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Transformation of wastewater impoundment into Qingjing Lake at Sino-Singapore Tianjin Eco-city

Case Studies | February 1, 2013 | By:

This project, submitted by TenCate Geosynthetics, won an Outstanding Achievement Award in the 2012 International Achievement Awards(IAA) / Geosynthetics presented by the Industrial Fabrics Association International. Each project in its own special way, exhibits outstanding innovation, technical skill and design excellence.

Submissions of geosynthetics projects for the 2013 International Achievement Awards are being accepted now. Submit your projects by June 15, 2013.


Tianjin Eco-city in China is a 30-square-kilometer modern township project currently under joint development by the governments of Singapore and China. Located 40km from Tianjin, 150km southeast of Beijing in northeastern China, the project is scheduled to build 100,000 sustainable homes for 350,000 residents by the time the entire project is completed around 2020.

Tianjin Eco-city will use sustainable technologies, such as solar and wind power, plus innovative wastewater treatment and seawater desalination to reduce carbon footprints. Sino-Singapore Tianjin Eco-city is designed to be ecologically friendly with existing wetlands and biodiversity preserved or improved.

The Sino-Singapore Tianjin Eco-city’s vision is to be a thriving city which is socially harmonious, environmentally-friendly and resource-efficient. The development aims to improve the living environment and to build an eco-culture that will serve as a role model for future developments in China.

The purpose of this specific project was to transform a wastewater impoundment into a wetland-cum-recreational lake that is integrated with the river system flowing through the development site.

Wastewater project

The eco-city is located on nonarable land. Prior to development, the site was one-third salt pan, one-third deserted beach, and one-third water, including a 270-hectare (667-acre) wastewater pond.

Geotube dewatering technology was used to help improve the ecology and biodiversity by transforming this wastewater impoundment into a wetland lake. The new Qingjing Lake was designed as both a recreational and a wetland lake and was integrated with the 1,000-year-old Ji Canal that flows through the development site, not only preserving, but also improving, the health and heritage of the canal.

This project used 18.7km of geotextile tube containers with circumferences ranging from 27.5m to 30.5m, filled with contaminated sediments, stacked in four layers and capped to form a 9m-high landscaped mound, with a footprint area of approximately 12 hectares (30 acres).

This is one of the rare projects where dredged contaminated sediments are put to beneficial use.


“Three years ago, this coastal area fit perfectly into the dictionary definition for wasteland. Its soil was too salty to grow crops. It was polluted enough to scare away potential residents. Sometimes the few fishermen who lived here saw investors driving in, but they quickly turned around and left, leaving nothing behind except dust.

“But then some people showed up to buy a piece of this land. It is about half the size of Manhattan. They restored the soil, cleaned up water pollution and began preparing the once-deserted place for a city that will host green businesses and some 350,000 residents by 2020.”

Quote from “China’s City of the Future Rises on a Wasteland,” The New York Times, Sept. 28, 2011.

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