Pharmaceuticals, personal care products (PPCPs) and other trace organic contaminants (TOrCs) encompass a diverse group of chemicals that are not currently monitored or regulated in US drinking water or wastewater. Researchers have found low levels of TOrCs in aquatic and terrestrial environments all over the globe, and observed negative effects on impacted biota. The primary source of TOrCs in the environment is domestic wastewater discharges. Centralized wastewater treatment plants present greater risks on a global scale, but on a local scale, onsite treatment systems may have more potent impacts on resources that are invaluable to residents, including groundwater, surface waters, and soils.
The objective of this thesis is to identify and characterize promising treatment technologies for onsite TOrC remediation. Receptors who could be impacted by TOrC discharges are assessed, and applications that may require alternative treatment are identified. The best treatment technologies are recognized as those that protect sensitive environmental receptors, provide permanent removal pathways for as many TOrCs as possible, and are not prohibitively expensive to install or maintain. Findings from a pilot study show increased removal of conventional pollutants and TOrCs in an aerobic treatment unit (ATU), two types of biofilter, and a hybrid constructed wetland, all relative to septic tank effluent. The constructed wetland achieved the highest nutrient removals with TN concentrations below 10 mg/L throughout the study. A system with an ATU and peat biofilters achieved the highest removals of persistent pharmaceuticals carbamazepine and lamotrigine (>85% and >95%, respectively). / Master of Science / Trace organic contaminants (TOrCs) are chemicals found in pharmaceuticals, laundry detergents, shampoo, flame retardants, food preservatives, and many other products used in a typical home, which are not currently monitored or regulated in US drinking water or wastewater. Researchers have found low levels of TOrCs in waters and soils all over the globe, and observed negative effects on the plants and animals that live in those environments. The primary source of TOrCs in the environment is treated wastewater from centralized wastewater treatment plants, which is usually released to rivers, lakes, and other surface waters. People in rural communities also have TOrCs in their wastewater, which is normally treated using a septic system. Water released in the septic field can add TOrCs to septic field soils, groundwater sources, or nearby surface water sources, and from there these chemicals have the potential to impact human health, soil fertility, livestock health, or fish and other living things in surface waters.
The objective of this thesis is to identify and characterize promising treatment technologies that would prevent or limit TOrC impacts to these important resources, which are called “receptors.” Receptors who could be impacted by TOrC discharges are assessed, and the situations in which these treatment technologies would be necessary are identified. The best treatment technologies are recognized as those that protect sensitive environmental receptors, remove as many TOrCs as possible, and are affordable to install or maintain. An experiment was designed to compare the performance of three different technologies that could remove TOrCs from septic tank effluent, including a peat filter and a constructed wetland. The constructed wetland removed the most nitrogen (total nitrogen <10 mg/L throughout the study), and a system with a peat filter removed the greatest amounts of persistent pharmaceuticals carbamazepine and lamotrigine (averaging >85% and >95%, respectively).
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/84966 |
| Date | 15 March 2017 |
| Creators | Greenberg, Chloe Frances |
| Contributors | Civil and Environmental Engineering, Boardman, Gregory D., Widdowson, Mark A., Helm, Richard F., Thompson, Theresa M. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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