Thursday, October 08, 2009

Minjur (Chennai) desalination plant delayed beyond nine months

It was orginally meant to be a Pongal gift for the city's residents, and later a Tamil New Year gift. However, it is almost Diwali and the

gift is not ready yet. The 100 MLD Minjur desalination plant has been delayed by "unfavourable sea conditions."

Although about 95% of the project work has been completed, the remaining marine work such as laying of the inlet pipeline to draw seawater and the outlet pipeline to discharge used water into the sea has been delayed. The work, scheduled to be completed by January 2009, was badly hit by Cyclone Nisha that caused widespread destruction along the Tamil Nadu last October. Completion was first re-scheduled for April and then to October.

"The plant will be delayed as the condition of the sea is not favourable for laying pipes. The company (Chennai Water Desalination Limited) has to look for a good weather window' for pipe layingcalmness of the sea and height of waves have to be taken into consideration. CWDL officers said it was not a good time to carry out pipe laying. Only after discussions with the company will we know when work will be completed," said a government source.

IVRCL sources, however, said that all onshore work had been completed and that the plant was already producing 60 MLD of potable water in trial runs. The water was being let into the sea again. An alternative system had been put in place instead of the proposed method of laying pipelines in the sea, they added.

According to a source, the seabed would be dredged using a machine and the pipes would be allowed to float on water. "Once the water starts entering the pipes, they will start sinking. They will then be lowered into the space that has been dug."

The Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) had given the task of executing the Minjur plant on a DBOOT (design, build, own, operate and transfer) basis to CWDL, launched by the Hyderabad-based IVRCL Infrastructures and Projects Ltd as a consortium with Befesa Constuccion Technologia Ambiental Ltd, Spain.

Based on the bulk water purchase agreement entered into with CWDL, CMWSSB would purchase desalinated water at a cost of Rs 48.66 a kilolitre and supply to industries at a rate of Rs 60 per kilolitre.

The site of the Rs 510-crore plant lies 200 metres from the coast, near Kattupalli in Minjur, 35 km from Chennai. A 600-metre pipeline of 1600 mm diameter, to be laid below the seabed, will connect the sea and the plant. Sea water would be drawn using pumps for desalination.

Of the five racks that have a capacity of producing 20 MLD of potable water each, three have been commissioned and are operational. About 10 pumps have been installed near the shore as a temporary arrangement to draw seawater. "This is because marine work has not been completed," sources said.

CMWSSB is currently dependent on groundwater and surface water resources to meet the city's demand. The desalination plant would mostly cater to the water requirements of industry, including the North Chennai Thermal Power Plant, Ennore Port Trust and the proposed special economic zone to come up in north Chennai. During drought, the water would be supplied to the public, CMWSSB officials said.





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