According to the WHO, 2.1 billion people (about 1 in 3 people) in the world do not have access to clean, safe drinking water at home. Billions of people have gained access to basic drinking water services since 2000, but these services do not necessarily provide safe water. “Safe water, effective sanitation and hygiene are critical to the health of every child and every community – and thus are essential to building stronger, healthier, and more equitable societies. As we improve these services in the most disadvantaged communities and for the most disadvantaged children today, we give them a fairer chance at a better tomorrow,” said UNICEF Executive Director Anthony Lake.

Lots of water purifiers are available in the market. However, due to high cost and requirement of frequent maintenance, they are not used much in the rural parts of poorly developed countries. An alternative option is the use of Biosand filters.

Dr. David Manz developed the household Biosand filter in the 1990s at the University of Calgary, Canada. A field study to evaluate the use and performance of Biosand filters was undertaken at the Artibonite Valley of Haiti. They found it as an attractive option for supplying safe water in rural areas of poorly developed countries with it producing water in safe range in 97% of the test cases. The Biosand filter is a robust water treatment technology for use in households, capable of effective removal of bacteria, viruses and other contaminants. Tested and approved by various health care institutions and research departments, Biosand filters have become an attractive option due to its low cost, ease of maintenance and reliability for use in any rural or urban household.

A Biosand filter is filled with layers of specially selected and prepared sand and gravel. The sand removes pathogens and suspended solids from contaminated drinking water. A biological community of bacteria and other microorganisms grow in the top layer of sand. This is called the bio-layer. The microorganisms in the bio-layer eat many of the pathogens in the water, improving the water treatment. Pathogens and suspended solids are removed through biological and physical processes that take place in the filter layers. These processes include: mechanical trapping, predation, adsorption, and natural death.

However, in conventional Biosand filters, with increased usage of the filter, the bio-layer thickness also increases resulting in a gradual decrease in flow rate. To maintain the flow rate, the biological layer needs to be stirred periodically which may cause skin allergies and other skin diseases. Also, there is no mechanism currently available to check if the water obtained after filtration is fit for consumption or not inbuilt within the filter itself. Additionally, the filter also requires water refilling every 5- 6 hours to maintain the bio-layer. It is estimated that today there are more than 400,000 BioSand filters in more than 70 countries in Africa, Europe, Asia, North, Central and South America, the Caribbean and the South Pacific. Many of these filters are made of concrete, which is prone to breakage and production consistency issues and can be difficult to transport making mass production difficult.

In order to solve the aforementioned issues, we have developed a completely automated Biosand filter design. We have used an Input water feed control mechanism to ensure that proper water refilling is done every 4-5 hrs. We have included water quality monitoring and flow rate monitoring systems on the basis of which, a stirring mechanism is operated to maintain the bio-layer of the filter. We have implemented fault detection systems within the filter. We have also used acrylic as the building material for the filter making it much more easier to fabricate than its concrete variants. This filter can be supplied directly from a mains outlet or from an in-built battery. All these systems combined creates a completely maintenance-free filter.

To ensure that the filter is working according to required standards, there was a need for remote monitoring of the filter systems. Thus, we needed to create an IoT framework to collect the several sensor data available on the filter and send it to a central monitoring station. We have used a GSM module for these data transmission purposes. The reason for choosing a GSM module over other IoT devices is due to the generally ubiquitous mobile network coverage (of at least 2G technology). The frequency and data rate required for the transmission sensor data is very low. This helps in reducing the power consumption of the filter. The GSM module sends the data to a central server. The data stored in this central server can be used to ascertain the condition of the filter and issue alerts to personnel in charge of maintenance of the filters.

Another advantage of using a centralized system to supervise these filters would be to collect data on the water consumption of the various households. This data can be used by government agencies to create a better water supply system.

Thus, through our project, we wish to create a filter system which would become an efficient, sustainable solution to the water crisis plaguing our world.


One of our team members was part of an NGO which wanted to develop solutions for bringing clean, potable water to 8 villages in Nandurbar district of Maharashtra, India. They chose to distribute Biosand filters to 150 families living in those villages. Within a span of 4-5 months of installation, the NGO received complaints about cumbersome maintenance procedures of the filters and also regarding the water quality. This was due to 2 reasons. The first reason was that a Biosand filter required a feed of water every 5-7 hours to ensure bio-layer growth. There had to be done manually. The other reason was that to ensure nominal flow rate, after a period of about 4-5 months, the bio-layer needs to be manually stirred. This, when not done carefully, could give rise to skin allergies or other skin diseases. It was also observed that among families which used Biosand filters, when these filters malfunctioned, they would revert back to unsafe means of water treatment such as boiling of water rather than going through the hassle of contacting trained personnel to repair the filters. To solve these problems, we wanted to automate the filter such that it could maintain itself and also ensure water quality. To ensure that the filters are properly working, we also wanted to create an IoT assisted system so that the fault management of all filter systems would become much easier.


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