Veolia - Ken Choi

In China, wastewater has become a source of renewable energy!

Posted on 07 September 2016.

In China, Veolia converts sewage sludge into biogas to increase the energy self-sufficiency of the Hedong plant located in the heart of a booming desert region.

On the ancient Silk Road in northwest China, the Xinjiang is a vast area of deserts, steppes and mountains. Of strategic importance to Beijing because of its location - it shares its 5,300 km border with eight countries – it benefits from the "Go West Policy", the western development program implemented by the Chinese government in the early 2000s.

Doubling the water volumes handled on the site

Result: its capital, Urumqi, is experiencing an economic boom and rapid urbanization, the consequences of which are an explosion in the demand for water and rapid growth in the city’s wastewater treatment requirements. In 2005, the municipality and Veolia signed a 23 year contract to modernize and operate the Hedong treatment plant, which collects the wastewater of nearly 1.5 million people.

Veolia carried out major construction and renovation works that helped double the volumes handled on the site, increasing its capacity from 200,000 m3 to 400,000 m3 of wastewater per day.

At the same time Veolia has installed anaerobic sludge treatment facilities in order to reduce the volume of sludge and transform organic material into biogas.

Hedong has six digesters treating 2700 m3 of sludge per day, reducing the volume by 30% and generating almost one million m3 of biogas per month. This biogas is then routed to the plant’s boiler, where a cogeneration system produces enough electricity and heat to cover all the heating needs of the site and almost 50% of its energy needs.

This source of green energy improves the Hedong treatment plant’s energetic autonomy and reduces its CO2 emissions (by 80% in 2014). In addition, the sludge is also composted to produce fertilizers used for landscaping and local agriculture. Manna from heaven, in a desert region where the soils are poor.

Hedong, an exemplary circular economy project in China

The example set by Hedong is both interesting and hopeful. It’s one of the most advanced biogas recovery projects in China and a benchmark for the circular economy in Asia.

It shows how a circular economy solution, advantageous both economically and from an environmental point of view, is able to support the development of a region and meet the challenges posed by significant growth in a context where there is a scarcity of natural resources.