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721.
阐述了环境适应性与环境工程的概念,对国内外环境适应性领 域的现状作了介绍和分析。提出了建立环境工程及其管理体系的思 路和建议措施,以及装备研制周期各阶段的各项环境工程工作项目 及工作重点。 相似文献
722.
重金属污染对环境造成了严重破坏,并威胁着人类的生命健康和财产安全。本文从重金属环境污染现状、重金属污染对微生物影响、微生物对重金属离子污染的修复作用、微生物修复方法的作用机理等方面,综述了微生物在重金属污染修复及治理中的研究概况,并对微生物修复及治理重金属污染存在的局限性进行分析,进一步提出相关改进建议,为处理重金属离子污染提供了理论依据。 相似文献
723.
经过对PH玻璃电极对比观测实验,总结其在日常观测中衰减变化规律,以及PH电极失效前所具有的特征;讨论了对现有PH观测数据进行修正的方法,并编著相关修正程序;分析日常存在的测量误差,提出提高观测精度的措施。 相似文献
724.
讨论了城市污水经过A/O工艺处理时活性污泥的二次污染问题。将原水、处理后的出水及活性污泥用甲苯萃取,萃取相经过真空浓缩后,采用GC/MS测定了样品中的有机化合物,结果表明,在A/O工艺处理城市污水过程中,活性污泥的吸附作用是主要的,降解作用是次要的;A/O工艺所排放的活性污泥仍然是一种危险的污染物。 相似文献
725.
726.
Synergistic effects of liquid and gas phase discharges using pulsed high voltage for dyes degradation in the presence of oxygen 总被引:8,自引:0,他引:8
The technology of combined liquid and gas phase discharges (LGD) using pulsed high voltage for dyes degradation was developed in this study. Apparent synergistic effects for Acid orange II (AO) degradation in the presence of oxygen were observed. The enhancement of AO degradation rate was around 302%. Furthermore, higher energy efficiency was obtained comparing with individual liquid phase discharge (LD) or gas phase discharge process (GD). The AO degradation in the presence of oxygen by LGD proceeded through the direct ozone oxidation and the ozone decomposition induced by LD. Important operating parameters such as electrode distance, applied voltage, pulse repetition rate, and types of dyes were further investigated. 相似文献
727.
Xiaofei Sun Yi Qi Bimin Mao Lei Yu Peijia Tang 《Journal of the Air & Waste Management Association (1995)》2019,69(4):391-401
Signalized intersections have been identified as vehicle emission hotspots, where drivers decelerate, idle, and accelerate their vehicles in response to signal changes. Advanced traffic signal status warning systems (ATSSWSs) can be applied to reduce traffic emissions at intersections by mitigating unnecessary braking and acceleration. In this study, two types of ATSSWSs, variable message sign (VMS) based and vehicle-to-infrastructure (V2I) based, were designed, and their environmental effectiveness was evaluated through driving simulator-based experiments. Three scenarios were designed and tested: (1) baseline without an ATSSWS, (2) with the VMS-based ATSSWS, and (3) with the V2I-based ATSSWS. The Motor Vehicle Emission Simulator model was used to evaluate and compare the environmental effectiveness of these two types of ATSSWSs. The results indicate that the proposed ATSSWSs can reduce traffic emissions at signalized intersections. In particular, the V2I-based ATSSWS can substantially reduce CO2, NOx, CO, and HC emissions. The results will help transportation practitioners with implementing advanced driver information systems and decision making on emission reduction policies.
Implications: Signalized intersection has been identified as one of hottest spots for vehicle emissions where signal control causes vehicles to frequently decelerate, idle, and accelerate. Advanced Traffic Signal Status Warning Systems (ATSSWS) can be applied to reduce traffic emission at intersections by decreasing vehicles’ unnecessary brakes and accelerations. The results of this study will assist transportation practitioners in implementing advanced driver information systems and making decisions on emission reduction policies. 相似文献
728.
Manganese uptake and accumulation by the hyperaccumulator plant Phytolacca acinosa Roxb. (Phytolaccaceae) 总被引:9,自引:0,他引:9
Xue SG Chen YX Reeves RD Baker AJ Lin Q Fernando DR 《Environmental pollution (Barking, Essex : 1987)》2004,131(3):393-399
The perennial herb Phytolacca acinosa Roxb. (Phytolaccaceae), which occurs in Southern China, has been found to be a new manganese hyperaccumulator by means of field surveys on Mn-rich soils and by glasshouse experiments. This species not only has remarkable tolerance to Mn but also has extraordinary uptake and accumulation capacity for this element. The maximum Mn concentration in the leaf dry matter was 19,300 microg/g on Xiangtan Mn tailings wastelands, with a mean of 14,480 microg/g. Under nutrient solution culture conditions, P. acinosa could grow normally with Mn supplied at a concentration of 8000 micromol/l, although with less biomass than in control samples supplied with Mn at 5 micromol/l. Manganese concentration in the shoots increased with increasing external Mn levels, but the total mass of Mn accumulated in the shoots first increased and then decreased. At an Mn concentration of 5000 micromol/l in the culture solution, the Mn accumulation in the shoot dry matter was highest (258 mg/plant). However, the Mn concentration in the leaves reached its highest value (36,380 microg/g) at an Mn supply level of 12,000 micromol/l. These results confirm that P. acinosa is an Mn hyperaccumulator which grows rapidly, has substantial biomass, wide distribution and a broad ecological amplitude. This species provides a new plant resource for exploring the mechanism of Mn hyperaccumulation, and has potential for use in the phytoremediation of Mn-contaminated soils. 相似文献
729.
730.
改进的硫酸盐-聚乙烯醇法包埋藻菌脱氮除磷研究 总被引:1,自引:0,他引:1
采用改进的硫酸盐-PVA固定化法将藻与菌混合固定。在三种不同藻菌比的情况下,固定化系统对氮去除均可达100%,但是去除速度与固定的细菌量有关,细菌量越大,对氮的去除速度越快;对磷的去除随实验进行,最大去除率逐步下降,其下降速度与固定藻的量有关,藻量越大,下降速度越慢。由此说明脱氮的主要贡献者是细菌,而藻对除磷起了主要作用。为达到有效的脱氮除磷,应适当提高固定化藻的浓度,藻菌比应大于2:1。透射电镜照片显示,在聚乙烯醇载体上,藻类的生长没有受到限制。 相似文献