The automated waste treatment plant in Babesa cleans six to eight million litres of waste water daily

YK Poudel                                            

Residents of Babesa, living near the open-air sewage ponds, can finally breathe easy, thanks to an advanced automated waste water treatment plant that processes between six and eight million litres of waste water daily.

This facility, operational since 2022, is a major upgrade from the old open-air sewage ponds, boasting a capacity of 12 million litres per day compared to the previous 1.75 million litre a day.

As part of the Green Infrastructure and Open Spaces Plan under the new Thimphu Structure Plan, efforts are underway to transform the old sewerage ponds into a recreational or ecological park.

This state-of-the-art facility, the only one of its kind in Bhutan, employs a fully automated sequential batch reactor system. Managed by Technofab Engineering Company and a dedicated team of 20, it operates under the supervision of Thimphu Thromde. The current contract runs until April 2027.

The plant handles a wide variety of waste, including raw vegetables, plastics, bottles, cloth pieces, electrical appliances, and at times, even dead bodies of infants.

Kinzang Dorji, who oversees the programmable logic controller and SCADA systems, said that the treatment consists of six stages (aerotic fill, react, settle, decant, idle and static fill) ensuring that wastewater is adequately purified before being released into the Wangchhu River.

At the headworks building, wastewater goes through three screening stages, effectively filtering materials down to 6mm. “Recovered plastics are sent to Memelakha, while organic waste is transformed into manure for local farmers.”

“The entire treatment process takes around four hours, concluding with chlorination before the water is released back into the environment,” he said.

The plant is designed to handle a total of nine million litres a day from Thimphu and an additional three million litres from the Babesa area.

Powered by electricity and generators, the facility incurs a monthly electricity bill exceeding Nu 200,000, which is covered by Thimphu Thromde.

According to Thimphu Thromde officials, the mechanised in-house treatment plant was established to address the growing population in Thimphu and to mitigate the unpleasant odours that plagued Babesa residents.

“After the completion of the contract, the Thromde may take its ownership or outsource it to a private firm based on its cost and efficiency,” the Thromde official said.

Currently, there are no plans to extend the plant’s services to other areas.

Thimphu Thromde does not have data on the number of households connected to the existing wastewater treatment plant.

Financed through a cost-sharing agreement with the Asian Development Bank and the government—totaling USD 8.87 million and Nu 74.86 million respectively—the plant construction began in November 2016 but faced delays due to the pandemic, ultimately becoming ready for operation in 2021.

There are seven sewer treatment plants developed by Thromde at Dechencholing, Taba, Jungzhina, Hejo, Lungtenzampa, and Babesa.