Mumbai: ‘Eco-friendly’ MMRCL monitors wastewater generated during Metro-III construction

Mumbai: The Mumbai Metro Rail Corporation Limited (MMRCL) have prepared a ‘Environmental Management Plan” to monitor wastewater generated during construction work of the metro three project work. The wastewater monitoring is a part of Environmental Impact Assessment (EIA) under environmental monitoring program which is a key component to ascertain quality of treated wastewater and assess efficiency of treatment units.

“This is one of the tools to improve the efficiency of treatment units and to ensure quality of treated wastewater and meet the quality for recycling as required. The wastewater from Metro-3 project is formed through contamination of underground water due to solid particles. This happens during the construction of launching shaft and tunneling work at various sites,” said a MMRCL official.

The other source of wastewater is caused due to various facilities installed at the site like the wheel washing facilities at stations, launching shaft site, allied facilities like concrete and casting yard which are operational at various locations are also the sources of wastewater.

Considering the nature of activities of Metro-3 project, major water pollutants of concern are potential of Hydrogen (pH), suspended solids and grease. “Wastewater can be defined as a contamination of water with pollutants which have a potential to cause pollution, chemical or biological properties of the water which may be harmful to public health and other living organisms when not treated,” added the official.

Officials also said the wastewater could also be termed as “effluent” which is released from various processes in industrial, infrastructure and construction projects.

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Even though the metro rail project benefits the commuters and have positive environmental impact, the negative impacts need to be mitigated through implementation of Environment Management. The Environment Management Plans are prepared by civil contractors and thereby the wastewater is being treated in sedimentation tank provided at stations, launching shaft sites and allied facilities locations.

“The wastewater quality is monitored regularly on monthly basis by civil contractors through Ministry of Environment, Forest and Climate Change (MoEF) recognized laboratories. Analysis reports of treated wastewater monitored during November 2017–January 2018 at various locations have confirmed to permissible standards laid down in Environment Protection Rules, 1986,” added the official.

Presently, treated wastewater is being used for dust suppression and for wheel washing to the maximum extent. “We are exploring the possibilities to recycle tunnel water completely back into cooling operations of tunnelling after ensuring the acceptable quality through adequate treatment. In this way, the wastewater can be treated and be put to use during the construction work,” added the official.