Using ABS pumps to help reduce the blooming of blue-green algae in the River Torrens.
OBJECTIVE
To provide a solution to transfer water, up to 20ML/day, out of the Torrens River at Lockleys when introduced dilution flows exceed 20ML/day into the Torrens Lake with the aim to minimise the build up of blue-green toxic algae and restore natural aquatic ecosystems and bio-diversity in the surrounding areas.
INTRODUCTION
Algae belong to a group of aquatic plants that include chlorophyll and other photosynthetic elements or pigments. While most algae are microscopic in size, some can grow very large. E.g. seaweed. Algae may multiply and breed as single cells, cell aggregations or colonies.
Adelaide’s hot and dry weather conditions trigger the growth of toxic blue-green algae in the Torrens Lake. This is a problem as the lake is used for many public purposes.
However, the low natural river flow and unwanted materials from the storm water can cause a sudden outburst of algae with significant levels of E. coli bacteria in the Torrens Lake. This happens mainly in the warm weather, making it unsafe for recreational activities.
A trial was undertaken to introduce a dilution flow through the Torrens Lake over last summer to see if this flow can keep cyanobacteria counts low, preventing a bloom.
PROBLEMS
Assessment of the cyanobacteria data collected and the hydrodynamics of the Torrens Lake shows under certain summer conditions the Lake would need to flows of around 20 to 40ML/day to prevent blooms.
The Torrens Task Force, comprising scientists and engineers recommended that this proposal be fully investigated. Led by Professor Don Bursill, the State’s Chief Scientist, it was considered timely to trial the water quality dilution flows.
Certain blue green algae (or cyanobacteria) are known to produce a toxic substance that can cause skin irritations and can affect the nervous system in a detrimental way. Furthermore, if this water is consumed, the algae may cause other medical problems such as nausea and gastrointestinal diseases.
Cyanobacteria are also known to trigger skin rashes and eye irritation. Some algae can cause asthma-like symptoms if inhaled as a fine mist. Some species of algae can also kill native birds and upset the ecological balance of the water bodies.
Within the trial period, comprehensive water samples from the Torrens Lake and downstream of the Torrens Weir were undertaken to detect the presence of blue-green algae (cyanobacteria) and sent to AWQC laboratory for examination. Results identified if more or less dilution flows were required.
SOLUTION
The Torrens Lake was subjected to these dilution flows ranging from 20ML/day to 40ML/day. When flows exceeded 20ML/day, an alternative method of discharging excess flows from the River Torrens was required to eliminate where possible, flows to West Beach foreshore and to sea during summer. This was done by installing 3 ABS submersible sewage pumps mounted on a pontoon installed within the River Torrens to divert water to West Lakes via the Henley and Grange stormwater system.
ABOUT The ABS Submersible Sewage Pump XFP Series
This pump is a high performance wastewater pump that operates in Australia, China, Malaysia and Singapore.
It’s suited for both clear and waste water as well as sewage with sludge containing solids and fibrous materials. It can efficiently pump algae-infested water. The pump is equipped with high efficiency motors that provide optimum performance.
Other advantages include:
- Long-term reliability.
- Greater energy efficiency.
- Excellent rag handling.
- Futuristic design.
- Sustainable manufacturing.
- Easy handling.
- Low maintenance.
Construction
The ABS submersible sewage pumps XFP series are made according to standards of the ATEX explosion-proof version and manufactured in accordance with international standards. These factors make it the ideal pump for this particular job.
ABS Submersible Sewage Pump XFP Series Working Mechanism
This pump was chosen to meet the requirements as specified. The pontoon contained three pumps so the Torrens water could be pumped to West Lakes.
The initial goal was to transfer 20 mega litres of water at a time. But at one point the ABS pumps had to be kept running for 3 weeks to move over 240 megalitres of water. The pumps were used only for the purpose of transfers and pumped at a rate of 220 litres per second.
The pump system and pontoon were installed in December 2011 and have been working efficiently ever since. The aim was to ensure reliable and satisfactory transfer of water to the Henley to Grange Stormwater system and prevent any discharge to the West Beach foreshore and to sea during summer.
The ABS submersible sewage pump XFP series has proven to be more efficient and easy to monitor and manage. This pump comes equipped with an Auto Dialler System. This control system enables pump operators to call in from any location to check for faults and to start or stop the pumps. The Auto Dialler System is programmed that it even dials certain numbers in case a fault occurs.
The ABS submersible sewage pump XFP series has been efficient in meeting the specific water pumping requirements for the River Torrens project.
Benefits Of Installing The ABS Submersible Pump
Some of the benefits obtained from the installation of these pumps in the River Torrens include:
- Transformation of the quality of storm water by clearing the toxins produced by the algae.
- Reducing the volume and extent of water to sea.
- Management of the flow of the River Torrens downstream of the weir.
- Potentially reducing future losses.
- Sustaining of bio-diversity in and around River Torrens.
Conclusion
The wastewater has been managed properly by installing these pumps. They have efficiently prevented the dilution flows from the Torrens Lake from reaching West Beach and possible environmental issues at the foreshore to the public These pumps have also been successful in sustaining the aquatic ecosystems and biological diversity of the river. In doing so, they have helped to uphold the integrity of the water resources of Adelaide which form the backbone of various assets related to public life and tourist scenery.
