Increase of multi-metal tolerance of three leguminous plants by arbuscular mycorrhizal fungi colonization

A greenhouse pot experiment was conducted to investigate the effects of the colonization of arbuscular mycorrhizal fungus (AMF) Glomus mosseae on the growth and metal uptake of three leguminous plants (Sesbania rostrata, Sesbania cannabina, Medicago sativa) grown in multi-metal contaminated soil. AMF colonization increased the growth of the legumes, indicating that AMF colonization increased the plant’s resistance to heavy metals. It also significantly stimulated the formation of root nodules and increased the N and P uptake of all of the tested leguminous plants, which might be one of the tolerance mechanisms conferred by AMF. Compared with the control, colonization by G. mosseae decreased the concentration of metals, such as Cu, in the shoots of the three legumes, indicating that the decreased heavy metals uptake and growth dilution were induced by AMF treatment, thereby reducing the heavy metal toxicity to the plants. The root/shoot ratios of Cu in the three legumes and Zn in M. sativa were significantly increased (P < 0.05) with AMF colonization, indicating that heavy metals were immobilized by the mycorrhiza and the heavy metal translocations to the shoot were decreased.     

亚铁催化声化学降解罗丹明B

比较了不同金属离子对罗丹明B的声化学降解作用，发现超声时加入Fe^2＋反应速率常数为单独超声波降解时的1．6倍，反应在前5h内符合假一级动力学。研究了亚铁离子强化声化学对罗丹明B的降解作用，考察了Fe^2＋用量，溶液初始pH值，曝气，反应温度和超声功率等因素对脱色速率的影响。研究表明，酸性条件有利于染料的脱色；有曝气时的声化学脱色速率常数是单独超声时的6倍；声化学反应的活化能较低，反应在低温就可以进行；超声功率的改变对脱色速率的影响不大。UV-VIS扫描图谱显示，染料在225nm和256nm处的紫外吸收明显降低，初步探讨了罗丹明B的降解机理。     

城市化与生态环境耦合协调度评价研究——以济南市为例

以济南市为研究区域,利用2006年-2015年的统计数据,建立城市化与生态环境协调度评价指标体系,对济南市城市化与生态环境耦合协调关系进行分析与评价。结果表明:2006年-2015年期间,济南市城市化与生态环境耦合度处于拮抗阶段;2006年-2008年期间,城市化与生态环境耦合协调度处于严重不协调阶段,2009年-2015年期间,城市化与生态环境耦合协调度处于基本不协调阶段。正确认识城市化与区域生态环境耦合协调度特征,采取恰当的城市发展战略,改善生态环境,对区域可持续发展具有重要意义。     

硝化抑制剂的加量对生化需氧量值影响的探讨

BOD作为衡量水体受有机污染程度的重要指标,其反映的可生化降解性是其他参数无法替代的。在5日生化培养时间内,硝化作用的耗氧量取决于是否存在足够数量的能进行此种氧化作用的微生物,许多二级生化处理的出水和受污染较久的水体中,往往含有大量硝化微生物,因此测定这种水样时应抑制其硝化反应。通过对特定水体硝化抑制剂添加与否及加量多少对BOD5测定结果的影响,分析并探讨抑制特定水体硝化过程的最佳条件。在严格质量控制的基础上,对特定行业和环境水体的实际样品进行硝化抑制剂添加与否和加量及时间培养曲线等对比实验,通过所得到的比对数据以化学需氧量值与BOD5之间关系为基准,对硝化抑制剂的加量进行了探究。     

Revealing photon transmission in an ultraviolet reactor: Advanced approaches for measuring fluence rate distribution in water for model validation

Fluence rate (FR) distribution (optical field) is of great significance in the optimal design of ultraviolet (UV) reactors for disinfection or oxidation processes in water treatment. Since the 1970s, various simulation models have been developed, which can be combined with computational fluidic dynamic software to calculate the fluence delivered in a UV reactor. These models strive for experimental validation and further improvement, which is a major challenge for UV technology in water treatment. Herein, a review of the simulation models of the FR distribution in a UV reactor and the applications of the current main experimental measurement approaches including conventional flat-type UV detector, spherical actinometer, and micro-fluorescent silica detector (MFSD), is presented. Moreover, FR distributions in a UV reactor are compared between various simulation models and MFSD measurements. In addition, the main influential factors on the FR distribution, including inner-wall reflection, refraction and shadowing effects of adjacent lamps, and turbidity effect are discussed, which is helpful for improving the accuracy of the simulation models and avoiding dark regions in the reactor design. This paper provides an overview on the simulation models and measurement approaches for the FR distribution, which is helpful for the model selection in fluence calculations and gives high confidence on the optimal design of UV reactors in regard to present methods.     

Environmental impacts of a large-scale incinerator with mixed MSW of high water content from a LCA perspective

Large-scale incinerators are applied widely as a result of the heavy burden of municipal solid waste(MSW) generated, while strong opposition is arising from the public living nearby. A large-scale working incineration plant of 1500 ton/day was chosen for evaluation using life cycle assessment. It was found that the corresponding human toxicity impacts via soil(HTs), human toxicity impacts via water(HTw) and human toxicity impacts via air(HTa)categories are 0.213, 2.171, and 0.012 personal equivalents(PE), and global warming(GW100)and nutrient enrichment(NE) impacts are 0.002 and 0.001 PE per ton of waste burned for this plant. Heavy metals in flue gas, such as Hg and Pb, are the two dominant contributors to the toxicity impact categories, and energy recovery could reduce the GW100 and NE greatly. The corresponding HTs, HTw and HTa decrease to 0.087, 0.911 and 0.008 PE, and GW100 turns into savings of- 0.007 PE due to the increase of the heating value from 3935 to5811 k J/kg, if a trommel screener of 40 mm mesh size is used to pre-separate MSW. MSW sorting and the reduction of water content by physical pressure might be two promising pre-treatment methods to improve the combustion performance, and the application of stricter standards for leachate discharge and the flue gas purification process are two critical factors for improvement of the environmental profile identified in this work.     

社会环境检测机构质量监管措施研讨

就目前的情况而言,我国在社会环境检测机构质量不容乐观。因此,我们应该根据实际情况,来设置相应的社会环境检测监管方案。我们可以通过严格规范社会环境检测机构市场准入门槛、创设专门的社会环境检测机构质量监管部门、创设社会环境检测机构网上投诉平台等方式,来提升监管力度,让社会环境检测机构正确发挥其应有的作用。     

Integrating decay, storage, kinetic selection, and filamentous backbone factors in a bacterial competition model.

Filamentous bulking in activated sludge systems occurs when filamentous organisms outgrow floc-forming bacteria and interfere with sludge settling. The competition between filaments and floc formers has been described previously using the kinetic selection and filamentous backbone theories. We hypothesized that differences in decay rates and storage abilities also affect this competition. We tested this hypothesis by integrating these four factors into a substrate-utilization model to predict and explain coexistence in a completely mixed reactor. In addition, filamentous and nonfilamentous sludges were developed in laboratory-scale reactors and analyzed to determine decay rates. The modeling results showed coexistence of the two organism types, and sensitivity analysis showed that the kinetic parameters, storage rate constants, and backbone coefficient had the greatest effect on the simulation results. Monte Carlo simulation showed the effect of storage, and the ranges of dilution rates wherein one group outcompeted the other were delineated.     

Incinerating Volatile Organic Compounds with Ferrospinel Catalyst MnFe2O4: An Example with Isopropyl Alcohol

Abstract

This paper concerns the incineration of isopropyl alcohol (IPA) using the ferrospinel catalyst MnFe₂O₄. It covers the preparation of the ferrospinel catalyst, the screening of catalytic activity, catalytic incineration testing, and 72-hr decay testing of the catalyst. The experimental results of catalyst screening reveal that the Mn/Fe catalyst is the best of five prepared catalysts (chromium/iron [Cr/Fe], manganese/iron [Mn/Fe], zinc/iron [Zn/Fe], nickel/iron [Ni/Fe], and pure magnetite [Fe₃O₄]). In tests of the catalytic incineration system used to convert IPA, 98% conversion was obtained at a space velocity of 24,000 hr^?1, an oxygen (O₂) content of 21%, 1700 ppm of IPA, and a reaction temperature of 200 °C.     

微涡旋絮凝-逆流气浮-纳滤集成工艺去除水中腐殖酸的动态运行特征

通过微涡旋絮凝逆流气浮-纳滤集成工艺的动态试验研究,确定其运行周期为72 h,能很好地去除水中腐殖酸有机物,但不同纳滤膜组成的集成工艺处理效果不同.采用PACl絮凝剂处理水样2时,以流程1运行的含TQ56-36FC型纳滤膜的集成工艺出水的高锰酸盐指数为0.45 mg/L,UV254nm在0.003 3左右波动,且有95%以上的脱盐率.以流程2运行的含M-N1812A型纳滤膜的集成工艺处理3种水样时的膜清水的高锰酸盐指数在0.75 mg/L左右波动,UV254nm大都远小于0.007 5,有时甚至为0.水样1和水样3的UV254nm平均值为0.005 4,水样2的最低,平均值为0.003 3,脱盐率只有6%～10%.以PACl为絮凝剂时,集成系统有较强的适应原水水质变化的能力.预处理中活性炭柱的存在提高了M-N1812A型纳滤膜清水样的水质,但并没有延长膜的使用周期.这也表明膜的污染更重要的是来自无机物的污染.