Environmental Science: Water Research & Technology blog

We are delighted to introduce our latest Emerging Investigator, Yujie Men! 

Dr. Yujie Men joined the Department of Civil and Environmental Engineering as an Assistant Professor in March 2016. Before that, she worked as a postdoctoral researcher in the Engineering Research Center for Re-inventing the Nation’s Urban Water Infrastructure at University of California, Berkeley, and a postdoctoral scientist at Swiss Federal Institute of Aquatic Science and Technology. She holds a B.S. and M.S. in Environmental Engineering from Tsinghua University, and earned her Ph.D. in Civil and Environmental Engineering at University of California at Berkeley. Her research focuses on the development of sustainable biotechnologies for cleaner water and a safer and more sustainable environment, by advancing the fundamental knowledge of microbial metabolic diversities and microbe-microbe interactions in built and natural environments. She is a member of the International Society for Microbial Ecology, the American Society for Microbiology, the American Chemical Society and the Association of Environmental Engineering and Science Professors.

Read Yujie’s Emerging Investigators article “Occurrence and fate of emerging organic contaminants in wastewater treatment plants with an enhanced nitrification step,” and find out more about her in the interview below:

Your recent Emerging Investigator Series paper focuses on occurrence and fate of emerging organic contaminants in wastewater treatment plants. How has your research evolved from your first article to this most recent article?

My first article is on bioremediation of chloroethenes, which are traditional organic contaminants in subsurface areas. This Emerging Investigator Series paper focuses on emerging organic contaminants in wastewater: their occurrence and transformation (mostly biological). No matter how the target pollutants change, from canonical to emerging ones and from anaerobic/anoxic subsurface environments to aerobic surface environments, my research goal remains the same: to obtain fundamental understanding of environmental microbial communities (physiological, molecular and ecological properties) and to apply to environmental biotechnologies solving real problems.

What aspect of your work are you most excited about at the moment?

I am most excited about my work on understanding interactions between environmental pollutants and the microbial communities they are exposed to. This includes how microbes transform/degrade the anthropogenic compounds and how the exposure to xenobiotic chemicals affect the metabolism of microorganisms.

In your opinion, what impact do you think this research will have on the development of wastewater treatment plants?

This research reveals important but limited roles of biological wastewater treatment steps (secondary treatment and the enhanced nitrification step) regarding the removal of emerging organic contaminants. Compounds recalcitrant to biotransformation were identified. Formation of incomplete transformation products and product-to-parent transformation were also observed. These findings suggest that advanced treatment of the residuals of emerging organic contaminants after biological treatment is needed in wastewater treatment plants for water reuse purposes, which require a significant reduction of dissolved organic carbon in the effluent.

What do you find most challenging about your research?

It is more and more challenging to find one single approach efficient enough to treat some emerging organic contaminants due to their persistence. A treatment train system combining physical, chemical and biological approaches would be needed to achieve effective separation and treatment.

In which upcoming conferences or events may our readers meet you?

I plan to attend ACS, ASM general meetings, and Gordon Research Conference in Applied and Environment Microbiology in 2019.

How do you spend your spare time?

I enjoy staying with my family and playing with my little one after work. If I still have extra time, I would go for Zumba and swimming. I hope I can go hiking with my family in a year or two when my little one grows bigger.

Which profession would you choose if you were not a scientist?

I would like to become a surgeon.

Can you share one piece of career-related advice or wisdom with other early career scientists?

A successful career is one you are fascinated about, one that makes you eager to learn more and persistent when facing hurdles, one that gives you a feeling of accomplishment and confidence, and one that never has a shortcut to reach.

We are delighted to introduce our latest Emerging Investigator, Daisuke Minakata!

Dr. Daisuke Minakata earned his Ph.D. in environmental engineering from Georgia Tech in 2010. He worked as a research engineer at the Brook Byers Institute for Sustainable System at Georgia Tech for 3 and half years.  Then he became an Assistant Professor at the Department of Civil and Environmental Engineering at Michigan Technological University in 2013. Dr. Minakata’s research interests include development of computational tools to predict the fate of various organic compounds in water and wastewater treatment technologies, including advanced oxidation and reverse osmosis membrane processes and engineered systems including in water distribution systems. Dr. Minakata also studies the nexus of food-energy-water to understand the interventions of sustainable technologies at household levels.

Read his Emerging Investigator article: “Ultraviolet and free chlorine aqueous-phase advanced oxidation process: kinetic simulations and experimental validation‘ and find out more about him in the interview below:

Your recent Emerging Investigator Series paper focuses on ultraviolet and free chlorine aqueous-phase advanced oxidation process. How has your research evolved from your first article to this most recent article?

Predicting the fate of an organic compound and the degradation products in the aqueous-phase advanced oxidation process requires three components: (1) reaction pathways; (2) reaction rate constants; and (3) solving the ordinary differential equations of all species involved in the degradation. We previously developed linear free energy relationships to predict the chlorine radical reaction rate constants for various organic compounds. This study identified elementary reaction pathways of acetone degradation in UV/free chlorine advanced oxidation process using the quantum mechanical calculations and predicted the fate of the degradation products using the previously developed linear free energy relationships.  Our predicted fate was compared to the experiments we conducted and we validated our elementary reaction-based kinetic model. 

What aspect of your work are you most excited about at the moment?

Couple ab initio and density functional theory quantum mechanical calculations with experimental measurements to predict the mechanistic fate of an organic compound and the degradation products in the aqueous phase advanced oxidation processes. With this approach, we can provide mechanistic insight into the degradation mechanisms and a comprehensive picture of radical-induced fate of organic compounds in complex aqueous phase advanced oxidation processes.

In your opinion, why is it important to understand the reaction mechanisms behind advanced oxidation processes and how does the model you have developed aid our understanding?

Understanding the elementary reaction mechanisms provides the most fundamental reaction pathways and kinetics and this information can be applied for many other products. It is not practical to study the degradation products of hundreds of organic compounds experimentally but understanding the most fundamental elementary reaction pathways and kinetics advances our ability to predict the fate of organic compounds in more comprehensive manners. 

What do you find most challenging about your research?

We have demonstrated our capability of predicting the fundamental elementary reaction pathways and kinetics for structurally simple organic compounds using ab initio and density functional theory quantum mechanical approaches. However, challenges remain in applying this approach for structurally more complex organic compounds because of numerous possible reaction pathways and difficulties in validating the predicted pathways and kinetics with the experiments. Also, predicting the fate of structurally diverse organic compounds requires a high throughput screening tool that will be developed based on the fundamental knowledge about the reaction pathways and kinetics discovered by both experiments and computational calculations. Combining the knowledge about the fate of organic compounds with toxicity to develop a comprehensive tool to predict the toxicity of degradation products is the ultimate challenge in this field.

In which upcoming conferences or events may our readers meet you?

ACS National Meeting in Boston, Division of Environmental Chemistry, Advanced Oxidation Process (AOP) session in August, 2018. I co-organize an AOP session with colleagues every year.

How do you spend your spare time?

I walk with our dog in nature.  

Which profession would you choose if you were not a scientist?

I would run a bookstore/coffee shop, collecting a lot of history books and providing good quality of coffee.

Can you share one piece of career-related advice or wisdom with other early career scientists?

Keep your mainstream research with you and focus on longer-term research goals.