Visitors enjoy a boat ride at the lake in Patna zoo. The waterbody would be purified using earthworms

Patna, March 1: A comprehensive waste management plan is on its way at Patna zoo with the use of earthworms.

The lake at the zoo would soon be purified using earthworms. Similarly, tonnes of animal excreta, leaves and other waste material produced at the zoo would be converted into fertilisers with the help of earthworms.

Similar technology would be used for wastewater discharged by Sudha Dairy plant at Phulwarisharif.

The credit for the initiative goes to Rajiv Kumar Sinha, a senior lecturer of environmental engineering at Griffith School of Engineering, Brisbane, Australia.

Authorities are now mulling to install earthworm-based sewage treatment plant (STP) to process wastewater at the two locations. A similar wastewater treatment plant may also be installed in the lake at Rajdhani Vatika (Eco Park).

A resident of Patna and a classmate of deputy chief minister Sushil Kumar Modi at St Michael’s High School, Sinha, recently addressed a workshop on waste management organised by Bihar State Pollution Control Board.

It was during the course of interaction with Modi and Deepak Kumar Singh, secretary of forests and environment department, that Sinha shared his idea of vermi-filtration technology-based wastewater treatment plant, which is in application in Gujarat. “The pollutants in water are mainly of three types — coliform bacteria and heavy metals (lead, cadmium and mercury) among others. The third kind of pollutants is termed endocrine-disrupting chemicals (EDC), which have been discovered in recent years and they affect human hormonal system and can even lead to cancer. While none of the conventional water treatment plants can remove EDC, earthworms can devour such harmful chemicals and other microbes. Moreover, such a waste water treatment plant does not generate sludge, which is highly hazardous and the electric consumption to run these plants is also less,” said Rajiv.

On the basis of discussions with Rajiv, authorities have agreed to consider setting up such earthworm-based vermi-filtration plants in Patna as well. “Based on the ideas suggested by Rajiv and a plant running on similar technology at Bhavnagar, Gujarat, we are open to the idea of setting up similar plants at Patna zoo and Sudha Dairy plant on a pilot basis. However, we must get a proposal from competent firms willing to undertake such projects and it should be technically feasible for the selected locations as well,” said Deepak.

Rajiv said he would soon communicate about the willingness of the state government to the Gujarat-based Tranchem Agritech Limited, which is operating vermi-filtration technology-based STP at Bhavnagar and Vadodara.

“On the basis of daily discharge of waste water at Patna zoo, I am of the view that a vermi-filtration-based STP with the capacity of 10,000 to 30,000 litres per day would be required to be installed. Similarly, the vermi-filtration based STP at Sudha Dairy plant would be of the capacity between one and two lakh litres of water per day. The water coming out from such STPs would be used for irrigation, cleaning and all purposes other than drinking,” said Rajiv.

He added: “The cost of installation and operation would be recovered from resources generated from nutritive water, fertilisers and earthworms.”