Pilot 5 – Anaerobic digestion with photoheterotrophic bioreactor

Location: Kharagpur (West Bengal)
Pilot Leaders: TU Delft/IITKGP

Water challenges in this location: The intensive use of groundwater in the region heavily affects the groundwater table. The river water procurement incurs high pumping expenditures in terms of energy expenses, manpower & machinery, and capital establishment. The total treatment cost of fresh water used on campus premises is around 25 INR per cubic metres. Depleting groundwater and water resources in and around the region calls for attention towards recycling and reuse of treated water. This can help remediating this critical situation and moving towards a sustainable future by attempting to divert fresh water for domestic uses. After successful demonstration of this technology, similar models can be adopted in across the state where the scarce sanitation infrastructure results in pollution of surface water bodies and groundwater. This unfavourably leads to high expenses on public health care and severe reduction of man-hours and societal productivity. A sustainable solution for black water treatment needs to be demonstrated to provide a healthy living condition for the mass.

Benefits of the technology: The composite process is attractive by combining production of VFA from organic matter via mixed-culture fermentation and production of a protein-rich photoheterotrophic biomass that can be valorised as fertilizer. The benefits of this attractive environmental biotechnology are multiple. It thrives on the implementation of anaerobic organisms, therefore suppressing aeration and minimizing energy costs, resulting in a full biological removal of nutrients from the wastewater. Overall, the technology will result in treatment of blackwater, full biological nutrients removal, pathogens inactivation, recovery of a high-yield and protein-rich biomass as fertilizer, and recovery of water for reuse, while protecting the environment and human health.

Potential for India: The treatment scheme proposed for this pilot uses minimum energy input and also focuses on resource recovery through a very basic innovative design, which can be constructed easily using local resources. It therefore has a lot of potential in terms of application.

Scope for replication/upscaling across India: The ability to implement this technology at a decentralised household level without much cost implication (by use of existing septic tank after certain minor modifications) and lesser footprint on land makes it more adoptable for upscaling in India. The proposition of resource recovery from sludge as fertilizers and reuse of water with limited, but dedicated manual intervention also increases the suitability of this technology for scaling up, both at household community level as well as for centralised treatment facility.