Occurrence and removal of selected organic micropollutants at mechanical, chemical and advanced wastewater treatment plants in Norway

In Norway the combined hydraulic capacity of all domestic wastewater treatment plants is relatively equally distributed between three major treatment plant types; mechanical, chemical, and combined chemical and biological. The Western coast from Lindesnes in the south to the Russian boarder in the North is dominated by mechanical treatment plants, constituting approximately 68% of the treatment capacity in that area. In the present study we report concentrations and removal efficiencies of polycyclic aromatic hydrocarbons (PAHs), nonylphenols, phthalates, polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) found in five Norwegian wastewater treatment plants (WWTPs) applying different levels of treatment. Concentrations of organic micropollutants in the influents to the WWTPs were generally in the low range of what have been reported by others for domestic wastewater in Europe and North-America. More than 90% removal could be obtained for nonylphenols, PBDEs, and the more hydrophobic 4-6 ring PAHs by chemical precipitation, however, biological treatment appeared to be necessary for efficient removal of the less lipophilic 2 and 3 ring PAHs, the medium- to short-chained nonylphenol ethoxylates and diethyl phthalate. SigmaPCB(7) was removed by more than 90% by combined biological/chemical treatment, while removal efficiency by chemical treatment was not possible to estimate due to low inlet concentrations. Low or insignificant removals of PAHs, phthalates and nonylphenols with their ethoxylates were observed at the mechanical WWTP, which was in accordance with the minuscule removal of TOC.     

Fate of nonylphenol polyethoxylates and their metabolites in four Beijing wastewater treatment plants

Four Beijing wastewater treatment plants (WWTPs) were selected to investigate behaviours of nonylphenol polyethoxylates and their metabolites in different wastewater treatment processes. The results showed that the total concentrations of nonylphenolic compounds in the influents of the four WWTPs ranged from 0.115 to 0.347 μmol/L, as well as their removal efficiencies ranging from 75.7% to 90.8%. Both influent concentrations and removal efficiencies of nonylphenol polyethoxylates were correlated to seasons as follows: higher in the summer than in the winter, and influent concentrations were lower during the rain weather. The analysis revealed that 21.8-47.6% of nonylphenol polyethoxylates and their metabolites entering WWTPs were released via effluents and excess sludge, leaving a great part of them for biodegradation. Nonylphenol and short-chain nonylphenol polyethoxylates were disposed to the environment mainly via sewage sludge, while carboxylated nonylphenol polyethoxylates were the most abundant group of nonylphenol polyethoxylates in effluents.     

Fate of beta blockers and psycho-active drugs in conventional wastewater treatment

The removal of beta blockers and psycho-active drugs was investigated in a representative conventional German WWTP by long-term measurement campaigns along different biological treatment processes. The activated sludge treatment with an elevated SRT of 18 d was the only process which led to a significant removal of certain beta blockers and psycho-active drugs. The removal efficiency was below 60% for all compounds except for the natural opium alkaloids codeine and morphine being removed by more than 80%. Primary biological transformation and sorption onto sludge as the main removal mechanisms were examined in lab-scale batch experiments. Sorption onto activated sludge was found to be negligible (<3%). The biological transformation could be described by pseudo-first order kinetics and the transformation constants k_biol were used to predict the removal of beta blockers and psycho-active drugs in an activated sludge unit with a model. For most compounds the removal efficiencies measured on the full-scale WWTP were within the 95% confidence intervals predicted by the model. The results from full-scale measurements and modeling indicate that biological transformation in the nitrification tank together with parameters such as the sludge retention time and the temperature is crucial regarding the biological transformation of beta blockers and psycho-active drugs in conventional WWTPs.     

Sources of endocrine-disrupting chemicals in urban wastewater, Oakland, CA

Synthetic endocrine-disrupting chemicals (EDCs) have been found in surface waters throughout the United States, and are known to enter waterways via discharge from wastewater treatment plants (WWTPs). Studies addressing EDCs in wastewater do not examine their specific sources upstream of WWTPs. Presented here are results of a pilot study of potential sources of selected EDCs within an urban wastewater service area. Twenty-one wastewater samples were collected from a range of sites, including 16 residential, commercial, or industrial samples, and five samples from influent and effluent streams at the WWTP. Samples were analyzed for the following known and suspected EDCs: five phthalates, bisphenol A (BPA), triclosan, 4-nonylphenol (NP), and tris(2-chloroethyl) phosphate (TCEP), using well-established methods (EPA 625 and USGS O-1433-01). Twenty of 21 samples contained at least one EDC. Phthalates were widely detected; one or more phthalate compound was identified in 19 of 21 samples. Measurement of two phthalates in a field blank sample suggests that the accuracy of sample detections for these two compounds may be compromised by background contamination. Triclosan was detected in nine samples, BPA in five samples, and TCEP in four samples; NP was not detected. The results of this and future source-specific studies may be used to develop targeted pollution prevention strategies to reduce levels of EDCs in wastewater.     

Occurrence and behaviour of linear alkylbenzenesulphonates, nonylphenol, nonylphenol mono- and nonylphenol diethoxylates in sewage and sewage sludge treatment

The fluxes of linear alkylbenzenesulphonates (LAS), nonylphenol (NP), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate (NP2EO) through sewage and sludge treatment of 29 Swiss sewage treatment plants were investigated. Reversed-phase high-performance liquid chromatography (HPLC) was used to determine LAS. Normal-phase HPLC was employed to measure NP, NP1EO and NP2EO which are metabolites of the nonionic surfactants of the nonylphenol polyethoxylate type (NPnEO). Quantitative determinations were performed of raw sewage, primary and secondary effluents and of sewage sludge. Under normal conditions of sewage and sludge treatment, LAS were efficiently removed from the raw wastewater (> 99% w/w) and were partly transferred to the sewage sludge (15–20% w/w). About 50% (molar base) of NPnEO in the sewage were transformed to NP and accumulated in the digested sludge. Large variations existed among different sewage treatment plants. It was estimated that 1.0 g m⁻² y⁻¹ of LAS and 0.3 g m⁻² y⁻¹ of NP are applied with sewage sludge to Swiss soils.     

Removal of selected pharmaceuticals, fragrances and endocrine disrupting compounds in a membrane bioreactor and conventional wastewater treatment plants

Eight pharmaceuticals, two polycyclic musk fragrances and nine endocrine disrupting chemicals were analysed in several waste water treatment plants (WWTPs). A membrane bioreactor in pilot scale was operated at different solid retention times (SRTs) and the results obtained are compared to conventional activated sludge plants (CASP) operated at different SRTs. The SRT is an important design parameter and its impact on achievable treatment efficiencies was evaluated. Different behaviours were observed for the different investigated compounds. Some compounds as the antiepileptic drug carbamazepine were not removed in any of the sampled treatment facilities and effluent concentrations in the range of influent concentrations were measured. Other compounds as bisphenol-A, the analgesic ibuprofen or the lipid regulator bezafibrate were nearly completely removed (removal rates >90%). The operation of WWTPs with SRTs suitable for nitrogen removal (SRT>10 days at 10 degrees C) also increases the removal potential regarding selected micropollutants. No differences in treatment efficiencies were detected between the two treatment techniques. As in conventional WWTP also the removal potential of MBRs depends on the SRT. Ultrafiltration membranes do not allow any additional detention of the investigated substances due to size exclusion. However, MBRs achieve a high SRT within a compact reactor. Nonylphenolpolyehtoxylates were removed in higher extend in very low-loaded conventional WWTPs, due to variations of redox conditions, necessary for the degradation of those compounds.     

Phthalates and nonylphenols in urban runoff: Occurrence, distribution and area emission factors

The urban water system is believed to be an important sink for the nonpoint-source pollutants nonylphenols and phthalates. The presence of nonylphenols (NPs), nonylphenol ethoxylates (NPEOs), and eight phthalates was analyzed in urban stormwater and sediment from three catchment areas in Sweden. Emission loads for these substances were then calculated for a specific urban catchment area. In addition, substance distribution in road runoff passing through a sedimentation facility was modeled using a modified QWASI-model for chemical fate. High concentrations of DEHP, DIDP and DINP (≤ 48, 66 and 200 µg/g dw, respectively) as well as nonylphenol mono- and di-ethoxylate (6.6 and 20 µg/g dw, respectively) were found in the sediment. Aqueous concentrations of the pollutants varied considerably; branched NP was detected in concentrations up to 1.2 µg/L, whereas di(2-ethylhexyl) phthalate (DEHP), diisodecyl phthalate (DIDP), and diisononyl phthalate (DINP) were the most frequently detected phthalates in concentrations up to 5.0, 17 and 85 µg/L, respectively. The fate modeling demonstrated that predicted substance levels in water agreed well with measured levels, whereas the modeled sediment levels were underestimated. Calculation of catchment area emission factors from an urban highway environment revealed that as much as 2.1 kg of total phthalates and 200 g of NP and NPEOs may be emitted per hectare and year. The results indicate that all monitored phthalates, branched NPs and lower NPEOs are present in Swedish urban water systems. The long-chain phthalates DIDP and DINP are believed to occur at higher concentrations than other phthalates because of their higher environmental persistence and their increasing use in Sweden.     

Sources and behaviour of bismuth active substances (BiAS) in a municipal sewage treatment plant

Non-ionic surfactants are widely used for household and industrial purposes. For different reasons the metabolites, e.g. 4-nonylphenol, nonylphenol monoethoxylate, nonylphenol diethoxylate and 4-tert-octylphenol, are especially considered to be endocrine disruptive and thus potentially harmful for the environment. In this study, field samples of raw wastewater from different point sources, including industrial effluents, household effluents, the influent and secondary effluent of a wastewater treatment plant that treats this wastewater were monitored simultaneously. Composite samples were taken five times over periods of 1 week at nine sample sites. The results showed that the concentrations and fluxes were varying. In addition industrial, influent and effluent samples were investigated for nonylphenol (NP). The highest concentrations of bismuth active substances (BiAS) were obtained by wastewater samples from a chemical and a cloth washing company ranging from 10,200 to 65,600 microg/l and 14,600 to 33,900 microg/l BiAS, respectively. Although the concentration of BiAS in the wastewater of the paper production was only between 460 and 1200 microg/l BiAS, the NP/BiAS ratio of 0.51% was considerably higher than in other industrial effluents. The BiAS concentration in wastewater samples from households ranged from 2200 to 7900 microg/l BiAS, but the NP concentration was quite low, 0.01% of BiAS. This could be due to the effort within the EU to phase out nonylphenol polyethoxylates in household detergents. Influent concentrations between 700 and 2200 microg/l BiAS with removal rates in the WWTP ranging from 70.7 to 99.4% with an average of 92.2% could be measured.     

Evaluation of the fate of perfluoroalkyl compounds in wastewater treatment plants

Recent studies have shown that the wastewater treatment plant (WWTP) is a significant source of perfluoroalkyl compounds (PFCs) in natural water. In this study, 10 PFCs were analyzed in influent and effluent wastewater and sludge samples in 15 municipal, 4 livestock and 3 industrial WWTPs in Korea. The observed distribution pattern of PFCs differed between the wastewater and sludge samples. Perfluorooctane sulfonate (PFOS) was dominant in the sludge samples with a concentration ranging from 3.3 to 54.1 ng/g, whereas perfluorooctanoic acid (PFOA) was dominant in wastewater and ranged from 2.3 to 615 ng/L and 3.4 to 591 ng/L in influent and effluent wastewater, respectively. Principal component analysis (PCA) results provided an explanation for this variation in PFC distribution patterns in the aqueous and sludge samples. The fates of PFCs in the WWTPs were related with the functional groups. The PFOS concentrations tended to decrease after treatment in most WWTPs, whereas PFOA increased. The different fates of PFOA and PFOS in WWTPs were attributed to the higher organic carbon-normalized distribution coefficient of perfluoroalkylsulfonate (PFASs) than that of the carboxylate analog, indicating the preference of PFASs to partition to sludge. Although industrial WWTPs contained high concentration of PFCs, they are not the main source of PFCs in Korean water environment because of their small release amount. WWTPs located in big cities discharged more PFCs, suggesting household sewage is one of the significant sources of PFCs contamination in the environment.     

Biodegradation of nonylphenol polyethoxylates by denitrifying activated sludge

Biodegradation of nonylphenol polyethoxylates (NPEOs) by denitrifying activated sludge was investigated. The results showed that NPEOs were readily degraded in the denitrifying activated sludge process. Organic substance, initial concentration, and temperature had great influence on biodegradation of NPEOs in the denitrifying activated sludge process while the influence of biodegradation intermediates such as nonylphenol (NP) could be neglected. Biodegradation of NPEOs was severely inhibited in the presence of organic substances. Different organic substances had different inhibition ability on the biodegradation of NPEOs. The maximum biodegradation rate increased 2.51 microM d(-1) for each 10 microM increase in initial concentration of NPEOs. This linear relationship was maintained even at relatively high initial concentration. The decrease in temperature caused a sharp decrease in the removal efficiency of NPEOs. The temperature coefficient (Phi) for the biodegradation of NPEOs in the denitrifying activated sludge process was 0.011 degrees C(-1). NPEOs were biodegraded through a nonoxidative pathway, through which NPEOs were degraded via sequential removal of ethoxyl units (as acetaldehyde) to NP. Compared to anaerobic activated sludge treatment, denitrifying activated sludge treatment had much higher removal efficiency of NPEO contaminants. To our knowledge, it is the first report on the biodegradation of NPEOs in denitrifying activated sludge process.     

基于生物营养盐去除工艺所产污泥的处理对策

青岛市两座采用生物营养盐去除工艺的污水处理厂的运行实践表明,初沉污泥和剩余污泥应尽可能在好氧状态下处理,以避免污泥反硝化上浮、磷酸盐和氨氮的厌氧释放以及由此带来的鸟粪石结垢问题.在生物营养盐去除技术背景下,采用厌氧消化进行污泥稳定的污水处理厂,可以利用"有控制的鸟粪石结晶析出技术"来解决鸟粪石结垢问题;如污泥可以土地利用,宜采用好氧堆肥技术对污泥进行稳定.传统活性污泥法污水厂升级时不但要增加营养盐去除措施,还要考虑到对污泥处理系统进行相应的改造.     

Degradation of phthalate esters in an activated sludge wastewater treatment plant

Efficient removal of phthalate esters (PE) in wastewater treatment plants (WWTP) is becoming an increasing priority in many countries. In this study, we examined the fate of dimethyl phthalate (DMP), dibutyl phthalate (DBP), butylbenzyl phthalate (BBP), and di-(2-ethylhexyl) phthalate (DEHP) in a full scale activated sludge WWTP with biological removal of nitrogen and phosphorus. The mean concentrations of DMP, DBP, BBP, and DEHP at the WWTP inlet were 1.9, 20.5, 37.9, and 71.9 μg/L, respectively. Less than 0.1%, 42%, 35%, and 96% of DMP, DBP, BBP, and DEHP was associated with suspended solids, respectively. The overall microbial degradation of DMP, DBP, BBP, and DEHP in the WWTP was estimated to be 93%, 91%, 90%, and 81%, respectively. Seven to nine percent of the incoming PE were recovered in the WWTP effluent. Factors affecting microbial degradation of DEHP in activated sludge were studied using [U-¹⁴C-ring] DEHP as tracer. First order rate coefficients for aerobic DEHP degradation were 1.0×10⁻², 1.4×10⁻², and 1.3×10⁻³ at 20, 32, and 43 °C, respectively. Aerobic degradation rates decreased dramatically under aerobic thermophilic conditions (<0.1×10⁻² h⁻¹ at 60 °C). The degradation rate under anoxic denitrifying conditions was 0.3×10⁻² h⁻¹, whereas the rate under alternating conditions (aerobic-anoxic) was 0.8×10⁻² h⁻¹. Aerobic DEHP degradation in activated sludge samples was stimulated 5-9 times by addition of a phthalate degrading bacterium. The phthalate degrading bacterium was isolated from activated sludge, and maintained a capacity for DEHP degradation while growing on vegetable oil. Collectively, the results of the study identified several controls of microbial PE degradation in activated sludge. These controls may be considered to enhance PE degradation in activated sludge WWTP with biological removal of nitrogen and phosphorus.     

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.     

Input characterization of perfluoroalkyl substances in wastewater treatment plants: source discrimination by exploratory data analysis

This paper presents a methodology based on multivariate data analysis for identifying input sources of perfluoroalkyl substances (PFASs) detected in 37 wastewater treatment plants (WWTPs) across more than 40 cities in the state of Minnesota (USA). Exploratory analysis of data points has been carried out by unsupervised pattern recognition (cluster analysis), correlation analysis, ANOVA and per capita discharges in an attempt to discriminate sources of PFASs in WWTPs. Robust cluster solutions grouped the database according to the different PFAS profiles in WWTP influent. Significantly elevated levels of perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA) and/or perfluorooctane sulfonate (PFOS) in influent have been found in 18 out of 37 WWTPs (49%). A substantial increase in the concentrations of PFHxA and/or PFOA from influent to effluent was observed in 59% of the WWTPs surveyed, suggestive of high concentration inputs of precursors. The fate of one precursor (8:2 fluorotelomer alcohol) in WWTP was modeled based on fugacity analysis to understand the increasing effluent concentration. Furthermore, population-related emissions cannot wholly explain the occurrence and levels of PFASs in WWTPs. Unusually high influent levels of PFASs were observed in WWTPs located in specific industrial areas or where known contamination had taken place. Despite the restriction on the production/use of PFOA and PFOS, this paper demonstrates that wastewater from industrial activities is still a principal determinant of PFAS pollution in urban watersheds.     

The occurrence of antibiotics in an urban watershed: From wastewater to drinking water

The presence of 28 antibiotics in three hospital effluents, five wastewater treatment plants (WWTPs), six rivers and a drinking water storage catchment were investigated within watersheds of South-East Queensland, Australia. All antibiotics were detected at least once, with the exception of the polypeptide bacitracin which was not detected at all. Antibiotics were found in hospital effluent ranging from 0.01-14.5 μg L^− 1, dominated by the β-lactam, quinolone and sulphonamide groups. Antibiotics were found in WWTP influent up to 64 μg L^− 1, dominated by the β-lactam, quinolone and sulphonamide groups. Investigated WWTPs were highly effective in removing antibiotics from the water phase, with an average removal rate of greater than 80% for all targeted antibiotics. However, antibiotics were still detected in WWTP effluents in the low ng L^− 1 range up to a maximum of 3.4 μg L^− 1, with the macrolide, quinolone and sulphonamide antibiotics most prevalent. Similarly, antibiotics were detected quite frequently in the low ng L^− 1 range, up to 2 μg L^− 1 in the surface waters of six investigated rivers including freshwater, estuarine and marine samples. The total investigated antibiotic concentration (TIAC) within the Nerang River was significantly lower (p < 0.05) than all other rivers sampled. The absence of WWTP discharge to this river is a likely explanation for the significantly lower TIAC and suggests that WWTP discharges are a dominant source of antibiotics to investigated surface waters. A significant difference (p < 0.001) was identified between TIACs at surface water sites with WWTP discharge compared to sites with no WWTP discharge, providing further evidence that WWTPs are an important source of antibiotics to streams. Despite the presence of antibiotics in surface waters used for drinking water extraction, no targeted antibiotics were detected in any drinking water samples.     

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.     

Enumeration of acetate-consuming bacteria by microautoradiography under oxygen and nitrate respiring conditions in activated sludge

Microautoradiography was used to enumerate bacteria able to take up radiolabelled acetate in activated sludge using oxygen or nitrate as electron acceptors. In each of three wastewater treatment plants (WWTP) with nitrification and denitrification (N-removal), the number of bacteria consuming acetate under aerobic and anoxic conditions was identical in contrast to the acetate removal rates. The rates were clearly lower under anoxic conditions suggesting that the specific activity of the cells and not the number of active cells was reduced under anoxic conditions. The fraction of bacteria able to consume acetate varied in three WWTPs between 47% and 93% of the total number of bacteria as determined by DAPI. In a WWTP without N-removal only 20% of the bacteria were able to consume acetate under aerobic conditions and very few of these were able to do it under anoxic conditions. The cell specific acetate removal rates in all WWTPs were found to be 3.0-13.2 x 10(-15) mol cell(-1) h(-1) under aerobic conditions and between 1.9 and 9.1 x 10(-15) mol cell(-1) h(-1) under anoxic conditions.     

The effect of primary sedimentation on full-scale WWTP nutrient removal performance

Traditionally, the performance of full-scale wastewater treatment plants (WWTPs) is measured based on influent and/or effluent and waste sludge flows and concentrations. Full-scale WWTP data typically have a high variance which often contains (large) measurement errors. A good process engineering evaluation of the WWTP performance is therefore difficult. This also makes it usually difficult to evaluate effect of process changes in a plant or compare plants to each other. In this paper we used a case study of a full-scale nutrient removing WWTP. The plant normally uses presettled wastewater, as a means to increase the nutrient removal the plant was operated for a period by-passing raw wastewater (27% of the influent flow). The effect of raw wastewater addition has been evaluated by different approaches: (i) influent characteristics, (ii) design retrofit, (iii) effluent quality, (iv) removal efficiencies, (v) activated sludge characteristics, (vi) microbial activity tests and FISH analysis and, (vii) performance assessment based on mass balance evaluation. This paper demonstrates that mass balance evaluation approach helps the WWTP engineers to distinguish and quantify between different strategies, where others could not. In the studied case, by-passing raw wastewater (27% of the influent flow) directly to the biological reactor did not improve the effluent quality and the nutrient removal efficiency of the WWTP. The increase of the influent C/N and C/P ratios was associated to particulate compounds with low COD/VSS ratio and a high non-biodegradable COD fraction.     

Fate of synthetic musks in a domestic wastewater treatment plant and in an agricultural field amended with biosolids

Synthetic musks are widely used as fragrance ingredients in personal care products, and they enter domestic wastewater treatment plants (WWTPs) through discharges into municipal sewage systems. Samples of aqueous sewage and biosolids collected from the Peterborough Wastewater Treatment Plant (WWTP), Ontario, Canada were analyzed for 11 synthetic musk compounds using GC/MS. The results showed that 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta[g]-2-benzopyrane (HHCB, 173.1+/-43.4 ng/L) and 7-acetyl-1,1,3,4,4,6-hexamethyl-tetrahydronaphthalene (AHTN, 41.6+/-15.8 ng/L) were the dominant fragrances in sewage, but other polycyclic musks and nitro musks were present at lower concentrations. The concentrations of HHCB and AHTN in the aqueous phase of the sewage were highly correlated with both BOD5 and TOC. The overall removal efficiency of synthetic musks from the aqueous sewage in the WWTP ranged from 43.3% to 56.9%, but removal occurred mainly by partitioning into the biosolids. Based on a mass balance model, the daily input and output of HHCB and AHTN in the Peterborough WWTP were 47 g and 46 g, respectively. In an agricultural field amended with biosolids from the Peterborough WWTP, HHCB and AHTN were detected in soil immediately after application at mean concentrations of 1.0 and 1.3 mug/kg, respectively, but concentrations declined relatively rapidly over the next 6 weeks, post-application.     

Occurrence and fate of endocrine disrupters in Greek sewage treatment plants

The occurrence of five endocrine-disrupting compounds (EDCs), namely 4-n-nonylphenol (4-n-NP), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO), triclosan (TCS) and bisphenol A (BPA), was assessed in the raw, treated wastewater and sewage sludge of eight sewage treatment plants (STPs) in Greece. The analytes were extracted by solid-phase extraction (dissolved phase) or sonication (solid phase). Qualitative and quantitative analyses were performed by gas chromatography-mass spectrometry (GC-MS). The average concentrations in the raw and treated wastewater ranged from 0.23 (4-n-NP) to 5.76microgL(-1) (NP1EO) and from 0.15 (BPA) to 1.84microgL(-1) (NP2EO), respectively. A great part of the detected EDCs was sorbed on suspended solids. In sewage sludge, the average concentrations ranged between 0.17 (4-n-NP) and 12.3microgg(-1)dw (NP1EO). Analysis of daily mass flows in STP of Athens showed that, with the exception of 4-n-NP, all other EDCs were significantly removed (>85%) during wastewater treatment. Regarding the fate of these compounds, a significant part ranging from 45% (for TCS) to more than 70% (for NP1EO, NP2EO and BPA) was transformed by abiotic or biotic mechanisms, while the rest was accumulated in sewage sludge or disposed to the environment via the effluents. Calculation of risk quotients showed the existence of possible threat due to the presence of certain EDCs in treated wastewater and sludge.