Characteristics of estrogen decomposition by ozonation.

Since the natural estrogens 17 beta-estradiol (E2) and estron (E1), and the synthetic estrogen 17 alpha-ethynyl estradiol (EE2) have strong endocrine disrupting effects and the tendency to persist in effluent from wastewater treatment plants, effective measures are needed to remove them from wastewater. In this research, to gain an understanding of the characteristics of estrogen decomposition by ozonation, experiments were conducted using effluent from an actual wastewater treatment plant. In this experiment, estrogen was added to effluent at a concentration of 200 ng/l and 20 ng/l before the ozonation experiments. The results showed 90% or more of estrogen concentration and estrogenic activity of E2, El and EE2 to be removed at an ozone dose of 1 mg/l. At an ozone dose of 3 mg/l, the estrogen concentration and estrogenic activity of E2, El and EE2 in the treated water fell below the detection limit. The removal rate was not influenced by the kind of estrogen. No generation of byproducts with estrogenic activity was observed. The authors conclude that estrogen in secondary treated wastewater can be almost entirely removed at the practical ozone dose rate applied for the purpose of disinfection, which is up to about 5 mg/l.     

Analysis and occurrence of estrogen in wastewater in Japan.

This paper describes an analytical procedure for free estrogens and their conjugates in domestic wastewater. The procedure demonstrated in this study is innovative in terms of levels of detection and quantification of the following substances: estrone (E1); 17beta-estradiol (E2); 17alpha-ethynylestradiol (EE2); estriol (E3); estrone-3-sulfate (E1-S); beta-estradiol 3-sulfate (E2-S); estriol 3-sulfate (E3-S); estrone beta-D-glucuronide (E1-G); beta-estradiol 17-(beta-D)-glucuronide (E2-G); estriol 3-(beta-D)-glucuronide (E3-G); beta-estradiol 3-sulfate 17-glucuronide (E2-SandG); and estradiol 3,17-disulfate (E2-diS). The detection limits of this method ranged from 0.1 to 1.4 ng/l. The recovery efficiencies of the estrogens in the analysis from influent and effluent of the secondary settling tank in a wastewater treatment plant (WWTP) were higher than 94% for the free estrogens, but were less than 50% for the conjugated estrogens. The field study using this method was conducted at twenty WWTPs in Japan. The median concentrations of the estrogens ranged from ND to as high as >100 ng/l. In the influent and secondary effluent samples, the concentrations of E1, E2 and E3 were the same levels as those previously reported. We found that the conjugated estrogens exist at higher concentrations in the influent and the secondary effluent than in the other studies, and that the concentrations of the conjugated estrogens were higher than those of the free estrogens.     

Calculation methods to perform mass balance of endocrine disrupting compounds in a submerged membrane bioreactor: fate and distribution of estrogens during the biological treatment

The purpose of this paper is to report the study of the fate and distribution of three endocrine disrupting compounds (estrogens); Estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) in a laboratory scale submerged membrane bioreactor (SMBR). For this matter, both aqueous and solids phases were analyzed for the presence of E1, E2 and EE2. The outcome of this study was that three SMBRs showed enhanced elimination of estrogens in different operational conditions; the estrogen removal was close to 100% in SMBR. Additionally, E1, E2 and EE2 were detected in SMBR sludge at concentrations of up to 41.2, 37.3 and 36.9 ng g(-1) dry weight, respectively. The estrogen removal in the SMBRs was directly influenced by a combination of simultaneous biodegradation-adsorption processes, indicating that the main removal mechanism of the estrogens in the SMBRs is the biodegradation process. The E1, E2 and EE2 were biologically degraded in the SMBR (87-100%). The sorption of estrogens onto activated sludge was from 2%. Therefore, a high potential for estrogen removal by biodegradation in the SMBR was observed, allowing less estrogen concentration in the dissolved phase available for the adsorption of these compounds onto biological flocs. Two different methods were carried out for mass balance calculations of estrogens in SMBR. For the first method, the measured data was used in both liquid and solid phases, whereas for the second one, it was in aqueous phase and solid-water distribution coefficients (K(d)) value of E1, E2 and EE2. The purpose of these methodologies is to make easier the identification of the main mechanisms involved in the removal of E1, E2 and EE2 in a SMBR. Both methods can be applied in order to determine the mechanism, fate and distribution of estrogens in a SMBR.     

Microbial degradation of estrogens using activated sludge and night soil-composting microorganisms.

In order to investigate the potential for microbial degradation of estrogens, and the products formed, activated sludge collected from Korea (ASK) and night soil-composting microorganisms (NSCM) were used to degrade estrogens. Results showed that both ASK and NSCM degraded almost 100% of the natural estrogens estrone (E1), 17beta-estradiol (E2), and estriol (E3) from initial concentrations of 20-25 mg/L, while synthetic estrogen, ethynylestradiol (EE2), was not degraded. Analysis of degradation products of E2 by using HPLC-ECD and a consecutive first-order reaction calculation confirmed that E2 was sequentially degraded to E1, which was further degraded to other unknown compounds by ASK and NSCM. We then used the yeast two-hybrid assay to show that the unknown degradation products did not appear to possess estrogenic activity when E1, E2 or E3 were degraded to below the detection limit after 14 days of incubation, indicating that ASK and NSCM not only degrade natural estrogens, but also remove their estrogenic activities.     

Removal mechanisms of 17β-estradiol and 17α-ethinylestradiol in membrane bioreactors

The fate and behavior of natural and synthetic estrogens in wastewater treatment processes is currently of increasing concern all over the world. In this study, the removal mechanisms of a natural estrogen, 17β-estradiol (E2), and a synthetic estrogen, 17α-ethinylestradiol (EE2) were investigated in membrane bioreactors (MBRs) with and without powdered activated carbon (PAC) addition. The experimental results showed that the average removal rates of E2 and EE2 by the MBR without PAC addition were 89.0 and 70.9%; PAC addition in the MBR increased the removal rate of E2 and EE2 by 3.4 and 15.8%, respectively. The greater impact of PAC dosing on EE2 removal was due to its greater hydrophobic property. Adsorption played a more important role in the removal mechanisms of EE2 than E2. Biodegradation was the dominant mechanism for the removal of E2 and EE2 in MBRs. Unlike their adsorption behavior, the biodegradation rates of both E2 and EE2 were not significantly different between the MBRs with and without PAC addition.     

Steroid estrogens in primary and tertiary wastewater treatment plants.

The concentrations of two natural estrogens (estrone (E1) and Estradiol (E2)) and one synthetic progestin (Ethinylestradiol (EE2)) were measured for different unit operations in an advanced sewage treatment plant and in a large coastal enhanced primary sewage treatment plant. The average influent concentration to both plants was similar: 55 and 53 ng/L for E1 and 22 and 12 ng/L for E2 for the advanced and enhanced primary STPs, respectively. The activated sludge process at the advanced STP removed up to 85% and 96% of E1 and E2, respectively. The enhanced primary sewage treatment plant was mostly ineffective at removing the steroids with only 14% of E1 and 5% of E2 being removed during the treatment process. EE2 was not been detected during the study period in the influent or effluent of either STP. The difference in the observed removal between the two plants is primarily linked to plant performance but the extent to which removal of steroid estrogens is due to bacterial metabolism (i.e. the advanced STP) rather than adsorption to the bacterial biomass remains unclear. The poor removal observed for the coastal enhanced primary STP may have implications for the receiving environment in terms of a greater potential for abnormal reproductive systems in marine animals, particularly if discharges are into large bays or harbours where flushing is limited.     

Treatability of cefazolin antibiotic formulation effluent with O3 and O3/H2O2 processes.

The effect of applying ozonation and perozonation to antibiotic cefazolin-Na formulation effluents were investigated in this study. Twenty minutes of ozonation at a rate of 1,500 mg/L-h was observed to remove COD by 38%, whereas a COD removal efficiency of 40% was achieved via H2O2 enhanced ozonation (same conditions + 31.25 mM H2O2). Both of the pretreatment alternatives were monitored to elevate the BOD5/COD ratio from 0.01 to 0.08. The initially inert COD was reduced by 38% using ozonation and by 60% employing H2O2 enhanced ozonation. In terms of the lowest achievable effluent COD levels after bio-treatment, ozonation was observed to yield a residual COD of 205 mgL(-1), while a residual COD of 135 mgL(-1) was involved for perozonation. According to the results of acute toxicity on Phaedactylum tricornutum, ozonated and perozonated samples exhibited more toxicity than the untreated effluent after 4 days. The activated sludge inhibition test demonstrated that both of the pretreatment alternatives efficiently eliminated the inhibition of investigated formulation effluent.     

Anaerobic biodegradation of estrogens--hard to digest.

Although many publications are available on the fate of estrone (E1), 17beta-estradiol (E2) and 17alpha-ethynylestradiol (EE2) during aerobic wastewater treatment, little is published on their fate under strictly anaerobic conditions. Present research investigated the digestibility of E1 and EE2, using digested pig manure, granular UASB sludge, UASB-septic tank sludge and activated sludge as inocula. Besides, actual concentrations were measured in a UASB septic tank treating black water. Under anaerobic conditions E1 is reduced to E2 but the extent of this reduction depends on type of inoculum. No significant loss of the sum of E1 and E2 and of EE2 was observed. Adsorption was responsible for a 32-35% loss of E1 and E2 from the liquid phase in the UASB septic tank and the effluent still contained considerable concentrations of respectively 4.02 microg/l and 18.79 microg/l for E1 and E2 with a large fraction present in conjugated form. No EE2 was detected in the UASB effluent.     

The use of enzyme-linked immunosorbent assays (ELISA) for the determination of pollutants in environmental and industrial wastes.

Twelve enzyme-linked immunosorbent assays (ELISA), for the determination of surfactants [linear alkylbenzene sulfonates (LAS), alkyl ethoxylates (AE), and alkylphenol ethoxylates (APE)], endocrine disruptors [alkylphenol (AP), AP + APE, and bisphenol A (BPA)], estrogens [17beta-estradiol (E2), estrone (El), estrogen (ES: El + E2 + estriol (E3)), 1 7alfa-ethynylestradiol (EE2)], dioxins and polychlorinated biphenyls (PCBs), were validated on environmental water and industrial wastes. The lowest quantification limits of these ELISAs were 0.05 microg/L (BPA, E2, El, ES and EE2), 2 microg/L (AE), 3 microg/L (dioxins and PCBs), 5 microg/L (AP, AP + APE) and 20 microg/L (LAS and APE). To apply these ELISAs to environmental or industrial waste samples, simple and appropriate pre-treatment methods were also developed for each ELISA. With optimized pre-treatments, the values of ELISAs were well co-related, in all cases, to those of instrumental analytical methods such as liquid chromatography (HPLC), liquid chromatography-tandem mass spectrometry (LC-MS/MS), and high-resolution gas chromatography mass spectrometry (HR-GC-MS), etc.     

Removal of endocrine disrupting chemicals in a large scale membrane bioreactor plant combined with anaerobic-anoxic-oxic process for municipal wastewater reclamation

The removal of eight typical endocrine disrupting compounds (EDCs) in a full scale membrane bioreactor combined with anaerobic-anoxic-oxic process (A(2)/O-MBR) for municipal wastewater reclamation located in Beijing was investigated. These EDCs, including 4-octylphenol (4-OP), 4-n-nonylphenol (4-n-NP), bisphenol A (BPA), estrone (E1), 17α-estradiol (17α-E2), 17β-estradiol (17β-E2), estriol (E3) and 17α-ethinylestradiol (EE2), were simultaneously analyzed by gas chromatography/mass spectrometry after derivatization. The concentrations of eight EDCs were also measured in sludge of anaerobic, anoxic, oxic and membrane tanks to measure sludge-water distribution coefficients (K(d) values) as the indicator of adsorption propensity of target compound to sludge. The removal efficiencies of EDCs reached above 97%, except for 4-n-NP removal efficiency of 72%, 4-OP removal efficiency of 75% and EE2 removal efficiency of 87% in the A(2)/O-MBR process. The high K(d) values indicated that the sludge had a large adsorption capacity for these EDCs, and significantly contributed to removal of EDCs. Yeast estrogen screen assay was performed on samples to assess the total estrogenic activity by measuring the 17β-E2 equivalent quantity (EEQ), expressed in ng-EEQ/L. The measured EEQ value was markedly reduced from 72.1 ng-EEQ/L in the influent to 4.9 ng-EEQ/L in the effluent. Anoxic tank and anaerobic tank contributed to 80% and 37% in total EEQ removal, respectively.     

Effect of ozone, chlorine and hydrogen peroxide on the elimination of colour in treated textile wastewater by MBR.

In treating textile wastewater, the application of membrane bioreactor (MBR) technology showed high efficiency in COD and BOD5 removal. However, insufficient colour removal was achieved for possible reuse. The aim of the work presented in this paper was to test the performance of chemical advanced oxidation on the elimination of the colour downstream of an MBR. To improve the quality of the membrane bioreactor effluent three different oxidation treatments were tested at lab-scale: ozonation, chlorination and hydrogen peroxide oxidation. Colour, COD and BOD5 were controlled in order to assess the effectiveness of each process. For chlorination, even with 250 mg/L (active chlorine) only 80% colour removal (SACin = 14; SACout = 2.8) was achieved which is considered unsatisfactory. For hydrogen peroxide, the colour removal was even poorer; it was just 10% at a concentration of 250 mg/L. In contrast, good results were obtained by ozonation. By using only 38 mg/L within 20 minutes, it was possible to achieve the reuse recommendation with a satisfactory colour removal of 93% (SACin = 14; SACout = 0.98). The results showed that ozonation was the most promising method.     

Fate of oestrogens during anaerobic blackwater treatment with micro-aerobic post-treatment.

The fate of oestrone (E1), 17beta-oestradiol (E2) and 17alpha-ethynyloestradiol (EE2) was investigated in a concentrated blackwater treatment system consisting of an UASB septic tank, with micro-aerobic post-treatment. In UASB septic tank effluent a (natural) total concentration of 4.02 microg/L E1 and 18.69 microg/L E2, comprising the sum of conjugated (>70% for E1 and >80% for E2) and unconjugated forms, was measured. During post-treatment the unconjugated oestrogens were removed to below 1 microg/L. A percentage of 77% of the measured unconjugated E1 and 82% of E2 was associated with particles >1.2 microm in the final effluent implying high sorption affinity of both compounds. When spiking the UASB septic tank effluent with E1, E2, EE2 and the sulphate conjugate of E2, removal in the micro-aerobic post-treatment was >99% for both E2 and EE2 and 83% for E1. The lower removal value for E1 was a result of (slow) deconjugation during the treatment, and in the final effluent still 40% of E1 and 99% of E2 was present in conjugated form. The latter was the result of incomplete deconjugation of the spiked E2(3S) in the post-treatment system.     

Antimicrobial resistance of fecal indicators in disinfected wastewater

The main objective of the study was to assess the potential of three systems (UV irradiation, ozonation, and micro/ultrafiltration) operated in a pilot scale in removal of antimicrobial-resistant fecal bacteria from secondary effluent of the local wastewater treatment plant (700,000 population equivalent). The effectiveness of the processes was analysed using the removal ratio of fecal indicators (Escherichia coli and Enterococcus spp.). The susceptibility of fecal indicators to antimicrobial agents important in human therapy was examined. Resistance to nitrofurantoin and erythromycin was common among enterococci and followed by resistance to fluoroquinolones and tetracycline. Resistance to high-level aminoglycosides and glycopeptides was also observed. E. coli isolates were most frequently resistant to penicillins and tetracycline. The extended-spectrum beta-lactamase-producing E. coli was detected once, after ozonation. Substantial attention should be paid to the E. coli and enterococci resistant to three or more chemical classes of antimicrobials (MAR), which in general constituted up to 15 and 49% of the tested isolates, respectively. Although the applied methods were effective in elimination of fecal indicators (removal efficiency up to 99.99%), special attention has to be paid to the application of sufficient disinfection and operation conditions to avoid selection of antimicrobial resistant bacteria.     

Effect of ozonation on sludge reduction in a SBR plant.

This paper provides new insights on the application of the ozonation process for the reduction of activated sludge production in a Sequencing Batch Reactor. The study was performed on two identical lab-scale SBRs plant, fed with domestic sewage: a fraction (1/3 of the working volume) of the activated sludge from one reactor (Exp SBR) was periodically subjected to ozonation for 30 minutes at 0.05 g O(3)/gSS and then recirculated before the beginning of the cycle; the other reactor was used as control and therefore managed at the same sludge retention time but without the application of ozonation. The effects of the recirculation of the ozonated sludge to the Exp SBR were evaluated in terms of biological nitrogen and carbon removal efficiencies, Mixed Liquor Volatile and Suspended Solids (MLSS and MLVSS, respectively) concentrations, effluent quality and sludge settleability. Besides, characterization of the ozonated sludge was carried out for different oxidant dosages (0.05, 0.07 and 0.37 g O(3)/gSS) and durations of the ozonation process (10, 20 and 30 minutes). The results show that at 0.05 g O(3)/gSS and 30 minutes contact time MLVSS as well as MLVSS/MLSS ratio do not change appreciably. Ozone dosage must be increased much further to obtain a relevant effect.     

三卤甲烷在臭氧工艺中的形成与控制

研究了臭氧氧化对三卤甲烷生成潜能的去除规律,发现臭氧对氯仿生成潜能有较好的去除效果,但对溴仿生成潜能的去除能力很差.在高臭氧投加量下,臭氧会明显促进溴仿的生成.臭氧对总三卤甲烷生成潜能的去除效果是其对"氯代三卤甲烷生成潜能的去除"和对"溴代三卤甲烷生成潜能的促进"两方面综合作用的结果.     

Treatment of oilfield wastewater by Fenton's process.

A combination of coagulation and Fenton's process was used for the removal of total oxygen carbon (TOC) from oilfield wastewater. Compared with aluminium sulfate, ferric coagulant had better TOC removal efficiency at the same mass dosage. In Fenton's process, the effect of H2O2 and Fe2+ dose on the removal of TOC was studied. The optimum conditions required for TOC removal were an Fe3+ concentration of 40-50 mg/L, an H2O2 dose of 50 mmol/L and an Fe2+ concentration of 1.0 mmol/L. GC-MS chromatographic analysis indicated that most of the alkyl hydrocarbons of carbon numbers < 21 were removed in the first minute of Fenton's process mainly through adsorption. Alkyl hydrocarbons and phenols were oxidized almost completely following 120 min of treatment. The pathway of newly formed intermediates in Fenton's process was proposed on the basis of the GC/MS chromatogram.     

Oxidative processes for olive mill wastewater treatment.

The present work describes an experimental study carried out in order to investigate the efficiency and feasibility of physical (lime coagulation) and advanced oxidation processes (Ozone and Fenton's process) for olive oil mill wastewater treatment. Particular attention was paid to the degradation of both organic and phenolic compounds. Lime coagulation reaches maximum removal at a pH of 12, with a TP (total polyphenols) and COD reduction of 37 and 26%, respectively. Ozone oxidation is also pH-dependent, showing the higher removal efficiency (91% for TP and 19% for COD) with an initial pH value of 12. Experimental results show a lower efficiency of Fenton's process than ozone in TP removal, reaching a maximum value of 60%. Oxidation trials carried out on gallic and p-coumaric synthetic solutions confirmed ozone and Fenton's efficiency at degrading phenolic compounds. Biological trials, both aerobic and anaerobic, highlighted a significant increase of biodegradability of treated OMW samples if compared to the untreated ones. Respirometric tests showed an increase in BOD of about 20% and anaerobic batch tests provided a methane production up to eight times higher.     

Long-term effects of the ozonation of the sludge recycling stream on excess sludge reduction and biomass activity at full-scale

This paper presents a full-scale experience of sludge minimization by means of short contact time ozonation in a wastewater treatment plant (WWTP) mainly fed on textile wastewater. The WWTP performance over a 3-year operational data series was analysed and compared with a two-year operation with sludge ozonation. Lab-scale respirometric tests were also performed to characterize biomass activity upstream and downstream of the ozone contact reactor. Results suggest that sludge ozonation: (1) is capable of decreasing excess sludge production by 17%; (2) partially decreases both N removal, by lowering the denitrification capacity, and P removal, by reducing biomass synthesis; (3) increases the decay rate from the typical value of 0.62 d(-1) to 1.3 d(-1); (4) decreases the heterotrophic growth yield from the typical value of 0.67 to 0.58 gCOD/gCOD.     

Ozone-based reclamation of an STP effluent

The system ozone and hydrogen peroxide was used to reclaim wastewater from the secondary clarifier from a Sewage Treatment Plant (STP) of Alcalá de Henares (Madrid-Spain). The assays were performed by bubbling a gas mixture of oxygen and ozone, with approximately 24 g Nm(-3) of ozone concentration, through a volume of wastewater samples for 20 minutes at 25 degrees C. The removal of dissolved micropollutants such as Pharmaceutical and Personal Care Products (PPCPs) and Organic Carbon (TOC) was enhanced by adding periodic pulses of hydrogen peroxide while keeping pH above 8.0 throughout the runs. Removal efficiency ratios in the range of 7-26 mg O3/mg TOC and 0.24 mg O3/ng micropollutants at 5 minutes of ozonation were assessed as reference data to reclaim wastewater from STP. The relation between the extent of TOC removed and ozone doses used was related by a second-order kinetic model in which the time-integrated ozone-hydrogen peroxide concentration was included.     

A mechanistic model for fate and removal of estrogens in biological nutrient removal activated sludge systems

Two estrogen fate and transformation models were integrated with a comprehensive activated sludge model (ASM) to predict estrogen removal based on biomass and solids production. Model predictions were evaluated against published full-scale plant data as well as results from a laboratory-scale sequencing batch reactor (SBR) fed synthetic wastewater. The estrogen fate model relating the rate of total estrogen degradation to soluble estrogen concentrations successfully predicted estrogen removals when compared with measured concentrations. Model fit 17α-ethinylestradiol (EE2) biodegradation rate constant was 19 to 43% of the estrone (E1) value and 31 to 72% of the 17β-estradiol (E2) value.