I took this picture at one of our test facility in Khipro city provided by Pak Mission Society.
Source: Field Office Pak Mission Society, Khipro City
My Company has been providing consultancy on water purification to a National NGO in Pakistan. The project is located in Nara Desert where people have no access to clean drinking water. Majority of people use NADI filter to purify lake water. NADI filter in English terms known as Bio-Sand filter. The filter is used to purify biologically contaminated water only and it cannot chemically contaminated water. The bio-sand filter is known as the most affordable technology for low-income households to purify biological contaminated water in the region. The idea is suitable to purify water for coastal communities with an excess of lake water or rain water. It is not suitable for saline water or chemically contaminated water. One of the prime functions of NADI filter is to kill E.Coli and Total Coli bacteria in the water. It also removes significant amount of turbidity from the water.
The bio-sand filter shown in the diagram 2 is known as NADI filter in desert areas of Pakistan. It depicts the major parts in the NADI filter. The bottom vessel is known as NADI and the upper part which serves as a small storage is known as Mutca. NADI filter is widely used in Nara Desert and Cholistan Desert. The figure also adumbrates the arrangements of sand bed inside the NADI vessel and how outlet pipe is being installed to get the fresh and clean drinking water.
Since NADI vessel is made up of clay and it has the ability to produce fresh and cold water. There is a layer of sand bed and gravel and stones inside NADI filter. The arrangement of bio-sand in the filter is very simple at the very bottom drainage gravel of more than 2 inches in size placed at the very bottom of the filter and as moving up from the bottom the size of gravel and sand particles decreases.
The sand is very fine in size and does not allow the pathogens and viruses to pass through bed. The outlet of pipe is installed around 20-25 inches from the bottom. The most upper part of sand layer is around 3 inches from the outlet pipe to build bio-layer. The function of bio-layer is to provide room for good bacteria to eat pathogens and bad bacteria. The most upper layer in NADI filter is very fine in nature and it function is to trap pathogens and viruses.
My company is helping the national NGO to develop the construction manual and user manual of NADI filter. The user manual is going to translate in the local language for people living in Nara Desert. Moreover, we are also working to conduct water testing and proved it form the lab. The results obtained from the water testing will be going to publish in a reputable journal.
We have successfully laid down the foundation for NADI filter in the region. My company has upgraded the system by introducing new modification in the system.
I request all stakeholders at national and international level to support us on WASH project in water scarce region to help ameliorate the living standard of people in Pakistan.
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