STP Una zone D - Secondary Wastewater Treatment Plant in Una, Himachal Pradesh

STP Una zone D is a wastewater treatment plant located in Una, a city in the Indian state of Himachal Pradesh. The plant serves a population of approximately 4,209 people and is designed with a capacity of 630 cubic meters per day. It is currently classified as non-operational. The plant provides secondary treatment, which is the standard level required under India's environmental regulations for municipal wastewater. Secondary treatment typically involves biological processes to reduce organic matter and suspended solids, ensuring that effluent meets basic quality standards before discharge. The plant is located inland, more than 50 km from the coast, so its discharge likely enters a local river or stream that eventually drains into the Indus River basin or a tributary of the Ganges, depending on the local hydrology. The surrounding area is part of the Shivalik Hills, a region with significant ecological importance.

The plant is situated in Una, Himachal Pradesh, in the foothills of the Himalayas. The local watershed drains into the Swan River, a tributary of the Sutlej River, which eventually flows into the Indus River and the Arabian Sea. The region supports diverse aquatic life and is important for groundwater recharge. The non-operational status of the plant may pose risks to local water quality if untreated wastewater enters the environment.