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961.
The recycling reverse osmosis(RO) membrane concentrate of some high-ammonia nitrogen(NH4+-N) organic wastewater to the biological unit could cause potassium ion(K+) accumulation, thereby affecting the removal of NH4+-N by activated sludge. Thus, the effects of high K+ stress on activated sludge nitrification performance was studied. The results showed that the high K+ stress promoted the floc sludge to produce more extr... 相似文献
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963.
A chlorbenzuron, diflubenzuron, and hexaflumuron-degrading bacterium strain M6, was isolated from the activated sludge of an insecticide factory. The strain was identified as Achromobacter sp. according to an analysis on the 16S rRNA gene sequences, morphological, and physiological characteristics. Strain M6 could degrade more than 91% of 100 mg/L chlorbenzuron, diflubenzuron, and hexaflumuron within 48 hours, which could act as the sole carbon source. Strain M6 showed more chlorbenzuron degradation at a temperature range between 25 and 40 ℃ and a pH range between 6.0 and 8.0. The optimal temperature and the initial pH of medium for chlorbenzuron degradation by strain M6 were 30 ℃ and 7.0, respectively; the maximum chlorbenzuron tolerated concentration of strain M6 was as high as 400 mg/L. Strain M6 hydrolyzed 4-acetaminophenol into a purple-red product. Moreover, an approximately 1.4 kb DNA fragment, which could be expressed into an amidase to degrade amide pesticides, was amplified from the genomic DNA of strain M6. The results preliminarily proved that 3 benzoylurea insecticides could be degraded because of strain M6 hydrolyzing their amide bonds. This study obtained a highly efficient degrading strain and provided new resources and valuable information on benzoylurea insecticide degradation. © 2018 Science Press. All rights reserved. 相似文献
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965.
随着地下矿山开采活动的进行,采空区已成为影响矿山安全的主要隐患之一。以某铜锌矿为背景,利用VS150空区精密探测系统对采空区进行精密探测,采用VoidScan-Geomagic-3Dmine耦合技术,分别建立了研究时段与设计时段采空区三维精细模型,进而对比分析了采空区空间结构演化过程,采用3Dmine-Midas GTS NXFLAC~(3D)耦合的数值模拟技术,结合矿区实际生产情况对设计时段空区进行数值模拟分析,并对空区空间结构演化过程中位移场、应力场及塑性区进行系统的研究,确定了空区顶板及围岩的稳定程度,并进一步揭示了未来时段空区的演化趋势。数值模拟结果与现场实测工作结果相吻合,研究结果为采空区后续的安全治理提供了科学依据。 相似文献
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Effect of electrokinetic treatment on copper partitioning and distribution in mine tailings were studied. In particular the effects of catholyte enhancement by HAc-NaAc, HCl, HAc-NaAc+EDTA and lactic acid+NaOH were evaluated. The results show that conditioning the catholyte plays a very important role in improving Cu removal. When HAc-NaAc is used in the catholyte, the removal percentage of total Cu from the mine tailings sample reached 12.3% under 40 V in 15 days of treatment. The removal percentage of Cu increased to 31.2% when EDTA was used together with HAc-NaAc in the catholyte. At the same time, increasing the applied voltage and treatment time result in an increase in the Cu removal from the mine tailings. Compared with HAc-NaAc (pH=3.52), the use of lactic acid+NaOH (pH=3.15) in the catholyte resulted in better performance in Cu removal from the mine tailings. HCl treatment resulted in removal of about 17.5% of Cu from the mine tailings; however, it resulted in production of significant amounts of toxic chlorine gas. Copper partitioning in the mine tailings was analyzed before and after the electrokinetic treatments. The analysis was conducted using 0.25 mol/l MgCl2 and 0.5 mol/l HCl as extractants, consequently, to assess the mobility of Cu after treatment. The results showed that lowering the pH of the mine tailings increased the exchangeable Cu fraction (or the portion extracted by MgCl2). Accordingly, further acidification results in an increased mobility of Cu and increase in the environmental risk of mine tailings. 相似文献
969.
根据国际标准化组织颁布的两个系列标准的特点,分析了如何运用管理循环于安全管理和环境管理实践中,提出了制约因素管理循环,并且阐述了管理职能循环、PDCA循环和制约因素管理循环运用于管理工作实践中三者的关系. 相似文献
970.