农田土壤重金属污染状况及修复技术研究

重金属污染因具有毒性、易通过食物链在植物,动物和人体内累积,对生态环境和人体健康构成严重威胁。随着工业快速发展、农药及化肥的广泛使用,农田土壤重金属污染越来越严重,研究农田土壤重金属污染现状及修复技术对农产品安全具有重要意义。综合国内外农田土壤重金属污染状况,农田土壤重金属污染主要来源于固体废弃物堆放及处置、工业废物大气沉降、污水农灌和农用物质的不合理施用。该文综述了国内外有关农田重金属污染土壤修复技术（物理修复、化学修复、生物修复、农业生态和联合修复）的研究进展,并针对各种修复方法,阐述了其原理、修复条件、应用实例及其优缺点,重点论述了植物修复的机理和应用,提出了草本与木本联合修复可有效提高农田土壤重金属复合污染的修复效率,为农田土壤土壤重金属复合污染修复提出了新的途径。最后在对已有研究分析的基础上,提出了联合修复技术（如生物联合技术、物理化学联合技术和物理化学-生物联合技术）可以在一定程度上克服使用单一修复手段存在的缺点,可提高复合污染的修复效率、降低修复成本,未来应深入探索联合修复技术间的相互作用机理,以期为农田土壤重金属综合治理与污染修复提供科学依据。     

污染场地河道底泥浸出液对斑马鱼胚胎的毒性效应

为了评价某污染场地河道底泥对水生生物的毒性效应及其潜在生态风险,以斑马鱼(Brachydanio rerio)为受试生物,进行了河道底泥浸出液对斑马鱼胚胎的发育毒性实验。结果表明,5种底泥浸出液(A1、A2、A3、A4、A5)对斑马鱼胚胎的发育均有毒性效应,浸出液对斑马鱼胚胎的死亡率存在一定的剂量-效应关系,随着浸出液体积分数的增加,死亡率显著上升。浸出液对胚胎孵化抑制作用明显,随着浸出液体积分数的增加,孵化率显著下降。且能引起斑马鱼胚胎多种中毒症状,如水肿,鱼体弯曲,发育不全等异常现象,表明该段河道底泥存在潜在的生态风险。因此,在后期的污染场地河道整治中,需对河道底泥进行挖掘清理和无害化处理。     

Effects of riparian land use on water quality and fish communities in the headwater stream of the Taizi River in China

Riparian land use remains one of the most significant impacts on stream ecosystems. This study focuses on the relationship between stream ecosystems and riparian land use in headwater regions. Four riparian land types including forest, grassland, farmland, and residential land were examined to reveal the correlation between stream water and fish communities in headwater streams of the Taizi River in north-eastern China. Four land types along riparian of 3 km in length were evaluated at 25, 50, 100, 200 and 500 m widths, respectively. Generally, the results found a significant relationship between riparian land uses and stream water quality. Grassland was positively correlated with water quality parameters (conductivity and total dissolved solids) at scales from 100 to 500 m riparian width. Farmland and residential land was negatively correlated with water quality parameters at scales from 25 to 500 m and from 50 to 200 m riparian widths, respectively. Although the riparian forest is important for maintaining habitat diversity and fish communities, the results found that only fish communities were significantly correlated with the proportion of riparian farmland. Farmland had a positive correlation with individual fish abundance within a riparian corridor of 25 to 50 m, but a negative correlation with fish diversity metrics from 25 to 100 m. This study indicates that effective riparian management can improve water quality and fish communities in headwater streams.     

污泥发酵产物应用于草坪基质的伴生杂草辨识与溯源

通过在工程化草坪生产基地设置污泥发酵产物施川处理,对在草坪应用的杂草问题进行了深入分析。结果表明．污泥发酵物料的掺人增加伴生杂草总量2．92～6．67倍。主要伴生杂草种类为牛筋草（Eleusine indica（Linn）Gaertn）,与对照相比,污泥发酵物处理的牛筋草密度增加O．84～1．67倍;种籽主要来自于污泥物料。适当增加施用深度和预喷施除草刹可昆著降低伴生杂草密度约50％。     

Optimization of process parameters for mature landfill leachate pretreatment using MAP precipitation

Chemical precipitation is a useful technology as a pretreatment to treat mature landfill leachate with high concentrations of ammonium-nitrogen (NH4+-N) and refractory organic compounds. Orthogonal experiments and factorial experiments were carried out to determine the optimal conditions enhancing the magnesium ammonium phosphate (MAP) precipitation process, and the experimental results demonstrated that the removal rate of NH4+-N was more than 85% when MgO and NaH₂PO₄·2H₂O were applied as external sources of magnesium and phosphorous under the optimal conditions that molar ratio n(Mg)∶n(N)∶n(P) = 1.4∶1∶0.8, reaction time 60 min, original pH of leachate and settling time 30 min. In the precipitation process, pH could be maintained at the optimal range of 8–9.5 because MgO could release hydroxide ions to consume hydrogen ions. Calcium ions and carbonate ions existed in the leachate could affect the precipitation process, which resulted in the decrease of NH4+-N removal efficiency. The residues of MAP sediments decomposed by heating under alkaline conditions can be reused as the sources of phosphorous and magnesium for the removal of high concentrations of NH4+-N, and up to 90% of ammonium could be released under molar ratio of n[OH]∶n[MAP] = 2.5∶1, heating temperature 90°C and heating time 2h.     

皮革废水对ABR分区进水微生物相的影响研究

在制革废水ρ(COD)=3 000～3 200 mg/L,HRT=24 h时,采用六格室厌氧折流板反应器(ABR),在1、3、5格室以5∶3∶2的比例进水,通过COD、挥发性脂肪酸(VFA)、辅酶F420等指标的变化研究反应器各格室的微生物相分布情况。结果表明:COD和VFA在3,5格室分别出现下降和升高,整体性能稳定,而格室内微生物种群大致相同但优势菌群有所差异,前端格室以产酸菌为主,后端格室以甲烷菌为主。     

水体沉积物中石油类物质释放过程动力学研究

模拟水体沉积物中石油类物质向水相中释放的动力学过程,探讨在不同石油污染强度下,石油物质在水相中饱和浓度的变化。研究结果表明:上述过程可以用滞膜模型进行描述,释放过程为典型的一级动力学过程,沉积物中石油含量与水相中石油的释放浓度呈正向关系,在相同的释放条件下,污染强度越高,水相中石油的饱和浓度越高,释放速度也越快。     

Study on tri-axial creep experiment and constitutive relation of different rock salt

To evaluate the effect of the long-term operation of a salt cavern in a given construction on rock deformation and its stability, tri-axial creep tests to the glauberite, anhydrite, and argillaceous rock salt are conducted, from which the creep curves as well as exponential functions of strain rate during the steady creep stage and creep constitutive equations of different rock salt in the experimental process derived are obtained. The study results show that: (i) Under the same deviatoric stress, the strain rate of argillaceous rock salt is lower than the glauberite and anhydrite, and the difference becomes larger with the increase of the deviatoric stress; (ii) The creep constitutive equations of different kinds of rock salt are in good agreement with the Burgers model, besides which the respective characteristics of these two creep models are compared. The change of creep parameters also illustrates the discrepancy of rock salt. The researching results can provide some references for long-term stability analysis of gas storage in salt caverns.     

3GY型粉体无尘装车机的开发与应用

应用自主知识产权,采用“密闭输送、最小落差、零匝输送、软连接和科学运行管理”技术,科学组合,研究开发成功粉体无尘装车机,科学消除了高温,高压、高料位条件下贮仓放料,常规除尘器出灰和粉体转输与装车的粉尘污染与资源流失。     

液化石油气站安全检查表的编制

1安全检查表的含义 安全检查表(Safety CheckList)是为系统地发现人-机-环境系统中的不安全因素而事先拟好的问题清单.它根据系统工程分解和综合的原理,事先把检查对象加以剖析,把大系统分割成若干个子系统,然后确定检查项目,查出不安全因素所在,以正面提问的方式,将检查项目按系统或子系统的顺序编制成表,以便进行检查和避免漏检查,这种表就叫安全检查表.安全检查表依据不同目的和不同对象,可编制多种类型.液化石油气站安全检查表便是其中之一.