NANCHANG (XINHUA) - A huge amount of ceramic waste in east China's Jiangxi Province has been transformed into a huge pile of cash as part of the ongoing sponge city project.

A sponge city is one in which urban precipitation is absorbed into the groundwater rather than running off into watercourses. The idea is to make better use of rainwater and prevent flooding.

These sponge cities typically feature roof gardens, large numbers of trees, vast areas of lawns and permeable pavement.

Luo, 60, is president of the Longfa Industrial Company in Jiangxi's Pingxiang City. The company is one of the biggest ceramics makers in the city that produces about 70 per cent of China's industrial tiles.

"The company has been doing great business for 17 years," Luo said. "But the waste we produced was a big headache."

High levels of quality control mean that while churning out ceramics, Luo's company also generates tonnes of waste, including substandard bricks, floor tiles and ceramic balls. Mountains of waste pile up behind the factories - dirty, ugly and hard to dispose of.

"I had to pay people to take the waste away," Luo said.

A big change came in 2014, when Luo travelled around Europe and found himself walking on footpaths made of water permeable bricks.

"The streets were dry even after heavy downpours, whereas in China, there is always flooding in cities," Luo said. "That's when I realized there was huge market for permeable bricks, and that the ceramic waste was just the material needed."

On his return, Luo began research on how to transform his waste into bricks. A year later, the government named Pingxiang as one of 16 "sponge cities" to pilot ways of tackling the dual challenges of water shortages and urban flooding.

By then, Luo's bricks made of the ceramic trash were ready for mass production.

"The bricks were in high demand as soon as the sponge city project was launched," he said. "I no longer needed to pay to clear the garbage behind the factories. On the contrary, people were now paying me to take it away."

According to Luo, one square metre of the bricks can absorb about 20kg of water.

"When the weather is dry, the bricks can release vapour into the air, which increases humidity and fights pollution," Luo said.

In Pingxiang, about 200,000 tonnes of industrial ceramic waste are produced each year. Luo's company turns around 240 tonnes of that into bricks every day, which "not only makes money, but protects the environment."

According to the sponge cities plan, 20 per cent of China's cities should have modern sewerage systems and infrastructure allowing efficient rainwater absorption by 2020, with the number rising to 80 per cent by 2030.

This means even higher demand for Luo's "garbage" bricks. His production line, which can make 100,000 tonnes of bricks a year, is in full swing, and bricks have been delivered to Ningxia, Hunan and Guangxi.

A new production line is already in operation.

"The bricks are mainly for municipal projects to make cities spongier," said Luo, who is looking for other ways to make even more bricks.

"Pingxiang has many steel-makers, and the quantity of waste they produce is equally staggering," Luo said.

"I plan to make steel waste into water permeable bricks, too."