Hawks Nest Sewage Treatment Plant

Environment Protection Licence #5909
The Hawks Nest sewage treatment plant Environment Protection Licence (# 5909) stipulates concentration limits for specific water quality parameters from treated effluent prior to discharge. The Hawks Nest licence has a range of concentration limits listed including 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. The 100 percentile limits are not to be exceeded, alternatively the maximum concentration.

 

The Hawks Nest licence monitoring period is reported upon annually with a 30th of June anniversary. As a condition of the licence effluent monitoring is to be undertaken fortnightly for: biological oxygen demand (BOD); total suspended solids (TSS); pH and faecal coliforms (FC). Ammonia; nitrate; total nitrogen (TN); and total phosphorus (TP) are monitored monthly. The corresponding concentration limits stated in the licence for each of the above parameters are listed in Table 1.

 

Table1.Hawks Nest licence effluent concentration limits for Biological Oxygen Demand, Total Suspended Solids, Total Phosphorus, Faecal Coliforms, Ammonia, Total Nitrogen,pH, Oil and Grease and Nitrate.
Hawks Nest STP
EPA I.D point No 1.
Discharge to waters
BOD
TSS
TP
FC
Ammonia
Total Nitrogen
pH
Oil & Grease
Nitrate
mg/L
mg/L
mg/L
cfu/100ml
mg/L
mg/L
pH units
mg/L
mg/L
90%ile
Limit
10
15
1.0
10
2
10
5
10
100%ile
Limit
20
30
6.5-8.5

 

EPA Licence

Hawks Nest Effluent Results EPA id point No 1