An eco-friendly wastewater treatment plant inaugurated yesterday at Hejo, Thimphu is yet to be operationalised and could not be demonstrated during the inauguration.

This is because Thimphu thromde is yet to connect the wastewater pipelines from the households to the treatment plant, which is constructed near the crematorium.

Construction of the treatment plant began in 2017 after the Department of Engineering Services signed a Memorandum of Understanding with Mokan-Joka System (MJS) of Japan and Japan International Cooperation Agency (JICA) in December 2016.

A monk performs thruesel at the treatment plant yesterday

A monk performs thruesel at the treatment plant yesterday

A small-scale sewage system with energy saving technology called Dojo-Joka system, the first of its kind is being piloted in Bhutan, which can not only manage wastewater but could also be used for recreational purposes.

The sewerage treatment system that would cater to 86 households and more than 700 people in lower Hejo would prevent secondary pollution such as foul smell, is cheaper, takes limited space and can be operated unattended.

An engineer with water and sanitation divison, Ugyen Wangchuk said the new sewerage plant has a capacity of 0.1 million liters a day (MLD), which will produce an effluent discharge in the river.

He said that effluent with Biological Oxygen Demand of 20 milligram per liter would be released, meeting the effluent discharge standard of Bhutan. The new sewer network is about 800 meters long and the treatment plant covers an area of about 1,000 m2.

“The system consists of three sedimentation tanks and three aeration tanks connected in series, tanks are underground and covered by soil,” Ugyen Wangchuk said. “The wastewater from the households once collected and enters the treatment system will undergo two digestion processes.”

Ugyen Wangchuk explained that after the collection and digestion, air would be fed through the diffuser pipes with the use of a blower into the system to enable aerobic digestion.

“But all this would be operationalised only when the thromde connects all the households with the plant,” he said. “This is why the blower could not be switched on for demonstrating since the plant was not filled with waste.”

The plant, which was constructed with locally available materials and using simple technologies would ease the residents from having to clean the septic tanks manually.

Funded by JICA, the treatment plant was constructed at a cost of 100 million Japanese Yen. Mokan Joka System Co. Ltd based in Japan with M/s Vajra Builders as the local constructor constructed the Plant.

Works and human settlement minister Dorji Tshering and Chief Resident Representative JICA Bhutan Office Koji Yamada inaugurated the treatment plant.

“Having inaugurated this, the ministry and the Thimphu Thromde would have constructed a state-of-art Japanese sewerage treatment system,” Lyonpo said. “It is hoped that the ministry, with the experience gained in having implemented and constructed the Dojo Joka System, will be able to promote and construct such and similar sewerage treatment systems around the country.”

Koji Yamada said that through this project, JICA could work in other areas such as wastewater treatment plants.

“This project will show that the public-private partnership with Japanese small and medium enterprises may emerge as a new instrument to be applied to Bhutan,” he said. “Since this is the first project of this kind in Bhutan, we have learnt a lot of lessons from its implementation. For instance, it was a good opportunity to learn how MoWHS and the municipality coordinate or do not coordinate.”

Koji Yamada explained that according to the MoU, the ministry was supposed to ensure sufficient land or space with all the auxiliary facilities to the site, including access for the installation of the product throughout the implementation period.

“However, it soon turned out that the thromde was not included in the information loop on the site selection and the MJS team received a new request from the mayor when they visited him in April 2017,” he said, adding the MJS team had to spend extra time and money to respond to the emerging situations and modify their original design.

He said that there seems to be a gap of perception over the definition of the pilot project.

“We all have to understand that the completion of the wastewater facility is just the beginning of the MJS’s commitment to prove the effectiveness of its technology,” he said. “MJS still has lots of things to do until the place receives wastewater supplied through the sewerage pipe network from each household.”

Thromde officials said it was waiting for the treatment plant’s construction to complete for it to connect the sewer lines to about 30 households. The officials will today hold public consultation in Hejo to connect the lines. Thromde will charge a connection fee of Nu 3,000 per household. Thromde will also construct a similar plant nearby to meet the requirement of Hejo’s population.

Yangchen C Rinzin 


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