1. For the purpose of Regulation
3(1)(a)(i) of Annex IV to the Convention, a sewage treatment
plant should satisfy the following effluent standards when tested
for its certificate of type test by the Administration:
-
(i) Faecal Coliform Standard
The geometric mean of the faecal coliform count of the samples
of effluent taken during the test period should not exceed 250 faecal
coliforms/100 ml M.P.N. (most probable number) as determined by a
multiple tube fermentation analysis or an equivalent analytical procedure.
-
(ii) Suspended Solids Standard
-
(a) Where the equipment is tested on shore, the
geometric mean of the total suspended solids content of the samples
of effluent taken during the test period shall not exceed 50 mg/l.
-
(b) Where the equipment is tested aboard ship,
the geometric mean of the total suspended solids content of the samples
of effluent taken during the test period shall be not more than 100
mg/l above the suspended solids content of ambient water used for
flushing purposes.
Analysis for suspended solids should
be conducted in accordance with gravimetric methods approved by the
Administration.
2. In addition to the above conditions, the plant
should be so designed that the geometric mean of 5-day Biochemical
Oxygen Demand (BOD5) of the samples of effluent taken during
the test period does not exceed 50 mg/l.
Administrations should satisfy themselves that the plant
is designed to reduce both soluble and insoluble organic substances
to meet this requirement.