Nutrient Offsetting Map

Cartoon map showing the various elements of nutrient offsetting, including Cities and Towns, Sewage, and Wetlands

Unitywater is pursuing nutrient offsetting as a low-cost alternative to treatment plant upgrades that also enables us to protect human health and the environment.

At Yandina Creek, Unitywater will make the most of the natural processes by re-establishing the wetland environment and allowing tidal water from the river to enter the site. The wetland plants and micro-organisms in the soil will take up the nutrients like nitrogen and phosphorus from the tidal water.

Unitywater calculates how much nutrients the site will take up and this is incorporated into its treatment plant environmental licence limits. The end result? We meet our licence limits, public health is safeguarded, the environment is protected and we cater for growth, all thanks to a sensible strategy of letting nature take its course.

Step 1: Towns and Cities

Population growth and increased development in urban areas means more sewage going to a sewage treatment plant (STP).

Step 2: Sewerage Treatment Plant

Licences issued by the Department of Environment and Heritage Protection set limits on the amount of nutrients our STPs can discharge into the local waterway. Too many nutrients (like nitrogen and phosphorus) can adversely affect the health of a waterway.

To prepare our network to handle increased loads, the TRADITIONAL APPROACH would have been to upgrade the STP to enable us to meet licence limits whilst protecting human and environmental health. These upgrades can be expensive and may result in increased sewerage costs to customers.

Step 3: Wetlands

The NEW APPROACH is nutrient offsetting, which:

* Allows nature to remove nitrogen and phosphorous from river water, because wetland plants and trees use nitrogen and phosphorous to grow.

* Allows Unitywater to defer or delay costly upgrades to sewage treatment plants while still remaining compliant with our DEHP licences.

* Means savings for Unitywater customers, who do not have to carry some of the cost of STP upgrades.

    Saving Tips
  • Watering Tip #1

    The best time to water the garden is in the cooler time of early morning or late evening where there is less water loss from evaporation.