Tech helps water purification plant in Suzhou lower emissions

As evening descends, residents take leisurely strolls through a city park in Suzhou High-tech Zone in Suzhou, east China's Jiangsu Province. Just beneath this tranquil park, Shishan Water Purification Plant operates efficiently.

The city park above Shishan Water Purification Plant. (Photo courtesy of Suzhou High-tech Zone)

Epitomizing the local philosophy of green city construction – "Build the city in the garden, and 'hide' the sewage treatment under the garden" – Shishan Water Purification Plant is a relocated version of a former sewage treatment plant in Suzhou High-tech Zone. The plant, which spans approximately 3.8 hectares, was initiated in June 2018 and commenced water trial operations in April 2022.

The plant is also the first underground water purification plant in Suzhou city. Built across three underground levels, the plant is equipped with an intelligent sewage treatment system that operates autonomously. Odor-producing processes are contained within additional underground compartments, while the surface area hosts public facilities like parks, parking lots, and display galleries. This innovative design eliminates the long-standing problem of unpleasant odors associated with sewage plants, expands public green spaces, and beautifies the environment.

Shishan Water Purification Plant is located underground. (People’s Daily Online/Yu Yang)

“The application of low-carbon products such as water source heat pumps and magnetic levitation fans in water purification plants promotes the recycling of water resources, thus achieving the goal of resource conservation,” said Du Shujuan from the management department of Shishan Water Purification Plant.

The plant‘s sewage source heat pump system, the first of its kind in Suzhou’s urban area, provides cooling and heating services for the surrounding office buildings. With a cooling capacity of 1,465 kilowatts and a heating capacity of 1,400 kilowatts, the system reduces carbon dioxide emissions by about 600 kilograms per day. Moreover, it saves 30 to 40 percent on operating costs compared to traditional central air conditioning.

The magnetic levitation blowers employed in the plant use magnetic bearings with minimal contact, friction, and mechanical loss, thus saving energy. They also adjust speed, solid pressure, and flow in response to changes in external factors, leading to an additional 30 percent in energy savings compared to traditional blowers.

Shishan Water Purification Plant has a designed capacity of 100,000 tonnes per day. Its treated water reaches the national first-class A standard, with 30 percent used as recycled water. Du pointed out that although the area of the Shishan Water Purification Plant is smaller than its predecessor, its sewage treatment capacity has increased, realizing win-win benefits for the environment and society.