Rawal Lake water purification: WASA plans installation of 17 solar bees, 10 treatment

[Naveed Yaseen]

* Project will cost Rs 400 million
* Proposal submitted to CDA for collaboration
* 2.4 km of total 8.8km surface area of Rawal Lake will be aerated to end water contamination

By Aamir Yasin

RAWALPINDI: Water and Sanitation Agency (WASA) has prepared a plan to install 17 Floating Solar Powered High Flow Circulators/Solar Bees and 10 Portable Wastewater Treatment Plants worth of Rs 400 million at Rawal Lake to clean contaminations from its water, sources told Daily Times on Wednesday.

They said WASA had submitted the proposal to Capital Development Authority (CDA) for its collaboration. Sources said CDA chairman had told WASA authorities that they would take a decision after thoroughly examining the specifications of the Solar Powered Circulators/ Aerators/Solar Bees and Portable Wastewater Treatment Plants.

They said Rawal Lake water was vulnerable to pollution and one of its major problems was eutrophication, as lake water had become artificially enriched with nutrients, causing abnormal plants growth.

“Rawal Lake, which is the main source of drinking water for Rawalpindi, has become more endangered,” they said, adding the Lake water is highly contaminated, as the waste generated by Quaid-i-Azam University, Diplomatic Enclave, Bari Imam and poultry farms is contaminating water of the lake, which is now more than an oxidation pond.

“There is a problem of taste and odour in the treated water. It is also highly contaminated with blue-green algae (BGA) cyanobacteria, invasive aquatic weeds and others, “ the sources said.

Keeping in view all these problems, they said, a huge aeration is required and Solar Bees are the best fit for this purpose.

They said of the total 8.8 km surface area of the Rawal Lake 2.4-km would be aerated and 17 Solar Bees would be required, as one solar bee covers 0.14 km area.

They said Rs 200 million were required for installation of Solar Bees at Rawal Lake, as the market rate of one solar bee is Rs 11.70 million.

They said solar bees would prevent and control harmful blue-green algae blooms, reduce taste and odour problems in drinking water, public health issues due to cyanotoxins and improve aesthetics, water clarity and biodiversity.

They said day and night operations, using solar energy, required minimal maintenance and no infrastructure changes. They said each Solar Powered Solar Bee unit could displace the mixing energy of about 30 horsepower of conventional grid-connected mixing equipment in wastewater treatment ponds and can displace high horsepower aeration/mixing equipment in freshwater reservoirs and other water bodies.

“The energy saving from each unit is equivalent to about 220,000 KW hrs per year or the annual energy requirement for about 20 homes thereby reducing equivalent carbon dioxide emissions by about 150 tons per year,” they said.

They said the Solar Bee represented the most innovative, energy efficient and environment-friendly technology on earth for providing beneficial, long-distance water circulation and throughout the world, it is providing quality water naturally.

Treatment plants: The sources said WASA had also proposed to construct wastewater treatment plants around the Rawal Lake. They said Rawal Dam had a catchment area of 275 sq km with a population of 0.2 million people.

They said a huge amount of wastewater was falling into Rawal Lake from its tributaries mainly Korang River and stream coming from Bari Imam with the flow rates of approximately 10 and 5 million gallon water per day (MGD) respectively.

They said the agency had recommended that waste treatment plant should be constructed to handle this problem. They said these plants should be portable so that they could be moved form one tributary to another according to requirement.

They said there was an urgent need to install 10 portable treatment plants around the Rawal Lake. The total cost of 10 portable treatment plants is Rs 200 million as one plant costs Rs 20.10 million, they added.

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