Stroud Sewage Treatment Plant

The Stroud sewage treatment plant Environment Protection Licence (#13042) stipulates concentration limits for specific water quality parameters from treated effluent prior to discharge. The Stroud licence operates under a range of concentration limits including 90 percentile and 100 percentile limits. These limits relate to monitoring results throughout the licence period.

To meet a 90 percentile limit, the monitoring results must not exceed the specified concentration limit for 90% of the time during the monitoring period. The 100 percentile limits are not to be exceeded, alternatively the maximum concentration.

The Stroud licence monitoring period is reported upon annually with a 14th of May anniversary. As a condition of the licence the treated effluent is monitored monthly. Discharge concentration limits are specified for: biological Oxygen demand (BOD); total suspended solids (TSS); faecal coliforms (FC); total phosphorus (TP); ammonia; total nitrogen and ph. The corresponding concentration limits stated in the licence for each of these parameters are listed in Table 1.