Rainwater harvesting can provide an alternative water source, which may demand little treatment, depending on the end use. Some starches have been used in water treatment as coagulant/flocculant/filtration aid, and might be applied as primary coagulant. Here, we show direct filtration with hydraulic rapid mixing, using 2–6 mg L−1 cationic corn starch as primary coagulant, considerably improves roof-harvested rainwater quality, achieving removal efficiencies of up to 71.7% of apparent colour, 78% of turbidity, 1.1 log-unit of total coliform, and 1.6 log-unit of Escherichia coli, meeting guidelines for turbidity, even for potable purposes. Cationic corn starch has proved to be a suitable primary coagulant when filtration is performed in a single-layer sand filter (coefficient of uniformity: 1.8, effective particle size: 0.52 mm), at hydraulic loading rate of 450 m day−1. However, a disinfection unit is required to meet an absence of faecal coliform.
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Research Article|
July 06 2015
Corn starch-based treatment improves rainwater quality Available to Purchase
Liane Yuri Kondo Nakada;
1Departamento de Saneamento e Ambiente, Faculdade de Engenharia Civil, Arquitetura e Urbanismo, Universidade de Campinas (UNICAMP), Avenida Albert Einstein, 951, Cidade Universitária, Campinas, São Paulo 13083-852, Brazil
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Rodrigo Braga Moruzzi
Rodrigo Braga Moruzzi
2Instituto de Geociências e Ciências Exatas, UNESP – Universidade Estadual Paulista, Departamento de Planejamento Territorial e Geoprocessamento, Avenida 24 A, 1515, Bela Vista, Rio Claro, São Paulo 13506-900, Brazil
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Water Supply (2015) 15 (6): 1326–1333.
Article history
Received:
March 13 2015
Accepted:
June 19 2015
Citation
Liane Yuri Kondo Nakada, Rodrigo Braga Moruzzi; Corn starch-based treatment improves rainwater quality. Water Supply 1 December 2015; 15 (6): 1326–1333. doi: https://doi.org/10.2166/ws.2015.097
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