Sewage treatment and monitoring


Review of Environmental Monitoring Programs - Dubbo Sewage Treatment Plant, Ballimore and Wongarbon (Pine Avon)

Review of Environmental Monitoring Programs (PDF 1.3MB)



Council provides sewerage reticulation and treatment services to 32,537 Dubbo residents and 687 Wongarbon residents. Sewage is transferred from the residential properties, through a series of pipelines and pump stations to the Dubbo and Wongarbon Sewage Treatment Plant.

 An Operational Environmental Management Plan (PDF 1MB) has been prepared to document the following:

  • Regulatory requirements
  • Management system components including reporting, document control, training, complaints and review, and
  • Environmental risk identification, monitoring and management strategies associated with the sewer operations.   


Dubbo Sewage Treatment Plant

The Dubbo Sewage Treatment Plant is licenced by the NSW Environment Protection Authority. The licence (PDF 139.3KB) number is 3850.


Effluent leaving the Dubbo Sewage Treatment Plant is monitored in accordance with the terms of the licence. Licencees are required to publish pollution monitoring data that has been collected as a result of a licence condition, in accordance with section 66(6) of the POEO Act and written requirements issued by the EPA.


The Dubbo Sewage Treatment Plant has two discharge points. The tables below refer to Point 1, which is the point of discharge to the Macquarie River. The monitoring frequency for this point is weekly when it is necessary to discharge effluent to the River. 

Sewage Treatment Plant Point 1 - 2016/2017 (PDF 232.4KB) 

Sewage Treatment Plant Point 1 - 2015/2016 (PDF 232.8KB)

Sewage Treatment Plant Point 1 - 2014/2015 (PDF 297.4KB)

Sewage Treatment Plant Point 1 - 2013/2014 (PDF 317.2KB)

Sewage Treatment Plant Point 1 - 2012/2013 (PDF 287.8KB)



Point 2 refers to monthly discharge of effluent to effluent irrigation. The licence does not state acceptable ranges for pollutants at this Point. Note that fewer pollutants are required to be monitored at Point 2 as compared to Point 1.


Sewage Treatment Plant Point 2 - 2016/2017  (PDF 192.9KB)

Sewage Treatment Plant Point 2 - 2015/2016 (PDF 190KB)

Sewage Treatment Plant Point 2 - 2014/2015 (PDF 200.7KB)

Sewage Treatment Plant Point 2 - 2013/2014 (PDF 203.7KB)

Sewage Treatment Plant Point 2 - 2012/2013 (PDF 200.8KB) 

Pollution Incident Response Management Plan (PIRMP)

Council has developed a Pollution Incident Response Management Plan (PDF 423KB) (PIRMP) that will guide Council's response in the event of any pollution incidents that may occur at the Dubbo Sewage Treatment Plant.

Sewage Treatment

The following table indicates some parameters of sewage received at the Dubbo Sewage Treatment Plant, called "influent", and the quality of the water after treatment, when it leaves the plant, called “effluent”.

Parameter Unit   Typical Influent  Typical Effluent
Total Coliforms cfu/100 mL 22,000  12,736 
Faecal Coliforms cfu/100 mL 1,180   216 
E Coli cfu/100 mL 1,032   205
pH 7.5  8.9
Electrical Conductivity µS/cm 1,280   929 
BOD – 5 Day mg/L 154   2.9
COD mg/L 389   38.6 
Chlorophyll ‘a’  µg/L   2  27.5 
Ammonia – N mg/L  35   0.25 
Nitrogen – Oxidised mg/L  1.89   1.17 
Nitrogen – Total Kjeldahl mg/L  1.4   1.35
Nitrogen – Total mg/L  54   2.51
Phosphorus – Total mg/L  9.2   4.48
Suspended Solids mg/L  169   6.71
Oil and Grease mg/L  <2   1

The unit “cfu/100 mL” refers to the number of colony forming units in a 100 millilitre sample. It is a biological measure of viable bacterial cells in the water.

Electrical conductivity is measured in units of micro Siemens per centimetre (µS/cm). It is an indication of the amount of nutrient, impurities or salts in solution.

Last Edited: 06 Dec 2016

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