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Plant's tasteful answer to wastewater problem

By Yuan Shenggao Updated: 2022-05-06


Workers package salt produced at the desulfurization facility at Yuguang Power Plant. [Photo by Wu Jia for China Daily]

Discharge of wastewater from coal-fired power plants is often a viable threat to the environment, but a power plant in the eastern Shanxi city of Yangquan has tackled the problem with its advanced zero-wastewater-discharge technology and a waste-to-resource solution.

The Yuguang Power Plant, based in Yangquan's Yuxian county, is operated by Yuguang Coal and Electricity-a subsidiary of Shanxi International Energy Group.

A close examination of the power plant's wastewater treatment facility shows no wastewater discharge. Instead, crystal-white salt comes out of the plant. The salt is packaged at the end of the conveyor belt and is then ready to be delivered to clients.

Yuguang is a new plant that began operations in March last year. According to Wang Fei, deputy general manager of Yuguang Coal and Electricity, it is one of the most advanced coal-fired power plants in Shanxi and China in terms of operational efficiency and emission and discharge reduction.

"Our investment in the plant's environmental protection facilities reached 1.4 billion yuan ($212 million)," Wang said. "With zero wastewater discharge, our environmental performance is much better than the national standard."

The secret behind such a performance is the plant's state-of-the-art desulfurization technology that can turn pollutants into salt for industrial use, according to Wang.

The main pollutants from a coal-fired power plant include dust, gases like sulfur dioxide, nitrogen monoxide and acid-alkali waste liquid.

"The most difficult part of waste disposal is desulfurization," Wang said. "After three years of research, we developed the evaporating-crystallization technology to turn sulfur dioxide gas into liquid and liquid into solid salt."

Through the process, the plant can produce about 1,000 metric tons of salt a year, according to Ma Zhiqiang, the power plant's manager for salt production.

Annual sales of the salt amounted to about 100,000 yuan. "This is a small amount in value compared to the scale of our power plant," Ma said. "But the environmental benefit is much higher than that value."

The plant has seen 100 percent of its wastewater disposed. The disposed water is recycled and used for power generation again. "We estimated the quantity of water saved from the process can reach 100,000 tons a year.

"A revolutionary change is that there is no more wastewater and sewage outlets from our plant," Ma said.

Yuguang's zero wastewater discharge is hailed by local residents.

Yang Wei, a worker at the power plant, is a resident from a village neighboring the plant.

"Our folk villagers' impression of a coal-fired power plant is the suffocating smoke and foul-smelling water it discharges," Yang said. "But this is not the case with Yuguang."

He noted that the zero wastewater discharge and substantially reduced emissions have ensured the "clear water and blue sky of its neighborhood".

Yuguang Coal and Electricity has applied for a patent for this wastewater desulfurization technology. The patented technology is also used in the second-phase project of Heyuan Power Plant, another subsidiary of the company.

Shanxi International Energy Group, the parent company of Yuguang Coal and Electricity, is a pioneer in Shanxi's energy revolution initiative.

In addition to upgrading its coal-fired power plants, the group has enhanced efforts in developing new energy resources, including wind and solar power.

The operator of 21 large wind and solar power plants in Shanxi and its neighboring regions, SIEG plans to increase its new-energy power generation capacity by more than 2 million kilowatts per year in the future.

Wu Jia contributed to this story.