New authorisation conditions for small sewage discharges in Scotland

date11 December 2014

Anyone applying for a small secondary treated sewage discharge from the Scottish Environment Protection Agency (SEPA) may notice that the way the discharges are authorised has changed.

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Effluent quality will now be specified by a mean standard, rather than the percentiles and single tier standards that were used before.

No changes need to be made by applicants, except the application will be for a mean standard. There is no need to alter the type of plant used, no replacements need to be made to existing plants and the quality of the discharge is not changing – only the way it is authorised.

This does not apply to existing authorisations or septic tanks.

It does apply to:

  • un-sampled secondary treated sewage discharges; 
  • secondary treated sewage discharges authorised by registrations;
  • un-sampled licensed secondary treated sewage discharges. These are smaller discharges, usually serving fewer than 200 people.


Manufacturers of package treatment plant performance will have to have their product independently tested to ensure it meets the European standard test EN12566 Part 3.

The new standard will provide a similar level of protection to the water environment, but should be more easily understood by the public and industry.

This change only relates to applications received on or after 2 December 2014. Applications received prior to 2 December will be processed and issued using the previous system.

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