microscopy in the filtered water. Results showed the potential of HSSF in microbiological risk reduction from river water, which increases the range of point-of-use water treatments in rural communities. However, additional studies of the HSSF biological layer must be performed.
KW - biosand filter
KW - decentralized treatment
KW - drinking water
KW - microscopy
KW - schmutzdecke
UR - http://www.scopus.com/inward/record.url?scp=85096136614&partnerID=8YFLogxK
U2 - 10.1080/09593330.2020.1841834
DO - 10.1080/09593330.2020.1841834
M3 - Article
C2 - 33092473
AN - SCOPUS:85096136614
JO - Environmental Technology
JF - Environmental Technology
SN - 0959-3330
ER -