Innovation

After arsenic problem in West Bengal & Bangladesh was highlighted in 1990s, the Govt & international funding agencies opened up their funds for R&D. The research institutes came up with cutting edge technologies for arsenic removal like Coagulation/Filtration, Lime Softening, Activated Alumina, Ion Exchange, Reverse Osmosis, Nanofiltration, etc. Among them, activated alumina filtration emerged as most popular and was used in manufacturing small scale & community scale arsenic filters. These filters pump up the arsenic contaminated water on the earth surface; pass it through costly chemical filter beds and trap the arsenic. Once the chemicals get exhausted, the filters stop working. They need to be recharged or replaced. Also, due to high iron content of ground water, they get clogged very easily & the toxic wastes they are filtering off may enter the food chain after its disposal. None of the above techniques provide a long term sustainable solution to this problem.

The scientists working on SAR noticed that high concentration of arsenic in groundwater in South Asia is due to the presence of bacteria that use arsenic bearing minerals as a source of energy among one of the available sources, turning insoluble As(V) to soluble As(III).

So, in the SAR process,

1. The underground aquifer is turned into a natural biochemical reactor that removes water-borne arsenic along with iron and manganese.

2. The oxidation processes are accelerated by the autocatalytic effect of the oxidation products and by the chemo-autotrophic micro organisms. No chemicals are used and no sludge is produced in the process, maintaining normal permeability of the aquifer.

Compared to the conventional technologies, SAR technique is totally sustainable, chemical free, waste free, community based, targeted towards aquifer restoration and completely safe for public health. It also involves low cost operation and maintenance with part time job generation for the village youth who will be trained as plant operator. The village technicians can also maintain it with basic training.

· This technology emerged as a winner among 2,525 competitors in the WB Development Marketplace Global Competition, 2006 for Innovation.

· Also, it was selected for the "Innovation Fair" in Cape Town, South Africa from among 230 project proposals worldwide.

· SAR also recieved IChemE, UK Dhirubhai Ambani Award for Innovation in Chemical Technology.