Blue Green Algae Control

Industry: Recreational Ponds
Product: Air Lift Dredge
Location: Gold Coast, Queensland, Australia

Project Brief

As part of the Rosser Park pond improvement project with the Gold Coast City Council, we undertook the process of sludge management and removal and blue-green algae control.

We faced some challenges in the early stages with regards to positioning and operation of the rope winch, pond bottom profiling along with a steep sloping bottom (making tracking difficult) as well as there being various unknown submerged hazards on the pond floor.

Blue Green Algae at Rosser Park Pond

Erosion and bird activity mobilising sediment

Erosion and bird activity, plus manure (water and land) mobilises sediments

Overhanging vegetation at Rosser Park Pond

One challenge was overhanging vegetation in the pond

Submerged objects at Rosser Park Pond

Another challenge that existed, multiple submerged objects of an unknown quantity

Existing infrastructure at Rosser Park Pond

The third major challenge was working around existing infrastructure in the pond

Nature and other considerations at Rosser Park Pond

Nature in the area was another consideration

Rosser Park Pond Sediment

Sediment directly from the pond

Preparing the Air Lift Dredge

Unloading the Air Lift Dredge

Air Lift Dredge Prepared

Preparing to connect hosing

Air Lift Dredge Ready

The Air Lift Dredge connected and ready to go

Floating the Air Lift Dredge

Sending the Air Lift Dredge out onto the pond

Improving water aeration and circulation for gentle sediment movement

Air Lift Dredge moving across the pond

The Air Lift Dredge in operation moving across the pond

Air Lift Dredge Operations on Rosser Park Pond

Our Air Lift Dredge operating on the pond

Sludge output from rosser park pond

The resulting sludge output

Resulting Sediment from Rosser Park Pond

Resulting sediment composition

Mulch Filtrate pH6-4

Resulting mulch filtrate with a pH 6.4

Pond Specifics

pH 6.0 – 7.0 sediment
pH 6.2 – 9.5 water
Av Depth 104 mm at 7.0% ww
Total P 2.58 mg/L average
Total N 11.46 mg/L average

Results

Our 12 month contract was successful in not only removing the sludge with minimal impact on the surrounds, but also in removing the blue-green algae. The algae has not returned since.

Project requirements

Gently remove sludge with little impact on water quality
Easy operations
Semi unmanned
Minimum pond floor disturbance
Quiet (we even had birds riding on the Air Lift Dredge while in operation)
Acceptable equipment presence and aesthetics
Safe for the public
No odour
Flood management
No polymer dosing of sediment or sludge
Onsite disposal – reuse of sludge and sediments