The Fate of Pharmaceuticals After Wastewater Treatment
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The Fate of Pharmaceuticals After Wastewater Treatment Jose A. Polar xpanding cities are shortening the (PhACs) are of special concern because of the lapse between the release of treated volumes introduced to the environment, their Jose A. Polar is a research analyst with Ewastewater into the environment and endocrine disrupting activity, and a potential the Applied Research Center at Florida the uptake by water drinking facilities. Even increase of bacterial resistance. International University though wastewater treatment plants usually It is estimated that hundreds of tons of exceed current discharge standards, the pres- PhACs are produced and consumed in devel- ence of unregulated pollutants in these efflu- oped countries each year (Castiglioni et al., secondary treatment, this analgesic has been ents is of concern (Petrovic et al., 2003). 2005, Kosjek et al., 2005, Daughton & Ternes, detected at an average concentration of 0.22 Unregulated contaminants, or emerging 1999, Tauxe et al., 2005). Most of them end up µg/l in treated wastewaters (Ternes, 1998). pollutants of concern (EPOCs), are defined as being excreted completely unchanged or only Salicylic acid, ASA metabolite, has been substances that were previously undetected or slightly transformed conjugated to polar mole- detected at very low concentrations in sewage had not been considered as a risk (Daughton, cules. These conjugates are often broken during effluent and surface waters (Ternes et al., 2001). The main sources of non-regulated sewage treatment, releasing the original PhAC, 1998; Quintana & Reemtsma, 2004). contaminants in the environment are waste- so they are constantly introduced into receiving Acetaminophen is also effectively water treatment plant effluents (Duaghton waters (Heberer, 2002a). The following sections degraded and removed by conventional and Ternes, 1999), which are not designed to will describe the fate of the most characteristic sewage treatment. In Germany it was detect- eliminate these compounds. They are present PhACs during and after wastewater treatment. ed in less than 10 percent of sewage effluents in treated wastewaters at trace levels (µg/l to and rivers (Ternes, 1998), and in the U.S. it ηg/l), and include personal care products, PhACs in Wastewater was detected in only 17 percent of the affect- pharmaceuticals, surfactants, flame retar- Treatment Plant Effluents ed surface waters analyzed in a National sur- dants, industrial chemicals, gasoline additives, & Receiving Surface Waters vey (Koplin et al., 2002). and disinfection byproducts. Some PhACs are easily removed and Some antibiotics also exhibit high These contaminants do not need to be degraded during sewage treatment, mainly by removal rates when exposed to conventional persistent in the environment to cause delete- adsorption and bio-degradation; however, activated sludge treatment. During this rious effects, since their high transformation they can still be detected at the low µg/l level process, penicillins are hydrolyzed and tetra- and removal rates can be offset by their con- in treated effluents and receiving waters. This cyclines precipitate with cations (Heberer, tinuous introduction into the environment is the case for the analgesics acetylsalicylic 2002b). Amoxicillin is also removed efficient- (Petrovic et al., 2003). Among the various sub- acid (ASA), fenofibrate, and acetaminophen. ly by biological treatment (Morse and stances that can be categorized as emerging Although ASA is easily degraded into its Jackson, 2004). These antibiotics are still pollutants, pharmaceutical active compounds metabolites, which are effectively removed by found in receiving surface waters, however (Koplin et al., 2002). High rates of oxic degradation for Ibuprofen during bench scale experiments resembling wastewater treatment conditions (Zweiner et al., 2003), and removals in the order of 96 to 99.9 percent during sewage treatment have been reported (Buser et al., 1999; Quintana and Reemtsma, 2004). In spite of these high removals, Ibuprofen is still detected in sewage effluents and surface waters at the µg/l level (Farre et al., 2002). Synthetic estrogens such as 17a- ethinylestradiol (EE2) and mestranol (used as birth control drugs) are of special concern because of their potent endocrine disrupting activity. Activated sludge treatment was found to reduce influent concentrations of estrone (E1), 17-estradiol (E2), and 17- ethinylestradiol 93 percent, 93 percent, and 82 percent, respectively, but they are fre- quently found in wastewater treatment plant effluents at the ng/l level (Heberer, 2002a, Quanrud et al., 2004 Aguayo et al., 2004, Verstraeten et al., 2003; Koplin et al., 2002). These remaining low concentrations can still 26 • JUNE 2007 • FLORIDA WATER RESOURCES JOURNAL exhibit endocrine disrupting activity (sulfamethoxazole, sulfadimethoxine, sul- µg/l level in the South District Wastewater (Verstraeten et al., 2003). famethazine and sulfathiazole), fluoro- Treatment Plant effluent in the Miami-Dade Some drugs appear to degrade very little quinolones (ofloxacin, ciprofloxacin, nor- area (Lietz and Meyer, 2006). or none when treated with conventional acti- floxacin, end enrofloxacin), chlorampheni- In general, wastewater treatment plants vated sludge. That is the case for iodinated X- col, tylosin, and trimethoprim (Koplin et al., with higher retention times have a better per- ray contrast media and the analgesic propy- 2002; Heberer., 2002b; Gobel et al., 2004, formance in removing analgesic/anti-inflam- phenazone (Ternes et al., 2001). Hirsch et al., 1999, Sedlak et al., 2005). atory drugs and lipid regulators. Tertiary Chemical structure seems to be a signifi- Other such compounds are beta-block- treatment eliminates these drugs more effi- cant factor in determining removal rates. ers such as atenolol, sotalol, celiprolol, meto- ciently than secondary treatment does. Medium polar drugs are removed on average prolol, propanolol, and bisoprolol (Ternes, Granular activated carbon appears to be between 60 and 90 percent (Ternes, 1998), 1998; Sacher et al., 1999; Ternes et al., 2003; effective in removing PhACs completely, while polar compounds exhibit lower Sedlak et al., 2005); the antiepileptic except for antibiotics (Sedlak et al., 2005), removals during wastewater treatment, since Primidone (Heberer, 2002b); the psychiatric and none of the previously mentioned com- they are less adsorbed onto activated sludge drugs diazepam and carbamezapine; and the pounds (lipid regulators, antiepileptics, anal- particles (Hirsch et al., 1999). Some of these anti-angina drug nifedipine (Ternes et al., gesics, antibiotics, and anti-inflamatories) polar drugs exhibit a maximum removal of 2001, Ternes et al., 2003). can be detected after treating tertiary effluent only 7 to 10 percent, such as the antiepileptic Blood lipid regulator compounds such with a micro-filtration/reverse osmosis com- carbamazepine (Ternes, 1998; Ternes et al., as bezafibrate, gemfibrozil, fenofibric acid bination (Drewes et al., 2003b). 2003; Heberer, 2002a; Stackelberg et al., 2004). (fenofibrate metabolite), and clofibric acid Not even extended retention times or (clofibrate metabolite) (Ternes, 1998; Ternes PhACs in Groundwater tertiary treatment seems to be effective when et al., 2003; Heberer, 2002b); the anti-diabet- Indirect potable reuse through soil treating this drug. Only micro-filtration fol- ic drug glibenclamide (Ternes et al.,2001); the aquifer treatment (SAT) and bank filtration is lowed by reverse osmosis has been reported X-ray contrast media compounds diatrizoate, a common practice in Europe and in some effective in eliminating anti-epileptics from iopamidol, iopromide, and iomeprol (Ternes regions of the U.S. SAT consists of the appli- the effluents (Drewes et al., 2003b). at al., 2003); and the antineoplastics cation of treated wastewater into the ground Another polar PhAC exhibiting low (chemotherapy drugs) ifosfamide and (usually through infiltration from a pond) removal (17 percent) during sewage treat- cyclophosphamide (associated with hospital with aquifer recharge purposes. Bank filtra- ment is the analgesic Diclofenac. High per- discharges) (Ternes, 1998) are all found in tion consists of the recharge of an aquifer centages (up to 95 percent) have been recov- treated effluents at the low µg/l level, along with water infiltrated from a river bank ered after treatment in traditional municipal with those listed in the preceding three para- before being used as a drinking water source. plants (Zwiener et al., 2003, Koutsouba et al., graphs. These two approaches have been proved 2003), and sometimes higher concentrations South Florida is no exception. effective in reducing total organic carbon are found in the effluents because of desorp- Salbutamol, cimetidine, ranitidine, 1,7- (TOC), pathogens, and disinfection byprod- tion processes (Quintana and Reemtsma, dimethylxanthine, diltiazem, warfarin, dehy- ucts (DBPs) precursors in recharged waters 2004). Despite its poor removal during drodifedipine, thiabendazole, diphenhy- (Weiss et al., 2003). Adsorption to soil parti- sewage treatment, diclofenac seems to be dramine, carbamezapine, and the antibiotics cles during infiltration seems to be a good readily photodegraded (Heberer, 2002a; erythromycin, trimethroprim, ciprofloxacin, barrier for non-polar compounds. This is the Buser et al., 1998). ofloxacin, sulfadiazine, sulfamethoxazole, case for the lipid regulator bezafibrate, which Clofibric acid (the blood lipid regulator and tetracycline