Phosphorus Fertilizer to be Manufactured from Treated Sewage Sludge

The city of Gifu in Gifu Prefecture, central Japan, announced on 24 January 2005 that it will start producing fertilizer from sewage sludge in 2009, based on its ongoing research.

As of 2005, sewage plants in Gifu incinerate about 30,000 tons of dehydrated sludge every year, producing about 1,000 tons of ash. It achieves zero sludge emission by converting this ash into common, kiln-fired bricks.

However, the ash contains as much phosphorus as crude phosphate rock due to the introduction of an advanced process that removes phosphorus from the waste water. Phosphorus is a substance essential for plant growth, but supplies of natural high-quality phosphate rock are rapidly decreasing world-wide, creating serious concern over a possible shortage of phosphorus in the mid- to late 21st century.

Gifu plans to separate phosphorus from its sewage sludge in order to produce high-quality fertilizer, foreseeing a steady demand for sludge-recycled products that will also help reduce the cost of sludge treatment. Since December 2003, the city's water and sewage division has been carrying out basic research on the plan jointly with NGK Insulators Ltd. More attention is being paid to this as a possible method for securing phosphorus, an important fertilizer.



Posted: 2005/06/03 10:33:10 AM
Japanese version