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

Household Water Treatment and Safe Storage
Fact Sheet: Nalgonda Technique Key Data
Inlet Water Criteria
Total dissolved solids (TDS) must be less than 1500 mg/L
The process cannot be used in cases of fluoride concentration above 20 mg/L
Treatment Efficiency
Bacteria Viruses Protozoa Helminths Turbidity Fluoride
>90 to >90 to >90 to >90 to
Laboratory
>99% 1 >99% 1 >99% 1 >99% 1 Not available Up to 70% 4
< 90% 2
Field
95% 3 Not available Not available Not available Not available Not available
1
Sproul (1974), Leong (1982), Payment and Armon (1989) as cited in Sobsey, 2002
2
Ongerth (1990) as cited in Sobsey, 2002
3
Wrigley, 2007
4
Fawell et al., 2006
Maximum effectiveness requires careful control of coagulant dose, pH and consideration of
the quality of the water being treated, as well as mixing
Operating Criteria
Flow Rate Batch Volume Daily Water Supply
Not applicable 40 litres Unlimited
Need to follow instructions
Discarding the sludge from the Nalgonda process is considered to be an environmental
health issue. The sludge is quite toxic because it contains the removed fluoride in a
concentrated form. The sludge should be properly disposed (e.g. buried and covered in a pit).
Robustness
Difficult to optimize without training and equipment
Requires supply chain, market availability 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:
The chemical products involved are difficult and complex to manufacture and local production
is not always feasible
Maintenance
Chemicals should be stored in a dry location and away from children