The project commenced production in October 2019 and is designed to handle the tail gases from the entire plant of the Precision Lead and Rare Metals Plant of Huanyuan Metal Group at Water Mouth Mountain. It includes the treatment of nitrogen oxide emissions from processes such as lead mud acid purification, Wang water solution, sodium sulfide reduction, gold electrolysis, nitric acid dissolution of silver, and silver electrolysis.

The project employs a two-stage bubble absorption plus three-stage spray absorption plus SDG adsorption process, followed by a two-stage alkaline foam tower for the treatment of nitrogen oxide emissions from sodium sulfide reduction, gold electrolysis, silver electrolysis, and other storage tanks and containers. Acidic emissions from these processes are directly treated using two-stage alkaline foam towers. The treated gases are then discharged through chimneys. Since entering service, the equipment has operated stably, with all emission indicators meeting national and client requirements.