Policy / Systems / Technology

December 4, 2009


Constructed Wetland Facility Established by Japanese University Purifies Livestock Farming Drainage

Keywords: Ecosystems / Biodiversity Environmental Technology Reduce / Reuse / Recycle University / Research institute 

Copyright Tohoku University

The Field Science Center at Tohoku University, Naruko Onsen, Osaki City, Miyagi Prefecture, started operation of a full-scale constructed wetland which can examine various advanced technology concerning water purification on September 1, 2009. The facility takes advantage of the wetland's ability to purify water without using additional energy.

The constructed wetland can formulate a system which covers aerobic treatment, anaerobic treatment, and sludge reduction treatment for wastewater with minimum energy. This feature allows it to establish a self-sufficient sewage treatment in combination with a solar or wind-power generation system. Such low-cost and low-energy wastewater treatment system using wetland technology has been introduced at a rapid pace in the United States and Europe, whereas there have been very few cases in Japan.

The facility receives approximately two tons of daily drainage from 30 dairy cattle and continuous water purification experiment is carried out to develop appropriate wetland technology in Japan The effective area of the wetland is 111 square meters, which is divided into five parts. The wetlands consists of filter layers with vegetation of common reed (Phragmites, sp), and wastewater is purified through a two-step process: first physical absorption filtration by filter layers, then biological decomposition by rhizosphere microorganisms takes place.

The study team intends to demonstrate the usefulness of the constructed wetland system as a next-generation, local, small-scale diffuse wastewater treatment facility through a four-year examination.

Posted: 2009/12/04 06:00:15 AM