Nutrient Neutrality Assessments + Mitigation Solutions

Schema has significant experience gained from working in the impacted areas within Norfolk. We are knowledgeable about all local procedures and factors unique to the area, whether they are phosphorus- or nitrogen-sensitive.

We have helped planners, developers and Land Agents to get their proposals through planning through our efficient and practical approach to mitigation.

‘Nutrient neutral’ development is required by Natural England (NE), as a statutory consultee to the local planning authority, on all new developments in the catchments of ‘designated sites’ whose background levels of nitrogen and/or phosphorus have reached ‘unfavourable’ status.

All developments within the designated areas will require a Nutrient Neutrality and Mitigation Strategy Report (NNAMS) to determine how much nitrogen/phosphorus will be generated. The developer must prove the development to be “nutrient neutral” to receive planning permission.

Schema are able to assist with proposing potential solutions which include: septic tank replacement, new high-tech onsite sewage treatment, wetlands, rural and urban sustainable drainage, and agricultural based mitigations which include livestock yards and land use changes.

We have seen that where land-based mitigation features on-site and off-site are not viable, then the use of Septic Tank replacements can be invaluable for many schemes.

We have undertaken a number of these assessments recently and follow the below approach:

  • Locating existing assets with the catchment area and looking at non-mains drained sites (Campsites, Farms, houses etc)
  • Contacting areas of interest to gauge their willingness to have their systems upgraded
  • We would usually go to the site to review the Existing Septic Tank location, outfall location and gather information on existing usage and model etc.
  • Once we have this information, we undertake calculations to assess the offset figures and whether any further mitigation is required.
  • We would undertake the Septic Tank Replacement Working Drawings for Tender incl. Existing Tank location and proposed tank details. It may be prudent that additional survey works are required to assess Invert Levels etc.
  • All this information would be placed into a mitigation strategy document to be issued to the LPA.

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