污水中不同COD组分下A/O脱氮工艺的反硝化效率

为了研究了不同COD组分进水对A/O工艺中反硝化的影响以及COD组分中溶解性易生物降解COD(SS)、颗粒性慢速可生物降解COD(XS)比例改变后系统反硝化速率和反硝化潜力的变化。以连续流A/O反应器脱氮效率为研究对象,通过改变碳源物质投配量来配置3种SS比例分别为15%、30%和50%的城市污水,系统地考察了进水中SS比例对反硝化的影响。结果表明,进水中SS比例由15%增加到50%后,可以明显提高A/O系统TN的去除率,脱氮率由82%提高到89%。同时通过缺氧反硝化间歇实验,从反硝化动力学角度分析,进一步确定进水中SS比例对反硝化速率和反硝化潜力的影响,发现进水SS比例分别为50%、30%和15%,系统反硝化速率分别为0.027 g NO-3-N/(g VSS·min)、0.022 g NO-3-N/(g VSS·min)和0.020 g NO-3-N/(g VSS·min),反硝化潜力分别为16.49、13.99和13.74 mg/L。可见随着进水中SS比例的升高,系统中反硝化速率和反硝化潜力也相应增加。得出进水中COD组分不同,尤其是SS所占比例大小,是影响反硝化效果的一个关键因素。     

两种生长在铜矿渣上的菊科植物的铜含量

对生长于云南鸡冠山铜矿渣上的艾蒿(Artemisiaargyi)和湖北铜绿山铜矿渣上的滨蒿(Artemisiascoparia)进行调查和铜含量测定,结果表明,2种菊科植物具有比较高的生物量,均为铜矿区的优势植物,其根周围土壤的铜含量高。艾蒿根和叶的铜含量都较高,其根部铜含量为41～156mg·kg-1,平均83±29mg·kg-1;叶部铜含量为58～464mg·kg-1,平均216±96mg·kg-1。滨蒿根部铜含量较高,其变化范围为58～513mg·kg-1,平均183±101mg·kg-1,而茎叶部铜含量相对于根部较低,为42～259mg·kg-1,平均97±52mg·kg-1(含铜量均以干重计)。研究还发现,2种植物对铜的耐受机制不同,艾蒿表现出较强的蓄积铜的潜力,而滨蒿表现出对铜污染土壤的植物固定潜能,因此2者均可作为植物修复铜污染土壤的先锋物种。     

四溴双酚A在潮土中的吸附和解吸

采用批量平衡实验方法,研究了四溴双酚A(TBBPA)在潮土中的吸附和解吸行为,并且探讨了pH值和离子强度对TBBPA吸附的影响.结果表明,TBBPA在潮土中的吸附过程可以分为快速吸附阶段(0～24 h)和慢速吸附阶段(24～48 h),其中快速吸附阶段在吸附过程中起主要作用,在48 h时吸附基本达到平衡.TBBPA在潮土中的吸附等温线呈现为非线性,其吸附行为可以很好地用Freundlich方程描述.在溶液pH值为6.0-8.0的范围内,TBBPA在潮土中的吸附量随pH值的增大而减少,当溶液pH>8.0后吸附量未表现出明显的变化趋势.离子强度也明显影响TBBPA在潮土中的吸附,随着离子强度的增加TBBPA的吸附量增加.吸附.解吸过程表明TBBPA在潮土中的解吸相对于吸附过程具有滞后性,说明潮土对TBBPA有较强的结合能力.     

Synthetic endocrine disruptors in the environment and water remediation by advanced oxidation processes

The present study is an overview of the literature on classes and types of compounds described as "endocrine disruptors" and their treatability in water by advanced oxidation processes, which generate hydroxyl radicals in water. The review is limited to details of the destruction of three classes of endocrine disruptors, namely bisphenols, alkylphenols and phthalates, which are among the most highly suspected endocrine disrupting compounds that interfere with the hormonal system of wildlife. It was found that photocatalysis with titanium dioxide was the most frequently tested advanced oxidation method most likely due its potential to render complete mineralization. There is sufficient research also with direct and indirect photolysis and ozonation, which were less effective for the overall mineralization but more representative of the conditions existing in real water treatment plants.     

Benzotriazoles, Alkylphenols and Bisphenol A in Municipal Wastewaters and in the Glatt River, Switzerland

- DOI: http://dx.doi.org/10.1065/espr2006.01.295 Background Many organic micropollutants occur at trace concentrations in municipal wastewater effluents and in the aquatic environment. Some of these xenobiotic chemicals can be considered as 'emerging' contaminants and some are suspect to have endocrine disrupting effects. Among the latter are nonylphenol (NP), octylphenol (OP) and bisphenol A (BPA), which deserve special attention due to their ubiquitous occurrence in the aquatic environment. The complexing agents benzotriazole (BT) and tolyltriazole (TT) are applied as anticorrosive agents (e.g. in cooling and hydraulic fluids, in antifreezing fluids, in aircraft deicing fluids, in dish washing liquids for silver protection), as antifogging agents and as intermediates for the synthesis of various chemicals. The environmental occurrence of NP and OP is caused by the fact that they are intermediate products (metabolites) in the biodegradation of alkylphenol polyethoxylate surfactants. BPA is globally used for the production of polycarbonate and epoxy resins. Methods BT, TT, NP, OP and BPA were quantitatively determined in municipal wastewater effluents in Switzerland and in the Glatt River. The analytes were enriched by solid-phase enrichment. BT and TT were determined underivatized by electrospray LC/tandem MS. Reversed-phase LC was performed on octylsilica columns with isocratic water/methanol elution. Multiple reaction monitoring of the positive ions provided selective and sensitive detection for reliable quantifications. NP, OP and BPA were determined by GC/MS after derivatization with N-methyl-N-(trimethylsilyl)-trifluoroacetamide. Results and Discussion BT and TT concentrations in primary and secondary effluents of municipal wastewater treatment plants varied from below 10 to 100 μg/L. The ranges of the concentrations in the Glatt River in ng/L were 636–3,690 for BT, 122–628 for TT, 68–326 for NP, 6–22 for OP and 9–76 for BPA. The corresponding mass flows in g/d were 93–1,870 for BT, 18–360 for TT, 24–183 for NP, 1–16 for OP and 2–72 for BPA. The concentrations and mass flows of NP in the River Glatt were drastically lower than the analogous values found 15 years ago. Thus, a substantially decreased environmental exposure can be observed due to the reduction of the use of alkyphenol polyethoxylate surfactants in Switzerland. The current concentrations of NP, OP and BPA are within the ranges reported for weakly impacted surface waters. Conclusion The investigated contaminants occur at quantitatively measurable but varying concentrations in municipal wastewaters and in the Glatt River reflecting their ubiquitous input into wastewaters and their different behaviour during biological wastewater treatment.     

Evaluating the impacts of some environmentally relevant factors on the availability of bisphenol A with negligible-depletion SPME

The effect of some environmentally relevant factors including salinity, pH, and humic acids on the availability of bisphenol A (BPA) was evaluated by using the negligible-depletion solid-phase microextraction (nd-SPME) biomimetic method. With the variation of salinity (0–500 mM NaCl) and pH (5.0–8.5) of aqueous solutions, the partition coefficients of BPA between the nd-SPME fiber and the aqueous solution varied in the range of log D = 3.55–3.86, which indicates that the salinity and pH can influence the availability of BPA. By using Acros humic acid as model dissolved organic matter (DOM), it was also demonstrated that the environmental factors such as salinity and pH could affect the partitioning of BPA between DOM and aqueous solutions. The determined partition coefficients of BPA between dissolved organic carbon (DOC) and aqueous solutions were in the range of log D_DOC = 4.03–5.60 for Acros humic acid solutions with 1–50 mg l⁻¹ DOC. The influence of salinity and pH on log D_DOC was more significant at low concentration (0–5 mg l⁻¹) of DOC.     

基于CAN总线的新型煤矿粉尘浓度检测系统的研究

为了实现对粉尘的实时在线检测和粉尘超限报警,以及实现煤矿粉尘浓度检测系统的高性能运行,本文设计了一种基于CAN总线的新型煤矿粉尘浓度检测系统.本文首先对粉尘浓度检测系统的整体设计方案进行了描述,然后对系统的传感器及调理转换电路、声光报警电路和CAN通信电路等硬件电路进行了设计,对粉尘检测系统的软件进行了详细的设计分析.最后给出了实验结果,并通过实验结果证明了该系统能长时间实时监测粉尘浓度,并通过CAN总线接口可以实现系统的远距离、高可靠性通信功能和远程监控功能.本系统具有测量准确、速度快、可靠性高和能及时报警等特点.     

多参数澴东湖多边形生态安全状态判别研究

基于对澴东湖流域水文、生态环境的长期调查和多边形生态安全状态判别方法,选取社会经济与生态环境的6个层面22个影响因子,构建了澴东湖多边形指数生态安全判别体系,进行了非模糊数矩阵和多边形指数生态安全计算分析与判别.结果表明,多边形指数在0.422 0～0.439 6,澴东湖A的生态系统处于临界安全状态.同时,多边形指数生态安全判别方法可以较好地描述澴东湖A的生态安全状态.     

A/O-MBR处理某经济区市政污水的效能

采用A/O-MBR法处理某经济区市政污水,对其进、出水的水质进行连续监测,考察系统稳定性和处理效果。结果表明,在水力停留时间12小时,污泥龄30天,回流比75%,好氧段DO浓度1.3～8.5 mg/L的条件下,系统对COD、氨氮、总氮、总磷的平均去除率分别为92.04%、93.66%、78.04%、91.06%。反硝化...     

乙酰辅酶A羧化酶:脂肪酸代谢的关键酶及其基因克隆研究进展

乙酰辅酶A羧化酶(Acetyl-CoA carboxylase,ACC)在脂肪酸合成和分解代谢中发挥着重要作用.系统介绍了该酶的结构与分类、生物学作用与应用、抑制剂的类型与作用机理以及基因克隆4个方面的进展.ACC在大多数原核生物中为多亚基型酶,而在大多数真核生物中为多功能型单亚基酶,在天蓝色链霉菌和古菌勤奋金属球菌中为另外两种特殊类型;但都具备3个关键的功能域,即生物素羧化酶(BC)、生物素羧基载体蛋白(BCCP)和羧基转移酶(CT).CT功能域作为潜在的靶标广泛应用于植物除草剂的筛选和哺乳动物肥胖、糖尿病等代谢疾病的药物设计中.ACC基因也成为转基因油料作物和生物柴油研究中重要的靶标基因.研究表明,植物质体中的β-CT亚基是多亚基型ACC的限制因子,而BCCP是脂肪酸合成的负调控因子.油脂的合成代谢十分复杂,且存在反馈抑制机制,因此克隆和表达ACC基因可以提高宿主中ACC的活性,但不一定能显著促进脂肪酸的积累.图2参52