In the fourth issue of the Wilson Center's China Environment Forum's InsightOut series, six experts from the United States and China explore the potential of sludge power in Chinese cities and offer recommendations based on their experiences. The authors of "Waste Power: Can Wastewater-to-Energy Revolutionize Pollution Control and Clean Energy in Chinese Cities?" argue that these solutions have the greatest potential for energy and pollution mitigation.
Methane—which is a dangerous greenhouse gas when released into the atmosphere—can be captured, burned, and used as a valuable energy source. Capturing and using methane lies at the heart of the waste-to-energy revolution. The success of China's waste-to-energy transition will hinge on whether the country can implement the right mix of policy directives, market incentives, partnerships, and successful operating models for methane capture.
Encouragingly, China's 2015 Water Pollution Action Plan tackles the country's long-overlooked wastewater/sludge problem by setting ambitious targets to improve its underdeveloped sludge treatment capacity. The plan mandates that most prefecture-level cities must achieve 90% toxic-free sludge treatment by 2020.
However, although methane capture and utilization technologies have existed for decades, Chinese city managers and energy and water utility operators have only just begun to explore how to turn sludge into energy. The 50+ sludge-to-energy pilots in China have faced policy, governance, and financing obstacles have kept most of them from succeeding.
As Chinese cities have grown rapidly over the past decades, untreated sludge—the toxic byproduct of the municipal sewage treatment process—has quietly contaminated China's soil, groundwater, and croplands. Strikingly, the magnitude of the country's sludge problem and pollution risks did not come to light until late 2013, when Caixin journalists followed trucks from a central Beijing wastewater treatment plant to the city's outskirts, where the drivers illegally dumped untreated sludge into farmers' fields. After this expose, concerned citizens mapped the more than 30 sludge mountains encircling the capital.
China's wastewater plants produce more than 40 million tonnes of sludge annually—enough to fill five great pyramids of Giza—but less than 20% is treated. Chinese cities have largely relied on exporting sludge to landfills and incinerators or illegally dumping untreated sludge into waterways or onto farmland.
China's wastewater treatment plants, incineration plants, and landfills are major contributors to air pollution. With hardly any space left in its landfills, China increased its incineration capacity tenfold between 2003 and 2013, releasing air toxins linked to higher rates of cancer. China is also the world's top emitter of greenhouse gases; its wastewater plants are responsible for a quarter of global wastewater emissions of methane, a potent greenhouse gas that traps heat 28 times more powerfully than carbon dioxide.
(Writing by William Gao Editing by Jessie Jia)
For any questions, please contact us by email@example.com or +86-351-7219322.