title: Point-of-use chlorination of turbid water: results from a field study in Tanzania.
abstract: Household-based chlorine disinfection is widely effective against waterborne bacteria and viruses, and may be among the most inexpensive and accessible options for household water treatment. The microbiological effectiveness of chlorine is limited, however, by turbidity. In Tanzania, there are no guidelines on water chlorination at household level, and limited data on whether dosing guidelines for higher turbidity waters are sufficient to produce potable water. This study was designed to assess the effectiveness of chlorination across a range of turbidities found in rural water sources, following local dosing guidelines that recommend a 'double dose' for water that is visibly turbid. We chlorinated water from 43 sources representing a range of turbidities using two locally available chlorine-based disinfectants: WaterGuard and Aquatabs. We determined free available chlorine at 30 min and 24 h contact time. Our data suggest that water chlorination with WaterGuard or Aquatabs can be effective using both single and double doses up to 20 nephelometric turbidity units (NTU), or using a double dose of Aquatabs up to 100 NTU, but neither was effective at turbidities greater than 100 NTU.
authors.affiliation: School of Environmental Science and Technology, Ardhi University, P.O. Box 35176, Dar es Salaam, Tanzania E-mail: hmohameds1@gmail.com; School of Public Health, Muhimbili University of Health and Allied Sciences, P.O. Box 65015, Dar es Salaam, Tanzania.
authors.forename: Hussein
authors.initials: H
authors.lastname: Mohamed
authors.affiliation: Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: Joe
authors.initials: J
authors.lastname: Brown
authors.affiliation: Ministry of Health and Social Welfare, P.O. Box 9083, Dar es Salaam, Tanzania.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Njee
authors.affiliation: Rollins School of Public Health, Atlanta, GA 30322, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Clasen
authors.affiliation: National Institute for Medical Research, P.O. Box 9653, Dar es Salaam, Tanzania.
authors.forename: Hamisi M
authors.initials: HM
authors.lastname: Malebo
authors.affiliation: School of Environmental Science and Technology, Ardhi University, P.O. Box 35176, Dar es Salaam, Tanzania E-mail: hmohameds1@gmail.com.
authors.forename: Steven
authors.initials: S
authors.lastname: Mbuligwe
mesh_terms: D060766:Drinking Water / Q000737:chemistry / Q000382:microbiology / Q000592:standards*; D005191:Family Characteristics; D054879:Halogenation; D006801:Humans; D009391:Nephelometry and Turbidimetry; D012424:Rural Population; D013636:Tanzania; D014867:Water / Q000737:chemistry; D018508:Water Purification / Q000379:methods*; D014881:Water Supply / Q000592:standards*
chemical_list: D060766:Drinking Water; D014867:Water