Abstract

Due to lack of strong legislation and guidelines to control untreated wastewaters and industrial effluents, surface and groundwater sources have been deteriorated seriously in Kathmandu Valley. Although, there are five centralized wastewater treatment plants in the valley, most of them are out of order. In recent years, constructed wetlands (CWs) have gained attention in the country for treating domestic wastewaters. The Nepal’s first CW was introduced in 1997 to treat the wastewaters from Dhulikhel hospital. Since then the number of CWs have been increasing in Nepal. At present, there are 13 CW systems in operation for treatment of domestic wastewaters including grey water and fecal sludge. Relatively higher pollutant removal efficiency (>95%) in terms of suspended solids, organic pollutants and ammonium ion (NH₄⁺-N) were found in all the existing CWs. Despite having higher removal rate of organic pollutants, CW technology is still in its infancy stage in Nepal. Therefore, further research and development is necessary for making the CW technology as a promising decentralized technology for treating wastewaters in Nepal.

Key words: Constructed wetland, domestic wastewater, scarcity of water, water pollution.