1. Profile
(1) Project site:
Southeast of Gongyixi Bridge, Fengtai District, Beijing.
(2) Owner:
Beijing City Drainage Refco Group Ltd.
(3) Capacity:
600,000 m³/d domestic sewage treatment.
(4) Date of operation:
October 2016.
(5) Investment, construction and operation:
It was invested, built and operated by the Owner.
2. Major environmental problems to be addressed
The domestic sewage discharge meets relevant standards after treatment. The treated effluent is mainly used for scenic environmental use, urban municipal water and industrial water.
3. Environmental standards and/or main index limits to be followed
According to B standard in Table 1 of the Discharge Standard of Water Pollutants for Municipal Wastewater Treatment Plants (DB 11 890-2012), CODcr≤30 mg/L, NH3-N≤1.5 mg/L, TN≤15 mg/L, SS≤5 mg/L and TP≤0.3 mg/L.
4. Technological process:
MBR + ozone + disinfection process is adopted.
5. Environmental pollution control effects
For the influent, CODcr≤550 mg/L, NH3-N≤50 mg/L, TN≤65 mg/L, SS≤300 mg/L, TP≤7 mg/L; for the effluent, CODcr≤30 mg/L, NH3-N≤0.5 mg/L, TN≤10 mg/L, SS≤5 mg/L and TP≤0.3mg/L.
6. Investment and operation cost
The investment was about RMB 5 billion and the direct operation cost was about RMB 1.20/t·water.
Case highlights: The project is the largest underground sewage treatment plant in the world using the membrane bioreactor technology, with high effluent criteria. An ecological wetland park has been built on the ground. It produces high-quality reclaimed water meeting the demands for ecological water supplement.