There can be beauty in sewage treatment

Over the past few years, more "most beautiful" landmarks in Jiading District have been recognized.
Ran Tao and Qin Yichao / Ti Gong

The “most beautiful” waste water treatment plant in Nanxiang Town is the first sunken water recycling plant in East China. 

Over the past few years, more “most beautiful” landmarks in Jiading District have been recognized.

The most beautiful library known to the public is Jiading Library and the most beautiful public toilet is in the Nanxiang Shine Land.

But a sunken water recycling plant in Nanxiang Town that looks like a garden is rarely known. In terms of appearance, it is no exaggeration to say that this first submerged water recycling plant in East China is the most beautiful sewage treatment plant in Shanghai.

A typical “nimby” (not in my back yard) project, sewage treatment plants has always been questioned by the people around although they are a must-have for a city.

How to turn the disadvantages into advantages is a problem for urban managers.

Jiading, which dared to be the first, attracted a top professional team in China through a public-private partnership to build a sewage treatment plant that looked like a garden.

On the last Sunday of January, a Nanxiang resident surnamed Cui took her child to a waterfront park near her home to take advantage of a spell of rare fine weather after a winter of changeable weather. She found a beautiful green space with flowing water to enjoy.

But what Cui didn’t know was that beneath the ground was a sunken water recycling and sewage treatment plant with many “firsts.”

Demonstration project

The site Cui visited at the intersection of Shunfeng Road and Kesheng Road is the first public-private partnership demonstration project in Shanghai and among the first of such demonstration projects around the country.

It is the first cast concrete sunken water recycling plant in the country and has the highest water quality standards in Shanghai at present.

The plant covers 11.32 hectares and treats 150,000 tons of wastewater every day to serve nearly 400,000 people of eight neighborhoods in an area of more than 36 square kilometers.

Most sewage treatment plants recycle wastewater to Class A standards, but the Nanxiang plant recycles wastewater to the higher Class IV standard, said Mao Rui, assistant general manager of the Jiading company of China Water Environment, which is responsible for operating the plant.

Apart from the water reused in the treatment, most of the recycled water is used to supply Yunzaobang River. In the past two years, Jiading has devoted great effort to purify its rivers. Treated sewage is directly used to supply local rivers, reflecting the high standard of the water quality.

Serving multi-functions

Environmental protection is also reflected in many aspects. For example, dehydrated silt can be transported to refuse incineration plants to produce electricity. The application of biofiltration mitigates odor and gas emissions in sewage treatment.

The temperature of communal wastewater (collected and channeled through the sewage system) is stable and averages between 10 and 20 degrees Celsius.

Hence, wastewater is one of the most ideal heat sources to serve offices, a popular science museum and other buildings around.

Compared with the conventional central air conditioning system and gas boiler system, it saves about 15 percent of the power consumption.

To overcome “nimby” opposition, the design of having the buildings below the ground makes the plant a secret and hidden place. As early as the 1930s, there were sunken sewage treatment plants in Europe. At present, more than 200 plants of such kind have been built around the world.

The technology is quite mature. It’s like building a sewage treatment plant in a closed box, according to Mao. “Then the whole box is buried underground to eliminate the adverse effects on the surrounding environment.”

Chu Wuyue, general manager of the East China company of China Water Environment, said: “Compared with sewage treatment plants constructed through the traditional way, the Nanxiang plant is not only technologically advanced and environmentally friendly but also has obvious advantages in intensive land use.”

Every day 30,000 tons of domestic waste water is flowing into the sunken water recycling plant through underground pipelines to accept the comprehensive treatment through the integrated improved AAO (anaerobic-anoxic-aerobic) technology.

Going to the entrance of the underground sewage treatment space, a large processing workshop comes into view.

This is the core area of the whole plant, clean and tidy, and with almost no smell.

After being treated by filtration, deodorization and precipitation, water will be disinfected by ultraviolet light.

In line with the design, 10,000 tons of treated sewage will be used to irrigate the plants in the park every day. The rest of the water needs to be further tested to confirm that the indicators are qualified before it is discharged into the Yunzaobang River.

The Nanxiang sunken water recycling plant had a total investment of 1.4 billion yuan (US$208 million), 30 percent of which was Jiading’s own funds and 70 percent social capital.

Special Reports