It is located in Shuangyu Town, Lucheng District, Wenzhou City, covering an area of 84.6 mu. The total treatment scale is 250,000 tons/day: the scale of the phase-1 project is 100,000 tons/day and the CAST + MBBR process is adopted; the scale of the phase-2 project is 150,000 tons/day, and the multi-stage A/O process is adopted. The phase-1 upgrading project and the phase-2 extension project were put into operation in January 2018. Its effluent quality meets the level 1-A standard in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002).