The Hindu 21.12.2009
Water treatment plant ready for commissioning
G. Mahadevan
| KWA officials to inspect JICA plant |
Plant will discharge 37 mld water to PTP Nagar reservoir
Quality control checks completed
THIRUVANANTHAPURAM: The drinking water treatment plant set up at Aruvikkara as part of the Japan International Cooperation Agency (JICA)-aided schemes being implemented in the city is ready for operations. The plant is awaiting final inspection by a team of the Kerala Water Authority (KWA).
The plant is expected to discharge 37 million litres a day (mld) to the reservoir at PTP Nagar. The executive engineer (quality control) will inspect the plant on Tuesday.
Before the water from the JICA plant flows to the reservoir at PTP Nagar, the main pipelines laid by the L&T have to be ‘flushed’ to ensure that they are fit to ferry potable water. For this, ‘super chlorinated’ water would be made to flow through them for fixed periods of time. Unlike the current treatment plants of the KWA, the JICA plant will use gravity for water flow to the reservoir .
An on-site engineer at the JICA plant said the full range of quality control checks on the water produced at the plant have been completed.
The process
After the filtering process, water is stored in the ‘chorine contact tank’ at the plant. “From here, the water will go to the clear water sump and then to the overhead tank before entering the main pipes to the reservoir at PTP Nagar. Water would be let out from the chlorine tank only after obtaining permission from the KWA,” the engineer said.
At the JICA plant, the raw water will first flow into a ‘flume chamber’ where lime and alum will be mixed. It will then flow into a ‘pulsator-clarifier’ — a mechanism that uses a technology patented by the French company Degremont. The suspended impurities in the water will be removed here through generation of vacuum inside a camber in the middle of the structure. The pulsator gets its name from the vertical pulsating motion it generates in the rectangular ‘clarifier.’ The plant has four pulsators.
From here, the water circulates through the six filters of the plant on its way to the chlorine contact tank where it repeatedly comes into contact with gaseous chlorine. At this point, the water is potable.
From the clear water sump —this sump at the JICA plant is connected to the clear water sump of the existing KWA plant at Aruvikkara — the water is pumped to the ‘break-pressure tank,’ an elevated structure.
From here ‘gravity flow’ of water would be effected to the main pipelines.
