Kavre, September 25:

Country’s first large-scale community-based waste water treatment plant accompanied with a biogas reactor has been set up at Srikhandapur of Dhulikhel Municipality to treat household waste water before discharging it into the river and generate biogas to meet the local energy need.

The plant will treat waste generated by around 200 households of Srikhandapur village and is expected to produce biogas for cooking purpose to around 60 families.

The plant has been established with a direct involvement of local community with the help of Dhulikhel Municipality and UN-HABITAT. The municipality provided four ropanis of land worth Rs 1.7 million for the project while the UN-HABITAT provided $90,000 financial aid.

In the past, the waste water generated in the village used to get directly mixed into the ‘Punya Mata’ river, which is known for the famous 12-year fair’ of Panauti.

The treatment plant will separate solid particles like human excreta from the liquid waste. The solid waste will be sent to two biogas reactors to produce biogas and the liquid will be sent to ‘Reed Bed Treatment Plants’. The treated water coming out from the reed bed plants will be discharged into the river.

The plant consists of a flow diversion manhole, a coarse screen and grit chamber, two diversion chambers, two 75 cubic metre biogas reactors, six horizontal reed-bed plants, two sludge drying beds and 11 collection manholes.

The plant is expected to reduce the BOD (Biological Oxygen Demand) of the waste water by up to 91 per cent.According to Purna Bahadur Karmacharya, the president of the Srikhandapur Wastewater Treatment Plant Users’ Committee, the gas generated from the plant would be supplied through pipelines to the local community and money raised from it would be utilised for the maintenance of the plant.

Dr Roshan Raj Shrestha, chief technical advisor of UN-HABITAT, said sludge management was always a problem in traditional waste water treatment plants.

The plant in Dhulikhel, however, is accompanied with a biogas reactor as well, thereby effectively solving the problem of sludge management and at the same time generating energy. The digested sludge can be used as compost fertiliser.

Kishor Thapa, joint secretary at the Ministry of Physical Planning and Works, similar technique could be used to solve the problem of waste water in bigger cities like Kathmandu as well.