“BHU scientists devise tech for wastewater treatment [Varanasi]” by Binay Singh, Times of India

Singh, B. “BHU scientists devise tech for wastewater treatment [Varanasi].” The Times of India.23 March 2011.

BHU scientists devise tech for wastewater treatment [Varanasi]

By Binay Singh, Times of India

March 23, 2011

VARANASI: While the World Water Day 2011 with its theme ‘water for cities to meet urban challenges’ was observed across the globe with a series of events on Tuesday, the scientists at Banaras Hindu University (BHU) were gearing up for the field experiment of an ozone-based technology for wastewater treatment.

The technology has been developed by a group of scientists led by B D Tripathi, a noted environmentalist and coordinator of the Centre for Environmental Science and Technology (CEST), BHU. He is also a member of National Ganga River Basin Authority (NGRBA).

B D Tripathi told TOI, “This is an advanced wastewater treatment technology for removal of organic materials from the wastewater and bacterial disinfection. The technology is under the process of patenting.”

The principle is that different concentrations of ozone gas are passed through the wastewater for different contact time. In this technology, ozone gas is used as strong oxidant and disinfectant, he said claiming that more than 95% of the organic materials are degraded in this process.

The technology has also demonstrated bacterial disinfection above 98%. The work was also published in an international journal ‘Bioresource Technology’ in February 2011, he said.

The work was aimed at studying the efficiency of ozone in oxidation processes, coliform inactivation and disinfection byproducts (DBPs) formation. The process uses the potential of ozone to increase the biodegradable dissolved organic carbon (BDOC) in secondary effluent with applied ozone doses of 5.0, 10.0 and 15.0 mg/l for contact times of 2, 5 and 10 minutes.

The wastewater used in this work was collected from the sewage treatment plant (STP) at Bhagwanpur. The other team members were Smriti Tripathia, Vinita Pathaka and Devendra Mani Tripathi.

“After satisfactory laboratory demonstration, we are going to make field experiments,” B D Tripathi said adding that it could be one of the best technologies to address the problems of water pollution. The existing technologies applied in sewage treatment plants cannot remove the bacteria.

The bacteria could be removed from wastewater through chlorination, but there is another health threat in it, he said explaining that generally industrial effluent is mixed with sewage and wastewater.

In the process of chlorination of such wastewater, carcinogenic compounds could be formed that are a threat to human health, he said.

The production of ozone was a costly affair in the past, but now with the use of ultra violet rays, the production cost of ozone has gone down, he said adding that the application of ozone in wastewater treatment could be described as the best technology.

Tripathi also worked on the biological treatment of domestic wastewater. According to him, it is an economic and eco-friendly technology in which aquatic plants like Eichhornia crassipes, Microcystis aeruginosa, Scenedesmus falcatus, Chlorella vulgaris and Chlamydomonas mirabilis are used for removal of pollutants from the domestic wastewater.

Besides, he also developed a technique for bio-filtration of heavy metals.

He said that it is an advanced technology which used for removal of heavy metals from wastewater through the application of aquatic plants. He claimed that more than 95% removal of Cr, Cd, Cu, Zn, Fe and Ni was demonstrated in this process.

The NGRBA report also suggests that in the Ganga basin, approximately 12,000 million litres per day (mld) sewage is generated, for which presently, there is a treatment capacity of only around 4,000 mld.

Approximately 3,000 mld of sewage is discharged into the main stream of the Ganga from the class I and II towns located along the banks, against which a treatment capacity of about 1,000 mld has been created till date.

The contribution of industrial pollution volume-wise is about 20% but due to its toxic and non-biodegradable nature, this has much greater significance.

In Varanasi, there are three sewerage treatment plants in Dinapur, Bhagwanpur and Diesel Locomotive Works (DLW) with capacities of 80 mld, 9.8 mld and 12 mld respectively.

These STPs were constructed under the first phase of Ganga Action Plan (GAP-I). These treatment plants are based on activated sludge process (ASP). Under GAP-II, a sewage treatment plant of 140 mld will be built at Sathwa, while another STP of 37 mld would be built in Ramna area.

In a survey conducted by the Japan International Cooperation Agency (JICA), the middle stretch of Ganga from Kanpur to Varanasi was found to be the most polluted. According to the report prepared under the Jawaharlal Nehru National Urban Renewal Mission (JNNURM), the quality of water in Varanasi is far below the ISI standards.

It is estimated that out of the total pollution load reaching the river stream, the load from point sources (urban wastewater and industrial effluent) is significantly high (94%), including 79% load from municipal sewage and 15% load from industries.

The industries that are contributing to high pollution content are mostly dying factories and units which are associated with making of Banarasi sari and are located in the old city area. The remaining 6% pollution is contributed by non-point sources like agricultural and forestry runoff and livestock.

Locals, kids form human chain

VARANASI: A human chain was formed along the Ganga ghats in Varanasi to mark the World Water Day under the auspices of Sankat Mochan Foundation (SMF), the organisation working for the cause of Ganga for three decades by running ‘clean Ganga campaign’ on Tuesday.

Local natives and students also took part in the event.

They also took pledge to try their best to stop pollution of Ganga and extend support to ‘clean Ganga mission 2020’. A function was also organised at Rajendra Prasad Ghat.

Addressing the function, SMF president Veer Bhadra Mishra said that though efforts are being made to clean the holy river, the untreated wastewater is still discharged into the river.

The SMF, under its clean Ganga campaign, has been organising ‘human chain formation’ event on the occasion of WWD for the last 11 years to spread awareness among the people.

He said that the SMF is collaborating with the Central government for pollution abatement of Ganga.

The schoolkids also presented a colourful cultural programme to highlight the importance of Ganga on the occasion.

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