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< prev - next > Water and sanitation Water quality and treatment Household water treatment systems (Printable PDF)
Household water treatment systems
Practical Action
Limited transportation due to weight.
Turbidity should not exceed 100 NTU.
Capital Costs: Tk. 1450.00 Tk. 1900.00
Operation and Maintenance: Minimal.
There may be educational and training costs associated with teaching users how to properly
maintain their filters. Costs will vary across regions depending on the availability of materials
and labour.
Arsenic Removal by Bio-sand Filter
Bio-sand filters may be used to remove arsenic from well water based on the principles of the
co-precipitation and filtration method.
A variety of technologies have been used for the treatment of arsenic in water, including
conventional co-precipitation with ferric chloride, lime softening, filtration using exchange
resins and adsorbents.
The divalent iron concentration is in the range of 0.2-12 mg/l and is positively correlated with
arsenic concentration in the groundwater. Fe/As ratios of greater than 40 (mg/mg) is required
to reduce arsenic to less than 50 mg/l in Bangladesh well water. Arsenic removal by the bio
sand filtration process included precipitation of arsenic by adding a packet of iron nails to the
top chamber.
After mixing the water with the iron for a few minutes, the iron will be oxidized to form ferric
hydroxide that passes through the sand bed by gravity removing the precipitates. Clean water
is collected from the outlet of the filter in the conventional way.
Also see A Small-scale Arsenic and Iron Removal Plant Practical Action Technical Brief
Small-scale water filter equipment
There are a number of options for household-scale water treatment which Practical Action has
not had any direct involvement with.
The Red Cross
The American Red Cross working with the Sri Lankan Red Cross, has developed a ceramic
filter within a plastic bucket which was originally made for the post tsunami situation and is
now being used in general rural situations, details of which are on the Practical Action
website. See The Clay Water Filter.
P.O. Box 5398
United Kingdom
Tel: & Fax: +44 (0)1629 825178
Emergency relief water tank and filtration kits - It is filled with a selection of warm clothing,
useful hardware and hygiene items. It also contains a filter cartridge and a matching supply
of water-treatment tablets. Once the welfare contents have been removed, each Aquabox can
be used to purify up to 1100 litres of water. The Aquabox Gold is a sponsored box that is
filled by Aquabox with welfare items and two filter kits extend its water purification life.
AQUA30 is for situations where the need is more prolonged or arises regularly, but permanent
solutions cannot yet be provided. AQUA30 is supplied filled with 30 filter cartridges and the
required water-treatment tablets.