Last week AL-2 Teknik director Peter Gronbjerg visited Huon Aquaculture’s (Huon) Whale Point Salmon Nursery to fine tune the company’s state of the art water treatment system.
Whale Point Salmon Nursery is a recirculation system that re-uses 98 per cent of the water used in its 12, 800 cubic metre grow out tanks and four smaller, 22- cubic metre, grading tanks.
However, with the water being pumped through the tanks twice every hour, the massive volume of water means that there is 225,000 litres of effluent water (the two per cent) every day that needs to be treated.
AL-2 Teknik’s world leading waste water treatment system was installed as part of the nursery’s construction, but Huon’s environmental manager Adam Chapman said the company always knew the system could do better, but hadn’t been able to source the treatment ingredients in the quantities required until now.
“What’s been coming out of here, until now, gets diluted 50 per cent to use in the bathing water (fresh water used in the well boats at sea to rid fish of amoebic gill disease), so we haven’t got the process just right yet,” said Adam.
AL-2 Teknik is a Danish based company that has been providing wastewater treatment solutions to the aquaculture industry since 1994.
“This site here is one of the most advanced sites in the world,” said Pete.
“They’re really pushing the envelope here, in terms of both their reuse of the water, and also the size they’re growing the fish to on land.”
In summary, solids are removed from the effluent water, and the solid and liquid particles are separated, first through a belt filter and then using centrifugal force.
This process also removes the majority of phosphorus, a rapidly declining resource that has been described as the gold of the future, from the water, and mixes it in the solid waste.
The clear water produced then goes through a de-nitrification filter to remove nitrogen, before being disinfected with ozone and leaving the unit to be re-used by the Ronja for bathing fish at sea, while the solids are transferred to a composting facility.
Pete spent two days last week training the Whale Point employees to ensure that the system runs as efficiently as possible.
Huon employee Kylie Short said that the system pretty much takes care of itself, but the staff run half hourly checks, change the compost bins and monitor the processes, ensuring that the quality of water that is leaving the plant is on track.
“The small amount of nutrients that are left in that water will break down themselves very, very quickly in mother-nature,” said Pete.
“We’ve taken all the bad stuff out.
“With a little bit of further treatment, it would be drinkable, it just needs some chlorination.”
At present the treatment plant is running between 9am and 5pm, however, should Huon wish to increase the amount of water that is being treated, there is capability to run the system for longer hours.
Pete says that the technology is not limited to aquaculture, with the AL-2 Teknik system being used in municipal wastewater treatment plants, biomass heating and power plants, abattoirs, laundries, oil handling and treatment, drilling rigs and many more.
“Huon’s system would probably treat the equivalent of a town with about 10,000 inhabitants,” said Pete.
“You put this technology in municipal systems, put this at the front end, and you don’t need all the other ponds and tanks.
“It really optimises the system, so it reduces the operating cost and also the capital cost of building the systems.”
Huon’s corporate communications and community relations manager Pene Snashall said, “Huon was proud to invest millions into this waste management treatment system, to ensure minimal impact on the local environment.
“There is only one other salmon farmer in the world paying as much attention to treating waste as we are!”
