Arsenic and fluoride are hard to spot. The water looks clear, smells normal and tastes fine. The harm shows up years later. Arsenic causes skin sores and cancer. Fluoride stains teeth and makes bones and joints stiff and weak.
India's drinking water standard (IS 10500) allows only 0.01 mg/L of arsenic, which is 10 micrograms per litre. For fluoride the limit is 1 mg/L, or 1.5 mg/L if there is no other water source. Government surveys have found arsenic above the limit in parts of about 230 districts, and fluoride above the limit in parts of about 469 districts.
First, test your water
The right fix depends on four things: how much arsenic or fluoride there is, whether there is iron too, how many people use the water, and whether there is power. A lab test tells you all of this. It costs far less than buying the wrong plant.
Filters for one home, with no power
For a single family, a home filter with a fine alumina powder removes both arsenic and fluoride. It gives 5 to 6 litres of safe water an hour. No water is wasted and good minerals stay in. If fluoride is the only problem, a bead filter for fluoride lasts about 2,000 hours before the beads need changing.
Plants that fit on the village hand pump
For a whole village, it is cheaper to clean the water at the hand pump. A village arsenic plant fits on the pump. Water flows through tanks of natural minerals that hold on to the arsenic. It gives 350 to 5,000 litres an hour, at 3.5 to 8 paise a litre. Once a week, someone runs water backwards through the tanks to clean them. This is called a backwash and needs no technician.
If the water has arsenic, fluoride and iron together, use one plant for all three. It removes iron first, then fluoride and arsenic. It has no RO membrane, so almost no water goes to waste.
When a simple filter is not enough
- Very high fluoride (5 to 10 mg/L). Electric treatment uses a small current to form tiny flakes that catch fluoride. One model runs on solar panels.
- No power at all. An arsenic resin plant catches both kinds of arsenic and gives 1,000 litres an hour without electricity.
- Very high arsenic with a lot of iron. A ceramic filter plant handles water that clogs sand filters in days. It gives up to 10,000 litres an hour and locks the arsenic waste in a solid block.
Ask what happens to the waste
Used filter material and sludge from these plants contain arsenic. Before you buy, ask who will collect it, how it will be made safe, and who pays. A plant that cleans the water but dumps arsenic in the village only moves the danger somewhere else.
Not sure which one suits your water?
Our NABL-accredited lab tests your water. Our engineers then match it to a proven method from our technology showcase.
Request a consultationFrequently asked questions
Does a home RO purifier remove arsenic and fluoride?
A well-kept RO removes most of both. But it throws away more than half the water and removes good minerals too. The filters above keep the minerals and waste almost no water.
How often does the filter material need changing?
It depends on how much arsenic is in the water and how much water you use. Village plants with a weekly backwash usually run for months. Testing the clean water regularly is the only sure way to know.
Can boiling remove arsenic or fluoride?
No. Boiling makes it worse, because water evaporates and the arsenic or fluoride stays behind.
Sources: Water Channel: arsenic and fluoride in India's groundwater, Bureau of Indian Standards, IS 10500. The results above come from real use of each method. Your results depend on your water, so test it first.
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