Delhi Jal Board (DJB) has decided to install ozone-based ammonia treatment plants at Chandrawal and Wazirabad plants, which draw water from the Yamuna. Japan based Toshiba Infrastructure Systems & Solutions Corporation (TISS) has signed a contract with Larsen & Toubro Limited (hereafter L&T) for three ozone generators at Chandrawal Water Treatment Plant.
This would be one of largest-scale ozonation systems for a water treatment plant in India. The project is being funded by Japan International Cooperation Agency (JICA) under the Delhi Water Supply Improvement Project. JICA assisted 477MLD Water Treatment Plant at Chandrawal, being constructed by L&T by replacing existing water treatment plants, would be equipped with Toshiba’s ozonation systems, having three ozone generators with each 31 kg per hour capacity.
Ozone is a powerful oxidant and has many applications, including dechlorination, deodorization, inactivation of viruses and bacteria, oxidation of organic and inorganic substances and a reduction in trihalomethane*1 formation during chlorination. In addition, ozone has hardly any adverse impact on environment because it simply reverts to oxygen after use.
“The present WTPs can treat low-level of ammonia contamination, but in recent past, high quantities of ammonia-based pollutants are being dumped into river entering Delhi, which has to closure of WTPs.
After installation of ozonation unit, the plants will be able to treat ammonia and other chemical and biological pollutants,” DJB said. In Japan, ozone treatment is commonly used at large water treatment plants especially in urban areas.
