Waste Management In Action

Biological treatment below the Bass Strait: Aerofloat

Aerofloat’s Michael Anderson talks about a newly installed wastewater treatment plant that is ensuring strict compliance with the Tasmanian EPA’s wastewater reuse guidelines.

In May last year, BioMar Australia commenced aqua-feed production at its state-of-the-art $56 million facility in Tasmania. Founded in 1962 by a group of Danish fish farmers, BioMar is a global leader in sustainable aquaculture, with product trials now underway for a variety of species in Australian and New Zealand.

BioMar Group CEO Carlos Diaz, who attended the virtual opening from Chile, noted that global aquaculture is expected to double by 2050.

“BioMar is committed to helping Tasmania and our wider region play an important role in this endeavour, supporting farmers to grow healthy, sustainable and safe food,” he said.

BioMar announced plans to establish Australian production in 2017, with the facility set to produce up to 110,000 tonnes of aqua feed to support the Australian and Oceania aquaculture industry each year.

To manage its Tasmanian operations sustainably, BioMar engaged wastewater treatment specialists Aerofloat to design and build a wastewater treatment system – allowing treated, compliant effluent to be disposed to the surrounding pine forest in line with strict guidelines set out by the Tasmanian EPA.

Wastewater generated from the factory’s biofilter and washwater from the production area is high in ammonia nitrogen. As such, Aerofloat recommended a biological system – installing its patented Sequence Batch Reactor (SBR) technology to ensure compliant effluent for BioMar’s facility.

According to Michael Anderson, Aerofloat General Manager Engineering, while there are a number of ways to biologically treat wastewater, Aerofloat’s approach is mechanically simple – meeting BioMar’s budget as well as EPA requirements.

“They knew what technology they needed and had very specific wastewater quality influent data for us, so we took the time to do a real deep dive on their wastewater problem prior to receiving a formal order,” Anderson says.

Similarly, Brian McWhirter, BioMar Facility Manager, explains that BioMar chose to work with Aerofloat because the company took the time to discuss all options, before helping BioMar decide what solution best suited their requirements.

“We were looking for a system that was easy to operate, with low maintenance and remote monitoring capabilities,” McWhirter says.

“As there is no sewer connection to our site, the only other option was to cart our wastewater off-site to a treatment facility, so it made sense to treat our wastewater on-site.

“As the treated wastewater was going to be irrigated, it needed to meet all the EPA wastewater reuse guidelines.”

Anderson explains that while the volume of wastewater produced at BioMar’s facility isn’t exceptionally high, when it rains, as is common in Tasmania’s Wesley Vale region, the volume goes up significantly.

“Our system takes water from an air scrubbing system, which includes leachate that comes off the biofilter, and when it rains, we receive that as well,” he says.

“While trucking away the waste would have been fine when it doesn’t rain, the plant is located in a high rainfall area, meaning that wouldn’t have been viable.”

Aerofloat’s technology is hydraulically designed to take the site’s rain events as well as the organic load from the biofilter, thereby eliminating the need to transport wastewater for later processing.

“We conducted a lot of studies and data gathering to determine that we were confident in our process,” Anderson says.

Aerofloat’s biological wastewater treatment solution utilises three SBRs, incorporating Aerofloat’s proprietary Air-Locked Syphon decanters (AeroALS).

“The decanter mechanism is very unique and was designed by our Managing Director Ray Anderson in the 1980s. I believe we’re one of the only companies in Australia that use this technology,” Anderson says.

He adds that Aerofloat didn’t use the technology for many years, however, saw the BioMar project as an opportunity to demonstrate its effectiveness, and have since installed AeroALS’ on eight other projects.

“The AeroALS is a robust, efficient and mechanically simple decanter. It’s also a low investment for the return, as we use polyethylene tanks as opposed to larger, more expensive concrete structures,” Anderson says.

“We’ve found the tanks to be very strong and long-lasting – providing a budget conscious solution for our clients without sacrificing on quality.”

Due to high ammonia levels in the wastewater, a dedicated anoxic reactor was installed prior to the SBRs to treat the wastewater to the required EPA standards, creating compliant effluent.

Anderson explains that while it’s the responsibility of Aerofloat’s clients to seek council and EPA approvals, Aerofloat works closely with them to support compliance.

“We provide our clients with all the necessary documents and guarantees of process to satisfy the EPA,” Anderson says.

“We then go through a rigorous testing period during commissioning and post-commissioning, where effluent is sampled and sent to a lab to verify that it’s doing what we said it would.

“Our clients aren’t just buying pumps, controls and tanks, they’re buying our process knowledge, so we’re committed to supporting them through that process.”

SBR technology is a suspended growth biological treatment process whereby the microorganisms in the wastewater are aerated, settled and the treated clear effluent is decanted in the same reactor, overcoming the need for a separate clarifier.

Given the regional location of the site, BioMar also wanted the system to be low maintenance and offer remote monitoring capabilities. Remote monitoring installed at the site allows Aerofloat engineers to log on and remotely monitor and optimise the system following commissioning.

“We can review trends, check plant performance, flow data and all additional parameters and run conditions. It also means the operator can view plant performance without leaving the site office,” Anderson says.

The BioMar treatment plant was completed on schedule, with the commissioning process handled efficiently by Aerofloat’s engineers despite COVID-19 restrictions.

According to McWhirter, the plant is running very well and achieving the desired results.

“Aerofloat staff have been readily contactable for ongoing advice and optimisations,” he says.

“Aerofloat have been super easy to work with right from the start. They have also assisted with issues outside their scope – the team have always been available and very helpful.

“I’d be happy to recommend Aerofloat to anyone looking for a wastewater treatment solution.”

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