Hallie Hartley (ETM): Plunging into wastewater research

Hallie in Jacksonville, NC, preparing to test wastewater parameters with the YSI Multi-meter.

As a Georgia girl, I know that when you mix warm weather with wet conditions, the mosquitoes of the season are bound to be especially nasty. Arriving in Jacksonville, NC on an abnormally warm October afternoon, I thought about the extremely wet North Carolina summer. As if reading my mind, Andrew (my former teaching assistant and a graduate student of NC State) warned, “Watch out for the mosquitoes. They are the biggest I have ever encountered in my fieldwork.”

After hearing his advice, I was a little worried about getting out of the car. Following Andrew’s lead, however, I walked into waist-deep grass and the breeding ground for the biggest mosquitoes I had ever seen.  What was I, with my sweet Georgia-peach skin, doing out in Jacksonville?

I was taking wastewater samples at an alternative wastewater facility located in Jacksonville, NC. This past fall semester and leading into this spring semester, I took the plunge into wastewater research. Funded by an undergraduate research grant and in collaboration with Andrew, I explored and compared the effects of two distinct wastewater treatment processes at two different sites in North Carolina.

Over the next three months, we collected water samples and measured different water quality parameters at these two sites. Andrew then used a method to concentrate the samples, so that the extractions could be analyzed at the Environmental Protection Agency located in Raleigh. He used half of the condensed samples on his targeted analysis and my half was used for a non-targeted analysis.

The purpose of my study was to compare the environmental inputs of pharmaceuticals and personal care products (PPCPs) between a conventional and an alternative wastewater treatment system. PPCPs are a class of unregulated emerging contaminants, which once in the environment, can have detrimental effects on wildlife, ecosystems, and potentially humans. A traditional wastewater facility treats water before discharging it back into the environment; however, this conventional practice does not completely treat for PPCPs before discharging into surface waters. Therefore, the occurrence and fate of these products are becoming increasingly important.

An alternative wastewater treatment process can be used to mitigate this problem. Applying wastewater to permitted lands is considered an alternative wastewater treatment process. The results of this study will show the efficiency at which PPCPs are mitigated through a land application system. The research is important for surface water quality, drinking water resources, and forested land application sites. It will also shed light on sustainable applications for wastewater treatment, like the use of treated water in areas of intense drought or depleted aquifers. I was drawn to this study because of its worldwide implications.

The conventional wastewater treatment plant was the North Cary Reclamation facility. It treats approximately 12 million gallons of wastewater with tertiary treatment per day. To my surprise, the surrounding area was quite beautiful with various nature trails for people to walk on. If I had not been doing research, I would have never known the facility was even there.

A typical day at this facility included sampling events at five points along the stream: the spot where the wastewater was expelled, at the spot where effluent from the facility entered the stream, a point under a bridge upstream from the wastewater facility, a spot approximately 50 meters downstream from the effluent, and the last one was about 150 meters downstream from entry. I took water quality measurements with an YSI Multi-meter and recorded the data in a field notebook.

At the alternative wastewater facility in Jacksonville, primary treated wastewater was sprayed onto 2,000 acres of managed hardwood and pine plantations. The wastewater undergoes secondary treatment with settling ponds and aeration before the spraying event. We collected water from two points downstream from the spraying events and from a few of the monitoring wells on site. Once analyzed, the water samples will indicate how the wastewater is affecting the groundwater and forested area

Compared to the conventional site in Cary, I really felt like a scientist doing fieldwork at Jacksonville as we battled sweltering heat and massive mosquitoes. I chuckled to myself the following Monday, when I saw Andrew scratching at his huge mosquito bites. They represented our own battle scars from fieldwork I won’t likely forget.

The water samples from each site were condensed into cartridges using a method called solid-phase extraction. Andrew had half of the samples analyzed at the UNC Biomaker Mass Spectrometry for the targeted analysis. On April 15th, we traveled to the Environmental Protection Agency in Raleigh to analyze my half of the samples using a Time-of-Flight machine. Driving up to the Environmental Protection Agency, I was surprised at the age and construction of the building. It had large white stacks protruding from the top. Andrew explained to me that these stacks help fumigate air from the chemical labs within the building. As expected in a government building, we had to check in with security before Mark Strynar could meet us in the lobby.

Walking back to the lab, Mark gave me a short synopsis on how the Time-of-Flight machine works. For identification of non-targeted pharmaceutical compounds, specified molecular features (peak height, area count, etc.) of each potential chemical found within a water sample are extracted and visualized using highly technical, computer software. Possible chemical formulas for an individual chemical within the sample are compared to a large database.

We used a forensic toxicology database for our analysis, which included information on over 9,000 compounds. Each potential chemical formula for an individual compound is ranked according to the difference between calculated and measured mass, isotopic abundance, and isotope spacing to determine the most likely match. A match scored at ninety-percent or above is considered accurate at the EPA.

Unfortunately, I had twenty-eight samples to be analyzed and each sample took about an hour and a half to be processed and compared through the database. Andrew and I left the EPA that afternoon with only one analyzed wastewater sample from the Jacksonville facility.

I was disappointed that I wouldn’t be able to compare the data from the conventional wastewater facility to the Jacksonville facility for the undergraduate research symposium. However, I did my best to work with what I had and decided to focus solely on the Jacksonville facility from both the targeted and non-targeted analysis.

In short, the data showed that the wastewater added some pharmaceuticals and personal care products to the downstream surface water. However, some of the compounds found within the wastewater were not present downstream. This means that the forested system could in fact be cleaning the wastewater. This has huge implications for places experiencing intense droughts. The non-targeted analysis showed that most compounds within the sample were veterinary drugs and prescriptions.

With these results, facilities can learn how to better clean the wastewater before application. Even with this limited data, the symposium went well. I was even awarded the Outstanding Sustainability-Related Research Project award with two other colleagues. I give great thanks to Andrew and Dr. Elizabeth Nichols for all their help in this endeavor.

The experience I gained doing this research has been truly valuable. The project and the process have furthered my interest in environmental forensics. I believe that my research can provide information for countries facing intense droughts and depleted aquifers. In a recent interview with an engineering firm, I used my undergraduate research as talking point on the importance of sustainable practices and innovative solutions to the problems our warming Earth now faces.

I hope those that attended the spring research symposium understood how wastewater can be used as a valuable resource. Knowing this research has worldwide implications made me more passionate about the fieldwork and lab analysis I was conducting. Even though I had to swat at monstrous mosquitoes, I really enjoyed being in the field and applying the technical skills from my undergraduate career. I encourage anyone interested in wastewater to simply take the plunge, get his or her hands dirty, and apply themselves to a worthy cause. It’s definitely worth it!