A Bio-Sand Filter can solve the fresh water problem of developing countries

A Bio-Sand Filter can solve the fresh water problem of developing countries


Yet, in many third-world countries, expensive equipment is hard to come by, and farmers struggle just to feed their families. Worldwide, around 10,000 people die every day due to lack of clean drinking water. The situation is alarming, but bio-sand filters offer a simple and affordable solution. This low cost model purifies water, is locally manufactured and can also help the local community with various livelihood options.

Water borne diseases are the number one cause of deaths worldwide, with WHO and CDC estimates pinning 3.5 million deaths every year to contaminated drinking water. In India alone, around 2,000 people die every day due to lack of clean drinking water, and out of these, children under the age of five are most vulnerable. 

Most villagers consume unsafe drinking water on a daily basis. Some of these families opt for boiling the water prior to drinking which can be costly. Those who can afford it, buy bottled water to reduce the risks of such diseases, while economically and financially weaker people continue to consume impure water which eventually causes disease and death. 


A Canadian scientist, Dr. David Manz, invented and designed an amazing tool that could solve this problem. He developed a low cost Bio-sand Water Filter that effectively removes all the dissolved particles and pathogens from the water. This slow purifying process manages to remove up to 98% of bacteria, 100% of viruses, 99% of parasites, protozoa, amoebae, and worms, 95% of heavy metals, and with a slight modification, 93% of arsenic. It manages to eliminate illnesses such as Typhoid, Cholera, Hepatitus A, Rotavirus, E-coli bacteria, and other dysentery causing organisms. 


Tested and approved by various governments, healthcare institutions, and research departments, the bio-sand technology has effectively been introduced in over 66 countries. The low cost Bio-sand filter costs about Rs.3,000 and works for 30 years. It is easy to maintain and filters 84 litres of water daily, enough for 10-12 people, or 70 schoolchildren. There are no ongoing costs, no maintenance costs, and no electricity costs. 

What is Bio-Sand filter (BSF)? 

As per Wikipedia, a bio-sand filter (BSF) is a point-of-use water treatment system adapted from traditional slow sand filters. Bio-sand filters remove pathogens and suspended solids from water using biological and physical processes that take place in a sand column covered with a biofilm. BSFs have been shown to remove heavy metals, turbidity, bacteria, viruses and protozoa. BSFs also reduce discoloration, odor and unpleasant taste. Studies have shown a correlation between use of BSFs and a decrease in occurrence of diarrhea. Because of their effectiveness, ease of use, and lack of recurring costs, biosand filters are often considered appropriate technology in developing countries. It is estimated that over 200,000 BSFs are in use worldwide. 

How does it work? 

The Bio-sand filter is made of locally available cement, sand and pebbles. It consists of various layers of sand and pebbles, and a 2-inch standing water layer known as the “bio-layer”. The dirty water is poured on top, and meets with the bio-layer where bacterial predation occurs. Then the water moves through the filtration sand and, because of an electrostatic charge, viruses adhere to the fine sand and are trapped within. This is known as adsorption. Furthermore, because there’s no food, no light, and no oxygen, further pathogen die-off takes place. The water then flows down into the pebbles and comes back up in an outlet tube, and is stored in a clean water container with a lid to protect it from re-contamination. 

The challenge 

The biggest challenge has been to spread awareness among people about the importance of clean drinking water. They are accustomed to their lifestyle – even though they spend a lot of sick days, yet there’s a resistance to something new. But we should try to change that through more awareness campaigns and with the help of media. Another challenge of the Bio-sand filter is the heavy weight, especially in mountainous regions. However, mobile units can help address this issue. Plastic versions have their own limitations and don’t last as long, so concrete filters are still preferable. (Source: ThebetterIndia)

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