PICRUSt2 functionally predicts organic compounds degradation and sulfate reduction pathways in an acidogenic bioreactor

• Over 70% reduction of sulfate was achieved for sulfate less than 12000 mg/L. • The decrease of genes encoding (EC: 1.3.8.1) induced the accumulation of VFAs. • The sulfate reduction genes were primary carried by genus Desulfovibrio. • Sulfate favored assimilatory, but inhibited dissimilatory sulfate reduction process. For comprehensive insights into the influences of sulfate on performance, microbial community and metabolic pathways in the acidification phase of a two-phase anaerobic system, a laboratory-scale acidogenic bioreactor was continuously operated to treat wastewater with elevated sulfate concentrations from 2000 to 14000 mg/L. The results showed that the acidogenic bioreactor could achieve sulfate reduction efficiency of greater than 70% for influent sulfate content less than 12000 mg/L. Increased sulfate induced the accumulation of volatile fatty acids (VFAs), especially propionate and butyrate, which was the primary negative effects to system performance under the high-sulfate environment. High-throughput sequencing coupled with PICRUSt2 uncovered that the accumulation of VFAs was triggered by the decreasing of genes encoding short-chain acyl-CoA dehydrogenase (EC: 1.3.8.1), regulating the transformation of propanoyl-CoA to propenoyl-CoA and butanoyl-CoA to crotonyl-CoA of propionate and butyrate oxidation pathways, which made these two process hardly proceed. Besides, genes encoding (EC: 1.3.8.1) were mainly carried by order Clostridiales. Desulfovibrio was the most abundant sulfate-reducing bacteria and identified as the primary host of dissimilatory sulfate reduction functional genes. Functional analysis indicated the dissimilatory sulfate reduction process predominated under a low sulfate environment, but was not favored under the circumstance of high-sulfate. With the increase of sulfate, the assimilatory sulfate reduction process finally overwhelmed dissimilatory as the dominant sulfate reduction pathway in acidogenic bioreactor.     

芳烃石油树脂生产的环境保护

乙烯装置的副产品在综合利用中存在着严重的环境污染问题。中原油田采取了一些措施。用催化剂对生产尾气进行吸收,将有毒的氟化物转化为钙盐用于磷肥生产;将石油树脂聚合液中BF3脱除,防止对大气、水进行污染;用冷却回收工艺对减压蒸馏放空的芳烃气体进行处理。通过上述治理大大改善了企业的环境,有效地防止了环境污染。     

企业安全文化的建设与活动模式

首先论述企业安全文化建设提出的时代背景。接着详细阐述了企业安全文化建设的主要内容，即物态安全文化建设、制度安全文化建设、心态安全文化建设和行为规范安全文化建设，以及企业安全文化的活动模式。     

东海内陆架沉积物中黑碳分布及其与持久性有机污染物的相关性研究

本文采用化学热氧化法测定了25个东海内陆架表层沉积物中黑碳的含量,探讨了沉积物中黑碳与总有机碳、粒度以及持久性有机污染物之间的关系.结果表明,东海内陆架表层沉积物中黑碳的含量范围为0.21～0.88 mg.g-1.沉积物中黑碳和总有机碳之间没有显著的相关性,表明两者具有不同的来源.区域内沉积物在粒度上有明显的空间分异,黑碳的空间差异则较小,表明黑碳的沉积过程受颗粒物分选过程的影响较小.沉积物中多环芳烃和滴滴涕的含量与黑碳无显著的相关性,可能与东海内陆架环境中强烈的水动力过程和持久性有机污染物来源的复杂性有关.     

北京城区冬季空气污染时期C2~C6碳氢化合物含量特征

本研究于2015年冬季,在北京市东南城区开展了C2~C6碳氢化合物大气环境浓度在线监测,研究共检出25种C2~C6碳氢化合物,但鉴于分析仪器的局限性,未包含苯这一重要物种.检出的25种碳氢化合物含量之和(C2~C6 HCs)在12.4~297.5×10~(-9)范围内,不同的空气质量条件下,C2~C6 HCs平均含量分别为29.4×10~(-9)(Ⅰ级,PM_(2.5):35μg·m~(-3))、63.2×10~(-9)(Ⅱ级,PM_(2.5):35~75μg·m~(-3))、85.5×10~(-9)(Ⅲ级,PM_(2.5):75~150μg·m~(-3))、94.9×10~(-9)(Ⅳ级,PM_(2.5):150~250μg·m~(-3))、131.8×10~(-9)(Ⅴ级,PM_(2.5):250μg·m~(-3)),且碳氢化合物的化学组成亦有所差异,烷烃、烯烃、乙炔的摩尔比分别从Ⅰ级条件的47%、45%、7%,变为Ⅴ级条件的59%、30%、12%,烷烃和乙炔的比重上升;烯烃的比重下降.碳氢化合物日变化规律显示,C2~C6 HCs在优良日(PM_(2.5)小时浓度均低于75μg·m~(-3))和污染日(PM_(2.5)小时浓度均高于75μg·m~(-3)),均在08:00~09:00、17:00~18:00存在两个明显的峰值,与日交通峰值时间一致,显示了道路源对局地碳氢化合物浓度的显著影响.通过HCs与CO浓度比值研究,发现随着污染情况的加重,HCs/CO(×10~(-9)/×10~(-6))呈显著下降趋势:90.6(Ⅰ级)、63.8(Ⅱ级)、56.9(Ⅲ级)、37.4(Ⅳ级)、36.4(Ⅴ级).具体化合物与CO比值在污染条件(Ⅲ~Ⅴ)与优良条件(Ⅰ~Ⅱ)的变化率,与各化合物的OH反应速率关联性很差(R=-0.31),由此判断污染时期C2~C6碳氢化合物并未发生强烈的化学衰减.HCs/CO比值变化更多反映了污染源贡献的变化,后向轨迹分析表明,在优良日北京城区多受北部和西北部清洁气团影响,北部地区燃烧源较少,其气团HCs/CO比值较高;而在污染日北京城区受南部和西南部污染气团输送,南部地区工业燃烧源和散煤燃烧源均偏多,其气团HCs/CO值偏低.综上所述,本研究认为重污染过程,北京城区C2~C6碳氢化合物(未包含苯)未体现出显著的化学衰减,碳氢化合物浓度的大幅提升,不仅源于本地污染源的排放累积,还受到南部污染气团的输送贡献.     

公路交通事故黑点分析系统的设计

在公路交通事故黑点分析系统需求分析的基础上,设计了公路交通事故黑点分析系统的总体结构、数据库和算法库,提出系统流程及各个模块的功能。数据库设计给出事故黑点分析系统的E-R图与逻辑结构;算法库设计重点实现对应分析法,提出运用对应分析法进行事故黑点成因分析的原理和步骤;应用面向对象的系统开发技术研发应用软件,通过事故黑点信息查询窗口、事故黑点判定窗口和事故黑点成因分析结果图的实现,论证了应用软件进行公路事故黑点成因分析的可行性和实用性。     

Sn(Ⅳ)掺杂纳米TiO2/AC降解橙黄G的动力学与机理研究

采用溶胶凝胶法制备了掺杂Sn(Ⅳ)的TiO2/AC光催化剂,以生物染料橙黄G为目标降解物,研究了多相光催化降解橙黄G的动力学规律.研究表明,该反应符合Langmuir-Hinshelwood动力学方程,速控步为吸附反应.同时,利用GC/MS联用仪探讨了橙黄的中间产物及其降解机理:橙黄G在强氧化性自由基·OH、·OOH、·O2-的作用下逐渐分解氧化为小分子有机醛、酮、酸,最后转化为CO2、NH4 、NO3-、NO2-、SO42-和H2O等无机小分子.     

Study of Thermal Decomposition Kinetics of Palm Oleic Acid-Based Alkyds and Effect of Oil Length on Thermal Stability

Thermal decomposition kinetics of three palm oleic acid-based alkyds with different oil lengths and having different molecular weights were studied using TGA measurements under non-isothermal conditions. Activation energies were obtained from Kissinger and Ozawa, Flynn and Wall (OFW) methods and subsequently the pre-exponential factor, A, degradation rate constant, k, for all the alkyds were also determined. From kinetic analysis of the thermal decomposition using the OFW method, it was found that degradation of all the alkyds has taken place in more than two stages, corresponding to different mechanisms. As shown from Ozawa and Kissinger methods, the chemical composition of the alkyds influenced the thermal degradation; increasing the phthalic anhydride and glycerol, and decreasing the oleic acid increased the thermal stabilities of the alkyds.     

A Review of Public Domain Water Quality Models for Simulating Dissolved Oxygen in Rivers and Streams

The review discusses six major public domain water quality models currently available for rivers and streams. These major models, which differ greatly in terms of processes they represent, data inputs requirements, assumptions, modeling capability, their strengths and weaknesses, could yield useful results if appropriately selected for the desired purposes. The public domain models, which are most suitable for simulating dissolved oxygen along rivers and streams, chosen in this review are simulation catchment (SIMCAT), temporal overall model for catchments (TOMCAT), QUAL2Kw, QUAL2EU, water quality analysis simulation program (WASP7), and quality simulation along rivers (QUASAR). Each of these models is described based on a consistent set of criteria-conceptualization, processes, input data, model capability, limitations, model strengths, and its application. The results revealed that SIMCAT and TOMCAT are over-simplistic but useful to quickly assess impact of point sources. The QUAL2Kw has provision for conversion of algal death to carbonaceous biochemical oxygen demand (CBOD) and thus more appropriate than QUAL2EU, where macrophytes play an important interaction. The extensive requirement of data in WASP7 and QUASAR is difficult to justify the time and costs required to set up these complex models. Thus, a single model could not serve all wide range of functionalities required. The choice of a model depends upon availability of time, financial cost and a specific application. This review may help to choose appropriate model for a particular water quality problem.