Recycling coal ash into environmentally-friendly building materials is one way China's largest coal-producing province of Shanxi is trying to cope with the 120 million tonnes of toxic dump.

Lying in the surroundings of Shentou No. 2 Power Plant, in Shuozhou City of the province in northern China, a 1.2 square-km landfill of coal ash has taken shape for three decades.

Annually, three million tonnes of ash leaks from three power plants in the area.

Coal ash contains toxic heavy metals, including arsenic, cadmium, mercury and lead, which leaks into the water system and is blown into the air on windy days.

Villagers nearby are worried that the pollution may have damaged land and affected the health of livestock and even humans.

"With even the lightest wind, tiny particles take flight, blotting out the sky like a thick sandstorm of ash," said Zhang Weipan, an engineer of Shuozhou Pingshuo opencast coal mine.

Faced with long-lasting pollution, the government of Shuozhou City plans to build a landfill into China's largest coal ash recycling base in an attempt to gradually remove the glacier-like ash dump.

"One source of optimism is that the coal ash leaked by Shuozhou's three power plants contains alumina and silicon that could be used as raw materials for building new products like bricks and ceramics," said Liu Yao, an expert with the Shuozhou branch of Shanxi Coal Transportation Co.,Ltd.

Close to the site, the Shuozhou municipal government is building an industrial zone with an area of 1,977 acres to recycle five million tonnes of coal ash annually, with an investment of 12 billion yuan (about 1.9 billion U.S. dollars).

The zone has attracted nine enterprises since April 2011.

With 16 ongoing projects and 13 products to be launched to market by the end of the year, the total consumption capacity of ash is expected to reach 2.4 million tonnes, said Li Zhengyin, the city's mayor.

Li said the use of recycled ash will help the industry become a pillar sector of the city, accounting for 5 percent of overall GDP.

Hu Yong, CEO of Shuozhou Runzhen Technology Co., Ltd, said he started recycling ash into bricks in 2005.

A square meter of recycled floor manufactured by the company uses 12 kg of coal ash. The company's annual output last year reached 400,000 square meters, which used 1.5 million tonnes of coal ash, about one seventh of the city's annual ash emission.

However, the path ahead is not smooth.

China's coal production is expected to hit 3.7 billion tonnes this year, up 3.5 percent from 2011, according to China Coal Industry Association.

The amount of coal ash generated from coal-fired power plants will rise.

While in Shuozhou, a major electricity supplier to Beijing, the installed capacity of power plants will reach 20 million kilowatts by the end of 2015, according to the mayor.

The emissions of coal ash will drastically increase to 18 million tonnes in 2015, while the processing speed lags far behind.

The utilization of the waste requires much more financial and technological investment, said Wang Jiwei, secretary of China Association of Resource Utilization

The economic benefits might not be as much as the environmental ones, but it will pay off in the long run, added Wang. Endit