A2O工艺中雌激素的行为变化和去除机理

研究了厌氧-缺氧-好氧(A2O)活性污泥工艺对生活污水中天然雌激素雌酮(Estrone,E1)、17β-雌二醇(17β-Estradiol,E2)以及17α-乙炔基雌二醇(17α-Ethynylestradiol,EE2)的去除性能。在对COD、N和P具有良好去除效果的前提下,对E1、E2和EE2的去除率可分别达到92.7%、100%和62.7%。通过对各反应单元内3种雌激素的物料平衡分析,表明A2O工艺对雌激素的去除主要发生在厌氧段和好氧段。以失活污泥作为对照组,好氧硝化过程中雌激素去除的小试实验发现,好氧过程中E1、E2的去除主要依靠生物降解作用,而EE2的去除则主要依赖于活性污泥对其的吸附作用。     

温度对17α-乙炔雌二醇在SBR工艺中去除效果的影响

17a-乙炔雌二醇(EE2)属于人工合成雌激素,是活性较强的环境内分泌干扰物之一.在污水处理厂中,EE2主要是通过活性污泥的生物降解作用得以去除.影响活性污泥对EE2生物降解的因素很多,温度是影响因素之一.分别采用一级缺氧/好氧(A/O)模式和三级缺氧/好氧(A/O/A/O/A/O)模式运行的SBR工艺.考察了温度对EE2去除的影响.试验发现,随着温度的升高,EE2在水相和泥相中的去除率明显增加,其中在30℃时EE2去除率达到最大,2种运行模式下水相中EE2去除率均达到了96%以上;泥相是EE2生物降解的主要场所;EE2生物降解主要发生在好氧阶段,缺氧阶段EE2生物降解效果不明显.     

重组基因酵母技术分析城市污水A~2/O工艺处理前后雌激素类化合物活性

采用重组基因酵母技术分析城市污水经厌氧—缺氧—好氧(A2/O)工艺处理前后雌激素类化合物活性。酵母经过雌激素类化合物激活,产生β-半乳糖苷酶,通过测定β-半乳糖苷酶活性能可以判断污水中雌激素类化合物活性。结果表明,原污水水样与酵母培养液体积比为5.000时,雌激素类化合物活性与摩尔浓度为10-8 mol/L的雌二醇(E2)相当;经过污水处理厂A2/O工艺处理后,雌激素类化合物活性下降,但仍具有潜在的环境与健康风险。     

SBR工艺去除模拟城市污水中双酚A的研究

依次改变SBR系统(厌氧-好氧-缺氧模式)的水力停留时间(HRT)、好氧-缺氧段时间比以及污泥龄(SRT),并采用液相色谱法对系统双酚A(BPA)浓度进行了检测,从BPA去除的角度对SBR工艺进行了评估,同时对部分工艺运行参数进行了优化.结果表明,SBR工艺对BPA有较好的去除能力;在温度为20 ℃、充水比(SBR工艺1个周期中进入反应器的污水量与反应器有效容积之比)为50%的条件下,最佳的工艺运行参数为总HRT=480 min,SRT=25 d,厌氧、好氧、缺氧段HRT分别为90、150、180 min;好氧-缺氧段时间比为0.83,此时COD、TN和PO43--P的总去除率分别达到89%、69%和95%,BPA总去除率达到99%,其中厌氧、好氧、缺氧段BPA去除率分别占BPA总去除率的66%、32%和1%.BPA在上述SBR系统中的去除主要是通过厌氧段污泥吸附和好氧段的生物降解实现的.     

分点进水对倒置A2/O工艺脱氮除磷效果的影响

在传统A2/O工艺基础上,提出了将缺氧池置于厌氧池前面的分点进水倒置A2/O工艺。通过改变α（进入厌氧区的污水分量）与β（进入缺氧区的污水分量）的比例,考察对倒置A2/O工艺脱氮除磷效果的影响。实验结果表明,当α：β为7∶3时,达到最佳的脱氮除磷效率,分别为74.3%和71.2%。     

深圳河典型内分泌干扰物分布和季节变化规律研究

2011年6月至2012年5月在深圳河沿程采集水样,采用固相萃取一氮吹一衍生化的预处理方法和气相色谱/质谱联用法,对壬基酚(NP)、辛基酚(OP)、双酚A(BPA)、雌酮(E1)、雌二醇(E2)、17α-雌二醇(17α-E2)、雌三醇(E3)、雌炔醇(EE2)等8种内分泌干扰物(EDCs)在深圳河的浓度分布和时空变化规律进行了研究.同时通过主成分分析考察了EDCs与常规水质污染物的关系.结果表明,NP、BPA、E1、E3、EE2在深圳河各河段均有检出,而OP、17α-E2、E2的检出率均低于20％,EDCs主要来源是NP和BPA;深圳河旱季和雨季EDCs的浓度变化大,其中NP浓度表现出旱季高雨季低的规律,旱季浓度是雨季的1.74～5.63倍,但BPA和3种甾醇类雌激素的浓度呈现出了雨季高旱季低的相反变化规律,这应该与污水处理厂雨季污水溢流有关;通过主成分分析发现,BPA与DO存在明显的负相关关系,生物作用可能在BPA去除和甾醇类雌激素转化中起到了重要作用,具体机制还有待进一步研究.     

好氧污泥对17β-雌二醇吸附性能的研究

研究了好氧活性污泥与失活好氧污泥对17β-雌二醇的吸附性能.17β-雌二醇初始质量浓度为500～10 000 ng/L,采用失活好氧污泥进行吸附,考察了吸附平衡时间、pH与温度对吸附的影响.研究结果表明,失活好氧污泥对17β-雌二醇的吸附在30 min内达到平衡;pH在6～9时对吸附没有影响,pH为9以上时,随着pH升高吸附量减少;温度升高吸附能力降低;其吸附符合Freundlich吸附,且呈线性吸附.在10、20、30 ℃时,Freundlich吸附常数KF分别为91.81、80.65、61.49 L/kg,分配系数Kd分别为561.80、 435.60、306.70 L/kg.另外研究了20 ℃时好氧活性污泥的KF与Kd,它们分别为91.72、514.90 L/kg,与同温下失活好氧污泥的KF和Kd差别均小于20%.     

高效液相色谱-二极管紫外阵列/荧光串联测定雌激素的方法及污水处理厂对雌激素的去除特性

建立了高效液相色谱-二极管紫外阵列(PDA)/荧光(FLD)串联法测定雌酮(E1)、雌二醇(E2)、乙炔雌二醇(EE2)、雌三醇(E3)和双酚A(BPA)5种典型雌激素的方法,并利用该方法测定了某城市污水处理厂5种雌激素的分布情况及去除特性。研究结果表明,二极管紫外阵列/荧光检测器对5种雌激素的检出限在4.30~9.54μg·L~(-1)之间,定量限在12.90~28.62μg·L~(-1)之间。5种雌激素日内精密度的相对标准偏差小于6.86%,日间精密度相对标准偏差小于9.47%;对100、500和1 000 ng·L~(-1)3个浓度的5种雌激素经富集浓缩后测定的加标回收率在62.8%~96.0%之间,方法符合痕量分析要求。利用该方法对城市某污水处理厂雌激素的含量进行测定,结果表明污水处理厂进水中5种雌激素的总浓度为3 073.1 ng·L~(-1),其中雌三醇(E3)的浓度最大,占5种雌激素总量的40.1%。出水中5种雌激素的总浓度为124.7 ng·L~(-1),5种雌激素的总去除率为95.9%。不同处理单元对雌激素的去除效率存在明显差异,生物处理单元对5种雌激素的去除效果最好,5种雌激素的去除率在73.6%~96.6%之间;一级处理工艺和消毒工艺对雌激素的去除效果较差。     

污水颗粒尺寸分布对深度过滤中雌激素去除的影响

采用两根平行运行的小试下向流砂滤柱以研究雌酮(E1)、雌二醇(E2)和炔雌醇(EE2)的去除与污水中悬浮颗粒粒度分布(PSD)的相互关系。研究表明,80%雌激素以溶解状态吸附在悬浮颗粒之上。平均粒径与颗粒的比表面积呈指数函数关系(R20.9)。随着滤池进水中悬浮颗粒平均粒径从1.493μm增至226.784μm,E1、E2和EE2在固相的吸附率分别从58.8%、56.3%和60.0%降至7.0%、1.3%和4.0%。砂滤池中雌激素的去除率与进水悬浮颗粒的平均粒径呈负相关,并可以用对数曲线拟合(R~20.9)。砂滤池因拦截了活性污泥絮体因而具有一定的生物活性,使得部分E2被生物降解(p0.05)。E1和EE2因其相对稳定以及砂滤池较短的水力停留时间而无显著的生物降解证据(p0.05),其去除主要依靠砂滤池所拦截的细微颗粒的絮体吸附作用。     

天然有机物共存时生物活性炭对17β-雌二醇的去除

以17β-雌二醇（E2）为目标物,研究了在天然有机物共存的情况下,生物活性炭（BAC）小柱和粒状活性炭（GAC）小柱去除E2的效果。结果表明,BAC小柱和GAC小柱都可有效去除E2,运行600d后出水仍未检出E2。从纵向浓度分布来看,BAC小柱对E2的处理效果略好于GAC小柱。BAC小柱去除E2主要是通过活性炭吸附作用和生物降解作用。空床接触时间也会对E2的去除产生影响。在BAC小柱和GAC小柱中,NOM的去除率随时间延长而降低,E2的去除率始终保持在100％,由此可以推断E2和NOM在活性炭的不同位置进行吸附。     

Biotransformation of estrogens in nitrifying activated sludge under aerobic and alternating anoxic/aerobic conditions.

Natural and synthetic estrogens present in municipal wastewater can be biodegraded during treatment, particularly in activated sludge. The objective was to assess the extent of transformation of 17-beta-estradiol (E2) and 17-alpha-ethinylestradiol (EE2) by nitrifying activated sludge and evaluate potential relationships between availability of oxygen, nitrification rate, and estrogen removal. For each batch experiment, two reactors were set up--aerobic and alternating anoxic/aerobic-which were then amended with E2 and EE2 from methanolic stock solutions. The EE2 was persistent under anoxic conditions; under aerobic conditions, the observed level of its removal was 22%. The E2 was readily converted to estrone (El)--faster under aerobic (nitrifying) than anoxic (denitrifying) conditions. During the initial anoxic conditions, a metabolite consistent with 17-alpha-estradiol transiently accumulated and was subsequently removed when the reactor was aerated. Higher removal rates of estrogens were associated with higher nitrification rates, which supports the contention that the nitrifying biomass was responsible for their removal.     

Removal of selected natural and synthetic estrogenic compounds in a Canadian full-scale municipal wastewater treatment plant.

The effect of a full-scale municipal wastewater treatment plant (WWTP) and each of the treatment units within the stream on the removal of endocrine-disrupting compounds was evaluated by tracking 17-beta-estradiol (E2), estrone (E1), and 17-alpha-ethinylestradiol (EE2). The overall performance of the WWTP compared well with other plants, as 90.5% removal of E1+E2 and 74.9% removal of EE2 were observed. A larger fraction of EE2 entered the plant in particulate form than E1 and E2, while a lower fraction of EE2 left the plant in particulate form than soluble form. The activated sludge units reduced the concentration of E1+E2 and EE2 in the liquid phase by 88.2% and 44.6%, respectively. The UV treatment process did not reduce the amount of estrogens. The aqueous phase of the tertiary lagoon solids contained higher levels of estrogens compared with the lagoon influent.     

Fate of sex hormones in two pilot-scale municipal wastewater treatment plants: conventional treatment

The fate of seven sex hormones (estrone (E1), estradiol (E2), estriol (E3), ethinylestradiol (EE2), testosterone, androstenedione, and progesterone) was determined in two pilot-scale wastewater treatment plants operated under conventional loading conditions. The levels of hormones in both the liquid and the solid matrixes of the plants were determined. Each of the two 20-l/h pilot-scale plants consisted of a primary clarifier followed by a three-stage aeration tank and a final clarifier. The primary sludge and the waste activated sludge (WAS) were digested anaerobically in one pilot plant and aerobically in the other. The pilot plants were fed a complex synthetic wastewater spiked with the hormones. Levels of testosterone, androstenedione and progesterone were close to method detection limit (MDL) concentrations in the final and digester effluents (both liquid and solid phases) and were considered as completely removed. Average mass flux removals from the liquid streams (plant influent minus secondary clarifier effluent) for the natural estrogens were 82% for E1, 99% for E2, and 89% for (E1+E2). An average overall removal of only 42% was achieved for EE2. These values reflect removals averaged for the two pilot plants.     

Factors controlling the biodegradation of 17beta-estradiol, estrone and 17alpha-ethinylestradiol in different natural soils

We conducted a series of laboratory microcosm incubations with [(14)C]-labeled 17beta-estradiol (E2), estrone (E1) and 17alpha-ethinylestradiol (EE2) in 17 different natural soils to characterize hormone mineralization. A significantly higher mineralization was observed for E1 (2.0-37.6%) and E2 (4.2-50.2%) than for EE2 (0.5-2.6%) in all test soils after 21 days. Soil physical or chemical parameters were not related to estrogen mineralization. Although sorption parameters varied greatly for E2 (K(F)=21.9-317.5 mL g(-1)), for E1 (K(F)=46.0-517.5 mL g(-1)) and for EE2 (K(F)=29.9-326.1 mL g(-1)) this apparently did not control estrogen bioavailability since it showed no effects on hormone mineralization. In order to elucidate the controlling factors, experiments with combined additions of radiolabeled estrogens and different substrates were conducted. Additions of ammonium nitrate or alanine to soil samples generally increased EE2 mineralization, thus indicating N-limitation. Additions of glucose induced higher E2 and EE2 degradation in comparison to control samples which is attributed to co-metabolism. Additions of saw dust, catechol or streptomycin influenced the microbial population in the test soils and affected the mineralization of E2 and EE2. Thus, we clearly demonstrate that different microbial communities are responsible for E2 and EE2 degradation in soils. We suggest that EE2 is mineralized by white-rot fungi and E2 by bacteria.     

Assessment of the importance of sorption for steroid estrogens removal during activated sludge treatment

Distribution coefficients (K(d)) between water and activated sludge particles (f(oc)=27.7+/-0.1%) were measured for the steroid estrogens (SE), estrone (E1), 17beta-estradiol (E2) and 17alpha-ethinylestradiol (EE2) in batch experiments. Experimental concentration levels ranged from environmentally realistic low ng/l to the high microg/l. In this range K(d)s were independent of their water concentration. The experimentally obtained K(d)s (with 95% confidence intervals) were 402+/-126 l/kg, 476+/-192 l/kg and 584+/-136 l/kg for E1, E2 and EE2, respectively. K(d)s were used to estimate the fraction of the total SE concentration that is expected to be sorbed in the activated sludge treatment tanks of a typical STP assuming equilibrium conditions. Assuming a suspended solids concentration of 4 g/l dissolved solids (ds), it was estimated that 61+/-9%, 66+/-13% and 70+/-6% of the total concentration of E1, E2 and EE2, respectively, would be sorbed during activated sludge treatment. The fraction of the SEs that was expected to be sorbed to suspended sludge particles in the effluents from a typical Danish STP was estimated to be only 0.20+/-0.06%, 0.24+/-0.10% and 0.29+/-0.07% of the total concentration of E1, E2 and EE2, respectively, at a suspended solids concentration of 5 mg/lds. For a typical STP the removal of steroid estrogens with excess sludge was estimated to be only 1.5-1.8% of the total loading if equilibrium conditions exists. Sorption is therefore not important for the fate of SEs in STPs compared to biodegradation.     

Oxidation of natural and synthetic hormones by the horseradish peroxidase enzyme in wastewater

Steroid estrogens, including both natural estrogens (e.g., estrone - E1; 17beta-estradiol - E2; and estriol - E3) and synthetic estrogens (e.g., 17alpha-ethinylestradiol - EE2), are known as endocrine-disrupting compounds. The objective of this research was to evaluate the feasibility of the enzymatic oxidation of estrogens and to optimize this process in municipal wastewater contaminated with steroid estrogens using horseradish peroxidase (HRP) and hydrogen peroxide. An initial HRP activity of 0.02 U ml(-1) was sufficient to completely remove EE2 from the synthetic solution, although greater HRP doses (up to 0.06 U ml(-1)) were required to remove E1, E2 and E3. The optimal molar peroxide-to-substrate ratio was determined to be approximately 0.45. Based on the Michaelis-Menten kinetics, the HRP had an increasing reactivity with E1, E3, E2, and EE2, in increasing order. In real activated sludge process effluent, an HRP dose of 8-10 U ml(-1) was required to completely remove all of the studied estrogens, while only 0.032 U ml(-1) of HRP was necessary to treat synthetic water containing the same estrogen concentrations.     

3种污泥对磺胺二甲基嘧啶的吸附性能

研究了厌氧颗粒污泥、厌氧污泥及好氧污泥对磺胺二甲基嘧啶(SM2)的吸附性能。当SM2初始浓度为50μg/L时,采用活性污泥灭活吸附,考察了吸附平衡时间、吸附等温线及温度对污泥吸附的影响,并比较了失活污泥与活性污泥的吸附性能。结果表明,3种污泥对SM2的吸附均在1 h内达到吸附平衡;3种失活污泥对SM2的吸附都可用Freundl-ich和Langmuir吸附模型来描述,并且Freundlich吸附模型的拟合效果要好于Langmuir模型(R2F>R2L);温度对3种污泥吸附影响规律一致,并且吸附常数KF(15℃)>KF(25℃)>KF(35℃),这说明吸附为放热反应,低温有利于吸附反应的进行。活性污泥对SM2的吸附与失活污泥吸附规律一致,都符合Freundlich模型。3种活性污泥对SM2的去除是吸附和降解的共同作用,并且都是降解占主导地位,降解效率为厌氧污泥>好氧污泥>厌氧颗粒污泥。     

Microbial degradation of 17β -estradiol and 17α -ethinylestradiol followed by a validated HPLC-DAD method

This work aimed at studying the biodegradation of two estrogens, 17α -estradiol (E2) and 17β -ethinylestradiol (EE2), and their potential metabolism to estrone (E1) by microbial consortia. The biodegradation studies were followed by High Performance Liquid Chromatography–Diode Array Detector (HPLC–DAD) using a specifically developed and validated method. Biodegradation studies of the estrogens (E2 and EE2) were carried out with activated sludge (consortium A, CA) obtained from a Wastewater Treatment Plant (WWTP) and with a microbial consortium able to degrade recalcitrant compounds, namely fluorobenzene (consortium B, CB). E2 was more extensively degraded than EE2 by CA whereas CB was only able to degrade E2. The addition of acetate as a supplementary carbon source led to a faster biodegradation of E2 and EE2. E1 was detected as a metabolite only during the degradation of E2. The 16S rRNA gene sequence analyses of strains recovered from the degrading cultures revealed the presence of the genera Pseudomonas, Chryseobacterium and Alcaligenes. The genera Pseudomonas and Chryseobacterium were retrieved from cultures supplied with E2 and EE2, while the genus Alcaligenes was found in the presence of E2, suggesting that they might be involved in the degradation of these compounds.     

3种污泥对活性黑KN-B的生物吸附及降解研究

对比研究了好氧污泥、厌氧污泥和厌氧颗粒污泥对染料活性黑KN-B的吸附和降解。结果表明,这3种污泥对活性黑的吸附均符合Freundlich模型(R~2为0.9665～0.9859)和Langmuir模型(R~2为0.9460～0.9906),但3种污泥对活性黑这种染料的吸附量较小;并且厌氧污泥对活性黑的吸附能力优于好氧污泥和厌氧颗粒污泥。实验还发现,3种污泥对活性黑的脱色主要是生物降解作用,而不是吸附作用。