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UNIVERSITY OF MANITOBA PHD STUDENT LOOKS AT FLOATING
TREATMENT WETLANDS TO CLEAN UP ALGAL BLOOMS AND OIL SPILLS
By Suzanne Forcese
Around the world irresponsible and uninformed practices are constantly threatening freshwater lakes. Wastewater treatment; agricultural fertilization and pesticide use; natural resource extraction; and the runoff of nutrients, contaminants, and petroleum products affect our water quality. Combined with the impacts of climate change our management histories have put our most valued and necessary resource in peril.
The International Institute for Sustainable Development (IISD) is an award-winning independent think tank that champions advanced science-based solutions to our planet’s greatest sustainability challenges including universal access to water and healthy ecosystems. With offices in Winnipeg, Geneva, Ottawa and Toronto, the work of IISD impacts nearly 100 countries and informs policy.
WaterToday had the pleasure of speaking with a Project Officer in IISD’s Water Program, PhD student, Madeline Stanley, who is “proud to be involved in an organization that has a global impact on policy decision. IISD is made up of various teams which allows for a great platform of collaborative efforts to address issues such as the interactions between watersheds and climate change.”
Stanley, whose past work includes examining the spatial variation of water quality and algal production in the relationship between land use and nutrient load in the Delta Marsh, Manitoba, says, “Winnipeg is a great place to live and do research because there is so much freshwater around.” Having grown up by water, fishing and spending time enjoying the outdoors she was always fascinated by the work being done by Winnipeg scientists. “When I started my studies at the U of M, I did not realize that I could do this work too until I introduced myself to Dr. Goldsborough who was researching algal blooms.”
Madeline Stanley in the field (IISD-ELA) Photo Credit Marina Puzyreva
With her work at the Fort Whyte Alive Centre, Stanley soon knew “what I wanted to do. "Restoration and remediation.” And the rest is history. Now working at IISD and doing field work at the Experimental Lakes, Stanley’s research for her PhD has centred around Floating Treatment Wetlands (FTWs).
Stanley considers herself most fortunate to be working in “the world’s only freshwater laboratory where our research informs global policy.” IISD Experimental Lakes Area (IISD-ELA) in Ontario is one of the world’s most influential freshwater research facilities. Here scientists manipulate the 58 lakes and their watersheds to determine the effects of human activity and offer solutions.
“Floating Treatment Wetlands (FTW) are used around the world,” Stanley told WT. “Natural wetlands are known to filter water as it passes through. Essentially the engineered floating wetlands are mimicking those same features on an artificial platform.” They are a proven concept for surface and storm water run-off, municipal wastewater effluent, landfill leachate and mine tailings ponds.
FTWs allow aquatic plants to grow in water that is typically too deep for them. The unique ecosystem that creates the potential to capture nutrients. Common pollutants are transformed into harmless by-products.
Stanley and her team harvest cattail from a donor site and transplant them onto floating wetlands. Over a few weeks the plants grow upwards and also downwards creating a root system that captures nutrients such as phosphorus. The growth process permanently removes its nutrients from the soil. The study that Stanley was involved in at the U of M discovered that FTW plants can also be effective at removing certain pharmaceuticals and herbicides from freshwater bodies.
The FTWs also proved to be an innovative bio-remediation option for smaller bodies of water that suffer from algal blooms. “For larger lakes, such as Lake Winnipeg, the FTWs could be placed at the source points to prevent nutrients from entering the lake,” Stanley said.
“Our research at IISD-ELA showed that a relatively small increase in phosphorus resulted in a rapid increase in plant productivity on the floating platforms.” This suggests that FTWs can be an effective bio-remediation option for eutrophic water bodies. Eutrophication is the over-enrichment of nutrients such as nitrogen and phosphorus that causes algal blooms and increased spread of invasive species. It can also cause fish die-offs and loss of other aquatic species due to the lack of oxygen and toxic blooms.
The research suggests the majority of the nutrient uptake and degradation is by the biofilm – the algae, bacteria and other microbes – “the slime” – that coat the extensive surface area of the plant roots and island surface. This slime also promotes the growth of invertebrates that provide food for fish and aquatic insects.
In nature, rooted plants go through alternate periods of flooding and drying which affects their growth. “The water level for plants on a floating wetland is effectively constant allowing them to become quickly established.” For a managed bio-remediation scenario this is a perfect natural infrastructure.
“Another plus, that people often overlook with FTWs is that the cover and shelter provided by the floating islands enables the settling of sediments by reducing the turbulence by wind and waves. They can also enhance the aesthetics of a water body by providing valuable wildlife habitat and acting as wind and wave breaks to protect the shoreline from erosion.”
Over the last few years a number of floating wetlands have been deployed in various locations, from the IISD-ELA to ‘real world’ applications including a stormwater pond in Lorette, Manitoba and the duck pond at Assiniboine Park.
For her PhD research, Stanley is now exploring the potential for FTWs to help clean up oil spills (of crude oil and diluted bitumen) in a planned study at IISD- ELA. “For me this is really exciting because no one else has looked at this possibility. Oil and its interactions with freshwater and marine life has been overlooked. Most research has been done in saltwater.”
North America has the largest network of energy pipelines in the world and unfortunately periodic oil spills do occur and end up in our freshwater.
IISD-ELA is the only place where an oil spill can be safely simulated in a real lake with controlled enclosures. It has already been estimated that 80% of the oil spilled remains in the freshwater systems when accepted industry clean up methods have been employed. The ground-breaking project Stanley is involved with “will look at how engineered floating wetlands can break down the remaining oil—without causing any more degradation.”
In Nature, wetlands clean out toxins and reduce flooding by preventing water from heading downstream. According to Ducks Unlimited Canada, “70% of Canada’s wetlands in settled areas have been destroyed or degraded.”
The project Stanley is working on, called FLOWTER (Floating Wetland Treatments for Enhanced Remediation) will look at how the root slime under the floating platforms – which is home to 100 fungi, 80 bacteria and 15 algae species – can metabolize oil. That colony which occurs naturally in lakes and wetlands has the ability to actually digest hydrocarbons like oil.
Stanley hopes to take the floating wetlands to the next step in developing non-invasive techniques to enhance natural biodegradation. “If we have more information on the impact of oil spills and the efficacy of cleanup methods this will help support government policies and industry practices in emergency situations.”
And what is Madeline Stanley’s compass pointing her toward next? “I want to continue learning and working with water quality and watershed development in innovative and effective ways to remediate the ecosystem that has been degraded either by human development or ecological change.”
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