Removal of antibiotics in conventional and advanced wastewater treatment: Implications for environmental discharge and wastewater recycling
Introduction
Water is a precious commodity in Australia and its management is critical for preserving the future of this resource. Despite being the driest continent on earth, Australia has one of the highest water consumption rates per capita of any country worldwide (OECD, 1999). Currently, 97% of urban runoff and 86% of effluent discharge is not reused and is discharged into our rivers and coastal areas (CSIRO, 2005). Initiatives such as the National Water Initiative (NWI, est. 2004), National Water Commission (NWC, est. 2004), Water Smart Australia (est. 2006) and the Australian Water Conservation and Reuse Research Program (AWCRRP, est. 2000) have been established to improve water management in this country. Consequently, wastewater re-use is topical in Australia, as water managers examine the possibilities for utilising this resource for purposes such as irrigation, aquaculture, indirect potable reuse (IPR) and even direct potable reuse (DPR).
Current global water recycling practices directly reflect surface water resources. For example, Windhoek (Namibia) have exhausted all available surfaces water supplies and are completely dependant on a direct potable reuse scheme (Marsalek et al., 2002). In contrast, Canada having the 3rd largest renewable water supply globally practices minimal water recycling (Gleick, 1998). The reuse of wastewater has twofold benefits through not only the reduction of discharged effluent to the environment but also a potential reduction of pressure on existing water resources. Public perception of wastewater recycling is highly variable, and tends to decline the closer its use is to the household as the chance of physical contact increases (Toze, 2006). This is directly related to the perceived risks associated with these types of waters and their potential to contain pathogens, trace organics, heavy metals, nutrients, endocrine-disrupting chemicals (EDCs) and pharmaceutically active compounds (PhACs) such as antibiotics. The recycling of wastewater must be treated with caution until we fully understand the potential negative consequences for the reuse of water containing low concentrations of these emerging contaminants. For example, a recent study has demonstrated the continued presence of these compounds in soils irrigated with reclaimed water (Kinney et al., 2006a, Kinney et al., 2006b). Research has demonstrated that even at low concentrations, these emerging contaminants can have detrimental effects. Wilson et al. (2003) demonstrated that three of these chemicals may potentially influence both the structure and the function of algal communities in stream ecosystems receiving WWTP effluents. Additionally, Bistodeau et al. (2006) showed that nonylphenolethoxylate/octylphenolethoxylate compounds, commonly used as surfactants, have an effect on the reproductive competence of male fathead minnows, with some effects seen below regulatory guidelines.
Until recently, antibiotics have received comparatively little attention as pollutants in the aquatic environment which is surprising considering that unlike many other pollutants, antibiotics have a direct biological action on microbes. Many of these antibiotics are not completely metabolised or eliminated in the body and between 30% and 90% are excreted unchanged into the waste system (Hirsch et al., 1999). Recent studies (McArdell et al., 2003; Miao et al., 2004; Clara et al., 2005; Batt et al., 2006a, Batt et al., 2006b; Brown et al., 2006; Karthikeyan and Meyer, 2006) have demonstrated that conventional WWTPs often only partially remove selected drugs (20–90%) demonstrating the potential for these compounds to be consistently present in effluents. Certain metabolites present in WWTP effluents can also be converted back to their parent form upon entering surface waters (Ternes, 1998; Heberer, 2002). Effluents containing antibiotics are of concern as there is potential to promote or maintain bacterial resistance and disrupt key cycles/processes critical to aquatic ecology (nitrification/denitrification) or crop (soil fertility) and animal (rudimentary processes) production (Kummerer, 2004a, Kummerer, 2004b; Costanzo et al., 2005; Crane et al., 2006; Kinney et al., 2006a, Kinney et al., 2006b). Biosolid components of WWTPs are an additional concern through their ability to act as a sink for some PhACs, including antibiotics (Kinney et al., 2006a, Kinney et al., 2006b; Xia et al., 2005). These biosolids are regularly applied to crops and land further exacerbating exposure to this group of chemicals. This has major implications for both effluents discharged to the aquatic environment and effluents used for wastewater recycling.
Little is known of the risks associated with effluents containing trace pollutants such as antibiotics, although research in this area is developing. Oetken and co-workers (2005) demonstrated that the antiepileptic carbamazepine had a significant and specific chronic effect against the oligochaete Chiromus at environmentally relevant concentrations. This is further highlighted by Flaherty and Dodson (2005) who observed chronic fluoxetine exposure at low concentration significantly increased Daphnia fecundity. Furthermore, a mixture of fluoxetine and clofibric acid caused significant mortality and deformities and mixtures of three to five antibiotics elicited changes in Daphnia sex ratio (Flaherty and Dodson, 2005). Similar results have been reported (Brain et al., 2005; Hernando et al., 2006; Pomati et al., 2006). Degradation productions of these chemicals can also be considered as contaminants contributing to these complex mixtures that are present. There is even some evidence that these degradation products can be as active and/or toxic as their parent (Halling Sorensen et al., 2002; Sengelov et al., 2003).
Current water quality and reuse guidelines in Australia do not include antibiotics or PhACs in general (ANZECC, 2000a, ANZECC, 2000b). While the presence of these compounds has been well documented in the Northern Hemisphere (Heberer et al., 1998; Ternes, 1998; Alder et al., 2001; Golet et al., 2002; Kolpin et al., 2002; Giger et al., 2003; Loffler and Ternes, 2003; Miao et al., 2004; Brown et al., 2006; Karthikeyan and Meyer, 2006), there is a significant lack of data concerning their presence in Australian effluents. Costanzo et al. (2005) reported on the presence of three antibiotics (ciprofloxacin, norfloxacin and cephalexin) in both sewage effluent and surface waters downstream from a sewage discharge and Khan and Ongerth have presented a number of fugacity model calculations of selected PhACs (Khan and Ongerth, 2002, Khan and Ongerth, 2004). The object of this study was to obtain data on the passage of selected antibiotics through a wastewater treatment plant (WWTP) utilising a conventional treatment process (activated sludge) and an additional advanced treatment process (microfiltration/reverse osmosis) and assess their potential for use in water recycling.
Section snippets
Sample collection and preparation
Target antibiotics were identified following review of current Australian import practices (Watkinson and Costanzo, 2005) and cover the range of most commonly used antibiotic groups (human and veterinary). As no antibiotics are produced industrially in Australia, this import data can provide a representative guide on the usage of antibiotics in this country (Collignon, 1997). Details of the 27 chosen target analytes, including average import volumes, are provided in Table 1. Standards were
Conventional treatment
Of the 28 investigated antibiotics, penicillin G, oleandomycin and salinomycin were the only drugs not detected in any samples within the conventional treatment plant (Table 2). These drugs are primarily used for animal applications (therapeutic or growth-promotion) in Australia (JETACAR, 1999), explaining their absence in domestic waste.
Cephalexin was the dominant antibiotic in the influent (med. 4.6 μg L−1, freq. 100%) followed by ciprofloxacin (med. 3.8 μg L−1, freq. 100%), both of which in
Conclusion
This study has identified that while both conventional and advanced treatment processes are efficient in removing antibiotics from the liquid phase, antibiotics were still detected in final effluents in the low μg L−1 concentrations. Other investigations have demonstrated the accumulation of these compounds within the biosolids (Kinney et al., 2006a, Kinney et al., 2006b; Xia et al., 2005), creating an alternative pathway for dissemination to the environment. Within the conventional system,
Acknowledgements
The authors wish to acknowledge technical assistance provided by Lesley Johnston, Masooma Trout and the staff at the National Measurement Institute. This project was supported through an ARC Linkage Grant (LP0453-708) and in part by the Wastewater Program of the Cooperative Research Centre for Water Quality and Treatment (Project number 666003). The use of trade, firm, or brand names in this paper is for identification purposes only and does not constitute endorsement by the National Research
References (77)
- et al.
Assessment of degradation of 18 antibiotics in the Closed Bottle Test
Chemosphere
(2004) - et al.
Lincomycin solar photodegradation, algal toxicity and removal from wastewaters by means of ozonation
Water Res.
(2006) - et al.
Investigating the environmental transport of human pharmaceuticals to streams in the United Kingdom
Sci. Total Environ.
(2004) - et al.
Evaluating the vulnerability of surface waters to antibiotic contamination from varying wastewater treatment plant discharges
Environ. Pollut.
(2006) - et al.
Occurrence of sulfonamide antimicrobials in private water wells in Washington County, Idaho, USA
Chemosphere
(2006) - et al.
Factors affecting the rejection of organic solutes during NF/RO treatment—a literature review
Water Res.
(2004) - et al.
Larval exposure to environmentally relevant mixtures of alkylphenolethoxylates reduces reproductive competence in male fathead minnows
Aquat. Toxicol.
(2006) - et al.
Effects of a mixture of tetracyclines to Lemna gibba and Myriophyllum sibiricum evaluated in aquatic microcosms
Environ. Pollut.
(2005) - et al.
Occurrence of antibiotics in hospital, residential, and dairy effluent, municipal wastewater, and the Rio Grande in New Mexico
Sci. Total Environ.
(2006) - et al.
Behavior of pharmaceuticals, cosmetics and hormones in a sewage treatment plant
Water Res.
(2004)
Oxidation of sulfonamides, macrolides, and carbadox with free chlorine and monochloramine
Water Res.
Removal of selected pharmaceuticals, fragrances and endocrine disrupting compounds in a membrane bioreactor and conventional wastewater treatment plants
Water Res.
Ecosystem response to antibiotics entering the aquatic environment
Mar. Pollut. Bull.
Chronic aquatic environmental risks from exposure to human pharmaceuticals
Sci. Total Environ.
Genetic exchange between bacteria in the environment
Plasmid
Comparing microfiltration-reverse osmosis and soil-aquifer treatment for indirect potable reuse of water
Water Res.
Effects of pharmaceuticals on Daphnia survival, growth, and reproduction
Chemosphere
Persistence of pharmaceuticals and other organic compounds in chlorinated drinking water as a function of time
Sci. Total Environ.
Characterisation of the abiotic degradation pathways of oxytetracyclines in soil interstitial water using LC–MS–MS
Chemosphere
Occurrence, fate, and removal of pharmaceutical residues in the aquatic environment: a review of recent research data
Toxicol. Lett.
Environmental risk assessment of pharmaceutical residues in wastewater effluents, surface waters and sediments
Talanta 1st Swift-WFD Workshop on Validation of Robustness of Sensors and Bioassays for Screening Pollutants—1st SWIFT-WFD 2004
Determination of antibiotics in different water compartments via liquid chromatography–electrospray tandem mass spectrometry
J. Chromatogr. A
Occurrence of antibiotics in the aquatic environment
Sci. Total Environ.
Determination of quinolones and fluoroquinolones in fish tissue and seafood by high-performance liquid chromatography with electrospray ionisation tandem mass spectrometric detection
J. Chromatogr. A
Occurrence of antibiotics in wastewater treatment facilities in Wisconsin, USA
Sci. Total Environ.
Modelling of pharmaceutical residues in Australian sewage by quantities of use and fugacity calculations
Chemosphere
Urban contribution of pharmaceuticals and other organic wastewater contaminants to streams during differing flow conditions
Sci. Total Environ.
Determination of acidic pharmaceuticals, antibiotics and ivermectin in river sediment using liquid chromatography–tandem mass spectrometry
J. Chromatogr. A
Susceptibility of Escherichia coli and Enterococcus faecium isolated from pigs and broiler chickens to tetracycline degradation products and distribution of tetracycline resistance determinants in E. coli from food animals
Vet. Microbiol.
Occurrence of drugs in German sewage treatment plants and rivers
Water Res.
Reuse of effluent water—benefits and risks
Agric. Water Manage.
Influence of molecular size, polarity and charge on the retention of organic molecules by nanofiltration
J. Membr. Sci.
Evolution of antibiotic occurrence in a river through pristine, urban and agricultural landscapes
Water Res.
Solid-phase extraction-high-performance liquid chromatography-ion trap mass spectrometry for analysis of trace concentrations of macrolide antibiotics in natural and waste water matrices
J. Chromatogr. A
Simultaneous extraction and analysis of 11 tetracycline and sulfonamide antibiotics in influent and effluent domestic wastewater by solid-phase extraction and liquid chromatography–electrospray ionization tandem mass spectrometry
J. Chromatogr. A
Removal of antibiotics from surface and distilled water in conventional water treatment processes
J. Environ. Eng.
Occurrence and fate of fluoroquinolone, macrolide and sulfonamide antibiotics during wastewater treatment and in ambient waters in Switzerland
Antibiotics in the environment: occurrence in Italian STPs, fate, and preliminary assessment on algal toxicity of amoxicillin
Environ. Sci. Technol.
Cited by (970)
Change characteristics, bacteria host, and spread risks of bioaerosol ARGs/MGEs from different stages in sewage and sludge treatment process
2024, Journal of Hazardous MaterialsInvestigating pharmaceuticals and personal care products in Musi River: A exploratory study in Hyderabad, India
2024, Journal of Hazardous Materials AdvancesApplications of hollow nanostructures in water treatment considering organic, inorganic, and bacterial pollutants
2024, Journal of Environmental ManagementPhotocatalytic degradation of persistent antibiotic pollutants by MOF-derived bird-nest ferric molybdate
2024, Journal of Water Process Engineering