ENVIRONMENTAL REMEDIATION
Our group study the fate of both organic and inorganic contaminants as well as microplastics in various types of environmental remediation systems: from contaminated groundwater environments to passive surface water treatment systems such as constructed wetlands, algal ponds, and bioretention cells. Our group is interested in remediation technologies that adhere to the following principles:
- Sustainability:
- Are respectful to the environment under current and future climate scenarios
- Result in an overall decrease of effluent toxicity
- Resource recovery
- Allow for water reuse
- Allow for essential nutrients to return to natural soil
- Attractive for industry
- Cost-effective
- Robust
- Predictable
Check out stories on our microplastics research here, here, and here!
Constructed wetlands
Constructed wetlands can help reduce environmental contamination. However, a better understanding of how contaminants behave in wetland systems is critical to help develop adequate guidelines for the operation, maintenance, and design of constructed wetlands. Some of our research in this field evaluates how to best design wetlands for the elimination of key contaminants: antimicrobial chemical triclosan, herbicide atrazine, several substituted chlorobenzenes (e.g., 2,3-dichloroaniline), and radioactive strontium pollution.
Algae and floating plants
Open-water wetlands and lagoons with no emerging plants can also have water treatment benefits. We have been investigating the role of various algal species as well as floating plant duckweed in the elimination of selected trace organic chemicals. Using series of lab-scale bioreactors constructed with field-collected lagoon water, we are studying the role of various reaction mechanisms on contaminant removal, including adsorption, photodegradation, biodegradation, and algae/plant uptake. We are particularly interested in the relationship between organisms, i.e. algae/microbes and plant/microbes and how these relationships affect contaminant transfer and transformation.
Bioretention cells
Urban green infrastructures such as bioretention cells are designed to collect runoff, reduce water volumes, and eliminate contaminants. Research projects on the topic are looking at the potential for adsorption and desorption of various contaminants such as phosphorus, benzotriazole, and naphthalene on engineered bioretention soil. We are also investigating the effects of freezing and thawing on nutrient dynamics, soil structure, and infiltration rates in bioretention cells. Finally, we also investigate the source, fate and removal of microplastics in bioretention cells. Because microplastic quantification is tedious and time-consuming, we are investigating alternative approaches based on machine learning to accelerate the process and allow for faster advances in microplastic research.
DEVELOPING A BETTER UNDERSTANDING OF CONTAMINANT FATE USING COMPOUND-SPECIFIC ISOTOPE ANALYSIS
At natural abundance, changes in the ratio of heavy vs light stable isotopes can often be used to infer reaction mechanisms and identify the presence of active transformation processes. This technique, termed Compound Specific Isotope Analysis (CSIA) has been employed successfully to track and characterize the fate of several groundwater contaminants in situ. We are developing new methods for some chlorinated aromatic compounds present at contaminated groundwater sites to help distinguish between the contribution of transfer and transformation processes.
In addition, our group aims at applying CSIA to newer emerging contaminants such as pharmaceuticals and personal care products that are typically present in surface water, groundwater, stormwater and wastewater at trace concentrations. One way to improve their detection and quantification is to use passive integrative sampling techniques such as Polar Organic Compound Integrative Sampler (POCIS) to increase contaminant sampled mass in situ. We showed that these samplers are compatible with C-, H-, and N-CSIA of substituted chlorobenzenes.