Charlotte Water (CLTWater) is using sophisticated equipment to monitor water quality, and yes even wastewater quality, to look for emerging contaminants like microplastics.
Microplastics are defined as plastic materials less than 5 millimeters in size. They can be seen without the use of a microscope. However, nanoplastics are an emerging topic because of the need for powerful microscopes to observe and quantify them. Microplastics shed from plastic products and end up flushed down the drain to wastewater treatment plants and eventually into creeks. Even washing clothes will break down polyester and spandex materials and flush the microplastics into wastewater plants.
CLTWater sponsored an internship program to research microplastics and possible ways to reduce their impacts before the treated water enters creeks. Jordan Landis, a Charlotte Water intern and PhD student at the University of Michigan, studied the presence of microplastics in wastewater under the direction of Muriel Steele, a Charlotte Water Wastewater Process Engineer, and tested possible ways to use certain algae to help break the plastics down and remove them.
The original scope of the project was to bioengineer an algae species that would be able to excrete an enzyme that could break down PET-type plastics. However, the scope of this research has shifted to using the original bacteria species that was found to naturally excrete this plastic-degrading enzyme (the enzyme gene from this bacteria was placed into the algae) and culture that to break down plastics. Macroalgae species are proposed to be used to help capture the plastics to keep them in the system during the treatment process while the bacteria can eat the plastics off the algae.
During the testing process, Ms. Landis was unable to obtain the preferred bioengineered algae species and decided to use the wild-type strain of the bioengineered algae.
Ms. Landis cultured the wild-type algae in CLTWater wastewater to understand the growth behaviors and nutrient uptake of the algae species. This knowledge will help optimize the bioreactor design with the algae before introducing plastics.
The preliminary results were more qualitative in nature, examining how well the algae would grow. Originally an algae-growing salt solution was used to jumpstart our cultures, but it was found that the wastewater was more effective.
In the future, the next step is to develop microplastic quantification methods at Charlotte Water that will help efficiently derive microplastic removal data from bioreactor studies. After this, the bacteria found to excrete the plastic-degrading enzyme naturally will be studied in CLTWater wastewater to understand its metabolic behavior and growth response to the wastewater growth medium.
Video at WSOC-TV news article (UNC Charlotte research hopes to use algae to remove microplastics from water)
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