Team:Lethbridge HS/Description
OUR JOURNEY
Working with water purification has always been our primary goal throughout this season. In light of goal six of the United Nations Sustainable Development goals, universal access to clean water and sanitation, we began by tackling the most prevalent water-related issue around the world—the lack of fresh potable water. To solve this problem, we developed our system, which we named Ctrl-Salt-Del, with the purpose of desalinating seawater by sequestering sodium ions. However, with some initial calculations, we determined that the concentration of sodium ions in seawater is higher than what our system could possibly handle. The concentration of sodium chloride in seawater is 0.6 M, while the maximum acceptable concentration for human consumption is 3.4 mM, or 0.0034 M. Going from 0.6 M to 3.4 mM is a 95% reduction rate that requires the removal of literally billions upon billions of salt particles per liter of water, which is well beyond the estimated capacity of our system.
Understanding the challenges of large-scale purification, we pivoted and took a less ambitious path — municipal wastewater treatment. We toured the Lethbridge Wastewater Treatment Plant and interviewed the process coordinator, Duane Guzzi, who informed us the possibility of integrating our system into the secondary clarifiers of the existing plant to take out heavy metals present in the wastewater. (For more information on this tour and interview, click here. ) By integrating our system into existing treatment plants, we can also take advantage of safety measures that are already put in place, such as ultraviolet radiation treatment, that will eliminate any surviving microorganisms potentially harmful to the environment before the treated water is released.
However, during a second interview we had with Dorothy Lok, an approval engineer for Alberta Environment and Parks, we learned that the presence of heavy metals is not a major concern in municipal wastewater. (For more information on this interview, click here. ) Therefore, although the integration of our system with existing treatment plants seems highly compelling, it will not have a significant impact in the community. Ms. Lok suggested that we look into the increasingly alarming problems posed by oil extraction tailings ponds in our province.
“You would really have to have a purpose for doing it [implementing our system in the wastewater treatment process]… whereas with tailings ponds, they need to be dealt with.” --Dorothy Lok
With her advice, we delved deeper into the impacts and characteristics of these ponds, and our findings convinced us that we had finally found our emphasis!
OUR PROJECT
Our project, “Cu Later”, aims at using a system of biological components to sequester and remove metal ions from oil and mining tailings ponds. These ponds contain high amounts of toxic metals (such as copper, nickel and lead) that create significant environmental concerns. When mixed with other chemicals, these metals can form acidic compounds that lower the pH of surrounding waters. They can also pose direct threats to aquatic organisms, causing irreversible damages to their nervous, cardiovascular, and reproductive systems. In one instance, the continuous discharge of 450 kilograms of copper every day into the Britannia Creek (near a former copper mine in British Columbia) exterminated every aquatic species in the creek. In another instance, over 1,600 ducks died in a Syncrude Canada tailings pond in Northern Alberta when they mistook the pond for a freshwater lake.
Upon speaking with a representative from Alberta Energy Regulator (AER), we learned that although there have been regulations in place to limit the production of tailings on the part of energy companies, there is currently no efficient method to treat or extract metals from tailings ponds. Traditional water purification methods, such as distillation, nanofiltration and reverse osmosis are theoretically possible but practically inefficient and extremely expensive. Additionally, we learned that the amount of tailings in Alberta has increased drastically over the past decades, from just below 10 gigalitres in 1970 to over 1,400 gigalitres in 2018.
Today, the amount of tailings in Alberta alone is enough to fill 560,000 Olympic-sized pools. With an average depth of five meters, these tailings cover a land area of 280 square kilometers, over one-third the size of the city of Calgary. These statistics are predicted to continue growing in the future, as millions of cubic meters of new tailings are produced every day.
“The big problem in oil sands tailings is the sheer volume, the magnitude of production you’re talking about, it’s millions of cubic meters per day.” --AER Representative
Although the accumulation of toxic tailings is a prevalent challenge in our oil-dependent provincial economy, the environmental concerns they present is a global issue. Their pollution of surrounding water bodies, prolonged damage to aquatic biodiversity, and ever-increasing size are especially detrimental to the global sustainable development effort. Successful implementation of our project will, therefore, benefit both our local industries and the global community.
REFERENCES
1. Cost of Distillation, Retrieved October 17th, 2018, from https://www.aquatechnology.net/distillationFAQ.html
2. Cost of Reverse Osmosis Nanofiltration Retrieved October 17th, 2018, from https://www.samcotech.com/much-reverse-osmosis-nanofiltration-membrane-systems-cost/
3. Cost of Water desalination plant Retrieved October 17th, 2018, from https://smipp.wordpress.com/2017/02/13/how-much-does-a-water-desalination-plant-cost
4. Environmental Effects of Tailings Ponds Water, Retrieved October 17th, 2018, from https://www.cbc.ca/news/canada/edmonton/alberta-oilsands-bird-deaths-suncor-tailings-ponds-1.4300715
5. Environmental Effects of Tailings Ponds Water, Retrieved October 17th, 2018, from https://www.thestar.com/news/atkinsonseries/2015/09/04/tailings-ponds-a-toxic-legacy-of-albertas-oilsands.html
6. British Columbia Mount Polley Mining Fears, Retrieved October 17th, 2018, from https://www.cbc.ca/news/canada/british-columbia/mount-polley-mining-fears-1.4235913