1. Profile

(1) Project site:

No.17, Group 4, Da’anqiao Village, Jinjiang District, Chengdu, Sichuan Province

(2) Owner:

Chengdu Drainage Co., Ltd.

(3) Capacity:

1,000,000 t/d domestic sewage treatment.

(4) Date of operation:

October 2015.

(5) Investment, construction and operation:

It was invested, built and operated by the Owner.

2. Major environmental problems to be addressed

It mainly deals with domestic sewage from the 7th drainage area of Chengdu. A reclaimed water pumping station has been built in No.9 Water Treatment Plant, delivering 300,000 tons of reclaimed water every day to the upper reaches of Qingshui River as the ecological water supplement, effectively improving the watercourse environment and enhancing the water resource utilization level.

3. Environmental standards and/or main index limits to be followed

According to Grade-1A standards of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002), for the effluent, COD≤50 mg/L, BOD₅≤10 mg/L, SS≤10 mg/L, NH₃-N≤5 mg/L (8 mg/L when the water temperature≤12℃), TN≤15 mg/L, TP≤0.5 mg/L.

4. Technological process

The modified A²O + fibrous filter chamber + ultraviolet disinfection process was adopted.

5. Environmental pollution control effects

For the influent, BOD₅≤200 mg/L, COD_Cr≤400 mg/L, SS≤240 mg/L, TN≤45 mg/L, NH₃-N≤35 mg/L and TP≤4 mg/L; for the effluent, BOD₅≤10 mg/L, COD_Cr≤50 mg/L, SS≤10 mg/L, TN≤15 mg/L, NH₃-N≤5 mg/L and TP≤0.5 mg/L.

6. Investment and operation cost

The total investment was about RMB 2 billion.

Case highlights: It is a 1,000,000 t/a sewage treatment project adopting the mainstream A²O process and a model for large-scale application of the traditional process.