Forster Sewage Treatment Plant

Environment Protection Licence #2562

The Forster sewage treatment plant Environment Protection Licence (#2562) specifies concentration limits for specific water quality parameters from treated effluent prior to discharge. The Forster licence has a range of concentration limits listed including: 50 percentile, 90 percentile and 100 percentile limits. These limits relate to the monitoring of 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. Likewise, 50 percentile concentration limits are to be achieved for 50% of the results throughout the monitoring period. The 100 percentile limits are not to be exceeded, alternatively the maximum concentration.

The Forster licence monitoring period is reported upon annually with an anniversary date of the 6th of August. As a condition of the licence the treated effluent is monitored monthly. Discharge concentration limits are specified for the biological oxygen demand (BOD), total suspended solids (TSS), oil and grease. The corresponding concentration limits specified in the licence for each of these parameters are listed in Table 1.

Faecal coliforms are also monitored weekly. Total phosphorus, total nitrogen, pH, oxidised nitrogen, and ammonia are monitored monthly. A suite of metals and pesticides are also monitored on a quarterly and bi annual basis, respectively. There are no specific concentration limits for these parameters.

Environmental monitoring of Enterococci is also conducted from the ambient waters at Janies Corner, the northern end of Seven Mile beach.  

Ambient water monitoring results:

Table1.Forster licence effluent concentration limits for Biological Oxygen Demand, Total Suspended Solids, Oil and Grease.
Forster STP
EPA I.D point No 1.
Discharge to waters
BOD
TSS
Oil & Grease
mg/L
mg/L
mg/L
50%ile
Limit
20
20
90%ile
Limit
30
30
100%ile
Limit
35
35
10

 

EPA Licence

Forster Effluent Results EPA id point No 3