Phase III Project of the Sewage Treatment Plant of Hefei Economic & Technological Development Zone in Anhui, China

1. Profile

(1) Project site:

It is located at the intersection of Yungu Road and Qingluan Road in Hefei Economic & Technological Development Zone

(2) Owner:

Hefei Drainage Management Office.

(3) Capacity:

100,000 m³/d sewage treatment.

(4) Date of operation:

January 2016.

(5) Investment, construction and operation:

It was invested and built by Hefei Construction Investment and Holding Co., Ltd. and operated by Anhui Guozhen Environment Protection Technology Joint Stock Co., Ltd.

2. Major environmental problems to be addressed

Reduce COD_cr, BOD₅, ammonia-nitrogen and total phosphorus discharged into Chaohu Lake, improve the water quality of Paihe River and Chaohu Lake in lower reaches, and protect the water source of Hefei City. The effluent shall be used as the supply source for Wangjiangou, a black and smelly water body in Hefei, so as to effectively improve the water environmental quality of Wangjiangou small watershed.

3. Technological process

Influent → coarse bar screen → inlet pump room → fine bar screen → grit chamber → oxidation ditch (A²O process ) → secondary sedimentation tank → secondary lifting pump house → coagulation reaction tank → inclined plate sedimentation tank → denitrification deep-bed filter → disinfection tank → effluent.

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

According to the Discharge Limits of Major Water Pollutants for Municipal Wastewater Treatment Plants and Industries in the Chaohu Basin (DB 34/2710-2016), for the effluent, COD_cr≤40mg/L, NH₃-N≤2.0mg/L, TN≤5mg/L, TP≤0.3mg/L.

5. Environmental pollution control effects

For the influent, BOD₅ 26.2~190.0mg/L, COD_cr 62~475mg/L, SS48~380mg/L, NH₃-N6.8~33.1mg/L, TN9.74~47.7mg/L, TP1.18~8.23mg/L；For the effluent, BOD₅ 2.0~4.0mg/L, COD_cr 6~26mg/L, SS≤6mg/L, NH₃-N 0.06~1.22mg/L, TN 0.83~4.72mg/L, TP 0.05~0.28mg/L.

6. Investment and operation cost:

The total investment of the project was about RMB 343 million, and the operation cost was RMB 0.49/t·water.

Highlights: Without changing the characteristics of oxidation ditch process, additional advanced treatment facilities were provided, and technological upgrade was integrated with energy saving and consumption reduction, so that the main indicators of effluent reached and maintained Class IV standards for surface water. The project is one of the sewage treatment plants in Anhui Province whose major indicators of the effluent firstly meet the Class IV standards for surface water.