Water Quality Offsets

Queensland Urban Utilities is seeking to have its Environmental Protection Act licence for the Beaudesert STP varied to increase its annual nitrogen discharge limit by 7 tonnes per year.

The national Coastal Catchments Initiative by the Australian and Queensland Governments may enable nutrient trading options between sources in Moreton Bay catchments to obtain water quality targets cost-effectively. 

Queensland Urban Utilities has commenced a water quality offsets program help reduce the amount of sediment and nutrients entering one of South East Queensland’s most impacted rivers.

I am wondering if the same logic and economics could be used to separate sources of nutrients like nitrogen, phosphorus and potassium at their source of generation through urine separation toilet technologies.

A report in November 2007, proposed a methodology for developing environmental equivalency for water quality offsets through an application in the Logan/Albert River catchments.

Queensland Urban Utilities is spending ~$1 million in a pilot water quality offsets scheme to repair approximately 500 metres of severely eroded riparian corridor near the Beaudesert Sewage Treatment Plant in the Logan River catchment.  This ‘green infrastructure’ project was chosen over a traditional sewage treatment plant upgrade which would have cost $8.0m and focused only on reducing nitrogen emissions.Other benefits for the Logan River will include reduced local turbidity, reduced total phosphorus mass load transfer and establishment of permanent native vegetation to improve biodiversity.  

Healthy Waterways, through its ongoing Report Card, will monitor the improvements in waterway health resulting from this vital program as Queensland Urban Utilities manage the amount of sediment and nutrients entering the Logan River.

The  Healthy Waterways 2013 Ecosystem Health Report Card provides an insight into the health of South East Queensland’s waterways and Moreton Bay.

The 2013 Report Card results show the mud and nutrients deposited into Moreton Bay during the 2011 and 2013 floods continues to reduce water clarity and stimulate the growth of algae.

There was a slight overall decline in Moreton Bay (B- to C), with Central Bay (A- to C+) showing the greatest decline. Last year, the health of seagrass beds and corals appeared to improve slightly. However, this year corals and seagrasses are showing signs of ongoing stress and decline due to the large amount of mud and nutrients deposited into Moreton Bay during the 2011 and 2013 floods.

On a positive note, most of Moreton Bay showed an improvement in the sewage indicator, which led to improvements in Broadwater (C- to B-) and Pumicestone Passage (C- to C+).