Faecal contamination of drinking water sources of Dhaka city during the 2004 flood in Bangladesh and use of disinfectants for water treatment

Abstract

Aims: To describe the extent of faecal pollution and point of use water treatment strategy during and after the 2004 flood in Dhaka. Methods: A total of 300 water samples were collected from 20 different drinking water sources in Kamalapur, Dhaka city from August 2004 to January 2005. The level of faecal contamination was estimated using measurements of faecal indicator bacteria (total coliforms, faecal coliforms and faecal streptococci) and isolation of Vibrio cholerae was carried out following standard procedures. Total dissolved solids, dissolved oxygen, hardness, chloride and pH were also monitored. The efficacy of four disinfectants including Halotab, Zeoline®‐200, alum potash and bleaching powder were tested as point of use water treatment agents. The unacceptable level of contamination of total coliforms (TC), faecal coliforms (FC) and faecal streptococci (FS) ranged from 23·8% to 95·2%, 28·6% to 95·2% and 33·3% to 90·0%, respectively. The isolation rates of V. cholerae O1 and O139 were both 0·33%, and non‐O1/non‐O139 was 7·0%. Conclusion: Water collected during and after floods was contaminated with TC, FC, FS and V. cholerae. Although alum potash, bleaching powder, Halotab and Zeoline®‐200 were all effective general disinfectants, Halotab and Zeoline®‐200 were superior to bleaching powder and alum potash against FC. Significance and Impact of the Study: During and after floods, point of use water treatment could reduce waterborne diseases among flood‐affected people.

Dual peak cholera transmission in Bengal Delta: A hydroclimatological explanation

“…[4] Cholera epidemics in Bangladesh have been historically linked to a range of environmental and climate variables including precipitation [Pascual et al, 2002;Hashizume et al, 2008], floods [Koelle et al, 2005], peak river level [Schwartz et al, 2006], sea surface temperature (SST) [Lobitz et al, 2000;de Magny et al, 2008], sea surface height [Lobitz et al, 2000], coastal salinity [Miller et al, 1982], and fecal contamination [Islam et al, 2006]. None of these studies, however, successfully quantified the role of the seasonal hydroclimatological processes with biannual cholera incidences in Bangladesh.…”

Short-term WASH interventions in emergency response: a systematic review

“…Cost may explain the low use in Madagascar (Dunston et al 2001) as the free distribution of the same product had much higher rates in the same area (Mong et al 2001). Excessive dosing was observed in Madagascar (FCR >3.5 mg/L) (Mong et al 2001) and taste was noted as a hindrance to use in Nepal and Philippines (Lantagne andClasen 2012, Plan 2013 Figure 18 ** 'Peak rates' mentioned but suitable for comparison in Figure 18 As noted in the chlorine tablet section above, the effectiveness of liquid chlorine on total and faecal coliforms was measured during a flood in Bangladesh in one document (Sirajul Islam et al 2007). Liquid chlorine was effective eliminating 82% of total coliforms and 77% of faecal coliforms.…”

“…One evaluation measured the effectiveness of alum in a field trial of water sources during a flood in Bangladesh (Sirajul Islam et al 2007). Alum was effective at treating total coliforms in 73% of samples, but was less effective with fecal coliforms (30%).…”

“…One evaluation measured the effectiveness of several HWT products in a field trial of water sources during a flood in Bangladesh (Sirajul Islam et al 2007). Chlorine tablets and bleaching powder eliminated total coliforms in 84% and 65% and samples, respectively.…”

Membrane-Based Point-Of-Use Water Treatment (PoUWT) System in Emergency Situations

“…Decentralized water treatment systems are recognized as one the 38 solutions used for emergency response [5][6][7]. Peter-Varbanets et al [6] came up with 39 an emergency response method involving ultra-low pressure with dead-end 40 ultrafiltration (UF) without backflushing and cleaning. Another example is a portable 41 mouth-suction device developed by LifeStraw (Clasen et al [8] and Frandsen [9]), 42 which is an ultrafiltration (UF) membrane-based purification water technology.…”