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pharmaceuticals sold, either to a landfill or wastewater treatment plant. Ultimately, these disposed PPCPs enter a municipal wastewater treatment facility, an on-site sewage system, or a reclaimed water treatment facility. Unused or expired PPCPs thrown away in the trashcan and disposed in a landfill can be mobilized in the environment via landfill leachate. The fate of PPCPs in the environment is complex for a number of reasons. First, there are thousands of chemicals used in the manufacture of a wide variety of PPCPs. Not all PPCPs are similar chemically, and the different types of chemicals react differently to different treatment processes. The individual chemical structure dictates whether PPCPs will biodegrade, volatilize, degrade into metabolites, or concentrate and persist in the environment. Treating The Problem The treatability of PPCPs depends upon the physicochemical properties of each compound of interest and the specific set of treatment processes. Some treatment processes efficiently remove some chemicals but are ineffective at treating others. Some treatment processes merely remove the chemical from one media and transfer it to another media without destroying it. For example, nonylphenol is removed from water through settling, but in the process it is partitioned into the sludge. Once land-applied, it remains in the environment, available for transport to groundwater or surface waters. Typical treatment processes include adsorption, filtration, volatilization, photodegradation, biodegradation, chemical alteration, and plant or animal utilization. In summary, no single treatment process effectively removes 100 percent of PPCPs. Some treatment processes reduce some pharmaceuticals to very low levels, while other pharmaceuticals remain resilient. In 2008, the Washington Department of Ecology and the U.S. EPA conducted a study to characterize PPCPs at five municipal wastewater treatment plants in the Pacific Northwest. The goal was to characterize wastewater treatment removal efficiencies for these compounds by monitoring a range of treatment processes and their effect on PPCP removal. This study compared untreated wastewater (influent), treated wastewater from secondary treatment, advanced tertiary treatment for nitrogen and phosphorus (nutrient) removal, tertiary treated reclaimed water, and biosolids. Target analytes included 172 organic compounds, PPCPs, hormones, steroids, and semi-volatile organics. Removal efficiencies were evaluated for each analyte at the five wastewater treatment plants. The study found PPCPs in all samples, and their concentrations were comparable to those reported in the literature from other studies. Overall, conventional secondary treatment reduced 21 percent of the 172 organic compounds to below detection levels and achieved high removals for hormones and steroids. Advanced nutrient removal and filtration technologies reduced the number of compounds detected by 53 percent. A total of 20 percent of the 172 compounds were found only in the biosolids, suggesting that some PPCPs can concentrate in solids. None of the wastewater treatment technologies was able to remove all of the compounds. These resilient compounds include carbamazepine, fluoxetine, and thiabendazole. These three PPCPs may serve well as human-influence tracer compounds in the environment. The results of this study indicate that PPCPs are routinely found in municipal wastewater, PPCP removal varies between wastewater treatment processes and specific chemicals, and advanced nutrient reduction and tertiary filtration may provide additional PPCP removal. Based on these findings, researchers recommend that consumers do not flush leftover, unwanted, or expired drugs. Instead, they should be taken to a pharmacy which has a take- back program. It's best to contact the local health department, law enforcement office, or pharmacy for information on local medicine take-back programs and initiatives to support pharmaceutical stewardship in a given area. If a take-back program is not available, medicines should be taken out of their original containers, mixed with an undesirable substance (such as kitty litter or coffee grounds) and placed in an impermeable container, then put in the trash. n Go to https://fortress.wa.gov/ecy/publications/documents/1003004.pdf to read the full study conducted by the state of Washington's Department of Ecology. Cited Work Lubliner, B., M. Redding, and D. Ragsdale, 2010. Pharmaceuticals and Personal Care Products in Municipal Wastewater and Their Removal by Nutrient Treatment Technologies. Washington State Department of Ecology, Olympia, WA. Publication Number 10-03-004. www.ecy.wa.gov/biblio/1003004.html. 32 wateronline.com n Water Innovations Melanie Redding, L.HG, a hydrogeologist, and Brandi Lubliner, PE, an environmental engineer, work for the Washington State Department of Ecology. About The Authors The results of this study indicate that PPCPs are routinely found in municipal wastewater, PPCP removal varies between wastewater treatment processes and specific chemicals, and advanced nutrient reduction and tertiary filtration may provide additional PPCP removal. SECONDARYTREATMENT