Phosphorous in package treatment plant effluents.
To improve the advice on the suitability of different types of small sewage discharges (SSDs) such as those from package treatment plants and septic tanks, sampling of package treatment plant systems was undertaken for Natural England by the Centre for Ecology & Hydrology, with contributions from the Environment Agency. The main aims of this work were to: (i) characterise the different package treatment plant SSD systems available and the different manufacturer designs, detailing how they treat phosphorous in particular, (ii) sample on a monthly basis 6 package treatment plants for soluble reactive phosphorous, total phosphorous and total dissolved phosphorous, and (iii) compare this to recent research on the effluent quality of septic tanks to understand if there is a difference. The findings contained within this report have allowed Natural England to further understand the risk of SSDs related to the different types of systems. It is hoped that the findings will also help steer further applied research in this area within the wider scientific community.