Agricultural recycling of treatment-plant sludge: a case study for a vegetable-processing factory

The present study evaluated the possibility of using the sludge produced by a vegetable-processing factory in agriculture. The sludge was amended with a soil mixture (i.e., a mixture of sand, soil, and manure) and was applied at 0, 165, 330, 495 and 660 t/ha to promote the growth of cucumbers. The effects of various sludge loadings on plant growth were assessed by counting plants and leaves, measuring stem lengths, and weighing the green parts and roots of the plants. We also compared heavy metal uptake by the plants for sludge loadings of 330, 495, and 660 t/ha with various recommended standards for vegetables. Our results showed that plant growth patterns were influenced to some extent by the sludge loadings. In general, the number of leaves, stem length, and dry weight of green parts exhibited a pronounced positive growth response compared with an unfertilized control, and root growth showed a lesser but still significant response at sludge loadings of 165 and 330 t/ha. The sludge application caused no significant increase in heavy metal concentrations in the leaves, though zinc (Zn) and iron (Fe) were found at elevated concentrations. However, despite the Zn and Fe accumulation, we observed no toxicity symptoms in the plants. This may be a result of cucumber's tolerance of high metal levels.     

Comparative Assessment of the Level of Plant Cover Synanthropization in Specially Protected Areas

Tendencies in plant cover synanthropization depending on the pattern and intensity of anthropogenic impacts on natural complexes have been revealed in specially protected areas of different classes (a nature reserve and a nature park).     

Studies of Thermal Transformations of Humic and Fulvic Acids in Soils I. Infrared Spectroscopy and Temperature-Programmed Pyrolysis Mass Spectrometry

Temperature-programmed pyrolysis mass spectrometry and Fourier-transform infrared spectroscopy have been used to monitor structural changes of humic and fulvic acids isolated from soils in China, in the temperature range of 25-550°C. in this work, we found that decarboxylation is obvious as the main reaction with dehydration reaction from 150°C to 400°C, the anhydride can be identified from FT-IR spectra at temperature range from 200°C to 400°C; there are evident changes of the aromatic nucleus of humic and fulvic acids above 400°C, even remaining up to 550°C. Besides, some changes of adsorption water can be distinguished before 200°C, and the mass signal of sulphur dioxide was detected.     

基于线性变换的水质综合评价方法

对于多个因子的水质综合评价存在很多不同方法,尚未形成公认的权威评价方法。因而,对水质综合评价方法进行探索有利于积累研究经验,丰富方法手段。在把数据向[0 1]区间标准化的基础上,通过线性空间变换,把水质样本数据与《地表水环境质量标准》(GB3838-2002)数据转换到同一线性空间。计算水质样本数据向量与5类水质划分等级标准数据向量的欧式距离,把欧式距离的最小值作为水质类别辨别的依据,最终得到水质的综合评价结果。借由已经公开发表的19个断面水质监测数据,运用大型工程计算软件Matlab 2010b进行计算,并与变权欧式距离模型、灰色聚类法、模糊综合指数法和BP神经网络法的评价结果相比较,符合性较好,验证了线性空间变换法应用于水质综合评价的科学性和合理性。方法可用于水质综合评价。在不对污染因子进行加权的情况下,基于线性变换的水质综合评价方法,获得的评价结果较轻。对于被评价为同一类水质的不同监测断面,可以借助"评价单元与5级水质标准的欧式距离矩阵",对评价单元水质差异进一步辨识。     

地下水对放射性废物地质处置库的影响

放射性废物处置库是一个受多种因素耦合作用的复杂系统。在多种因素中,地质环境中的水对废物处置库有着至关重要的作用。着重分析阐述了地下水的辐射分解作用以及水中核素迁移这2方面对地质处置库造成的影响。地下水是将核素带入生物圈的载体,能够引起核素迁移;另一方面,地质处置库所形成的强放射场能促进周围的地下水辐射分解,加速工程屏障氧化侵蚀。指出了我国目前有关放射性废物处置系统的设计方案中应该注意的一些问题以及针对这些问题应该采取的措施。     

异化铁还原对土壤中重金属形态转化及其有效性影响

铁的微生物还原是以Fe(Ⅲ)为末端电子受体在厌氧条件下氧化有机物的产能过程,在生物地球化学循环中起着重要的作用.铁呼吸被认为是地球上最古老的微生物代谢形式,与水体、土壤及沉积物中物质循环息息相关.铁的微生物还原对土壤中重金属形态转化有显著影响,对修复重金属及放射性核素污染的场地有着重要意义.本文综合评述了近年来铁微生物还原研究进展,从生态安全和可持续发展角度,探讨了异化铁还原对重金属的形态改变及重金属污染土壤修复的潜在价值,并对其应用前景进行客观分析.异化铁还原对重金属形态转化的影响机制,可初步归纳为异化铁还原对重金属的氧化还原作用、对重金属的甲基化作用、对重金属的固定作用,其作用机制包含生物过程和化学作用的相互穿插,值得进一步深入研究.     

Fe3+对同步硝化反硝化过程氮元素迁移转化及N2O释放的影响

采用SBR反应器,研究了不同浓度的Fe3+对同步硝化反硝化(simultaneous nitrification denitrification,SND)过程中氮元素迁移转化去除和N2O释放的影响.结果表明,在同步硝化反硝化过程中,系统中Fe3+浓度为20 mg·L-1时可以提高系统对氮的去除率,而60 mg·L-1的Fe3+则会对其产生抑制效果.并且,高浓度的Fe3+会刺激SND过程中N2O的释放,N2O转化率也有所提高.这主要是因为:1高浓度的Fe3+会导致污泥脱氢酶活性降低,使得NO-2在好氧阶段大量累积;2高浓度的Fe3+减少了SND过程前置厌氧阶段胞内聚合物(polyhydroxybutyrate,PHB)的含量,使得后续反硝化过程碳源减少.Fe3+对SND过程中总磷的去除有促进作用,并且Fe3+浓度越高,总磷去除率越高,这主要是因为Fe3+的存在使系统中发生了化学除磷作用.     

某塑料公司生产车间除尘系统改造与实践研究

针对重庆某塑料公司车间生产工艺、现场条件及粉尘污染现状,对其生产线进行除尘系统改造。改造后的除尘系统在充分考虑车间尘源点的变动情况,通风阻力和风量要求的基础上重新设计,实施后关键工位总粉尘平均浓度为2．6mg／m。,除尘效果显著。     

La/Ce-codoped Bi2O3 composite photocatalysts with high photocatalytic performance in removal of high concentration dye

A series of La/Ce-codoped Bi_2O_3 composite photocatalysts were fabricated via hydrothermal–calcination process. The as-prepared products were intensively characterized by some physicochemical characterizations like N_2 physical adsorption, X-ray powder diffraction(XRD), scanning electron microscope(SEM), transmission electron microscope(TEM), UV–Vis diffuse reflectance(UV–Vis DRS), Fourier transform infrared spectroscopy(FT-IR),photoelectrochemical measurements, and photoluminescence(PL) spectroscopy. The characterization results indicated that La and Ce doping induced obvious crystal phase transformation in Bi_2O_3, from monoclinic to tetragonal phase. La and Ce codoping also gave rise to the obvious synergetic effects, e.g., the lattice contraction of Bi_2O_3, the decrease of crystal size and the increase of surface area. The photocatalytic performance of the prepared catalysts was evaluated by removal of dye acid orange II with high concentration under visible light irradiation. Results showed that La/Ce-codoped Bi_2O_3 displayed much higher photocatalytic performance than that of bare Bi_2O_3, single La or Ce doped Bi_2O_3 samples. The superior photocatalytic activity was mainly attributed to the improved texture and surface properties and the synergistic effects of La and Ce codoping on suppressing the recombination of photo-generated electrons(e~-) and holes(h~+).     

地级市环评审批制度创新研究

自党的十八大以来,简政放权和职能转变已成为中国政府当下的行政理念,全面贯穿中国政府的施政过程,优化和完善环评审批制度的改革创新以顺应国内行政理念显得尤为必要.基于国内各地现有环评审批创新改革实践,以国内自贸示范区横琴新区为例,结合横琴新区发展实际情况,审视横琴新区现有环评审批制度存在的问题,分别从审批、监管和服务三个层面上提出了横琴新区环评审批制度的创新策略,为相关地区的环评审批创新改革提供借鉴.