An engineering team at Water Corporation’s Subiaco Water Resource Recovery Facility (WRRF) has turned a basic principle – pool skimming – into an innovative, cost-saving solution for a longstanding wastewater treatment challenge.
All Water Resource Recovery Facilities (WRRFs) have to deal with familiar issues. When dealing with so much wastewater scum builds up in the form of light matter and foam-like material. This scum accumulates at the inlet point and, if not removed, can lead to high odour levels and dangerous gas buildup.
Subiaco WRFF previously used a bulky mechanical harvester built with chains and troughs to solve this problem but according to Adam Graham, Senior Technical Advisor – Mechanical Field Support, “The machine was very large with lots of moving parts, which led to many points of failure.”
It was eventually decommissioned and replaced with a temporary, high-cost workaround: hiring vacuum trucks to manually extract the floating waste.
“But this costs around $100,000 per year,” said Graham, “so we needed something sustainable and safe.”
A better solution
The Skimoil floating skimmer is a device originally designed to collect oil from marine spills. Repurposed for wastewater operations by Principal Engineer – Water Resource Recovery, Evert Joubert, this solution was adapted to suit WRRF inflow dynamics.
“Evert suggested trialling the Skimoil head after doing some research into how we could best remove scum in our WRRFs,” Graham said. “The Subiaco trial was to see if the unit could be that solution, meaning we could roll it out to other facilities.”
The device works like a pool skimmer box, using a self-priming pump to suction floating scum off the surface and pump it away from the inlet channel. The modified skimmer floats up and down with changes in water level, maintaining consistent performance without intervention.
“The simplicity is its strength,” said Graham. “Removing the scum manually with a vac truck was awkward and slow. This new system is effective, reliable and significantly improves safety and efficiency.”
Expanding the trial
“With a successful trial under our belt, we’re now considering further opportunities to use this method at our other WRRFs,” said Graham.
The trial at Subiaco was conducted in partnership between the engineering and Treatment and Resource Recovery (TaRR) teams, with strong support from site operations staff.
“So far, working on this project has shown me how innovation really gets people working together collaboratively to achieve a common goal.”
The skimmer performed well enough to warrant a permanent design looking to address shortfalls that were identified in the trial, before implementing a long-term solution.
installation is now being considered for broader roll-out across other Water Corporation sites.
To find out more information please reach out to Adam Graham, Senior Tech Advisor – Mechanical Field Support Engineering at Water Corporation
Adam.Graham@watercorporation.com.au
