Understanding and Optimising Water Quality in the Laratinga Wetlands

Background:

The UAiPhD is an innovative 4 year program which includes the completion of a 6 month industry placement together with selected Career and Research Skills Training (CaRST) and industry development activities.

A placement provides an opportunity for the student to work on an industry problem which is distinct from a student’s PhD research topic.

The placement may be undertaken on a full-time or part-time basis provided that the student maintains their full-time enrolment status and completes the agreed number of placement days.

March 2022

If you’ve walked through Laratinga Wetland recently you may have seen a lot of air bubbles in one of the basins. Don’t fear it’s not a sci-fi movie. It’s all part of an important study to understand and optimise water quality.

Council is working closely with PhD student Danielle from the The University of Adelaide to study water quality in the wetland.

The work Danielle is doing includes assessing trends in water quality to see if there are any impacts from increased residential population, and the improvement of water quality with the use of artificial aeration.

Danielle has really enjoyed working on the project and at Laratinga Wetland, “I’m also working in collaboration with the CSIRO and UniSA which enables me to complete laboratory work for this study”.

“Maintaining a healthy wastewater treatment system, including the lagoons, treatment plant and wetland is very important to maintain a healthy habitat for a variety of animals and plants, as well as the recreational and aesthetic benefits to the community” adds Danielle.

The aeration trial:

The use of aerators in constructed wetlands have been found to be a successful tool to deliver dissolved oxygen to the water to increase nutrient removal and improve water quality. It has also been communicated in previous research that partial aeration (aerating for half of the day) can be more beneficial than continuously aerating the water to achieve optimal nutrient removal to further improve water quality.

Based on the findings from previous research, a trial will be conducted as part of a collaborative PhD program involving the University of Adelaide and the Mount Barker District Council. This trial has been designed to look at the current nutrient levels and water quality indicators and how these change with various dissolved oxygen concentrations using a newly installed aerator and porous tubing. The oxygen delivery is able to be controlled to compare whether partial aeration or continuous aeration is more beneficial.

The PhD program:

This work is part of a collaborative University of Adelaide industry PhD (UAiPhD) program and is funded by both the university and the Mount Barker District Council. The program incorporates numerous studies that aim to develop and trial innovative science-based strategies for optimising water quality management in the Laratinga wetlands. The first component looks at long-term analysis of the performance of the wetland to further treat domestic wastewater with various hydraulic and nutrient loadings. The second component is the aeration study mentioned above. The study that follows will focus on determining nutrient fluxes from the sediment to the water using advanced techniques, how these fluxes vary under different dissolved oxygen conditions, and how these can vary throughout the day and season. This will help to better understand internal nutrient loading to the wetland. The program will also enable further development and calibration of water quality models to enable simulation of wetland management strategies.

Outcomes

The ideal outcomes of the PhD program will be to:

improve water quality discharged from the wetland to the Mount Barker Creek,
increase flow through the wetland and maximize wetland discharge volumes to the Mount Barker Creek via improved management scenarios,
have the ability to predict water quality outcomes with greater accuracy using monitoring and modelling strategies.

Danielle Allen

May 2021

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