Shenzhen Shangyang: coping with first-tier city challenges in China
Shenzhen is the first special economic zone established upon China's reform and opening-up, and is now one of the four first-tier cities in China. SUEZ NWS has built its first large-scale sludge centralized treatment project for the city and will take charge of its operation.
As one of the most developed cities in China, Shenzhen boasts prosperous industry and commerce, and is densely populated. Its resident population reached more than 11 million in 2016, thus giving rise to a large quantity of domestic and industrial wastewater every day. Therefore, Shenzhen has built many large-scale WWTPs to keep the city clean and to protect the environment. However, sludge, as a byproduct of WWTP, is another issue to take care of. Shenzhen must find an economic and effective solution to apply centralized treatment of the sludge in large quantity in the minimizing, defusing, and recycling manner, so as to prevent secondary pollution caused by sludge.
The first centralized sludge treatment project in Shenzhen
The first sludge centralized treatment plant of Shenzhen, built by SUEZ NWS, was the group's first sludge plant applied with its proprietary Thermylis® process in China. It is used for treating the dewatered sludge from more than 10 municipal WWTPs in the central area of Shenzhen and Longgang District.
With SUEZ's proprietary Thermylis® and its two-stage waste heat recovery process, i.e. the waste heat of tail gas upon incineration is used respectively to preheat air and produce steam, to realize direct sludge incineration upon preliminary drying in the high-temperature air condition, thus reducing the auxiliary energy consumption to the maximum extent. The project employs the combination of dry process of dust removal and wet process of acid removal for tail gas purification, so as to meet the stringent emission standards.
After incineration, the sludge is most thoroughly reduced, stabilized and defused, while featured with environment-friendliness. This can be used as a reference for solving the dilemma with large-scale urban sludge treatment.
Shenzhen Shangyang Sludge Project has a treatment capacity of 800 tons wet sludge per day, it is the largest sludge treatment facility in Shenzhen. In 2018, SUEZ NWS enters into an agreement, in order to set up a joint venture to operate and maintain the project for a contract duration of 30 years.