Rispri LabsENGINEERING A CIRCULAR FUTURE

TECHNOLOGY SEGMENT / 01

18 technologiesReady level 6 to 9

Safe drinking water.
Arsenic, fluoride, iron and germs.

Ways to make borewell, hand pump and surface water safe to drink, from a filter for one home to a plant for a whole village. Most need no electricity.

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Safe drinking water
Safe drinking water

Problem 01

Arsenic and fluoride in borewell water.

Arsenic and fluoride have no colour, smell or taste, so the water looks safe. Over years, arsenic causes skin sores and cancer, and fluoride damages teeth and bones. These methods make the water safe to drink, and most of them need no electricity. Read the guide →

Ready: level 6 to 9 of 9One home

Home filter for arsenic and fluoride

The problem
A family drinks borewell water with arsenic or fluoride, and power cuts are common.
How it works
Water drips through a cartridge filled with a fine alumina powder.
What it has achieved
Gives 5 to 6 litres of safe water an hour. You only replace the cartridge.
See full details
Ready: level 9 of 9One home

Bead filter for fluoride

The problem
Children in the family have yellow or brown stains on their teeth, a common sign of too much fluoride.
How it works
Water passes through small round beads that hold on to fluoride.
What it has achieved
Works for about 2,000 hours at 3 litres an hour on water with 2.5 to 3 mg/L fluoride.
See full details
Ready: level 6 to 7 of 9Village

Village arsenic plant on the hand pump

The problem
The village hand pump gives clear water that tests high for arsenic.
How it works
The plant fits on the hand pump.
What it has achieved
Brings arsenic below the safe limit of 10 µg/L. Treated water costs 3.5 to 8 paise a litre. Sizes from 350 to 5,000 litres an hour.
See full details
Ready: level 9 of 9Village

Arsenic resin plant for villages

The problem
The village has arsenic in its water and no steady power supply.
How it works
Water passes through a resin (small plastic beads) made to catch arsenic only.
What it has achieved
1,000 litres an hour without electricity.
See full details
Ready: level 9 of 9Home or village

Natural mineral filter for arsenic and iron

The problem
The water has both arsenic and iron, which often come together in shallow borewells.
How it works
A natural iron and manganese mineral is used as the filter material.
What it has achieved
Works for a single home or a whole village.
See full details
Ready: level 6 of 9Village

One plant for fluoride, arsenic and iron

The problem
The water has two or three problems at once, for example fluoride and iron.
How it works
The water is cleaned in stages.
What it has achieved
Arsenic below 10 µg/L, iron below 0.3 mg/L and fluoride below 1.5 mg/L. Sizes from 450 to 10,000 litres an hour.
See full details
Ready: level 6 to 9 of 9Home to town

Electric treatment for very high fluoride

The problem
Fluoride is so high (5 to 10 mg/L) that ordinary filters run out within weeks.
How it works
A small electric current passes through metal plates in the water.
What it has achieved
Brings fluoride from 5 mg/L to below 1 mg/L. Makes much less sludge than adding chemicals.
See full details
Ready: level 9 of 9Town or factory

Ceramic filter plant for heavy arsenic and iron

The problem
The water has very high arsenic and so much iron that sand filters clog within days.
How it works
Iron and arsenic are first turned into tiny solid particles.
What it has achieved
Arsenic below 10 µg/L and iron below 0.3 mg/L. Up to 10,000 litres an hour, at about 10 paise a litre.
See full details

Problem 02

Yellow water, iron and muddy water.

If water turns yellow or brown after standing, stains buckets and clothes, or tastes of metal, it has iron in it. If it looks muddy, it has fine soil in it. Both are easy and cheap to fix. Read the guide →

Ready: level 7 to 9 of 9Village

Iron removal plant on the hand pump

The problem
People have stopped using the village hand pump because the water turns yellow and stains everything.
How it works
Water is sprayed into the air so the iron turns into rust.
What it has achieved
800 litres an hour. One plant gives 40 litres a day each to about 250 people, at about 2.5 paise a litre.
See full details
Ready: level 7 of 9School or small town

Large iron filter for schools and small towns

The problem
A school, hostel or small town needs a lot of iron-free water every day.
How it works
Water is cleaned in three stages that turn iron into rust and filter it out.
What it has achieved
3,000 to 3,500 litres an hour. Handles iron up to about 12 mg/L at under 2 paise a litre.
See full details
Ready: level 6 to 8 of 9One home

Home iron filter, 15 litres

The problem
A home or anganwadi gets yellow water from its tube well.
How it works
A steel filter with a special filter bed.
What it has achieved
Brings iron from 15 mg/L down to the safe limit, at 4 to 5 paise a litre.
See full details
Ready: level 9 of 9Home or village

Baked clay filter for iron and muddy water

The problem
Village water is both muddy and full of iron, and families cannot keep buying new cartridges.
How it works
A filter made from baked local clay has tiny holes that trap rust and mud.
What it has achieved
Removes 90 to 95% of iron and almost all the mud. One filter lasts about 3 years or 20,000 litres, at about 3 paise a litre.
See full details
Ready: level 9 of 9Home or village

Cheap filter for muddy water

The problem
In the monsoon, pond or river water turns brown with mud and families have no way to clean it.
How it works
A simple filter made from materials found locally.
What it has achieved
Very muddy water (100 to 300 NTU, a measure of muddiness) comes out clear, below 3 NTU.
See full details
Ready: level 9 of 9Town

Ceramic filters for muddy river water

The problem
A water plant on a muddy river has sand filters that clog all the time.
How it works
Banks of ceramic filter tubes hold back mud and fine particles.
What it has achieved
Up to 1 lakh litres a day in 12 hours of running.
See full details

Problem 03

Killing germs without chlorine cylinders.

Chlorine gas cylinders are dangerous to store and carry. These methods make the disinfectant on site, or do the job without chlorine. Read the guide →

Ready: level 6 to 7 of 9Home to town

Make your own disinfectant from salt

The problem
A small water supply or hospital needs disinfectant but cannot store chlorine safely.
How it works
Salt water and a small electric current make liquid bleach (sodium hypochlorite) on site.
What it has achieved
No chlorine to store or transport. No leftover chemicals to throw away.
See full details
Ready: level 6 of 9Home to factory

Germ killing with bubbles and plant oils

The problem
You want to kill germs without adding chlorine.
How it works
Water is forced through a narrow gap so tiny bubbles form and burst, which damages germs.
What it has achieved
Killed all E. coli and other common bacteria in tests.
See full details

Questions

Frequently asked questions.

How do I pick the right technology?

Start with a test of your water. Our NABL-accredited lab checks the sample, then our engineers shortlist the methods on this page that suit your problem, the amount of water, your budget and your site.

What does the ready level mean?

It shows how far a technology has come, on a scale of 1 to 9. Level 6 means a working model has been tested in real conditions, and level 9 means it is already in use. Every technology here is level 6 or higher.

Can we try it before building a full plant?

Yes. Most of these can be tried on a small scale with your own water first, so you see results before you invest.

THE NEXT STEP

Not sure which
one you need?

Send us a water sample or a test report. We will tell you which proven method fits and what it costs to run.

Discuss your problem
OTHER SEGMENTSalty water, RO and membranesOTHER SEGMENTIndustrial wastewater and ZLD