Only full-scale marine sewage treatment plants should be
accepted for testing purposes. The Administration may certify a range
of the manufacturer's equipment sizes employing the same principles
and technology, but due consideration should be given to limitations
on performance which might arise from scaling up or scaling down.
In the case of very large, very small or unique sewage treatment plants,
certification may be based on results of prototype tests. Where possible,
confirmatory tests should be performed on the final installation of
such sewage treatment plants.