The removal of pharmaceuticals, personal care products, endocrine disruptors and illicit drugs during wastewater treatment and its impact on the quality of receiving waters

A 5-month monitoring program was undertaken in South Wales in the UK to determine the fate of 55 pharmaceuticals, personal care products, endocrine disruptors and illicit drugs (PPCPs) in two contrasting wastewater plants utilising two different wastewater treatment technologies: activated sludge and trickling filter beds. The impact of treated wastewater effluent on the quality of receiving waters was also assessed.PPCPs were found to be present at high loads reaching 10 kg day⁻¹ in the raw sewage. Concentrations of PPCPs in raw sewage were found to correlate with their usage/consumption patterns in Wales and their metabolism. The efficiency of the removal of PPCPs was found to be strongly dependent on the technology implemented in the wastewater treatment plant (WWTP). In general, the WWTP utilising trickling filter beds resulted in, on average, less than 70% removal of all 55 PPCPs studied, while the WWTP utilising activated sludge treatment gave a much higher removal efficiency of over 85%. The monitoring programme revealed that treated wastewater effluents were the main contributors to PPCPs concentrations (up to 3 kg of PPCPs day⁻¹) in the rivers studied. Bearing in mind that in the cases examined here the WWTP effluents were also major contributors to rivers' flows (dilution factor for the studied rivers did not exceed 23 times) the effect of WWTP effluent on the quality of river water is significant and cannot be underestimated.     

Contribution of combined sewer overflows to trace contaminant loads in urban streams

The present study examines the contribution of combined sewer overflows (CSO) to loads and concentrations of trace contaminants in receiving surface water. A simple method to assess the ratio of CSO to wastewater treatment plant (WWTP) effluents was applied to the urban River Spree in Berlin, Germany. The assessment indicated that annual loads are dominated by CSO for substances with removal in WWTP above ∼95%. Moreover, it showed that substances with high removal in WWTP can lead to concentration peaks in the river during CSO events. The calculated results could be verified based on eight years of monitoring data from the River Spree, collected between 2000 and 2007. Substances that are well removed in WWTP such as NTA (nitrilotriacetic acid) were found to occur in significantly increased concentration during CSO, while the concentration of substances that are poorly removable in WWTP such as EDTA (ethylenediaminetetraacetic acid) decreased in CSO-influenced samples due to dilution effects. The overall results indicate the potential importance of the CSO pathway of well-removable sewage-based trace contaminants to rivers. In particular, high concentrations during CSO events may be relevant for aquatic organisms. Given the results, it is suggested to include well-removable, sewage-based trace contaminants, a substance group often neglected in the past, in future studies on urban rivers in case of combined sewer systems. The presented methodology is suggested for a first assessment, since it is based solely on urban drainage data, which is available in most cities.     

Assessment of full-scale natural systems for the removal of PPCPs from wastewater in small communities

This study assessed the ability to remove pharmaceuticals and personal care products (PPCPs) of three different full-scale hybrid pond-constructed wetlands and a conventional wastewater treatment plant (WWTP). The four systems were fed with primary-treated urban wastewaters. The three hybrid systems consisted of several different subsystems (ponds, surface flow constructed wetlands and horizontal subsurface flow constructed wetlands) connected in series, and their PPCP degradation efficiency was monitored. In addition, the enantiomeric behaviour of ibuprofen was studied in all the subsystems. The hybrid systems were at least as efficient in PPCP removal as the WWTP, removal efficiencies mainly exceeding 70%. Moreover, enantiomeric analysis indicates that ibuprofen removal followed a predominantly aerobic and microbiological pathway. Constructed wetlands and ponds are therefore successful technologies for removing PPCPs from wastewater and the most significant removal process in these systems is biologically mediated.     

A rapid method to measure the solid-water distribution coefficient (Kd) for pharmaceuticals and musk fragrances in sewage sludge

Pharmaceuticals and personal care products are omnipresent in wastewater world-wide. In order to predict their sorption quantities onto sludge in wastewater treatment plants (WWTPs), the solid-water distribution coefficients (Kd values) of selected pharmaceuticals (antiphlogistics, estrogens, lipid regulators, anti-epileptic and cytostatic agents) and polycyclic musk fragrances (HHCB, AHTN) were determined in primary and secondary sludges taken from a German municipal WWTP. For the Kd determination, batches of primary and secondary sludge slurries were spiked with the respective target compounds and slowly stirred under defined conditions (e.g. an argon atmosphere). Finally, the water and solid sludge phases were analysed. The Kd values of pharmaceuticals ranged from <1 to 500 L kg(-1), while those for the polycyclic musk fragrances AHTN and HHCB proved to be up to 5300 and 4900 L kg(-1), respectively. The primary and secondary sludge showed significant differences for some pharmaceuticals such as Diclofenac and Cyclophosphamide due to the different pH and composition of the two sludges. The removal rate from the water phase caused by sorption in a WWTP can be reasonably predicted on the basis of the Kd values.     

A comparison of human pharmaceutical concentrations in raw municipal wastewater and yellowwater

Currently, many articles report on pharmaceutical residues detected in various compartments of the environment. A major pathway into the aquatic environment is municipal wastewater. This article discusses the relevance of yellowwater (urine) as pharmaceutical source within this wastewater stream. Literature data about concentrations of 28 pharmaceutical residues detected in raw wastewater are compared to their theoretically calculated concentrations in urine. The study shows that these pharmaceuticals and their metabolites are excreted predominantly via urine although some substances show reasonable excretion via faeces. It is demonstrated that the influence of pharmacokinetic activities is one important issue affecting the presence of pharmaceuticals in the aquatic environment. Nevertheless, only a weak correlation between concentrations of pharmaceuticals calculated in yellowwater and analysed in raw wastewater was observed. This is due to environmental effects taking place between the excretion of urine and the entrance of sewerage into the wastewater treatment plant. The data show that urine separation and separate handling/treatment of this wastewater stream represents a promising approach to protect the aquatic environment safely from human pharmaceuticals.     

EU-wide monitoring survey on emerging polar organic contaminants in wastewater treatment plant effluents

In the year 2010, effluents from 90 European wastewater treatment plants (WWTPs) were analyzed for 156 polar organic chemical contaminants. The analyses were complemented by effect-based monitoring approaches aiming at estrogenicity and dioxin-like toxicity analyzed by in vitro reporter gene bioassays, and yeast and diatom culture acute toxicity optical bioassays. Analyses of organic substances were performed by solid-phase extraction (SPE) or liquid–liquid extraction (LLE) followed by liquid chromatography tandem mass spectrometry (LC-MS-MS) or gas chromatography high-resolution mass spectrometry (GC-HRMS). Target microcontaminants were pharmaceuticals and personal care products (PPCPs), veterinary (antibiotic) drugs, perfluoroalkyl substances (PFASs), organophosphate ester flame retardants, pesticides (and some metabolites), industrial chemicals such as benzotriazoles (corrosion inhibitors), iodinated x-ray contrast agents, and gadolinium magnetic resonance imaging agents; in addition biological endpoints were measured. The obtained results show the presence of 125 substances (80% of the target compounds) in European wastewater effluents, in concentrations ranging from low nanograms to milligrams per liter. These results allow for an estimation to be made of a European median level for the chemicals investigated in WWTP effluents. The most relevant compounds in the effluent waters with the highest median concentration levels were the artificial sweeteners acesulfame and sucralose, benzotriazoles (corrosion inhibitors), several organophosphate ester flame retardants and plasticizers (e.g. tris(2-chloroisopropyl)phosphate; TCPP), pharmaceutical compounds such as carbamazepine, tramadol, telmisartan, venlafaxine, irbesartan, fluconazole, oxazepam, fexofenadine, diclofenac, citalopram, codeine, bisoprolol, eprosartan, the antibiotics trimethoprim, ciprofloxacine, sulfamethoxazole, and clindamycine, the insect repellent N,N′-diethyltoluamide (DEET), the pesticides MCPA and mecoprop, perfluoroalkyl substances (such as PFOS and PFOA), caffeine, and gadolinium.     

Removal of selected endocrine disrupting chemicals (EDCs) and pharmaceuticals and personal care products (PPCPs) during ferrate(VI) treatment of secondary wastewater effluents

We investigated the removal efficiencies of 68 selected endocrine disrupting chemicals (EDCs) and pharmaceuticals and personal care products (PPCPs) spiked in a wastewater matrix by ferrate (Fe(VI)) and further evaluated the degradation of these micropollutants present in secondary effluents of two wastewater treatment plants (WWTPs) by applying Fe(VI) treatment technology. Fe(VI)treatment resulted in selective oxidation of electron-rich organic moieties of these target compounds, such as phenol, olefin, amine and aniline moieties. But Fe(VI) failed to react with triclocarban, 3 androgens, 7 acidic pharmaceuticals, 2 neutral pharmaceuticals and erythromycin-H₂O.Thirty-one target EDCs and PPCPs were detected in the effluents of the two WWTPs with concentrations ranging from 0.2 ± 0.1 ng L⁻¹ to 1156 ± 182 ng L⁻¹.Fe(VI) treatment resulted in further elimination of the detected EDCs and PPCPs during Fe(VI) treatment of the secondary wastewater effluents. The results from this study clearly demonstrated the effectiveness of Fe(VI) treatment as a tertiary treatment technology for a broad spectrum of micropollutants in wastewater.     

传感器技术与污水处理过程控制技术的协同发展现状

仪表、控制和自动化(ICA)技术是污水处理厂降低运行成本、提高处理效率的有效手段,而ICA技术在污水生物处理领域的应用与发展,主要依赖于仪表技术尤其是传感器技术的发展.介绍了传感器技术在活性污泥法污水处理厂的应用现状,以及基于DO传感器、营养物传感器、间接参数测量传感器所发展起来的过程控制技术,并对传感器技术与过程控制技术在未来的协同发展趋势进行了讨论,以期为该技术的发展提供参考.     

Leaching behaviour of pharmaceuticals in soil-testing-systems: a part of an environmental risk assessment for groundwater protection

The leaching behaviour of six selected pharmaceuticals was tested in different soils. Leaching experiments are a part of environmental risk assessment to estimate the distribution and fate of these pharmaceuticals in the environment. Based on the results of this assessment their mobility in soil and their potential to contaminate groundwater was evaluated. When assessing the leaching behaviour of these compounds, the influence of the properties (e.g. grain size distribution, pH, Corg) of different soils has to be taken into account. The test results indicated that the leaching potential found could be rated as low for diazepam, ibuprofen, ivermectin and carbamazepine. Therefore, contamination of the groundwater with these substances seems to be unlikely if the groundwater level is covered with sufficient layers of the soils investigated. Clofibric acid and iopromide were very mobile under the experimental conditions and thus, groundwater contamination would be possible if the soil is exposed to these pharmaceuticals, i.e. wastewater irrigation. These results are more or less in agreement with groundwater monitoring data found in the literature for ibuprofen and diazepam which were in general not present in groundwater, while clofibric acid and iopromide were frequently detected. However, a discrepancy was found for carbamazepine, since it occurs very often in groundwater. This discrepancy might be explained by the fact that the leaching tests were performed with soil, whereas in reality the groundwater contamination occurs mainly over river sediments and sub soil from receiving waters.     

Kinetics of aqueous chlorination of some pharmaceuticals and their elimination from water matrices

Apparent rate constants for the reactions of four selected pharmaceutical compounds (metoprolol, naproxen, amoxicillin, and phenacetin) with chlorine in ultra-pure (UP) water were determined as a function of the pH. It was found that amoxicillin (in the whole pH range 3-12), and naproxen (in the low pH range 2-4) presented high reaction rates, while naproxen (in the pH range 5-9), and phenacetin and metoprolol (in the pH range 2.5-12 for phenacetin, and 3-10 for metoprolol) followed intermediate and slow reaction rates. A mechanism is proposed for the chlorination reaction, which allowed the evaluation of the intrinsic rate constants for the elementary reactions of the ionized and un-ionized species of each selected pharmaceutical with chlorine. An excellent agreement is obtained between experimental and calculated rate constants by this mechanism.The elimination of these substances in several waters (a groundwater, a surface water from a public reservoir, and two effluents from municipal wastewater treatment plants) was also investigated at neutral pH. The efficiency of the chlorination process with respect to the pharmaceuticals elimination and the formation THMs was also established. It is generally observed that the increasing presence of organic and inorganic matter in the water matrices demand more oxidant agent (chlorine), and therefore, less chlorine is available for the oxidation of these compounds. Finally, half-life times and oxidant exposures (CT) required for the removal of 99% of the four pharmaceuticals are also evaluated. These parameters are useful for the establishment of safety chlorine doses in oxidation or disinfection stages of pharmaceuticals in treatment plants.     

广州市城市污水处理厂污泥处理处置初步研究

论述了广州市城市污水处理厂污泥的产生、特性、处理和处置问题。概述了污泥处理和处置方法的进展,并结合广州市污泥成分复杂、资金利用等实际情况,提出了近远期结合的污泥处理处置方法,逐步实现污泥的稳定化、减量化、无害化与资源化。     

Suspended biofilm carrier and activated sludge removal of acidic pharmaceuticals

Removal of seven active pharmaceutical substances (ibuprofen, ketoprofen, naproxen, diclofenac, clofibric acid, mefenamic acid, and gemfibrozil) was assessed by batch experiments, with suspended biofilm carriers and activated sludge from several full-scale wastewater treatment plants. A distinct difference between nitrifying activated sludge and suspended biofilm carrier removal of several pharmaceuticals was demonstrated. Biofilm carriers from full-scale nitrifying wastewater treatment plants, demonstrated considerably higher removal rates per unit biomass (i.e. suspended solids for the sludges and attached solids for the carriers) of diclofenac, ketoprofen, gemfibrozil, clofibric acid and mefenamic acid compared to the sludges. Among the target pharmaceuticals, only ibuprofen and naproxen showed similar removal rates per unit biomass for the sludges and biofilm carriers. In contrast to the pharmaceutical removal, the nitrification capacity per unit biomass was lower for the carriers than the sludges, which suggests that neither the nitrite nor the ammonia oxidizing bacteria are primarily responsible for the observed differences in pharmaceutical removal. The low ability of ammonia oxidizing bacteria to degrade or transform the target pharmaceuticals was further demonstrated by the limited pharmaceutical removal in an experiment with continuous nitritation and biofilm carriers from a partial nitritation/anammox sludge liquor treatment process.     

天津开发区第一污水厂升级改造工艺的选择与分析

随着国家和地方对城镇污水处理厂污染物排放标准的逐年提高,已经建成的很多污水处理厂均面临升级改造,如何确定改造工艺是众多设计人员面临的严峻问题。以天津开发区第一污水处理厂升级改造工程为例,在处理规模不能减量及用地受限等约束条件下,分析探讨了污水处理厂升级改造工艺的选择要点。指出,对污水处理厂的升级改造需充分挖掘现有工艺的潜力,结合工程投资、运行成本、工程周期、处理效果等,根据具体情况确定改造工艺。     

The occurrence of selected pharmaceuticals in wastewater effluent and surface waters of the lower Tyne catchment

This paper presents the results of a survey of the wastewater effluent and surface waters of the lower river Tyne, UK. Samples were analysed by reversed-phase high-performance liquid chromatography-electrospray tandem mass spectrometry following solid phase extraction, for the presence of 13 pharmaceuticals selected from the priority lists of the UK Environment Agency and the Oslo and Paris Commission (OSPAR). The pharmaceutical compounds measured were acetyl-sulfamethoxazole, clofibric acid, clotrimazole, dextropropoxyphene, diclofenac, erythromycin, ibuprofen, mefenamic acid, paracetamol, propranolol, sulfamethoxazole, tamoxifen and trimethoprim. Of the wastewater treatment works (WTW) samples (n=9) analysed, all compounds except sulfamethoxazole and acetyl-sulfamethoxazole were detected at concentrations ranging from 11 to 69,570 ng l(-1) (in raw effluent). In the surface water samples (n=18), clotrimazole, dextropropoxyphene, erythromycin, ibuprofen, propranolol, tamoxifen and trimethoprim were detected at concentrations ranging from 4 to 2370 ng l(-1). Results of this study show that various pharmaceutical compounds are effectively reduced during their passage through a tertiary wastewater treatment works, whilst others are sufficiently persistent to occur in estuarine systems.     

A combined approach for a better understanding of wastewater treatment plants operation: statistical analysis of monitoring database and sludge physico-chemical characterization

Biological wastewater treatment plants (WWTP) are complex systems to assess. Many parameters are recorded daily in WWTP to monitor and control the treatment process, providing huge amounts of registered data. A combined approach of extracting information from the WWTP databases by statistical methods and from the sludge physico-chemical characterization was used here for a better understanding of the WWTP operation. The monitored parameters were analysed by multivariate statistical methods: Principal Components Analysis and multiple partial linear regression. The WWTP operational conditions determine the sludge characteristics. The bacterial activity of the sludge in terms of extra-cellular polymeric substances (EPS) production was assessed using size exclusion chromatography and the internal structure of sludge flocs was observed by confocal laser scanning microscopy. The diagnosis of three paper mill WWTP enabled the identification of an important EPS production, the presence of the nitrification process and the presence of PO₄³⁻ nutrient in WWTP-A. These three main characteristics of WWTP-A were related with a systematically good sludge settling. In WWTP-B and C with bad settling, the bacterial activity was weak.     

Fate and distribution of pharmaceuticals in wastewater and sewage sludge of the conventional activated sludge (CAS) and advanced membrane bioreactor (MBR) treatment

In this paper we report on the performances of full-scale conventional activated sludge (CAS) treatment and two pilot-scale membrane bioreactors (MBRs) in eliminating various pharmaceutically active compounds (PhACs) belonging to different therapeutic groups and with diverse physico-chemical properties. Both aqueous and solid phases were analysed for the presence of 31 pharmaceuticals included in the analytical method. The most ubiquitous contaminants in the sewage water were analgesics and anti-inflammatory drugs ibuprofen (14.6-31.3 μg/L) and acetaminophen (7.1-11.4 μg/L), antibiotic ofloxacin (0.89-31.7 μg/L), lipid regulators gemfibrozil (2.0-5.9 μg/L) and bezafibrate (1.9-29.8 μg/L), β-blocker atenolol (0.84-2.8 μg/L), hypoglycaemic agent glibenclamide (0.12-15.9 μg/L) and a diuretic hydrochlorothiazide (2.3-4.8 μg/L). Also, several pharmaceuticals such as ibuprofen, ketoprofen, diclofenac, ofloxacin and azithromycin were detected in sewage sludge at concentrations up to 741.1, 336.3, 380.7, 454.7 and 299.6 ng/g dry weight. Two pilot-scale MBRs exhibited enhanced elimination of several pharmaceutical residues poorly removed by the CAS treatment (e.g., mefenamic acid, indomethacin, diclofenac, propyphenazone, pravastatin, gemfibrozil), whereas in some cases more stable operation of one of the MBR reactors at prolonged SRT proved to be detrimental for the elimination of some compounds (e.g., β-blockers, ranitidine, famotidine, erythromycin). Moreover, the anti-epileptic drug carbamazepine and diuretic hydrochlorothiazide by-passed all three treatments investigated.Furthermore, sorption to sewage sludge in the MBRs as well as in the entire treatment line of a full-scale WWTP is discussed for the encountered analytes. Among the pharmaceuticals encountered in sewage sludge, sorption to sludge could be a relevant removal pathway only for several compounds (i.e., mefenamic acid, propranolol, and loratidine). Especially in the case of loratidine the experimentally determined sorption coefficients (K_ds) were in the range 2214-3321 L/kg (mean). The results obtained for the solid phase indicated that MBR wastewater treatment yielding higher biodegradation rate could reduce the load of pollutants in the sludge. Also, the overall output load in the aqueous and solid phase of the investigated WWTP was calculated, indicating that none of the residual pharmaceuticals initially detected in the sewage sludge were degraded during the anaerobic digestion. Out of the 26 pharmaceutical residues passing through the WWTP, 20 were ultimately detected in the treated sludge that is further applied on farmland.     

MBR工艺在无锡三座城市污水厂中的应用分析

膜生物反应器(MBR)是一种新型高效的污水处理技术,在城市污水处理与回用及升级改造中具有良好的应用前景。从工程概况、运行效果及技术经济指标入手,对无锡三座采用MBR工艺的城市污水厂(硕放污水厂、梅村污水厂及新城污水厂)进行了分析比较。结果表明,各污水厂出水水质基本能实现稳定排放并达到GB 18918—2002的一级A标准;增加后置缺氧段的硕放污水厂脱氮除磷效果优于其他两座污水厂;各污水厂能耗为0.6～0.7 kW.h/m3,膜化学清洗药剂消耗费用约5 000元/月;因进水碳源不足,视天气及冲击负荷影响,各污水厂均不定期投加醋酸,以保证出水水质达标。根据三座污水厂的运行情况,指出膜组件和生物段的合理布置及优化,是未来城市污水MBR工艺处理的研究方向。     

Degradation of emergent contaminants by UV,UV/H2O2 and neutral photo-Fenton at pilot scale in a domestic wastewater treatment plant

This study focuses on the removal of 22 selected micropollutants in an effluent from a municipal wastewater treatment plant (MWTP) at pilot scale. A reactor of 37 L with five low pressure mercury lamps emitting at 254 nm (UV₂₅₄) was used. The 22 micropollutants include 15 pharmaceuticals, 2 X-Ray contrast medias, 1 corrosion inhibitor and 4 biocides/pesticides. Five of these 22 compounds were used as indicative substances as proposed by the Swiss Federal Office for the Environment (FOEN) (carbamazepine, diclofenac, sulfamethoxazole, benzotriazole and mecoprop).     

Electro-oxidation of reverse osmosis concentrates generated in tertiary water treatment

This work investigates the application of the electro-oxidation technology provided with boron doped diamond (BDD), an electrode material which has shown outstanding properties in oxidation of organic and inorganic compounds, for the treatment of reverse osmosis (RO) concentrates generated in tertiary wastewater treatment plants (WWTP). Chemical oxygen demand (COD), ammonium and several anions were measured during the electro-oxidation process, and the influence of the applied current density (20-200 A/m²) was analysed on process kinetics. Analytical assessment showed that several emerging pollutants (pharmaceuticals, personal care products, stimulants, etc.) were presented both in the effluent of the secondary WWTP as well as in the RO concentrate. For this reason, a group of 10 emerging pollutants, those found with higher concentrations, was selected in order to test whether electro-oxidation can be also applied for their mitigation. In the removal of emerging pollutants the electrical current density in the range 20-100 A/m² did not show influence likely due to the mass transfer resistance developed in the process when the oxidized solutes are present in such low concentrations. Their removal rates were fitted to first order expressions, and the apparent kinetic constants for the anodic oxidation of each compound were calculated. Finally, the formation of trihalomethanes (THMs) has been checked; concluding that after selecting the appropriate operational conditions the attained concentration is lower than the standards for drinking water established in European and EPA regulations.     

人工湿地在污水深度处理中的应用与工程设计

分析了城市污水处理厂污水深度处理回用技术存在的问题,指出应重新认识人工湿地的作用,改变传统的将人工湿地作为城市污水处理厂二级处理工艺的观念,而应将其用于污水深度处理.此外,还探讨了人工湿地深度处理工程的设计要点.