Soil microbial community structure and function responses to successive planting of Eucalyptus

Many studies have shown soil degradation after the conversion of native forests to exotic Eucalyptus plantations. However, few studies have investigated the long-term impacts of short-rotation forestry practices on soil microorganisms. The impacts of Eucalyptus successive rotations on soil microbial communities were evaluated by comparing phospholipid fatty acid （PLFA） abundances, compositions, and enzyme activities of native Pinus massoniana plantations and adjacent 1st, 2nd, 3rd, 4th generation Eucalyptus plantations. The conversion from P. massoniana to Eucalyptus plantations significantly decreased soil microbial community size and enzyme activities, and increased microbial physiological stress. However, the PLFA abundances formed ＂U＂ shaped quadratic functions with Eucalyptus plantation age. Alternatively, physiological stress biomarkers, the ratios of monounsaturated to saturated fatty acid and Gram＋ to Gram- bacteria, formed ＂∩＂ shaped quadratic functions, and the ratio of cy17：0 to 16： 1ω7c decreased with plantation age. The activities of phenol oxidase, peroxidase, and acid phosphatase increased with Eucalyptus plantation age, while the cellobiobydrolase activity formed ＂U＂ shaped quadratic functions. Soil N：P, alkaline hydrolytic nitrogen, soil organic carbon, and understory cover largely explained the variation in PLFA profiles while soil N：P, alkaline hydrolytic nitrogen, and understory cover explained most of the variability in enzyme activity. In conclusion, soil microbial structure and function under Eucalyptus plantations were strongly impacted by plantation age. Most of the changes could be explained by altered soil resource availability and understory cover associated with successive planting of Eucalyptus. Our results highlight the importance of plantation age for assessing the impacts of plantation conversion as well as the importance of reducing disturbance for plantation management.     

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,     

低氮燃烧+选择性非催化还原烟气脱硝技术(SNCR)在循环流化床锅炉脱硝工程上的应用

采用低氮燃烧+选择性非催化还原烟气脱硝技术对循环流化床锅炉烟气进行脱硝处理.烟气NOx初始浓度为280 mg/Nm3时,排放浓度低于100 mg/Nm3,去除率达65％以上.达到国家《火电厂大气污染物排放标准(GB13223-2011)》限值要求.工艺稳定运行后年处理费用为202.40万元.     

小飞扬草(Euphorbia thymifolia L.)中镉的亚细胞分布及化学形态

采用差速离心法和逐步提取法,分析Cd超积累植物小飞扬草根、茎、叶中Cd的亚细胞分布和化学形态。培养液中Cd浓度5mg/L和10mg/L条件下,在小飞扬草根、茎、叶中,细胞壁和细胞膜是Cd主要的结合场所,含量分别占总量的47.1%～49.0%、39.7%～41.4%、42.9%～56.2%,其次是胞液组分,含量分别占37.5%～41.4%、28.2%～40.7%、35.2%～46.8%,细胞器组分中Cd含量较少。Cd在小飞扬草根、茎、叶中均以氯化钠提取态为主,含量分别占70.5%～84.8%、72.4%～83.0%、50.0%～74.8%。根部各提取态含量依次为CNaCl>CHAC>CEtOH>CHCl>CW>CR,茎、叶中各提取态含量依次为CNaCl>CHCl>CHAC>CEtOH>CW>CR。在小飞扬草中,Cd与细胞壁和细胞膜中的果胶酸和蛋白质等物质结合固定,而进入细胞的Cd大部分与有机酸络合而隔离于液泡内,这可能是小飞扬草忍耐并超积累Cd的机制。     

压缩天然气加气站日常运营环境影响分析——以洛阳市某加气站为例

鉴于压缩天然气(CNG)加气站日常运行对周边环境影响的高风险状态,文章依据洛阳市某CNG加气站生产运营状况,对其运营过程中可能造成的环境影响进行预测、评析,并提出了合理的防范措施。     

活性焦烟气脱硫技术在大型燃煤电站的应用

本文通过分析活性焦烟气脱硫技术的主要原理、工艺流程、主要原料消耗、脱硫副产品综合利用、SO2污染物达标情况,探讨该技术在内蒙古地区大型燃煤电站脱硫工程应用的可行性.     

遥感技术在环境监测中的作用

本文对遥感(3S)技术在环境监测中的应用方法、技术等进行了论述.     

生物炭环境效应和在农业面源污染防治中的作用

生物炭能够延缓肥料养分释放,提高肥料利用率,降低肥料及土壤养分流失,从而减轻农业面源污染。同时,生物炭进入土壤中,实现碳的封存固定,减少碳排放。     

某城市生活垃圾填埋场周边大气环境影响趋势实例研究

针对生活垃圾填埋场的主要恶臭污染物NH3、H2S、臭气浓度,以某城市生活垃圾填埋场为例,采用该填埋场自筹建至今近十年的历史监测数据进行统计分析,给出垃圾填埋场随填埋年龄增长对周边大气环境的影响趋势.     

基于灰色关联理论的民航事故影响因素分析

确定事故各影响因素对事故的影响程度,对提高民用航空安全至关重要。本文根据欧盟联合航空事故和事故征候报告系统分析模型,结合基元事件分析法构建了民航事故影响因素指标体系,并在此基础上依据1991—2010年间世界民航事故信息,运用灰色关联分析方法对其影响因素进行了关联度分析。结果表明:人自身因素对民航事故的影响程度最大,而其中的个人工作管理与人自身因素关系最为密切。最后针对个人工作管理层面提出了相应的改进建议。该研究可为民航安全管理工作提供决策依据。