From Waste Streams - Apr/May 2006
www.WasteStreams.com.au
Technology for the reduction of filterable reactive phosphorous (FRP)
During the last decade, the significance of FRP reduction from the water column and the sediment P release control in preventing algal blooms has been recognised. In order to control the P level in water bodies, a number of chemical methods, such as alum or ferric chloride, have been used over the last few decades. However, many scientific studies have demonstrated significant limitations associated with these methods, including the re-release of the sorbed P when physiochemical characteristics of the water body, such as its alkalinity or redox conditions, are changed. In addition, key water quality parameters, such as the ph and conductivity of the water body, can also be affected.
Given the role of the FRP in phytoplankton activity and the limitations of the currently used chemical methods, there is a great need for a technology that can reduce the FRP concentration of the water column and prevent the release of the sediment P under a wide range of chemical conditions (ph, salinity and redox), without affecting the key water quality parameters. The need has been met by a modified bentonite product known as Phoslock.
It removes FRP effectively as it descends through a water column. As it settles, it forms a capping on th e bottom sediment preventing any further release of FRP into the water column.
The product has been demonstrated to have a rapid FRP uptake kinetic, removing 90% of it within the first four hours. In addition, it is shown to operate within a wide ph range (5-11), without any significant change to the ph of the water body.
It performs efficiently in a wide range of water bodies, ranging from natural waterways, aquaculture and a variety of waste waters such as sewage treatment holding lagoons, farm dams, poultry, dairy and piggeries. Furthermore, the removal of arsenate , selenate and molybdate has also been demonstrated.
Phoslock Water Solutions Ltd
235 Sutherlands Road, Riddells Creek 3431
