Book Description

Indirect potable water reuse is considered an effective management practice for augmenting declining water resources. However, the occurrence of emerging organic contaminants (EOCs) such as prescription and non-prescription drugs, health and beauty products, among others in wastewater effluent challenges reuse practices due to the underlying risk to aquatic ecosystem health and potential human health impacts. It is important therefore to understand the fate, transport and risks of EOCs in surface and groundwater drinking water sources that are impacted by various indirect potable reuse practices. The objectives of this study were to evaluate the occurrence and removal of selected EOCs during wastewater treatment, assess their fate, transport and risks in impacted surface and groundwater sources, and evaluate their removal during conventional drinking water treatment. While land application of wastewater effluent is beneficial for recharging groundwater aquifers and avoiding direct pollutant discharges to surface waters, it provides a pathway of EOCs that persist in wastewater effluent to underlying aquifers. The extent to which effluent irrigation activities at the Penn State Living Filter has impacted groundwater was investigated. Commonly used pharmaceuticals (acetaminophen, ampicillin, caffeine, naproxen, ofloxacin, sulfamethoxazole, and trimethoprim) were targeted for analysis in wastewater influent, effluent and monitoring wells at the spray irrigation site. In wastewater influent, acetaminophen and trimethoprim were the most frequently detected (93%) above the limit of quantification (LOQ), while in the effluent, caffeine and trimethoprim were detected most frequently (70%). Acetaminophen and caffeine were generally well removed (>88%) during wastewater treatment while other compounds including antibiotics and the anti-inflammatory drug naproxen were removed to a lesser extent and in some cases, were present at higher concentrations in effluent samples. The removal efficiencies of the pharmaceuticals varied seasonally with the least removals recorded in colder months. The impact of long-term wastewater irrigation on groundwater was observed through the presence of studied compounds at levels above the LOQ. Detection frequencies were however lower in groundwater samples compared to the effluent, with sulfamethoxazole (40%) and caffeine (32%) as the most frequently detected compounds. Similarly, average concentrations of pharmaceuticals in groundwater were nearly two orders of magnitude lower than concentrations in the effluent. Effluent irrigation performs an ecosystem service by mitigating an ecosystem risk to aquatic organisms as wastewater effluent posing medium to high risk to aquatic systems is not discharged directly in streams but allowed to infiltrate through the soil and decrease in concentration before recharging groundwater. Furthermore, human health risk assessments indicate that concentrations of studied EOCs in groundwater, which is used as a drinking water source, appear to pose minimal risk.Domestic drinking water wells are common in the U.S. and serve about 1 million homes and farms in the commonwealth of Pennsylvania. These private wells are often located in areas served by onsite wastewater treatment systems such as septic systems where treated domestic wastewater effluent is discharged in subsurface leach fields for further treatment before recharging groundwater. The occurrence, range of concentrations, and potential human health risks of seven pharmaceutical compounds (acetaminophen, ampicillin, caffeine, naproxen, ofloxacin, sulfamethoxazole, and trimethoprim) in 26 private wells located in central PA were evaluated. Ofloxacin (100%) and sulfamethoxazole (58%) were the most frequently detected compounds while naproxen was not detected in any sample and other pharmaceuticals were present in