水溶液中臭氧和溴离子的反应研究

为探明O3氧化Br-的反应机制,采用离子色谱、PDA紫外-可见光度仪研究了水中Br-被O3氧化的反应过程.离子色谱分析表明,被氧化的Br-中只有约10%被O3氧化成BrO3-.进一步研究表明,除了生成BrO3-外,Br-被O3氧化过程中还产生了Br2,Br2又与溶液中存在的Br-结合形成Br3-,并首次得到了Br3-的吸收光谱,测得Br3-的最大吸收峰λmax为260 nm,提出了Br-与O3的基元反应.该研究补充和完善了O3氧化Br-的反应机制,也为O3处理含Br-水时Br-的归趋提供了有益信息.     

间歇性饥饿对厌氧氨氧化菌混培物保藏特性的影响

厌氧条件下,采用4℃、4℃并每隔10 d换1次NO-2-N/NH+4-N浓度比为1.32的基质、4℃并每隔10 d换1次NO-2-N/NH+4-N浓度比为1.63的基质3种方法保藏厌氧氨氧化菌混培物,研究间歇性饥饿对厌氧氨氧化菌混培物保藏特性的影响.结果表明,间歇性饥饿对厌氧氨氧化菌混培物的危害大于长期性饥饿,且亚硝态氮浓度越高危害越大;另厌氧氨氧化菌混培物活性还与血红素c含量有直接相关性,无外界颜色干扰时厌氧氨氧化菌混培物颜色还可直观反映其活性和血红素c含量,且厌氧氨氧化菌混培物的颗粒结构及其富含的胞外多聚物能增强其抵抗外界不利因素的能力.在试验的5个月内,3种方法下的活性衰减速率均先快后趋于稳定,趋于稳定时的三者活性保留率分别为75.3％、70.8％、62.7％.     

麦草及其烟尘中正构烷烃的组成

在明火和闷烧条件下对6种麦草进行焚烧试验,用GC/MS测定了秸秆和烟尘中正构烷烃的组成.结果表明,从麦秆和烟尘中检出的正构烷烃主要是C16~C33.麦秸中正构烷烃的总含量变化范围是19.6~62.3 mg·kg-1,平均值为36.0mg·kg-1.低碳数(碳数相似文献   

密云水库底泥和库滨区土壤中氨氧化细菌的多样性和丰度

采用分子生物学方法（T-RFLP、定量PCR）研究了密云水库底泥沉积物和库滨带土壤中氨氧化细菌（AOB）的多样性和丰度特征,并使用Canoco for Windows 4.5软件和皮尔森相关系数法,探究了环境因子对AOB群落的影响.结果表明,沉积物和库滨区土壤中AOB的多样性和数量都存在较大的差异.其中,AOB群落被聚成两大类：沉积物与土壤.沉积物样品中AOB群落结构与其它样品差异较大.沉积物中AOB的多样指数最低,而在农田土壤中AOB多样性指数最高.农田土壤中的amoA基因拷贝数最大,是底泥沉积物中的48倍.此外,RDA（Redundancy Analysis）分析表明,在沉积物和水陆交错带土壤中,AOB的优势种与NH₄⁺-N、NO₃^--N、TOC、pH成正相关关系,而在陆相土壤和农田土壤中,AOB的优势种与这些环境因子成负相关关系.其中,TOC是影响AOB的群落结构的关键理化因子.     

中国农业污染成因及转向路径选择

在水土资源严重短缺条件下,中国数千年的传统农业应对资源紧约束而形成的"村社治理+家庭经营",本来一直具有"两型农业"和食物安全的"双重正外部性"。而改为以发展主义现代化为目标以来,则直接造成资本深化的农业"双重负外部性";农业既要向城市工业提供原始积累,又要承担工业品(化肥农药除草剂等)     

基于臭氧溶胞的活性污泥减量化技术

目前常见的活性污泥减量技术主要包括解偶联技术、微生物的捕食作用以及隐性生长三种方法。基于臭氧氧化溶胞作用从而强化细菌隐性生长的污泥减量技术具有较好的处理效果及良好的应用前景。着重探讨了臭氧溶胞作用的机理及溶胞过程的影响因素。考虑到污泥减量技术在实际污水处理系统中的应用,探讨了臭氧溶胞对污水生物处理系统的影响。     

三槽氧化沟内底推位置与积泥厚度的分析研究

氧化沟工艺由于进水中含有大量的无机颗粒,无机颗粒的沉淀导致沟内积泥较厚。为了不影响正常生产,依据经验数据,依次对1号、2号氧化沟安装底推。对沟内积泥情况及影响因素进行分析比较,得出氧化沟的积泥主要由进水中密度较大的无机颗粒造成,且积泥规律与底推安装位置和运行情况相关。     

Effects of physical and chemical characteristics of surface sediments in the formation of shallow lake algae-induced black bloom

Surface sediments are closely related to lake black blooms. The dissolved oxygen （DO） distribution and its penetration depth in surface sediments as well as the migration and transformation of redox sensitive elements such as Fe and S at the sediment-water interface are important factors that could influence the formation of the black bloom. In this study, dredged and undredged sediment cores with different surface properties were used to simulate black blooms in the laboratory. The Micro Profiling System was employed to explore features of the DO and ∑H2S distribution at the sediment-water interface. Physical and chemical characteristics in sediments and pore waters were also analyzed. The results showed that sediment dredging effectively suppressed the black blooms. In the undredged treatment, DO penetration depth was only 50 μm. Fe^2＋ concentrations, ∑H2S concentrations, and ∑H2S production rates were remarkably higher in surface sediments and pore waters compared to control and dredged treatments. Furthermore, depletion of DO and accumulation of Fe^2＋ and ∑H2S in surface sediments and pore waters provided favorable redox environments and necessary material sources for the blooms. The study results proved that physical and chemical characteristics in surface sediments are important factors in the formation of the black bloom, and could provide scientific guidance for emergency treatment and long-term pre-control of black blooms.     

Electrochemical and spectroscopic characteristics of dissolved organic matter in a forest soil profile

Dissolved organic matter （DOM） represents one of the most mobile and reactive organic compounds in ecosystem and plays an important role in the fate and transport of soil organic pollutants, nutrient cycling and more importantly global climate change. Electrochemical methods were first employed to evaluate DOM redox properties, and spectroscopic approaches were utilized to obtain information concerning its composition and structure. DOM was extracted from a forest soil profile with five horizons. Differential pulse voltammetry indicated that there were more redox-active moieties in the DOM from upper horizons than in that from lower horizons. Cyclic voltammetry further showed that these moieties were reversible in electron transfer. Chronoamperometry was employed to quantify the electron transfer capacity of DOM, including electron acceptor capacity and electron donor capacity, both of which decreased sharply with increasing depth. FT-IR, UV-Vis and fluorescence spectra results suggested that DOM from the upper horizons was enriched with aromatic and humic structures while that from the lower horizons was rich in aliphatic carbon, which supported the findings obtained by electrochemical approaches. Electrochemical approaches combined with spectroscopic methods were applied to evaluate the characteristics of DOM extracted along a forest soil profile. The electrochemical properties of DOM, which can be rapidly and simply obtained, provide insight into the migration and transformation of DOM along a soil profile and will aid in better understanding of the biogeochemical role of DOM in natural environments.     

Waste oyster shell as a kind of active filler to treat the combined wastewater at an estuary

Estuaries have been described as one of the most difficult environments on Earth. It is difficult to know how to treat the combined wastewater in tidal rivers at the estuary, where the situation is very different from ordinary fresh water rivers. Waste oyster shell was used as the active filler in this study in a bio-contact oxidation tank to treat the combined wastewater at the Fengtang Tidal River. With a middle-experimental scale of 360 ma/day, the average removal efficiency of COD, BOD, NH3-N, TP and TSS was 80.05%, 85.02%, 86.59%, 50.58% and 85.32%, respectively, in this bio-contact oxidation process. The living microbes in the biofilms on the waste oyster shell in this bio-contact oxidation tank, which were mainly composed of zoogloea, protozoa and micro-metazoa species, revealed that waste oyster shell as the filler was suitable material for combined wastewater degradation. This treatment method using waste oyster shell as active filler was then applied in a mangrove demonstration area for water quality improvement near the experiment area, with a treatment volume of 5 × 10^3 m^3/day. Another project was also successfully applied in a constructed wetland, with a wastewater treatment volume of 1 ×10^3 m^3/day. This technology is therefore feasible and can easily be applied on a larger scale,