TAYLOR BOROWETZ

Instruments on a yellow buoy floating in Buffalo Pound Lake transmit water quality data back to researchers and the nearby water treatment plant — near-real-time data that will be used to optimize plant operations and treat water more efficiently.

Helen Baulch is an assistant professor in the University of Saskatchewan’s School of Environment and Sustainability and the Global Institute for Water Security. She is the lead investigator on the project that pairs the institute with the Buffalo Pound Water Treatment Plant, with funding from the Natural Sciences and Engineering Research Council of Canada and the Canada Foundation for Innovation.

Though the work is in its first year, Baulch said that she sees a lot of opportunities for this project and that real progress is being made.

“We’re able to use a buoy in the lake to measure different chemical conditions, and that allows us to understand a lot about the ecology of the lake,” she said.

Buffalo Pound Lake is a shallow and nutrient-rich lake located approximately 28 kilometres north of Moose Jaw on the Qu’Appelle River. It provides drinking water for the cities of Regina, Moose Jaw and surrounding communities — approximately one quarter of Saskatchewan’s population. The lake was formed during a glacial period about 10,000 years ago.

The Buffalo Pound Water Treatment Plant uses water piped from the lake as its main source, and it is one of the most advanced water treatment facilities on the continent.

Baulch says that the buoy is the first sensor of its kind in Canada that communicates directly with a treatment plant. She explained that the expertise from the research team provides an irreplaceable basis for the project, and that their “decades of data are of tremendous use to us in understanding the lake ecology, and the ecology of harmful algal blooms.”

Every two hours the buoy transmits data on pH, oxygen and carbon dioxide concentrations, temperature and chlorophyll. The data is then uploaded onto a website shared by the researchers and the plant.

Because the sensor can look at rapid changes in the lake and relay that information to the plant, it will give them advanced knowledge about the content of water intake and will warn of algal blooms. Baulch said that this information will allow them to fine-tune chemical doses with the potential for cost savings.

Notably, even though the plant will benefit from the ability to use treatments more judiciously, no one receiving their drinking water from the Buffalo Pound Treatment Plant will notice differences in the taste, smell or quality of the water provided.

Baulch said that the operators have been able to use the data to adapt their operations, and that they know how the chemistry is changing.

With the additional warmth of the summer months, the conditions of the lake are ideal for blooms of cyanobacteria, or blue-green algae, which causes the water to take on a distinctive murky, greenish hue and are one of the sources behind unpleasant water taste and smell.

Algae can also cause problems in the water treatment process. When it photosynthesizes, it produces oxygen, leading to bubbles that can float some of the chemicals that are designed to sink particles in the water. Weather can also impact operations at the plant.

“The operator has to respond to all of these things very quickly — sometimes literally within a half-hour or so — as the water quality can change very quickly,” said plant chemist Dan Conrad.

Conrad explained that there are processes to deal with cyanobacteria and algae including physical removal of the algae as well as oxidation or adsorption of their metabolites. Consumers are very sensitive to the odour of one algal contaminant called geosmin, which can be detected at 10 parts per trillion — an exceedingly small amount.

Processes at the plant can reduce geosmin to levels lower than the 10 parts per trillion threshold, however they have a limited operational time before they must be taken off line and regenerated. This process is very expensive and time-consuming, and involves regular maintenance of the regeneration facilities.

“By continuously monitoring the lake chemistry for conditions that affect treatment processes, or conditions that may trigger algal blooms, it is our hope that the buoy and its data will also help us optimize the initial physical removal process and the judicious application of [granular activated carbon] treatment,” Conrad said. “Other portions of this study will examine searching for other algal metabolites and changes in lake water biota through time. Those historical studies are important when planning effective watershed management plans.”

The buoy will remain on the lake through October, and will be re-deployed in the spring of 2015 and 2016.

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Graphic: Stephanie Mah/Graphics Editor