Researchers at Tongji University are trying to build the first domestically produced biofilter to recycle sewage, allowing filtered water to be used for cleaning roads, flushing toilets and watering gardens and lawns.

 

Beijing already uses similar technology to filter its sewage, but the foreign-made filters are considered too expensive to be put into widespread use in the city, researchers said. It costs 3,000 yuan (US$375) to 4,000 yuan to treat a cubic meter of sewage with that technology.

 

Cao Dawen, a professor in Tongji's environmental science and engineering college and leader of the research program, said domestically made filters should cut that cost by about 70 percent.

 

The project recently received 600,000 yuan in funding from the Shanghai Educational Development Commission and a local environmental protection company, Tongji officials revealed yesterday.

 

The technology uses fungus to create a membrane that can filter sewage.

 

About 25 percent of the 5.8 million cubic meters of tap water used in the city each day could be recycled, but isn't, researchers said. Instead, most used tap water is treated and discharged into rivers and creeks.

 

"As we have already taken great efforts to treat sewage, it is a big waste to just discharge it without making use of it again," said Cao.

 

His team hopes to have completed the device and have it ready for production by the end of 2008.

 

It will take several more years, however, to put it into widescale use across the city.

 

In order to provide water that can be used for flushing toilets, but not bathing or cooking, the city would have to create a separate pipeline for the treated sewage water. Property management firms around the city would also have to install a separate set of pipes in residential and office buildings - an expensive and time-consuming task.

 

(Shanghai Daily December 29, 2006)