土壤中乐果与微生物的相互作用研究

采用室内模拟实验,研究了土壤中乐果与微生物的相互作用.结果表明:(1)50、500、5 000 mg·kg-1的乐果在灭菌土中的降解速度十分缓慢,加药后15d,50 mg·kg-1的降解率为69.3%,500 mg·kg-1的降解率为26.7%,5 000 mg·kg-1的降解率为19.6%.在施过乐果的土壤中的降解速度非常迅速,加药后15d,50 mg·kg-1的降解率为99.7%,500 mg·kg-1的降解率为78.4%,5 000 mg·kg-1的降解率为54.6%.在未施过乐果的土壤中的降解速度则介于二者之间.说明微生物在乐果的降解中起着非常重要的作用,同时,施药可以诱发乐果降解菌的生成从而加速乐果的降解.(2)在各处理的土壤中,50 mg·k-1的乐果对细菌数星有一定的刺激作用,500、5 000 mg·kg-1的乐果抑制细菌的生长.且随质量浓度的升高,抑制作用增强.但随加药时间的延长,又有所恢复.3种不同质量浓度的乐果对土壤真菌和放线菌种群数量的影响均表现为明显的抑制作用,且随药剂质量浓度的提高和加药时间的延长抑制趋势越明显.因此,可以选择真菌和放线菌作为土壤受乐果污染的敏感指示菌.(3)在同样处理条件下,施过乐果土壤中的微生物种群数量并不比未施过乐果土壤中的占优势,表明乐果在施过药的土壤中降解速度的加快并不是由微生物的数量决定的,而是由它们的降解能力决定的.     

荧光光纤传感器测定废水中邻硝基苯酚

将２－（４－二苯基）－６－苯基苯并恶唑包埋在增塑的ＰＶＣ膜中,基于邻硝基苯酚对ＰＢＢＯ荧光的猝灭,研制了一种邻硝基苯酚荧光光纤传感器。该传感器对邻硝基苯酚的响应具有良好的可逆性和重现性,响应时间小于５０ｓ,在１．２＊１０＾－４－２．０＊１０－６ｍｏｌ／Ｌ邻硝基苯酚浓度范围内具有好的线性关系。环境水中可能存在的常见阳离子、阴离子、酚、硝基化合物对邻硝基苯酚的测定不产生干扰,将传感器用于废水中的邻硝基     

光电催化氧化处理反渗透浓水

采用光电催化氧化技术对天津市某石化企业反渗透单元浓水进行处理。经光催化、电化学及光电催化氧化处理后浓缩液出水的COD、氨氮及色度去除率进行了对比研究。详细探讨了不同电流密度、反应时间及紫外灯功率对COD、氨氮及色度去除效果的影响。结果表明,在电流密度为2.0 mA/cm2,紫外灯光强度为30μW/cm2的条件下,处理150min后,COD的去除率为92.06%,氨氮浓度从44.61 mg/L下降至2.84 mg/L,色度去除率达到100%。对光电催化氧化法处理不同时间的出水进行了三维荧光光谱及凝胶色谱分析。结果表明,光电催化氧化法可将反渗透浓水中大部分大分子有机物结构破坏,使其分解成小分子有机物。     

生物墙对地下水中六价铬的去除效果模拟研究

通过土柱实验模拟地下水环境,研究以发酵树皮为主要反应介质的渗透性生物墙对地下水中六价铬的去除效果,为六价铬污染地下水的修复提供方法和依据。结果表明,模拟生物墙运行数天后,墙内形成弱碱性(pH 7~8)、强还原(Eh<-100 mV)环境,有利于六价铬转化为三价铬并生成沉淀。在进水六价铬浓度为20 mg/L、水流速度为3.7 cm/d的运行条件下,3周期间生物墙对六价铬的去除率稳定在98%左右,生物墙内沿水流方向三价铬的浓度先上升后下降(最高达6.6 mg/L),出水三价铬约为1.0 mg/L。吸附和微生物转化是生物墙对水中六价铬去除的主要反应。     

微气泡曝气 O3/ H2O2处理 RO 浓水的效能及影响因素简

采用O₃/H₂O₂高级氧化工艺处理炼油厂反渗透（RO）浓水,用溶气泵加压溶气并产生微气泡强化传质,确定装置运行条件,考察气体中臭氧浓度、H₂O₂/O₃初始摩尔比、pH和温度对O₃/H₂O₂处理RO浓水效果的影响,并对RO浓水处理效能进行研究。结果表明,随着气体中臭氧浓度的增加,COD的去除率基本呈线性增加;加入适当量H₂O₂能提高臭氧氧化RO浓水的效果,H₂O₂/O₃初始摩尔比在0~0.8范围内,COD的去除率先增加后下降,H₂O₂/O₃初始摩尔比为0.5时COD去除率最大;pH从6.84增加到9.01,COD去除率逐渐增大,pH为10.03时COD去除率反而降低;在14~28℃范围内,温度低时,升高温度COD去除率增加较大,温度较高时,升高温度对COD去除率的影响较小。为考察该工艺的稳定性,在H₂O₂/O₃初始摩尔比为0.5、溶液pH为8~9、臭氧浓度为80~100 mg/L、温度为10~28℃条件下,对COD为90~140 mg/L的RO浓水氧化处理4~10 h,出水COD维持在39.9~49.9 mg/L,达到《城镇污水处理厂污染物排放标准（GB 18918-2002）》中的一级A标准;去除1 g COD消耗O₃ 1.4~3.3 g,消耗O₃与H₂O₂的总氧量为2.2~4.4 g。     

Practices and opportunities of ecosystem service studies for ecological restoration in China

New approaches have emerged in integrating ecosystem services, their structure and function for ecological restoration. As the concept relating with ecosystem services has become widely accepted in last decade in China, its linking with ecological restoration will provide good opportunities and make substantial progress towards sustainable development. By analyzing the traditional ecological restoration procedure in China, we developed a framework of ecological restoration based on ecosystem services valuation. Relevant researches of ecological restoration based on ecosystem services are also carefully reviewed. China’s ecosystem services studies and payments for ecosystem services (PES) experiences were extensively discussed to show the ecological restoration strategy and its change. Two case studies in China were presented to show the framework for ecological restoration based on PES. We suggested that despite the limitations of valuation uncertainties at present, PES could be an opportunity for ecological restoration by evaluating the trade-offs of different stakeholders. In current state in China, challenges and opportunities coexist and scientists should work together in the integrated research of sustainable ecological management and economic development policies.     

Resource allocation for mitigating regional air pollution–related mortality: A summertime case study for five cities in the United States

An important issue of regional air quality management is to allocate air quality management funds to maximize environmental and human health benefits. In this study, we use an innovative approach to tackle this air quality management issue. We develop an innovative resource allocation model that allows identification of air pollutant emission control strategies that maximize mortality avoidances subject to a resource constraint. We first present the development of the resource allocation model and then a case study to show how the model can be used to identify resource allocation strategies that maximize mortality avoidances for top five Metropolitan Statistical Areas (MSAs) (i.e., New York, Los Angeles, Chicago, Dallas-Fort Worth, and Philadelphia) in the continental United States collectively. Given budget constraints in the U.S. Environmental Protection Agency’s (EPA) Clean Air Act assessment, the results of the case study suggest that controls of sulfur dioxide (SO₂) and primary carbon (PC) emissions from EPA Regions 2, 3, 5, 6, and 9 would have significant health benefits for the five selected cities collectively. Around 30,800 air pollution–related mortalities could be avoided during the selected 2-week summertime episode for the five cities collectively if the budget could be allocated based on the results of the resource allocation model. Although only five U.S. cities during a 2-week episode are considered in the case study, the resource allocation model can be used by decision-makers to plan air pollution mitigation strategies to achieve the most significant health benefits for other seasons and more cities over a region or the continental U.S.Implications: Effective allocations of air quality management resources are challenging and complicated, and it is desired to have a tool that can help decision-makers better allocate the funds to maximize health benefits of air pollution mitigation. An innovative resource allocation model developed in this study can help decision-makers identify the best resource allocation strategies for multiple cities collectively. The results of a case study suggest that controls of primary carbon and sulfur dioxides emissions would achieve the most significant health benefits for five selected cities collectively.     

硫酸亚铁用于污水厂二沉池出水化学除磷

为了获得影响硫酸亚铁化学除磷效果的因素,研究了反应时间,溶液p H值以及碱度对硫酸亚铁化学除磷效果的影响。并研究了不同进水磷酸盐浓度下,硫酸亚铁投加β值与除磷率以及余P的关系,使用MATLAB软件对实验结果进行了模拟,获得了进水含磷量、硫酸亚铁投加β值以及出水余P含量三者之间的关系方程,并通过实验验证了该方程的准确性,该方程可用于指导计算水厂在使用硫酸亚铁化学除磷时的投加量。     

Application of plant carbon source for denitrification by constructed wetland and bioreactor: review of recent development

Water quality standard for nitrate becomes more and more strict, and the plant carbon source is widely used for denitrification by constructed wetland (CW) and bioreactor. However, the nitrate removal efficiency by different types of plant carbon source are not evaluated comprehensively. Denitrification performance of different plant carbon sources, and the influence of dosing method and pretreatment are thoroughly reviewed in this paper, which aims to investigate the accurate utilization of plant carbon source for nitrogen (as nitrate) removal. It is concluded that plant carbon source addition for all types of CWs and bioreactors can improve the nitrate removal efficiency to some extent, and the dosing method of plant carbon source for denitrification should be further studied and optimized in the future. The popular carbon sources for CW and bioreactor denitrification enhancement are woodchip, chopped macrophytes, crop plants, macrophytes litters, etc. The recommended optimum C:N ratios for CW and bioreactor are 4.0:5.0 and 1.8:3.0, respectively. The physical and biological pretreatments are selected to supply organic carbon for long-term denitrification.     

Adsorption of ammonium on biochar prepared from giant reed

Giant reed was used as precursor for making biochar in order for the adsorption of NH₄ ⁺–N from aqueous solution. And the adsorption of the product to NH₄ ⁺–N was examined. The surface features of biochar were investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy/energy dispersive spectrometer (SEM-EDS), and X-ray diffraction (XRD). XRD patterns showed several peaks and correspond to the high amount of crystalline material. The crystals contain KCl, K₂O, CaO, MgO, and SiO and possess high surface area which enhances adsorption. The influence of different parameters such as initial concentration, adsorption time, pH, and ionic strength has been carried out. The adsorption could reach equilibrium through 24 h reaction and had the best adsorption amount at the solution pH values from 7 to 9. The cation has great influence on the adsorption of NH₄ ⁺–N, whereas the anion exerted a weaker effect. The adsorption followed pseudo-first-order and pseudo-second-order models. And the intraparticle diffusion and desorption studies further elucidated that the mechanism of adsorption on the product was ion exchange. The product equilibrium data was well described by the Langmuir and Freundlich model. The maximum adsorption capacities were 1.490 mg/g. Biochar derived from giant reed at 500 °C was suggested as a promising adsorbent for the removal of NH₄ ⁺–N from slightly polluted wastewater.