Household Water Treatment and Safe Storage Factsheet: Source ...

Household Water Treatment and Safe Storage
Fact Sheet: Chemical Coagulants Key Data
Inlet Water Quality
No specific limits
Treatment Efficiency
Bacteria Viruses Protozoa Helminths Turbidity
Laboratory >90 to >99% 1 >90 to >99% 1 >90 to >99% 1 >90 to >99% 1 Not available
Field
< 90% 2
3
95%
Not available Not available Not available Not available
1
Sproul (1974), Leong (1982), Payment and Armon (1989) cited in Sobsey (2002)
2
Ongerth (1990) cited in Sobsey (2002)
3
Wrigley (2007)
Maximum effectiveness requires careful control of coagulant dose, pH and consideration of the
quality of the water being treated, as well as mixing
Effectiveness of chemical coagulants varies from one to another
Operating Criteria
Flow Rate Batch Volume Daily Water Supply
Not applicable Unlimited Unlimited
Need to follow manufacturer’s instructions
Robustness
Difficult to optimize without training and equipment
Requires coagulant supply chain and regular purchase
Estimated Lifespan
6 months in liquid form and 1 year in solid form
Manufacturing Requirements
Worldwide Producers:
Many producers around the world
Local Production:
Most chemical products are difficult and complex to manufacture and local production is not
feasible
Maintenance
Chemicals should be stored in a dry location and away from children
Direct Cost
Capital Cost Operating Cost Replacement Cost
US$0 US$9-91/year 1 US$0
Note: Program, transportation and education costs are not included. Costs will vary depending on location.
1
Sobsey (2002). Assumed 25 litres/household/day.