The Hindu 09.03.2011
Corporation to improve efficiency of borewells in Coimbatore
The Coimbatore Corporation will soon embark on a drive to improve the efficiency of the 782 borewells in the city. In the process it will also save power.
The civic body's decision is based on a study the ICLEI, an NGO, carried out. The South Asia office of the organisation on a trial basis studied 18 borewells in Ward 27 and 28 of the Corporation to improve energy efficiency in water supply.
The Corporation spent, the study said, a considerable amount on operating the borewells, which it used to meet the gap between the demand and supply in water supply and also to avoid the use of drinking water for non-drinking purposes like washing, gardening and cleaning.
The study covered the present status of the borewells in Wards 27 and 28, reviewed and analysed the energy consumed by the wells, measured the actual power absorbed and the water output rendered by the installed pumps for calculating ongoing ‘watergy' (energy index), assessed the over-all performance of the borewells and provided suggestions and recommendations to improve the energy efficiency.
Watergy is the commonly accepted term used to signify the relative energy index of a water supply installation. It is the energy consumed for supplying unit quantity of water. Watergy is inversely proportional to the energy efficiency. Lower the watergy index, higher is the energy efficiency of the installation, the study explains.
ICLEI took up borewells at Kadalaikara Sandhu, Kadalaikara Junction, VOC Park, Kaliswara Nagar, Mariappakonar Street, Anuparpalayam, Anuparpalayam High School, VOC Park zoo and VOC Co-optex Ground in Ward 27. And, borewells at Vivekananda Road I, Vivekananda Road II, Sarojini Street, Ansari Street, Rengakonar Street, Kalidas Road, Ranganathapuram School, Central bus stand and town bus stand in Ward 28.
Between April 2007 and October 2009, the ICLEI studied the energy consumed, money spent, age of the borewell, measurements, pump type, model, pumping hours, etc. at each of the 18 installations.
Based on the results, the NGO suggested to the Corporation that capacitors should be installed on pump sets as the power factor of all the pumps measured was extremely poor.
The delivery non-return valve malfunctioned and allowed the backflow of the pumped water from the delivery pipeline every time the pump was switched off or tripped due to power failure. Repair of the non-return valve (NRV) was necessary to avoid loss in delivery of pumped water.
It also told the Corporation to install pump running meters for each borewell to enable monitoring the daily pumping duration and identifying any unauthorised excess pumping.
Aside from the over-all recommendation, the organisation also submitted specific recommendation for each of the borewells studied.
For example, for the Kadalaikara Sandhu borewell, ICLEI suggested that the old non-return valve should be replaced by the ball-type NRV, a provision for mounting pressure gauge should be provided, etc. It also mentioned the benefits that the civic body would derive after carrying out such measures.
The measures, a Corporation official said, had resulted in savings of about 35 per cent energy and money. Water pumping efficiency had also improved. He said the civic body would soon study all the borewells and improve efficiency.
