Mumbai : The development of suburban areas along Mithi river in the past several years has drastically degraded its water quality. The river is being used by locals to dump raw sewage, industrial and municipal waste.
Today, the river is full of sludge, garbage and vegetation growth which has resulted in stagnation of water. This has been the prime reason for mosquito menace and stench emanation along the entire stretch of the river.
A pilot project is being undertaken by Mumbai Metropolitan Region Development Authority (MMRDA) along 3.5 kilometer stretch between Vakola Nalla and Kala Nagar junction (1 km in Vakola Nalla & 2.5 km in Mithi river) to remove the foul odour emanating from the river. The project intends to improve qualitative parameters of Mithi waters which are responsible for degradation of any water body.
“The storm water drainage for the Mithi river catchment areas has been disrupted due to the encroachment of hutments in large numbers, storage facilities, processing industries, workshops and scrap yards situated along the banks of the river,” said an environmentalist from The Energy and Resources Institute (TERI), Navi Mumbai.
The direct discharges of untreated sewage, wastewater from the unauthorized settlements along the river’s course has been a major cause of concern.
The city administration has directed MMRDA and Municipal Corporation of Greater Mumbai (MCGM) to take the necessary action. The cleaning work of the river was divided in two parts, the 11.84 km upstream stretch from Vihar Lake to Chhtrapati Shivaji Maharaj Terminus (CSMT) Bridge was given to MCGM and the downstream part of the remaining six kilometer is being undertaken by MMRDA.
The MMRDA has used the technology based on the bioremediation measures to remove the pollutants which are basically organic in nature from the polluted water. In this project odour control is being carried out through bioremediation method.
“This process involves adding a live bacterium namely ‘Persnickety-713’ proportionately to the sewage discharged in to the river on daily basis. It is a process used to treat contaminated water by altering environmental conditions to stimulate growth of microorganisms and remove the target pollutants,” said an MMRDA official.
The work order after inviting global bids was issued in 2011 to lowest bidder J.M. Enviro Technologies Private Limited. “In addition to this work, the contractor has installed a floating jetty and purchased two boats to spray manually at the opposite bank of the river for the effectiveness of the treatment. It also installed manually operated ‘Debris Collection Mechanism’ on each of the boats,” added the official.
During day at high tide, a large quantity of floating garbage and Hyacinth weeds (which are seen in monsoon season) are being collected with the help of collection device fitted to the boats.
“The total cost of project work is at least Rs 6 crore. The water samples from the river is being tested at the laboratories of Municipal Corporation of Greater Mumbai, Veermata Jeejabai Technical Institute (VJTI) on regular basis. The process of odour control of the river is slow. However, it is moving in the right direction,” added an MMRDA official.