Japanese Companies Develop Technology to Recycle Construction Sludge

Shimizu Corporation, a major Japanese construction company, and Nisshin Flour Milling Inc., part of the Nisshin Seifun Group, announced July 23, 2007, that together they have developed a technology to treat and recycle construction site sludge containing cement instead of hauling it away for disposal. The technology involves using microorganisms to neutralize the sludge on-site and treat it to make it harmless enough to use as backfilling soil. "Neutral Compo," the fermentation accelerator the companies developed, is made out of natural ingredients including wheat.

Construction sludge containing cement is generally strongly alkaline. It is therefore classified as industrial waste and needs to be hauled away, and then treated at controlled disposal facilities. Up to now, this has meant paying huge costs for transportation and disposal, while also causing environmental impacts, including carbon dioxide emissions. The companies said that 20 percent of disposal costs are related to transport alone

The co-developed technology, dubbed the "bio-neutral method," succeeded in neutralizing sludge with a pH of around 10 to below 8 in one month by incorporating a feeder and mixer of the Neutral Compo fermentation accelerator into turbid water treatment facilities on-site. Once treated the product can be utilized as a fertilizing soil after being mixed with compost to increase soil aggregation.

Shimizu Corporation plans to start using the new technology to recycle construction sludge at its dam and tunnel construction sites.

http://www.shimz.co.jp/english/index.html
http://www.nisshin.com/english/index.html

Posted: 2007/11/29 10:00:17 AM
Japanese version