All areas in Thimphu thromde except for periphery E4 areas such as areas above Semtokha dzong and Lubding are not connected to the city’s sewerage system, according to thromde officials.
There are a total of 7,609 buildings in Thimphu Thromde. There are 188 buildings in Semtokha.
An engineer with the Thimphu thromde sewerage division, Samten Lhendup said that the thromde has two types of sewerage system – a separate and gravity system. “With this system there is no need for pump except for areas in lower Babesa. We design the sewerage networks according to the natural ground system.” Separate type sewer systems are not connected to the drainage.
The construction of Thimphu sewerage system began in 1993 with funding support from Danida and was commissioned in 1996. The project-covered core Thimphu city area, lower Changzamtog, Tashichhoedzong area, Chang-gayney (NPPF colony), areas below Doebum lam, and Chubachu area.
The government funded the construction of sewerage system in the Olarongchu workshop area, upper Changzamtog, Changidaphu, lower part of Changangkha and above Royal Insurance Corporation of Bhutan Ltd (RICB) colony. Sewerage system in Changjalu was constructed through aid from UN-Habitat.
Through World Bank’s funding, lower Langjophakha and Dechencholing area are connected to the sewerage system while an ongoing project in lower Taba is yet to be completed. Asian Development Bank funded the project to connect south Thimphu (Changbangdu till Babesa) to the sewer network. “However, only areas until Olakha area are connected to the treatment plant in Babesa as the existing plant has a capacity of 1.75 MLD,” he said.
The treatment plant in Babesa also caters to sewer lines coming from the core city area. The treatment plant is currently being upgraded to hold a capacity of 12 MLD.
Samten Lhendup said that although all the necessary components of sewerage system such as manhole and pipes are laid, the system would be connected to the treatment plant only after it is upgraded in 2019. “Property owners of Olarongchu and Babesa area have been asked to construct septic tanks. Once the plant commissions, we will ask them to connect to the sewerage system.”
Samten Lhendup said that including the one in Babesa, currently there are three functioning wastewater treatment plants. The other two are in Dechencholing, and Langjophakha.
The treatment plant in Dechencholing funded by World Bank has the capacity of 0.75 million litres per day (MLD) and caters to residents living in Dechencholing area.
The newly constructed treatment plant in Langjophakha is also funded by World Bank and has a capacity of 0.6MLD catering to residents of the area.
The Government of India is also funding a treatment plant in Yangchenphu, behind the Road Safety and Transport Authority office. The plant with a capacity of 2MLD will cater to sewer lines from Motithang, Kawajangsa, upper Changangkha, and Yangchenphu area.
The treatment plant completed on September 30 this year will commence next year. Another eco-friendly treatment plant is being constructed through Japan International Cooperation Agency (JICA) in Hejo.