What methods can be used at the village or household level?
It is more expensive for small systems to remove arsenic from drinking water than for larger system because the cost is spread over a smaller pool of customers. Also - dosing chemicals to water and removing residue is not easily done in small systems.
Chemical methods
- coagulation-assisted microfiltration may be the most overall cost-effective method for treatment and residual costs
- ion exchange processes, while the most expensive overall,
have the lowest
treatment costs and the highest residual costs of all the methods sampled - iron-based adsorption systems have the largest
capacities and have a disposal
type most widely used in small systems because it takes the least amount of attention - activated alumina to zeolites are other chemicals that can possibly absorb Arsenic
- uv-irradiation or
ozone treatment to oxidize Arsenic +3 to Arsenic +5 and
then filtration is another option
Filter methods
- the only filter method known to remove Arsenic +3 without previous oxidation is membrane distillation.