Yass Valley
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 Yass Valley
Effluent from Yass Valley Council area is treated at the Yass Sewage Treatment Plant. Effluent generated in rural areas of Yass Valley is treated by septic tanks, absorption trench and pump out systems, aerated waste treatment systems, and waterless and wet composting systems.
The New South Waled (NSW) Department of Environment and Climate Change (DECC) has licensed the Yass plant to discharge from the outlet pipe from the maturation pond to Banjo Creek, a tributary of Yass River, and to council owned land for irrigation. The plant has a volume limit of 1,300 KL/day.
The DECC also has a discharge to waters licence for the Yass Water Treatment Plant to discharge the backwash water from the sedimentation lagoon into the Yass River. The plant has a maximum daily volume limit of 140 KL/day.
The high phosphorus load in the discharge water may contribute algae growth in Yass River (Table 1). Currently Yass Sewage Treatment Plant has no facility to remove the phosphorus load. A new plant is currently under construction, which is expected remove a significant proportion of the phosphorus load, when commissioned at the end of 2009.
| 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 | 210 | Sewage | Nil | Nil | Banjo Creek | 1604 | 1509 |
| 2005–06 | |||||||
| Licensed | 280 | Sewage | Nil | Nil | Banjo Creek | 2943 | 2074 |
| 2006–07 | |||||||
| Licensed | 156 | Sewage | Nil | Nil | Banjo Creek | 2248 | 1361 |
| 2007–08 | |||||||
| Licensed | 227 | Sewage | Nil | Nil | Banjo Creek | 4131 | 2198 |
| 2008–09 | |||||||
| Licensed | 205 | Sewage | unknown | Nil | Banjo Creek | 3417 | 1564 |
Source: Yass Valley Council
In 2004-05, the Yass Sewage Treatment Plant exceeded the daily volume limit of 1,300 KL/day on 79 occasions, as well as exceeding the river discharge volume and dilution ratio 125 times. The pH limit was also exceeded on three occasions in 2004-05. In 2005-06 the daily volume limit was exceeded on 74 occasions, as well as discharged effluent to the river when river flow is below 50 Mega litres per day on 236 occasions. In 2005-06 the pH limit was again exceeded on three occasions.
The volume limit was exceeded in 2006-07 on 16 occasions. In addition, effluent discharged to the river when river flow is below 50 Mega litres per day was exceeded on 304 occasions. No reports were available for 2007-08 at the time of reporting.
Trade Waste Agreements
Yass Valley Council has no large scale trade waste dischargers in the Council area.
About the data
Information was supplied by Yass Valley Council. Additional information was obtained from the DECC’s public register of protection licences.
References
DECC - see Department of Environment and Climate Change
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 30 September 2008.
