Hawks Nest Sewage Treatment Plant

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.