Power and Water are conducting two research trials at the Leanyer Sanderson Waste Stabilisation Ponds (WSPs) as part of the Continuous Improvement Program to reduce odours.
The first trial is focused on trialling a biological additive, which operates much like the probiotic drinks people consume in that it adds good bacteria to the water. The additive is being trialled to assess whether the additive will:
- Reduce odours
- Reduce sludge volumes
- Reduce ammonia in final effluent
- Reduce algae in final effluent
To allow for the trial, a dosing facility has been constructed at the Malak pump station that enables dosing of six litres per day. Power and Water has been monitoring the results since May 2018, which so far are indicating a positive response. This research work is being delivered in partnership with Charles Darwin University and monitoring will continue through to October 2018.
The second trial involves alkali dosing over a six to eight week period, again to improve the odour. Magnesium hydroxide liquid (MHL) is being added to the water and new dosing systems have been constructed at Lakeside and Tiwi pump stations. The dosing is hoped to increase the pH, which makes conditions less favourable for the release of hydrogen sulphide a dominant source of odour. MHL is a relatively slow acting and safe alkali agent which can be added to the sewerage network at single points and reaches far into the system.
Throughout this trial, continuous monitoring of pH levels will be undertaken to ensure the dosing is implemented at controlled levels, and that the levels continue to be appropriate for the biological treatment processes that occur within the ponds.
Both of these trials will inform the future methods Power and Water implements as permanent odour mitigation solutions.