Water Sanitation Health

Managing water in the home: accelerated health gains from improved water supply

Summary tables

Table 20. Comparison of Recommended Technologies for Household Water Treatment


Criterion Boiling with Fuel Solar Disinfection with UV + Heat (SODIS or SOLAIR) Solar Disinfection with Heat Only (Opaque Vessels and Solar Panels) UV Disinfection with Lamps Free Chlorine and Storage in an Improved Vessel ("CDC Safewater") Chemical Coagulation-Filtration + Chlorine Disinfection
Microbial Reductions Yes, extensive Yes, extensive for most pathogens Yes, extensive for most pathogens Yes, extensive for most pathogens Yes, extensive* for most pathogens Yes, extensive
Diarrheal Disease Reductions Yes Yes, 9-26%; two studies None reported from epid. studies, but expected due to high temperature (55+oC) None reported from epid. Studies, but expected due to germicidal effects Yes, 15-48%; many studies None reported from epid. Studies yet, but expected due to multiple treatments
Disinfectant Residual No No No No Yes Yes
Quality Requirements of Water to be Treated No Low turbidity (<30 NTU) for effective use; pre-treat turbid water None Low turbidity (<30 NTU) and low in UV-absorbing solutes, such as NOM, iron and sulfites Low turbidity (<30 NTU) and low chlorine demand for effective use; pre-treat turbid water None; applicable to poor quality source water
Chemical changes in water No, usually except deoxygenating and chemical precipitation None or not significant None or not significant None or very little Yes; may cause taste and odor and disinfection by-products Yes, may cause taste and odor and disinfection by-products
Microbial regrowth potential in treated water Yes, with storage beyond 1-2 days Yes, with storage beyond 1-2 days Yes, with storage beyond 1-2 days Yes, with storage beyond 1-2 days None to low if chlorine residual maintained None to low if chlorine residual maintained
Skill level and ease of Use Low skill, easy use Low skill; very easy use Low skill; easy use with training Moderate skill, training needed for maintenance cleaning and lamp replacement Low skill; easy use with training Moderate, training needed in adding chemicals, mixing, decanting and filtering
Availability of Needed Materials Requires a source of fuel Requires plastic (PET) bottles and dark surface (on one side of vessel or on surface where vessel is placed Requires black bottles of cook vessels and a solar reflector or solar cooker Requires UV units and replacement lamps and a reliable source of electricity (power) Requires source of free chlorine or chlorine generator and source of safe storage vessels Requires a source of the chemical mixture (coagulants and chlorine disinfectant); may limit availability
Limits to Water Volume Treated Yes, difficult to scale up above usual cooking volumes Yes, treats 1-1.5 liters per bottle; can simultaneously treat multiple bottles Yes, treats 1-4 liters per container; can simultaneously treat multiple vessels with multiple solar panels or solar cookers No, units can treat several liters per minute and much, depending on lamp size and number and reactor volume No, easily scaled up Yes, chemical mixture treats fixed volumes of 10-20 liters; repeated treatment of additional volumes
Performance verification requirements Observe water for a rolling boil Measure that target temperature is reached (thermometer or wax indicator Measure that target temperature is reached (thermometer or wax indicator) Must verify lamp output; may be a limitation if unit lacks a UV sensor Measure chlorine residual or microbial quality (indicators) or both Observe (measure) turbidity reduction and measure chlorine residual
Accept-ability* High High to Moderate High to Moderate High High to Moderate High to moderate
Sustain-ability High, unless fuel is scarce High, probably High, probably High, probably High High, probably; limited data
Length of Treatment Time Minutes to tens of minutes Hours (full sun), days (clouds), not effective if no sun Hours (full sun), days (part sun), not effective if no sun Seconds to minutes, depending on water volume treated and reactor design Tens of minutes Tens of minutes

*High is >75%; moderate is 50-75%

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