New Filter and Doser Projects in India

Since May of this year, I've been in India working with Pradan to implement AguaClara's new Low Flow Stacked Rapid Sand Filter (LFSRSF) along with our chemical doser controller (CDC) in two villages in the Khunti district in the Jharkhand state of India. There were several challenges in arriving at an efficient system from beginning to end, and we went down many suboptimal paths along the way. After more than three months, we have finally zeroed in on a sleek pilot system for AguaClara technology in the Indian village. In anticipation of successful execution, and we are preparing to implement the systems in an additional three sites immediately.

In the conceptual design stages, we cycled through many different systems that each had an element of lingering discomfort. We had to integrate the CDC and LFSRSF into the usual water supply schemes where water from a lowland well was pumped up to an elevated storage tank large enough (about 25000 liters) to serve the daily demand of about 500 people. We discarded our initial idea of using a solar pump to lift water to the LFSRSF followed by a diesel pump to lift water to the overhead storage tank, since it required the operator to manage two different pumping technologies. Then, we decided to pump water up to an extra elevated storage tank, which would then gravity feed through the treatment system. At the time, we couldn't see an efficient way to handle the huge difference in flow rate between the filter and the diesel pump. 

After fabricating the body of a 24" diameter filter, we learned that in the village of Dharaidih, Pradan had installed a solar pump that was providing nearly 1 liter per second of flow over 30 meters of height. This pump opened up new doors for a more efficient system design; it was now possible to get a high-lift pump that provided a flow rate close to that of the filter. We hit the drawing board again. The result was a design that eliminated the additional storage tank and utilized three 12" diameter LFSRSFs to handle the fluctuating flow from the solar pump.

AguaClara Water Treatment Facility. The LFSRSFs and CDC are housed above the elevated storage tank.

In addition to the LFSRSF, there has been a lot of excitement about the chemical dosers. The current chemical dosing methods involve throwing matchboxes of alum, lime, and chlorine directly into the drinking water wells. UNICEF, having a close relationship with Pradan, learned about our CDCs and was eager to have a chemical dosing option that was simple to use and enabled accurate dosing. UNICEF asked Pradan to install our chemical dosers in the remaining 18 sites where they are building government-funded overhead tank water supply systems. They are also interested in making it government policy to use our dosers for new schemes.

After extensive discussions and planning for the LFSRSF-CDC systems as well as the stand-alone CDC systems, we all agreed that filtration is a critical piece of water treatment and that we should assume filters would eventually be included in the remaining 18 sites. Now we had to balance efficiency, innovation, and standardization in deciding how to tackle the rest of the projects. For us to install efficient stand-alone CDC systems now would make for a less than elegant retrofit with filters later. Similarly, for us to install the CDCs such that the filters could easily snap into place later would make for a very inefficient dosing layout now. We also did not wish to commit to building too many filters before testing and evaluating its performance in the field. In the end, we settled on installing our filter systems in an additional 3 sites -- two villages in the Koderma district and another village in Khunti. For the remaining 15 sites, we will make an efficient but flexible chemical dosing system.

In progress mild steel model of the LFSRSF.

Pradan has shown a lot of dedication to providing water treatment to villages. They are looking to form a new Water and Sanitation "thematic group," to build up this new focus area within the organization. Additionally, they have had many meetings with the Drinking Water and Sanitation Department and build up the department's interest in deploying 50 new water treatment schemes utilizing AguaClara's LFSRSF and CDC. Through their networks and personal motivation, we are very quickly nearing a stage where we can take our systems to scale.