Turbidity and chlorine demand reduction using alum and moringa flocculation before household chlorination in developing countries

Abstract

Over 1.1 billion people in the world lack access to improved drinking water. Diarrhoeal and other waterborne diseases cause an estimated 1.87 million deaths per year. The Safe Water System (SWS) is a household water treatment intervention that reduces diarrhoeal disease incidence among users in developing countries. Turbid waters pose a particular challenge to implementation of SWS programmes; although research shows that a 3.75 mg l 21 sodium hypochlorite dose effectively treats turbid waters, users sometimes object to the strong chlorine taste and prefer to drink water that is more aesthetically pleasing. This study investigated the

Evaluating coagulant activity of locally available <i>Syzygium cumini</i>, <i>Artocarpus heterophyllus</i> and <i>Moringa oleifera</i> for treatment of community drinking water, Uganda

“…Results for protein, ash, dry matter and fibre revealed characteristics similar to those reported by other authors (Akinmutimi, 2006;Kalibbala 2007;Ndyomugyenyi, 2008;Pritchard et al, 2009;Rahman et al, 2009;Sodamade et al, 2013;Olagbemide and Alikwe, 2014). The study of coagulant activity on Moringa (Moringa oleifera), Java plum (Syzygium cumini) and Jackfruit (Artocarpus heterophyllus) revealed promising level of turbidity removal from dirty water that is comparable to previous studies on Moringa and other plant seeds (Kalibbala 2007;Amagloh and Benang, 2009;Preston et al, 2010;Ali et al, 2010;Wilson and Andrews, 2011;Nand et al, 2012;Sanchez-Martin et al, 2012;Kabore et al, 2015). This can be attributed to probable similarity in the turbidity removal agents in the seeds, known to be cationic proteins with pI >9.6 (Ghebremichael et al, 2005).Java plum and Jackfruit seeds demonstrated good protein contents (Table 1) and therefore would be expected to exhibit evident coagulant activity as in Moringa oleifera that was confirmed by this study.…”

“…Microbial removal potential of all the plant seeds extracts was very promising similar to study by Doughari et al (2007) and can deliver water of acceptable quality (WHO, 2011a) for immediate use. It is however known that such treated water contains high organic content that encourages microbial regrowth (Preston et al, 2010;SanchezMartin et al, 2012;Kabore, 2015). Water from such treatment therefore must be consumed immediately if possible and in any case, it should not be drunk after 24 hours.…”

“…Water from such treatment therefore must be consumed immediately if possible and in any case, it should not be drunk after 24 hours. This shortcoming could be addressed by simple household chlorination using chlorine tablets commonly used by communities in developing countries and in emergency situations (WHO, 2011b).However, Preston et al (2010) found that chlorine use for disinfection of water is not successful after treatment with Moringa since the high residual organic content increases chlorine demand. Therefore, even though the use of chlorine tablets is common among communities in Uganda, it will not be effective on water treated with natural coagulants.…”

“…Although the use of the natural coagulant treated water may be unsafe from 18 hours after treatment because of possible bacterial regrowth (Preston et al, 2010;Sanchez-Martin et al, 2012;Kabore et al, 2015), pre-treatment such as solar water disinfection (SODIS) is known to make such water safer (Wilson and Andrews, 2011). In Africa where there is plenty solar radiation the poor communities could put their water in the sun for some hours as a pre-treatment method before the application of coagulants.…”

Disinfection By-Product Formation and Mitigation Strategies in Point-of-Use Chlorination with Sodium Dichloroisocyanurate in Tanzania

“…Further research on locally available mechanisms to reduce chlorine demand and turbidity is not indicated in the laboratory setting because this research has already been well established in the literature. 32,33 Targeted research in specific locations where household chlorination is promoted with known high concentrations of THM precursors, such as bromine, is indicated. Bromine presence increases the health risks associated with THMs, as brominated THMs, with higher risk and therefore lower guideline values than chloroform, are formed.…”