Article

Biological Degradation of Pharmaceuticals in Municipal Wastewater Treatment: Proposing a Classification Scheme

Swiss Federal Institute of Aquatic Science and Technology, Eawag, 8600 Dübendorf, Switzerland.
Water Research (Impact Factor: 5.53). 06/2006; 40(8):1686-96. DOI: 10.1016/j.watres.2006.02.014
Source: PubMed

ABSTRACT

A simple classification scheme is suggested to characterize the biological degradation of micropollutants such as pharmaceuticals, musk fragrances and estrogens during wastewater treatment. The scheme should be a basis for the discussion about potential removal efficiencies. Hence, the biological degradation of 25 pharmaceuticals, hormones and fragrances was studied in batch experiments at typical concentration levels using activated sewage sludge originating from nutrient-eliminating municipal wastewater treatment plants. Since pseudo first-order degradation kinetics was observed for all compounds down to ng L(-1) levels, the removal rates can be predicted for various reactor configurations. Therefore dilution of wastewater (e.g. by extraneous water) is expected to reduce the degree of biological removal. Wastewater segregation and treatment at the source are therefore to be favoured for elimination of persistent micropollutants over centralized end-of-pipe treatment. For reactor configurations typical for nutrient removal in municipal wastewater, the derived formula for predicting removal allows the identification of three groups of micropollutants according to their degradation constant k(biol): compounds with k(biol)<0.1 L g(SS)(-1)d(-1) are not removed to a significant extent (<20%), compounds with k(biol)>10 L g(SS)(-1)d(-1) transformed by >90% and in-between moderate removal is expected. Based on the degradation of a heterogeneous group of 35 compounds (including literature data), state of the art biological treatment schemes for municipal wastewater are not efficient in degrading pharmaceuticals: only 4 out of 35 compounds are degraded by more than 90% while 17 compounds are removed by less than 50%.

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    • "However, the contribution of biotransformation and adsorption to biomass to the total removal performance of this chemical varied between the two seasons as discussed above. Hydrophilic chemicals which have a K biol ≤ 0.4 L·gMLSS − 1 ·d − 1 such as sulfamethoxazole, trimethoprim, and diclofenac generally displayed poor removal by biotransformation as well as poor total removal by the MBR (Fernandez-Fontaina et al., 2013;Joss et al., 2006;Abegglen et al., 2009). Results from a previous CAS study showed that the impacts of temperature variation on overall removal of TrOCs with moderate to low K biol were greater than that of TrOCs with high K biol (Suárez et al., 2012). "
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    ABSTRACT: Trace organic chemical (TrOC) contaminants are of concern for finished water from water recycling schemes because of their potential adverse environmental and public health effects. Understanding the impacts of seasonal variations on fate and removal of TrOCs is important for proper operation, risk assessment and management of treatment systems for water recycling such as membrane bioreactors (MBRs). Accordingly, this study investigated the fate and removal of a wide range of TrOCs through a full-scale MBR plant during summer and winter seasons. TrOCs included 12 steroidal hormones, 3 xeno-estrogens, 2 pesticides and 23 pharmaceuticals and personal care products. Seasonal differences in the mechanisms responsible for removing some of the TrOCs were evident. In particular the contribution of biotransformation and biomass adsorption to the overall removal of estrone, bisphenol A, 17β-estradiol and triclosan were consistently different between the two seasons. Substantially higher percentage removal via biotransformation was observed during the summer sampling period, which compensated for a reduction in removal attributed to biomass adsorption. The opposite was observed during winter, where the contribution of biotransformation to the overall removal of these TrOCs had decreased, which was offset by an improvement in biomass adsorption. The exact mechanisms responsible for this shift are unknown, however are likely to be temperature related as warmer temperatures can lower sorption efficiency, yet enhance biotransformation of these TrOCs.
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    • "The poor heterotrophic biomass activity in the aerobic stage because of the low organic content in the effluent of the UASB limited the biotransformation under aerobic conditions of some OMPs. In fact, the calculated aerobic k biol coefficients were significantly lower (Table 1) than those reported in previous works (Alvarino et al., 2014; Joss et al., 2006; Blair et al., 2015). In order to overcome this limitation, a pulse of OMPs (20 mg/L for estrogens and 100 mg/L for each of the other OMPs) and organic matter (140 mg TOC/L) was spiked in the aerobic chamber of the reactor system (by diluting OMPs in methanol) to increase the heterotrophic activity and to provide the experimental conditions to determine the maximum biodegradation coefficients. "
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    ABSTRACT: An innovative plant configuration based in an UASB reactor coupled to a hybrid aerobic membrane bioreactor designed for sustainable treatment of municipal wastewater at ambient temperatures and low hydraulic retention time was studied in terms of organic micropollutants (OMPs) removal. OMPs removal mechanisms, as well as the potential influence of biomass activity and physical conformation were assessed. Throughout all periods of operation (150 days) high organic matter removals were maintained (>95%) and, regarding OMPs removal, this innovative system has shown to be more efficient than conventional technologies for those OMPs which are prone to be biotransformed under anaerobic conditions. For instance, sulfamethoxazole and trimethoprim have both shown to be biodegradable under anaerobic conditions with similar efficiencies (removal efficiencies above 84%). OMPs main removal mechanism was found to be biotransformation, except in the case of musk fragrances which showed medium sorption onto sludge. OMPs removal was strongly dependent on the efficiency of the primary metabolism (organic matter degradation and nitrification) and the type of biomass.
    Full-text · Article · Feb 2016 · Chemosphere
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    • "Pharmaceuticals and personal care products (PPCPs) have increasingly drawn attention due to their universal consumption as well as indiscriminate discharge to the aquatic environment. PPCPs residuals are usually drained into sewer or on-site sanitation system, while most wastewater treatment plants (WWTPs) lacks with PPCPs removal facility, resulting the release of these contaminants into surface water (Joss et al., 2006). Recent technologies such as; ozonation (Andreozzi et al., 2005), reverse osmosis (Kimura et al., 2009), and advanced oxidation process (Ternes et al., 2003), as well as process optimization (e.g. "
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