间歇投加碳源模式下SND的脱氮效能

采用模拟碳源偏低的城市污水,于连续曝气的SBR内,在不同间歇投加碳源的模式下,考察氮转化和DO、ORP及pH的变化规律。结果表明,随间歇投加碳源次数的增加,同步硝化反硝化(SND)的脱氮效率得到提高,DO浓度和ORP值的波动降低。由此可知,间歇多次投加碳源的运行模式是碳源偏低城市污水实现稳定而高效脱氮SND的有效控制策略。     

Photolysis of mono- through deca-chlorinated biphenyls by ultraviolet irradiation in n-hexane and quantitative structure-property relationship analysis

The photolysis of 16 polychlorinated biphenyls （PCBs） （including mono- through deca-chlorinated） in n-hexane was investigated under ultraviolet irradiation using a 500-W high-pressure mercury lamp. Photolysis of PCBs follows pseudo-first-order reaction kinetics, with photolysis rate constants ranging between 0.0011 s^-1 for PCB-52 and 0.0574 s^-1 for PCB-118. The degradation rates of PCBs by high-pressure mercury lamp irradiation were remarkably independent with respect to the degree of chlorination. Furthermore, partial least squares （PLS） models were developed to provide insight into which aspect of the molecular structure influenced PCB photolysis rate constants. It was found that the photolysis rates of PCBs increased with an increase in the net charge on the carbon atom （qc）, （ELUMO-EHOMO）^2, and the Y-axis dipole moment （μy） values, or the decrease in the energy of the second highest occupied molecular orbital （EHOMO-1）, energy of the lowest unoccupied molecular orbital （ELUMO）, ELUMO ＋ EHOMO, ELUMO - EHOMO, most positive atomic charge （q^＋）, and the twist angle of the chlorine atom （TA） values.     

Emergency membrane contactor based absorption system for ammonia leaks in water treatment plants

Because of the suspected health risks of trihalomethanes (THMs), more and more water treatment plants have replaced traditionalchlorine disinfection process with chloramines but often without the proper absorption system installed in the case of ammonia leaksin the storage room. A pilot plant membrane absorption system was developed and installed in a water treatment plant for this purpose.Experimentally determined contact angle, surface tension, and corrosion tests indicated that the sulfuric acid was the proper choice as the absorbent for leaking ammonia using polypropylene hollow fiber membrane contactor. Effects of several operating conditionson the mass transfer coefficient, ammonia absorption, and removal efficiency were examined, including the liquid concentration,liquid velocity, and feed gas concentration. Under the operation conditions investigated, the gas absorption efficiency over 99.9%was achieved. This indicated that the designed pilot plant membrane absorption system was effective to absorb the leaking ammonia in the model storage room. The removal rate of the ammonia in the model storage room was also experimentally and theoretically foundto be primarily determined by the ammonia suction flow rate from the ammonia storage room to the membrane contactor. The ammoniaremoval rate of 99.9% was expected to be achieved within 1.3 h at the ammonia gas flow rate of 500 m3/h. The success of the pilot plantmembrane absorption system developed in this study illustrated the potential of this technology for ammonia leaks in water treatmentplant, also paved the way towards a larger scale application.     

中国南方红壤丘陵区湖南水环境时空变化研究

以中国南方红壤丘陵区的典型区域-湖南省为例,利用1990～2000年湘、资、沅、澧四水和洞庭湖区重要断面的水质数据,采用综合污染指数方法和污染分担率方法,研究了湖南省水环境质量时空变化特征,并选取1990～2005年经济和废水排放数据,分析了经济因子与废水排放之间的相互关系,建立湖南省废水排放的库兹涅茨曲线模型。研究结果表明,从时间上看,湖南省的总体水环境污染有加重的趋势;从空间上看,水环境质量是从湖南省的西部向东部恶化。在流域和地区对比中,湘江和位于该流域的株洲市最为严重,总氮和汞是湖南省最主要的污染因子;通过环境库兹涅茨曲线模型模拟表明,湖南水环境与经济发展的关系位于环境库兹涅茨曲线上升段。本研究结果对于改善整个湖南省水环境污染状况,以便采取正确的防治策略具有一定的实践意义。     

柠檬酸废渣石膏综合利用研究进展及前景展望

柠檬酸废渣石膏主要由二水石膏组成,化学成分与天然石膏相近,只要工艺合理,就可以实现柠檬酸废渣石膏的资源化利用。综述了柠檬酸废渣石膏生产石膏粉、石膏砌块和石膏板材,用于硫铝酸盐水泥生产,用作水泥缓凝剂、制备晶须等方面的研究进展;提出了柠檬酸废渣石膏在生产粉笔、用于水泥矿化剂和与石英尾砂等工业废渣联合使用等方面的应用前景。     

钛基表面电沉积钌的工艺研究

说明了一种能在钛基上直接电镀金属钌的新工艺.该工艺在三氯化钌体系中进行,通过在电镀液中加入氨基磺酸、氯化铵和一些添加剂,提高了钌镀工艺的电流效率,且镀层光亮平整.试验还通过电化学测试、扫描电镜(SEM)和XRD等方法研究了电流密度、温度、pH值、主盐和添加剂浓度等参数对镀层性能的影响.结果表明:电镀钌工艺最佳电流密度范围是0.5～0.8 A/dm2,添加剂浓度的最佳范围是20～30g/L,微观电镜图也显示了钌镀层较为致密.最后,该镀钌工艺实现了在主盐浓度不高的情况下仍然镀出了致密的钌层.     

利用hypermesh和feko软件来仿真舰艇RCS

利用feko软件,结合hypermesh剖分的优化网格,对舰艇RCS进行了仿真计算。经过hy—permesh剖分得出的优化网格较feko自己剖分的网格质量更好,更符合MOM三角面元网格的需要,而且在计算时间以及内存需求方面均有明显的优势,有利于更好地对舰船RCS进行仿真。最后计算了某型舰艇的RCS,结果验证了这种方法的精度。     

电磁环境数据采集及实验室模拟技术研究

对电磁环境数据采集技术和实验室模拟技术进行了介绍和分析,并结合混响室技术对MIL-STD-464A给出的舰船甲板上工作的外部电磁环境(200 MHz～4.2 GHz)进行了实验室模拟.结果表明,现有的测试仪器能够模拟出MIL-STD-464A中的强射频环境.     

长三角大都市带人口容量与资源环境支撑能力建设

为推动长三角都市带人口稳定扩容,寻求提高长三角地区资源环境支撑能力的途径。基于国外已经成熟的大都市带,认为产业集聚规模、资源支撑条件、环境承受能力是影响大都市带人口容量的主要因素。根据预测,长三角都市带未来的人口规模为107亿~117亿。通过对支撑长三角都市带经济-人口容量的资源环境要素分析,认为扩大长三角地区的人口容量,关键在于提高长三角地区资源环境的支撑能力,认为未来经济发展所需各类用地保障程度的高低、战略性矿产资源供〖JP2〗给能力的强弱以及区域环境容量的大小是影响长三角都市带人口容量大小的关键因素。建议在国家层面通过土地政策的调整提高长三角大都市带各类功能用地的保障能力,通过建立国家石油储备制度等方式加强战略性矿产资源供给能力建设,同时在长三角大都市带地区率先实施循环经济战略。     

盐沼植物翅碱蓬对沉积物中磷环境化学行为影响

研究了翅碱蓬生长区根际、非根际(根上部和根下部)沉积物和未生长区沉积物对应断面(亚表层、表层和深层)P的环境化学行为.结果表明,无论有无植物生长,沉积物总磷(TP)由表层(根上部)至深层(根下部)呈现逐渐减少的趋势且均以无机磷(IP)为主,有机磷(OP)含量最少,但植物生长区沉积物中总磷含量显著地增加,特别是根际沉积物 IP含量高达83%.对植物生长区和未生长区沉积物中IP的化学形态进一步分析表明,无论有无植物生长IP均以Ca-P为主,但在植物根际沉积物DP、Al-P和Fe-P均有显著增加,分别为未生长植物亚表层沉积物的3.5、8.3和3.7倍,从而导致活性磷比例增加,生物可利用性变大.