Determining the nutrient performance levels of Onsite Wastewater Treatment Systems for nutrient neutrality calculations: Methodology and tool development

The aim of this project is to develop a methodology and system/tool which will determine the nutrient performance levels of Onsite Wastewater Treatment Systems (OWTS) for nutrient neutrality calculations. The tool will be used by NE when assessing planning development applications in nutrient neutrality catchments, in order to ensure i) consistency in our approach and advice, and ii) the use of precautionary discharge effluent nutrient concentration values (for total Phosphorous and total Nitrogen). The system can also be used by planning authorities when conducting the nutrient neutrality calculations. The project involves a review of the British standards accreditation and a consideration of an approach that will be applied to OWTS of different technologies and different accreditation status.