title: 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(-1) 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 efficacy of two locally available chemical water treatments-alum and Moringa oleifera flocculation-to reduce turbidity and chlorine demand at turbidities of 10, 30, 70, 100 and 300 NTU. Both treatments effectively reduced turbidity (alum flocculation 23.0-91.4%; moringa flocculation 14.2-96.2%). Alum flocculation effectively reduced chlorine demand compared with controls at 30, 70, 100 and 300 NTU (p=0.01-0.06). Moringa flocculation increased chlorine demand to the point where adequate free chlorine residual was not maintained for 24 hours after treatment. Alum pretreatment is recommended in waters>or=30 NTU for optimum water disinfection. Moringa flocculation is not recommended before chlorination.
authors.affiliation: Department of Civil and Environmental Engineering, Lehigh University, 13 E. Packer Avenue, Bethlehem, PA 18015, USA.
authors.forename: Kelsey
authors.initials: K
authors.lastname: Preston
authors.forename: Daniele
authors.initials: D
authors.lastname: Lantagne
authors.forename: Nadine
authors.initials: N
authors.lastname: Kotlarz
authors.forename: Kristen
authors.initials: K
authors.lastname: Jellison
mesh_terms: D000534:Alum Compounds / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry; D003258:Consumer Behavior; D003906:Developing Countries; D005191:Family Characteristics; D054879:Halogenation; D006801:Humans; D029587:Moringa / Q000737:chemistry*; D012973:Sodium Hypochlorite; D014867:Water / Q000737:chemistry*; D018508:Water Purification / Q000592:standards*; D014881:Water Supply
chemical_list: D000534:Alum Compounds; D014867:Water; C041524:aluminum sulfate; D002713:Chlorine; D012973:Sodium Hypochlorite