New technologies for waste water treatment

The National Engineering Research and Development Centre (NERD), has developed a low cost technology to treat DC mill waste water, a media statement said.

Sri Lanka is the second largest producer of desiccated coconut in the world. Of its total export revenue from the coconut industry, 40% is generated through export of desiccated coconut.

According to the Central Environmental Authority, the value of Chemical Oxygen Demand (COD) Standards should be less than 250 mg/litre before discharging the waste water into waterways. COD represents the level of pollution of waste water and generally the value of waste water released from a DC mill is as high as 35,000 – 45,000 mg/litre. As the acidity is high, there is a difficulty in deploying a biological treatment method. Bacteria cannot withstand acidic conditions.

Under the technology developed by NERD, the COD value is reduced to about 80 mg per litre.

This system works continuously and already this process has been established at Rathkarawwa DC mill at Puttalam Road, in Kurunegala district. Kamal Wanasinghe, the Quality Controller, of this mill said that for eight years people in the surrounding areas have been complaining about releasing waste coconut water as they are very harmful to the environment and smelly when it flows through the ground water. Subsequently a court case was filed by neighbours against this company for releasing unhygienic water to environment. “We are now successfully using this technology to prevent waste coconut water polluting the environment. As a result of using this technology, the company was able to win the court case which was filed by the residents against them,” he said.

Ms. Banduni Premarathne, a Consultant to Industrial Services Bureau at Kurunegala, explained how their company coordinated to provide this service to Rathkerawewa DC Mill.

She said Sarath Jayalath, the owner of Rathkerawewa DC Mill, had contacted her regarding this problem of releasing coconut waste water. The Industrial Services Bureau which deals with applying strategies in regard to water pollution, environment pollution and other consequent health problems then coordinated with the NERD centre to find a solution to this problem through some technology development.