Elimination of pharmaceuticals in sewage treatment plants in Finland

The occurrence of eight pharmaceuticals (beta-blockers: acebutolol, atenolol, metoprolol and sotalol; antiepileptic: carbamazepine; fluoroquinolone antibiotics: ciprofloxacin, norfloxacin, ofloxacin) were assessed in the raw and treated sewage of 12 sewage treatment plants (STPs) in Finland. The average concentrations in the raw and treated sewage ranged from 100 to 1060 ng L(-1) and from <24 to 755 ng L(-1), respectively. The average daily loads ranged from 36 to 405 mg/1000 inh and from 2 to 302 mg/1000 inh, respectively. In the treatment plants, fluoroquinolones were eliminated by >80%. Carbamazepine was not eliminated during the treatment and in fact even higher concentrations were frequently found in the treated than in the raw sewages. The increase in concentration was shown to be most likely due to enzymatic cleavage of the glucuronic conjugate of carbamazepine and release of the parent compound in the treatment plant. The beta-blockers were eliminated in average by less than 65% and the elimination varied greatly between the treatment plants. Especially the dilution of raw sewage by rainwater and a consequent decrease in the hydraulic retention time of a treatment plant was found to deteriorate the elimination of the beta-blockers. The work shows that especially carbamazepine and the beta-blockers may reach the recipient waters and there is a need to enhance their elimination in the sewage treatment plants. In this attempt, a denitrifying biofilter as a tertiary treatment could be of minor importance since in this study it did not result in further elimination of the target compounds.     

Removal of cosmetic ingredients and pharmaceuticals in sewage primary treatment

Two physico-chemical processes, coagulation-flocculation and flotation, have been assessed for enhancing the removal of some selected pharmaceutical and personal care products (PPCPs) present in sewage. Eight compounds, representative of three main groups of PPCPs according to their physico-chemical properties, have been selected: lipophilic compounds (the synthetic musks Galaxolide and Tonalide), neutral compounds (the tranquillizer Diazepam and the antiepileptic Carbamazepine) and acidic compounds (the anti-inflammatories Ibuprofen, Naproxen and Diclofenac). During the coagulation-flocculation assays, the main parameters considered were the selection of the additives, their doses and the temperature of operation (12 or 25 degrees C). Musks-which are highly lipophilic and Diclofenac-with significant sorption affinity-were removed around 50-70% at both temperatures independently of the dose and type of coagulant used. However, the rest of the compounds, which are more hydrophilic, were affected to a lesser degree (with maximum reductions below 25%). The exceptions to this behavior were Carbamazepine and Ibuprofen, which were not removed under any condition tested. During the flotation assays, the parameters studied were the initial content of fat in wastewaters and temperature. Again, musks were removed to a greater degree (35-60%), followed by Diazepam (40-50%) and Diclofenac (20-45%) and, to a lesser extent, Carbamazepine (20-35%), Ibuprofen (10-25%) and Naproxen (10-30%). The best results were always obtained at 25 degrees C, although in some cases the operation at 12 degrees C gave similar results. The removal of musks and neutral compounds was higher in wastewaters with a high fat content (around 150 mgl(-1)).     

Occurrence and fate of quinolone and fluoroquinolone antibiotics in a municipal sewage treatment plant

This study developed a method for analysis of nineteen quinolone and fluoroquinolone antibiotics (FQs) in sludge samples, and investigated the occurrence and fate of the FQs in a municipal sewage treatment plant (STP) with anaerobic, anoxic, and aerobic treatment processes. Eleven compounds, including pipemidic acid, fleroxacin, ofloxacin, norfloxacin, ciprofloxacin, enrofloxacin, lomefloxacin, sparfloxacin, gatifloxacin, moxifloxacin, and sarafloxacin (only in sludge), were detected in the STP. The predominance of ofloxacin and norfloxacin, followed by lomefloxacin, ciprofloxacin, gatifloxacin, and moxifloxacin, were found in wastewater, suspended solids, and sludge. The total concentrations of FQs were 2573 ± 241 ng/L, 1013 ± 218 ng/L, and 18.4 ± 0.9 mg/kg in raw sewage, secondary effluent, and sludge, respectively. Extremely low mass change percentages were observed for FQs in anaerobic, anoxic, and aerobic treatment units, suggesting biodegradation to be of minor importance in the removal of FQs in STPs. 50-87% of the initial FQs loadings (except for pipemidic acid (36%)) were ultimately found in the dewatered sludge. Mean removal efficiencies of FQs in the STP were 56-75%, except for new generation drugs such as moxifloxacin (40 ± 5%) and gatifloxacin (43 ± 13%). A significant positive correlation was found between removal efficiencies and K_d of FQs. The major factor in the removal of FQs in the STP was sorption to sludge, which was not governed by hydrophobic interactions. The long-term cycling and persistence of FQs in the STP has made activated sludge as a huge reservoir of FQ antibiotics.     

Oxidation of pharmaceuticals during water treatment with chlorine dioxide

The potential of chlorine dioxide (ClO2) for the oxidation of pharmaceuticals during water treatment was assessed by determining second-order rate constants for the reaction with selected environmentally relevant pharmaceuticals. Out of 9 pharmaceuticals only the 4 following compounds showed an appreciable reactivity with ClO2 (in brackets apparent second-order rate constants at pH 7 and T = 20 degrees C): the sulfonamide antibiotic sulfamethoxazole (6.7 x 10(3) M(-1) s(-1)), the macrolide antibiotic roxithromycin (2.2 x 10(2) M(-1) s(-1)), the estrogen 17alpha-ethinylestradiol (approximately 2 x 10(5) M(-1) s(-1)), and the antiphlogistic diclofenac (1.05 x 10(4) M(-1) s(-1)). Experiments performed using natural water showed that ClO2 also reacted fast with other sulfonamides and macrolides, the natural hormones estrone and 17beta-estradiol as well as 3 pyrazolone derivatives (phenazone, propylphenazone, and dimethylaminophenazone). However, many compounds in the study were ClO2 refractive. Experiments with lake water and groundwater that were partly performed at microgram/L to nanogram/L levels proved that the rate constants determined in pure water could be applied to predict the oxidation of pharmaceuticals in natural waters. Compared to ozone, ClO2 reacted more slowly and with fewer compounds. However, it reacted faster with the investigated compounds than chlorine. Overall, the results indicate that ClO2 will only be effective to oxidize certain compound classes such as the investigated classes of sulfonamide and macrolide antibiotics, and estrogens.     

Removal of selected pharmaceuticals and personal care products (PPCPs) and endocrine-disrupting chemicals (EDCs) during sand filtration and ozonation at a municipal sewage treatment plant

We investigated the efficiencies of removal of 24 pharmaceutically active compounds (PhACs) during sand filtration and ozonation in an operating municipal sewage treatment plant (STP). The target compounds were 2 phenolic antiseptics (thymol, triclosan), 5 acidic analgesics or anti-inflammatories (ibuprofen, naproxen, ketoprofen, fenoprofen, mefenamic acid), 4 amide pharmaceuticals (propyphenazone, crotamiton, carbamazepine, diethyltoluamide), 7 antibiotics (sulfapyridine, sulfamethoxazole, trimethoprim, azithromycin, erythromycin anhydride, clarithromycin, roxithromycin), 3 phenolic endocrine-disrupting chemicals (EDCs) (nonylphenol:NP, octylphenol:OP, bisphenol A:BPA) and 3 natural estrogens (17 beta-estradiol:E2, estrone:E1, estriol:E3). Ozonation removed approximately 80% or more of the phenolic antiseptics, crotamiton, sulfonamide and macrolide antibiotics, and 17 beta-estradiol. Their removal is discussed in terms of chemical structure. The study ascertained the validity of ozonation mechanisms proposed by previous studies in an actually running STP. Compounds with a CC double bond or an aromatic structure with electron donors (e.g., phenol, alkyl, methoxy, or non-protonated amine) were susceptible to ozonation. Compounds with amide structures were resistant. Removal of the PhACs during sand filtration was generally inefficient, probably because of their low hydrophobicities. The combination of ozonation and sand filtration with activated sludge treatment gave efficient removal (>80%) of all the target compounds except carbamazepine and diethyltoluamide. Among all the steps in the plant, ozonation contributed substantially to overall removal of naproxen, ketoprofen, triclosan, crotamiton, sulfapyridine, macrolide antibiotics, and estrone.     

Occurrence and removal of pharmaceuticals and hormones through drinking water treatment

The occurrence of fifty-five pharmaceuticals, hormones and metabolites in raw waters used for drinking water production and their removal through a drinking water treatment were studied. Thirty-five out of fifty-five drugs were detected in the raw water at the facility intake with concentrations up to 1200 ng/L. The behavior of the compounds was studied at each step: prechlorination, coagulation, sand filtration, ozonation, granular activated carbon filtration and post-chlorination; showing that the complete treatment accounted for the complete removal of all the compounds detected in raw waters except for five of them. Phenytoin, atenolol and hydrochlorothiazide were the three pharmaceuticals most frequently found in finished waters at concentrations about 10 ng/L. Sotalol and carbamazepine epoxide were found in less than a half of the samples at lower concentrations, above 2 ng/L. However despite their persistence, the removals of these five pharmaceuticals were higher than 95%.     

Occurrence and removal of antibiotics, hormones and several other pharmaceuticals in wastewater treatment plants of the largest industrial city of Korea

Occurrence and removal efficiencies of 20 pharmaceuticals and personal care products (PPCPs) including antibiotics, hormones, and several other miscellaneous pharmaceuticals (analgesics, antiepileptics, antilipidemics, antihypertensives, antiseptics, and stimulants) were investigated in five wastewater treatment plants (WWTPs) of Ulsan, the largest industrial city of Korea. The compounds were extracted from wastewater samples by solid-phase extraction (SPE) and analyzed by High-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The results showed that acetaminophen, atenolol and lincomycin were the main individual pollutants usually found in concentrations over 10 μg/L in the sewage influent. In the WWTPs, the concentrations of analgesic acetaminophen, stimulant caffeine, hormones estriol and estradiol decreased by over 99%. On the contrary, the antibiotic sulfamethazine, the antihypertensive metoprolol, and the antiepileptic carbamazepine exhibited removal efficiencies below 30%. Particularly, removal of antibiotics was observed to vary between − 11.2 and 69%. In the primary treatment (physico-chemical processes), the removal of pharmaceuticals was insignificant (up to 28%) and removal of majority of the pharmaceuticals occurred during the secondary treatment (biological processes). The compounds lincomycin, carbamazepine, atenolol, metoprolol, and triclosan showed better removal in WWTPs employing modified activated sludge process with co-existence of anoxic-oxic condition. Further investigation into the design and operational aspects of the biological processes is warranted for the efficient removal of PPCPs, particularly antibiotics, to secure healthy water resource in the receiving downstream, thereby ensuring a sustainable water cycle management.     

Triclosan in a sewage treatment process--balances and monitoring data

In a German sewage treatment plant that processes 200000 m(3) wastewater per day, the concentrations of 2,4,4'-trichloro, 2'-hydroxy-phenylether (triclosan) in the in-flowing ( approximately 1000 ng x l(-1)) as well as in the out-flowing water ( approximately 50 ng x l(-1)) are compared to the concentrations measured in sludge (1200 ng x g(-1)). Considering the mass flow of water and sludge in the respective plant, balances including water and sludge are calculated. Thirty percent of the triclosan is sorbed with weak bonds to the sludge, while some amounts are sorbed as bound residues in the sludge. About 5% is dissolved in the out-flowing water. Thus most of the in-flowing material is not recovered as the parent compound but it is likely that it is transformed to other metabolites or unrecovered bound residues. These data are compared to the monitoring of sewage sludge of 20 different plants in this region, most of which are smaller, though. The concentrations found in these sludges vary from 1000-8000 ng x g(-1).     

Occurrence, partition and removal of pharmaceuticals in sewage water and sludge during wastewater treatment

During 8 sampling campaigns carried out over a period of two years, 72 samples, including influent and effluent wastewater, and sludge samples from three conventional wastewater treatment plants (WWTPs), were analyzed to assess the occurrence and fate of 43 pharmaceutical compounds. The selected pharmaceuticals belong to different therapeutic classes, i.e. non-steroidal anti-inflammatory drugs, lipid modifying agents (fibrates and statins), psychiatric drugs (benzodiazepine derivative drugs and antiepileptics), histamine H2-receptor antagonists, antibacterials for systemic use, beta blocking agents, beta-agonists, diuretics, angiotensin converting enzyme (ACE) inhibitors and anti-diabetics. The obtained results showed the presence of 32 target compounds in wastewater influent and 29 in effluent, in concentrations ranging from low ng/L to a few μg/L (e.g. NSAIDs). The analysis of sludge samples showed that 21 pharmaceuticals accumulated in sewage sludge from all three WWTPs in concentrations up to 100 ng/g. This indicates that even good removal rates obtained in aqueous phase (i.e. comparison of influent and effluent wastewater concentrations) do not imply degradation to the same extent. For this reason, the overall removal was estimated as a sum of all the losses of a parent compound produces by different mechanisms of chemical and physical transformation, biodegradation and sorption to solid matter. The target compounds showed very different removal rates and no logical pattern in behaviour even if they belong to the same therapeutic groups. What is clear is that the elimination of most of the substances is incomplete and improvements of the wastewater treatment and subsequent treatments of the produced sludge are required to prevent the introduction of these micro-pollutants in the environment.     

Occurrence of acidic pharmaceuticals in raw and treated sewages and in receiving waters

The occurrence of five acidic pharmaceuticals, ibuprofen, naproxen, ketoprofen, diclofenac and bezafibrate, in seven different sewage treatment plants (STP) and three receiving waters were determined. The analytical procedure included solid phase extraction, liquid chromatographic separation and detection by a triple-quadrupole mass spectrometer. The studied pharmaceuticals were found in all the STPs. The pattern of the occurrence of individual compounds was the same in every STP and matched the consumption figures reported in the literature. Ibuprofen is the most used pharmaceutical in Finland and was accordingly found to be the most abundant compound in the raw sewage. In the treatment processes, the highest removal rate was observed for ibuprofen and the lowest for diclofenac, 92%+/-8% and 26%+/-17%, respectively. Due to the incomplete removal in the STPs, the pharmaceuticals were found in rivers at the discharge points of the STP effluents. Downstream from the discharge points, the concentrations decreased significantly mainly due to dilution in the river water. The risk to the aquatic environment was estimated by a ratio of measured environmental concentration (MEC) and predicted no-effect concentration (PNEC). At the concentrations the compounds were found in the surface waters, they should not pose risk for the aquatic environment. However, at dry seasons and/or during malfunctions of STPs, ibuprofen could be associated with a risk in small river systems.     

Removal of estrogenicity in Swedish municipal sewage treatment plants

The human estrogen receptor alpha-test, hosted in a yeast strain, was used to quantify estrogenicity in three-week composite samples of untreated and treated effluents from 20 Swedish municipal sewage treatment plants. The treatment plants were selected to represent different treatment processes regarding chemical precipitation and microbial procedures. The discharge from Swedish domestic sewage treatment plants contained estrogenic compounds corresponding to <0.1-15 ng estradiol equivalents/L. Low levels of estrogenic activity were also found in a river receiving municipal effluents, 3.5-35 km downstream the outlet from a sewage treatment works. The range of estrogenicity in untreated, raw sewage effluents was found to be 1-30 ng estradiol equivalents/L. Generally, wastewater treatment reduced the estrogenicity and extended biological treatment was most effective in its removal. Activated sludge treatment tended to be more effective than trickling filters, whereas chemical precipitation using iron or aluminium salts without biological treatment showed little effectivity. The study showed that treatment methods in current use are able to eliminate or largely reduce estrogenicity in domestic wastewater.     

抚州市污水处理厂二期工程工艺设计特点

抚州市中心城区污水处理厂二期工程规模6万m^3／d,文中主要介绍了污水处理厂二期的工艺流程、主要构筑物的主要参数、设备配置等。     

Occurrence and removal of pharmaceuticals in a municipal sewage treatment system in the south of Sweden

The occurrence and removal rate of seven pharmaceuticals (ibuprofen, naproxen, diclofenac, fluoxetine, ofloxacin, norfloxacin, ciprofloxacin), two metabolites (norfluoxetine, clofibric acid), one degradation product (4-isobutylacetophenone) and 3 estrogens (17α-ethinylestradiol, 17β-estradiol, estrone) were studied in the inlet and outlet of a tertiary sewage treatment plant (STP) in Sweden as well as between different treatment steps in the STP which includes a conventional activated sludge step. Pharmaceuticals in raw household and raw hospital sewage streams leading to the STP were as well investigated. Hydraulic retention times (HRT) of each treatment step was considered for sampling and for the calculation of the removal rates. These rates were above 90%, except for diclofenac, clofibric acid, estrone and ofloxacin. However, only diclofenac and naproxen showed significant effluent loads (> 145 mg/d/1000 inh). Diclofenac was not eliminated during the treatment and in fact even higher concentrations were found at the effluent than in the inlet of the STP. 17α-Ethinylestradiol was not detected in any of the samples. Results indicate that a STP such as the one in Kristianstad, Sweden, with a tertiary treatment is sufficient to remove significantly most of the investigated pharmaceuticals. The chemical treatment improved the removal of several pharmaceuticals especially the antibiotics, which showed step removal rates between 55 and 70%. The expected concentration levels of the pharmaceuticals in the surface water (dilution 1 to 10) close to the outlet of the STP are below the no-observed effect-concentration (NOEC). However, despite that this would imply no important effects in the aquatic environment one cannot rule out negative consequences nearby the STP because most of the NOEC values are derived from acute toxicity data. This may underestimate the real impact of pharmaceuticals in the aquatic ecosystem.     

Persistent organic pollutants (POPs) in the sewage treatment plant of Thessaloniki, northern Greece: occurrence and removal

The occurrence and the removal of persistent organic pollutants (POPs) during the conventional activated sludge treatment process were investigated in the wastewater treatment plant of the city of Thessaloniki, northern Greece. POPs of interest were seven polychlorinated biphenyls (PCBs) and 19 organochlorine pesticides. Target compounds were determined at six different points across the treatment system. Most abundant compounds in raw wastewater at all treatment stages were PCB-52, PCB-110, PCB-180 and Heptachlor-exo-epoxide. Quintozene occurred frequently but in relatively low concentrations. Hexachlorocyclohexanes, DDT and its metabolites (DDE, DDD) and Aldrin, Dieldrin, Endrin, Isodrin ("Drins") were found at medium or low frequencies and in concentrations close to their detection limits. Removal percentages throughout the whole treatment process ranged from 65% to 91% for individual POP species. Significant linear relationship was observed between removal efficiency and log Kow for PCBs suggesting that compounds with a strong hydrophobic character are principally removed through sorption to sludge particles and transfer to the sludge processing systems. Total PCBs' concentrations in sewage sludge ranged between 185 and 765 ng g(-1) dw being below the EU limit for use of sludge in agriculture.     

Occurrence of androgens in sewage treatment plants influents is associated with antagonist activities on other steroid receptors

The occurrence of endocrine disrupting chemicals such as estrogens in raw urban sewage is well documented. By contrast, the presence of other steroidal activities in wastewater has been poorly studied, although they can cause undesirable biological responses in the environment. In this work, extracts of raw wastewater were tested for agonist and antagonist activities on estrogen, androgen, progesterone, mineralocorticoid and glucocorticoid receptors. We detected strong estrogenic activities that correlated well with the concentration of natural estrogens (estrone, estriol and 17β-estradiol) measured by chemical analysis. We also measured strong androgenic activities which were not due to estrogen receptor ligands based on the use of recombinant estrogen receptor α affinity columns. Several molecules with androgenic activities were identified in wastewater samples, testosterone, dihydrotestosterone and epiandrosterone being the most abundant. However, they explain only a small part of the detected androgenic activity, as indicated by the comparison of the detected biological responses with the results of the targeted chemical analysis. Finally, we found that our samples also contained strong antagonist activities on progesterone, glucocorticoid and mineralocorticoid receptors. Very interestingly, we identified pregnenolone (the precursor to all steroid hormones in humans) as a major endocrine disrupting chemical which accounts for most of the anti-mineralocorticoid activities present in raw wastewater. In conclusion, this study demonstrates the occurrence of androgen agonists as well as other steroid receptor antagonists such as pregnenolone in raw wastewater. Further research is needed to assess the fate of such compounds during sewage treatment and their potential effect on living organisms.     

Biological degradation of pharmaceuticals in municipal wastewater treatment: proposing a classification scheme

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%.     

Environmental risk assessment of antibiotics in the Swedish environment with emphasis on sewage treatment plants

The potential risks associated with antibiotics present in the Swedish environment were assessed using concentrations found in hospital effluent, and sewage treatment waters and sludge, in combination with data on their environmental effects obtained from the literature. For the aqueous environment, measured environmental concentrations and effect/no observed effect concentration ratios were much lower than one in most cases. The only exceptions, where concentrations of the investigated substances were high enough to pose potential risks, were the concentrations of the two fluoroquinolones, ofloxacin and ciprofloxacin, in the hospital effluent. Treating digested dewatered sludge by heat did not fully eliminate norfloxacin or ciprofloxacin, thus pellets may still contain high amounts of these substances (sub to low mgkg(-1)dw). In leaching tests less than 1% of the amounts of these fluoroquinolones in the sludge or pellets reached the aqueous phase, indicating that their mobility is limited if sludge is used to fertilize soil.     

东北某市污水处理厂生化池伸缩缝渗漏治理技术

在对东北某市污水处理厂渗漏原因分析的基础上,提出了渗漏治理的方案,介绍了所用的防水密封材料,阐述了施工要点。     

城市污水处理厂污泥现状及处置对策

结合工作实际,对比国内外污泥处理的先进经验,对几种处置方法进行了列举分析,并通过优缺点比较,提出了城市污水厂污泥处置与利用的最佳方案,以减少污泥造成的环境污染。     

Determination of sorption of seventy-five pharmaceuticals in sewage sludge

Sorption of 75 active pharmaceutical ingredients (APIs) to three different types of sludge (primary sludge, secondary sludge with short and long sludge age respectively) were investigated. To obtain the sorption isotherms batch studies with the APIs mixture were performed in four nominal concentrations to water containing 1 g of sludge. The range of APIs concentrations was between ng L⁻¹ to μg L⁻¹ which are found in the wastewater effluents. Isotherms were obtained for approximately 45 of the APIs, providing distribution coefficients for linear (K_d), Freundlich (K_f) and Langmuir (K_L) isotherms. K_d, K_f and K_L ranging between 7.1 × 10⁴ and 3.8 × 10⁷, 1.1 × 10⁻² and 6.1 × 10⁴ and 9.2 × 10⁻³ and 1.1 L kg⁻¹, respectively. The obtained coefficients were applied to estimate the fraction of APIs in the water phase (see Abstract Graphic). For 37 of the 75 APIs, the predicted presence in the liquid phase was estimated to >80%. 24 APIs were estimated to be present in the liquid phase between 20 and 80%, and 14 APIs were found to have <20% presence in the liquid phase, i.e. high affinity towards sludge. Furthermore, the effect of pH at values 6, 7 and 8 was evaluated using one way ANOVA-test. A significant difference in K_ds due to pH changes were found for 6 of the APIs (variation 10-20%).