Palerang
Indicator: Discharge to Waters
Results for this indicator are also available for [an error occurred while processing this directive]
Please note: Text or data highlighted in this colour represent an update to this indicator for the period 2008/09.
What the results tell us for Palerang
Effluent from Palerang Council's residential areas is treated at three sewage treatment plants in the towns of Braidwood, Bungendore and Captains Flat. Effluent generated from rural areas outside of these townships is treated in on-site systems such as septic tanks, composting toilets and aerobic septic systems.
The New South Wales (NSW) Department of Environment and Climate Change and Water (DECCW) regulates most sewage treatment plants owned by state and local government. DECCW has issued the following licenses relating to discharge to water in Palerang Council area:
- Braidwood Sewage Treatment Plant is licensed to discharge from the outlet from the fourth polishing pond into a pipe culvert that flows into Flood Creek, with a maximum daily volume of 300 KL/day.
- Bungendore Sewage Treatment Works is licensed to discharge from the final polishing pond to Millpost Creek at a maximum daily discharge of 960 KL/day.
- Captains Flat Sewage Treatment Works is licensed to discharge from the tertiary lagoon outlet pipe to Molongo River. The maximum daily volume for this plant is 240 KL/day.
Braidwood has an upward trend of Nitrogen concentrations, and Phosphorus concentrations to a lesser degree. This may be caused by the limited capability of the existing sewage treatment plant which is scheduled to be replaced. There were no other trends in the data over the reporting period (Table 1).
| Licensed/ unlicensed | Volume (ML/year) | Type | Estimated volume discharged illegally (L/year) | Estimated volume discharged accidentally (L/year) | Receiving waters | Mass load of Nitrogen (kg) | Mass load of Phosphorus (kg) |
|---|---|---|---|---|---|---|---|
| 2004–05 | |||||||
| Licensed | 143.1 | Treated Sewage | Nil | Nil | Millpost Creek | 2600 | 1437 |
| Licensed | 32.6 | Treated Sewage | Nil | Nil | Molonglo River | 359 | 218 |
| Licensed | 78.6 | Treated Sewage | Nil | Nil | Flood Creek | 140 | 103 |
| 2005–06 | |||||||
| Licensed | 159.1 | Treated Sewage | Nil | Nil | Millpost Creek | 5946 | 1600 |
| Licensed | 33 | Treated Sewage | Nil | Nil | Molonglo River | 179 | 288 |
| Licensed | 84.4 | Treated Sewage | Nil | Nil | Flood Creek | 219 | 94 |
| 2006–07 | |||||||
| Licensed | 147.8 | Treated Sewage | Nil | Nil | Millpost Creek | 2645 | 1619 |
| Licensed | 29.8 | Treated Sewage | Nil | Nil | Molonglo River | 168 | 211 |
| Licensed | 83.3 | Treated Sewage | Nil | Nil | Flood Creek | 279 | 241 |
| 2007–08 | |||||||
| Licensed | 169.6 | Treated Sewage | Nil | Nil | Millpost Creek | 3638 | 1686 |
| Licensed | 29.6 | Treated Sewage | Nil | Nil | Molonglo River | 239 | 235 |
| Licensed | 74.5 | Treated Sewage | Nil | Nil | Flood Creek | 393 | 354 |
| 2008-09 | |||||||
| Licensed | 209.5 | Treated Sewage | Nil | Nil | Millpost Creek | 1596.6 | 1120.9 |
| Licensed | 26.1 | Treated Sewage | Nil | Nil | Molonglo River | 260.8 | 219.9 |
| Licensed | 73.4 | Treated Sewage | Nil | Nil | Flood Creek | 1759.1 | 733.1 |
Source: Palerang Council
During 2004-05, the Braidwood sewage treatment plant exceeded the maximum daily discharge volume 17 times due to moderate or significant rainfall events. The total suspended solids limit was also exceeded on two occasions in 2004-05.
Similarly during 2005-06, the maximum daily volume was exceeded on 20 occasions at the Braidwood sewage treatment plant. The total suspended solids limit was exceeded three times, twice linked to high algal levels and the Biochemical Oxygen Demand (BOD) limit once.
In 2006-07 the Braidwood sewage treatment plant exceeded the maximum daily discharge volume 21 times due to rainfall events. The total suspended solids was exceeded three times and BOD limit was exceeded twice corresponding with high algae levels.
During 2007-2008 the Braidwood sewage treatment plant exceeded the maximum daily discharge volume 19 times due to rainfall events. The total suspended solids was exceeded seven times and BOD limit was exceeded once corresponding with high algae levels.
During 2008-09 the Braidwood sewage treatment plant exceeded the maximum daily discharge volume six times due to rainfall events. The total suspended solids was exceeded six times and BOD limit was exceeded four times corresponding with high algae levels.
The Captains Flat sewage treatment plant reported no compliance issues during 2004-2005, however exceeded the 240 KL/day volume limit on five occasions during 2005-2006 as well as exceeding the total suspended solids limit twice and the BOD limit once.
In 2006-2007 the Captains Flat sewage treatment plant exceeded the maximum daily discharge volume 19 times due to rainfall events. The total suspended solids was exceeded three times, twice related to high algal levels, and the BOD limit was exceeded twice corresponding with the same periods of high algae levels. During 2007-2008 the Captains Flat sewage treatment plant just exceeded the total suspended solids limit once, possibly due to algae.
During 2008-09 at the Captains Flat the total suspended solids and BOD limits were exceeded two times corresponding with high algae levels.
No non-compliance reports were submitted for the Bungendore sewage treatment plant during 2004-2005 and 2005-2006. Suspended solids were exceeded twice in 2006-2007 and once in 2007-2008. Suspended solids were exceeded twice in 2008-2009 corresponding to high algae levels.
About the data
Information was supplied by Palerang Council. Additional information was obtained from the NSW Department of Environment and Climate Change’s Public Register of environment protection licences.
References
Department of Environment and Climate Change NSW (2008), Public Register for Licences, Applications or Notices, Environment Protect Licence, Section 55 Protection of the Environment Operations Act, viewed at http://www.environment.nsw.gov.au/prpoeoapp/searchregister.aspx on 25 September 2008.
