Experimental study on Cr(Ⅵ) reduction by Pseudomonas aeruginosa

Investigation on Cr(Ⅵ) reduction was conducted using Pseudomonas aeruginosa. The study demonstrated that the Cr(Ⅵ) can be effectively reduced to Cr(Ⅲ) by Pseudomonas aeruginosa. The effects of the factors affecting Cr(Ⅵ) reduction rate including carbon source type, pH, initial Cr(Ⅵ) concentration and amount of cells inoculum were thoroughly studied. Malate was found to yield maximum biotransformation, followed by succinate and glucose, with the reduction rate of 60.86%, 43.76% and 28.86% respectively. The optimum pH for Cr(Ⅵ) reduction was 7.0, with reduction efficiency of 61.71% being achieved. With the increase of initial Cr(Ⅵ) concentration, the rate of Cr(Ⅵ) reduction decreased. The reduction was inhibited strongly when the initial Cr(Ⅵ) concentration increased to 157 mg/L. As the amount of cells inoculum increased, the rate of Cr(Ⅵ) reduction also increased. The mechanism of Cr(Ⅵ) reduction and final products were also analysed. The results suggested that the soluble enzymes appear to be responsible for Cr(Ⅵ) reduction by Pseudomonas aeruginosa, and the reduced Cr(Ⅲ) was not precipitated in the form of Cr(OH)3.     

Efficiency analysis for organic agricultural producers: the role of soil-improving inputs

Greater emphasis is being placed on indicators of agri-environmental efficiency of organic production systems. Linking environmental measures with profitability measures based on net income is the only way to develop such indicators. A stochastic production frontier model that explicitly incorporates farm decisions about acquiring and managing organic soil-improving inputs is used to measure efficiency. The results confirm that on-farm self-sufficiency in soil-improving inputs is positively related to farm-level efficiency.     

Persistence and developmental transition of wide seismic lines in the western Boreal Plains of Canada

This study examined the fate of seismic lines utilized in oil and gas exploration in Canada's western Boreal Plains. It retrospectively followed the persistence, recovery and developmental transition of seismic lines established between the 1960s and the mid-1970s through to 2003. We examined lines that passed through three forest types; aspen, white spruce, and lowland black spruce. In general, the recovery rates of seismic lines to woody vegetation were low. After 35 years, 8.2% of seismic lines across all forest types had recovered to greater than 50% cover of woody vegetation. Only the upland forest types recovered; aspen and white spruce. Most seismic lines ( approximately 65% at 35 years) remained in a cleared state with a cover of low forbs. The most common transition for seismic lines was to tracked access ( approximately 20% at 35 years). Transition to other anthropogenic developments such as roads, pipelines, buildings, and timber harvest blocks was 5% after 35 years. The pulse of industrial activity initiated in the mid-1990s greatly increased the transition rate of seismic to tracked access for a short period of time. The discussion focused on natural and anthropogenic factors that hinder recovery and on the management directions that would facilitate greater recovery rates.     

Comprehensive Assessment of Regional Circular Economy Development Based on Efficiency of Resource & Environment:A Case Study of Jiangsu Province

In the first, the paper gave a retrospective analysis on the comprehensive assessment of circular economic development. According to the requirement of improving resource & environment efficiency, the paper designed an analytical framework for a comprehensive assessment of regional circular economic growth, which consists of the goal, object and technical line of the comprehensive assessment of regional circular economic development. Given that, the paper discussed the criterion for choosing the assessment index, the approaches of index's weighing determination, the means of data standardization, and the reference system of assessment index value and so on. According to the framework of regional circular economic development evaluation,the paper made a comprehensive evaluation of Jiangsu Province's circular economic development. The result shows that from temporal change, Jiangsu Province's circular economic development had different stages;from the spatial comparison, there is variance among different regions, which could be divided into different types according to the spatial variance and the relation between the development of circular economy and the aggregative index number. There was a remarkable correlation between circular economic development level and GDP or the 2nd industry GDP. Finally, the paper gives some suggestions on how to promote the development of circular economy in Jiangsu Province.     

我国开发区土地资源配置效率的区域差异研究

应用比较优势理论，以国家级53个经济技术开发区为例。研究了不同区域间开发区土地利用的比较优势。结果表明。按照区域土地利用的比较优势来配置土地资源能够提高土地利用的总福利水平。整体上．中西部国家级开发区的比较优势高于东部地区：而区域内部东部地区的京津苏沪及中西部地区的中心城市在开发区建设用地的利用上具有比较优势。因此，按照开发区土地利用的比较优势度计算结果，在排除开发区自身发育不完善和管理层面因素后，对于确实不适宜进行开发区工业建设的应进行空间布局的调整，恢复其农业生产；而对于比较优势度较高的地区可根据实际需要增设相应的开发区。以实现耕地保护与开发区建设的双赢。     

臭氧氧化去除二级出水中PPCPs的研究

药品及个人护理用品(PPCPs)是一类痕量、顽固的新兴有机污染物,采用传统水处理工艺不易去除,需深度处理。采用批量试验方法,研究了臭氧氧化二级出水中添加的19种PPCPs的去除效果,考察了臭氧投加量、p H值、自由基抑制剂对去除效率的影响,并根据氧化产物推断可能的反应途径。结果表明,在原水水样p H=7.1条件下,臭氧质量浓度为1.2 mg/L时,能有效去除大多数PPCPs。其中,抗生素类PPCPs和个人防护类PPCPs的去除率分别达到了68%和70%,而雷尼替汀和噻苯咪唑去除效果不明显,仅为17.73%和12.3%。增加臭氧投加量或提高反应p H值会显著提高除雷尼替汀和噻苯咪唑外的PPCPs去除率。加入的自由基抑制剂对臭氧氧化PPCPs有明显抑制作用。PPCPs的氧化降解产物有机酸会降低反应p H值,进而影响PPCPs的去除效果。     

多级驯化嗜酸菌淋滤电子废弃物拆解地土壤重金属的效果

冶金用嗜酸性硫杆菌的驯化材料多为单一重金属,为了解决驯化后菌种在处理多种类重金属污染的土壤时存在效果不佳的问题,将电子废弃物拆解地实际污染的土壤作为驯化材料,分析了不同驯化周期内嗜酸性硫杆菌对污染土壤中重金属的去除效果。结果表明,电子废弃物拆解地土壤以Zn、Cu、As、Cd、Pb、Ni污染为主。经不同代时的驯化,嗜酸氧化亚铁硫杆菌(Acidithiobacillus ferrooxi-dans,A. f菌)和嗜酸氧化硫硫杆菌(Acidithiobacillus thiooxi-dans,A. t菌)的生长pH值下降幅度不同,培养液中氧化还原电位(φ)均有所上升,表明其生物活性有所提高。重金属质量比对菌种的生物活性和产酸能力有一定的影响,多级驯化可提高菌种对重金属的去除能力。A. f菌对Zn、Ni、Cd、Cu、As的去除率均优于A. t菌,其中A. f菌对Cd的去除率高于A. t菌2倍以上,为79. 2%,但A. t菌对Pb的去除率优于A. f菌,可达66. 6%。     

金属矿山掘进巷道新型通风除尘系统研究与应用

为了减少掘进巷道的粉尘危害,以某金属矿掘进工作面为研究对象,经过现场调研和理论分析,研究开发了1种适合掘进巷道的新型通风除尘系统。介绍了新型通风除尘系统的结构和工作原理,并将该通风除尘系统应用于掘进巷道的粉尘治理,对该系统在掘进巷道的应用效果进行现场测定。研究结果表明:该通风除尘系统将压风筒布置在巷道中心位置的顶部,抽风筒布置在巷道两侧的呼吸带高度,使得掘进工作面的风流位置控制在1.5 m之下,保障了作业人员的职业健康。系统的湿式除尘风机对掘进巷道粉尘除尘效率达到了91%以上,彻底解决了掘进巷道粉尘污染问题。同时该系统能够实现按需通风除尘,净化后的风流可以循环利用,节能效果显著,在金属矿山掘进巷道生产系统具有较好的应用前景。     

石油污染土壤微生物联合修复技术研究进展

石油是一种具有生物毒性的复杂有机物,土壤中石油烃的过量积累会给生态环境和人类健康造成严重威胁。微生物联合修复技术因处理成本低、环境影响小、无二次污染等优点,且较微生物修复或植物修复效率更高,耗时更短,成为当前的研究热点。文章介绍了植物-微生物联合修复、电动-微生物联合修复、氧化-微生物联合修复和表面活性剂强化微生物修复四种联合修复技术,简要阐述了修复机理、适用范围和工艺参数,为生物修复技术的选择提供了参考,并对以后生物修复的研究重点进行了展望。     

Monograph on desilting basins sizes estimation for hydropower projects

At times, various analytical and empirical approaches used to estimate the initial sizing of a desilting basin in a hydropower project would give very different results and the designer has to take a call judiciously. The purpose of this study is to develop a monograph based on Teaching–Learning-Based Optimization and Gravitational Search algorithm for a practical range of depth of desilting basins. The parameters commonly used in hydropower projects for estimation of desilting basins sizing and its efficiency are used in this study. The outcome is further verified using a list of mega hydropower projects. This study will be useful in fixing the best optimized dimension of desilting basins.