HACCP原理在某醋酸装置职业病防控中的应用

目的运用危害分析与关键控制点原理对某新建醋酸装置进行职业病危害控制效果评价,探讨HACCP原理应用于建设项目职业病危害控制效果评价的科学性和实用性。方法通过对某醋酸装置的工程分析和职业卫生调查,识别各种职业病危害因素;并依据职业病危害因素检测和健康检查结果,分析其危害程度。运用HACCP原理,找出职业病危害控制的关键控制点,提出预防控制技术,并验证其效果。结果检测结果显示醋酸充装站、醋酸泵、醋酸精馏塔采样口醋酸浓度超标,醋酸外操岗位8h等效连续A声级超过85dB(A)。结论 HACCP可以运用到化工企业职业病危害防控中,为预防、控制和监督工业企业职业病危害提供科学依据。     

下辽河平原旱田氮对地下水污染贡献研究

以下辽河平原旱田土壤为研究对象,通过对土壤中铵态氮的吸附动力学过程进行定量分析,预测铵态氮流失及其对地下水环境的潜在影响。结果表明:粒径<0.001mm粘粒含量、pH值、有机质含量与铵态氮的平衡吸附量呈正相关,大民屯地区铵态氮对地下水造成污染的潜力最大。     

醋酸铅对大鼠胰岛瘤细胞INS-1自噬与凋亡的影响

为了研究环境中常见重金属污染物铅对大鼠胰岛瘤细胞INS-1自噬与凋亡的影响及其可能的分子机制,使用不同浓度醋酸铅暴露大鼠胰岛瘤细胞INS-1,利用磺酰罗丹明B(sulforhodamine B,SRB)法检测细胞存活率;Western blot法检测不同浓度醋酸铅对细胞中自噬与凋亡标志蛋白及哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路标志分子表达的影响;利用活性氧(reactive oxygen species,ROS)试剂盒检测细胞内ROS水平;用ROS清除剂N-乙酰-L-半胱氨酸(N-acetylcysteine,NAC)预处理细胞,检测醋酸铅引起的细胞自噬与凋亡是否受到影响。使用统计学软件SPSS 17.0对数据进行统计学分析后,与对照组相比,醋酸铅导致INS-1细胞的存活率下降(p0.05),且呈时间-剂量依赖性;随醋酸铅浓度增大,自噬和凋亡标志蛋白表达增加,mTOR信号途径标志分子没有明显变化;NAC预处理后醋酸铅引起的细胞自噬和凋亡减少。实验结果表明,醋酸铅可通过mTOR-非依赖途径诱导INS-1细胞的自噬与凋亡,其可能机制为刺激细胞内ROS的产生。     

硫酸盐还原菌促进市政污泥厌氧发酵产乙酸

添加各浓度钼酸盐考察不同抑制水平下硫酸盐还原菌(SRB)对市政污泥发酵产酸的作用. 结果表明:在有硫酸盐存在时,未抑制SRB体系中ρ(乙酸)占ρ(总VFAs)的比例可达83%,无丙酸、丁酸积累;而在SRB高抑制水平体系中,ρ(乙酸)只占约40%. 随后以未添加硫酸盐体系为对照,研究了硫酸盐投加方式及在发酵中后期抑制SRB对产物中挥发性脂肪酸(VFAs)成分及其浓度的影响;同时,通过对dsrA酶的编码基因含量定量分析发现,随着硫酸盐的加入,SRB数量速增,产物中丙酸、丁酸先后转化为乙酸,且ρ(乙酸)占ρ(总VFAs)的比例可达90%以上. 添加SRB可作为实现污泥发酵定向累积乙酸的调控手段.      

Continuous nitrifying granular sludge bioreactor: Influence of aeration and ammonium loading rate

Granulation of nitrifying bacteria was investigated in a continuous bubble column bioreactor. Then, the combined effect of aeration and ammonium loading rates on dissolved oxygen (DO) concentration as well as nitrification process was evaluated in the system using an experimental design technique. After 120 days, stable nitrifying granules with average diameter of 1.4 mm and settling velocities of 55 m/h were obtained. The influence of increasing ammonium loading rate (ALR) was found to be more significant than decreasing aeration rate on the reduction of DO concentration inside the nitrifying bioreactor. The system could handle the ALR values of 0.48–1.92 gNH₄⁺-N/L d with the ammonium removal efficiency from 65% to nearly 100% at the tested airflow rates of 2.5 and 4.5 L/min. At the low aeration, the complete ammonium conversion to nitrate was replaced with nitrite when the ALR increased to 1.44 gNH₄⁺-N/L d. At the high aeration, however, almost complete nitrification was achieved except the high ALR in which the nitrite accumulation was observed up to 38%. The study demonstrated that the continuous bioreactor had a considerable performance for obtaining stable nitrifying granules to have nitrite accumulation under control with changing the ratio of aeration rate and ALR.     

富磷污泥厌氧发酵过程中乙酸浓度对磷释放的影响

以强化生物除磷(EBPR)污泥为研究对象,考察了不同初始乙酸浓度条件下富磷污泥厌氧发酵过程中磷及相关指标的变化,并探讨释磷机制.结果表明:初始乙酸浓度对污泥最大释磷量影响不大,(73.1±2.2)%的污泥总磷量(TP)以磷酸盐的形式释放到液相中,其主要来自聚磷的分解.聚磷的分解途径包括:1)聚磷菌(PAOs)通过吸收乙酸贮存聚β-羟基烷酸酯(PHA)的厌氧生物释磷机制释放磷酸盐;2)PAOs的维持作用导致的聚磷直接分解过程.当初始乙酸浓度不充足时,生物释磷过程受限制,聚磷以相对较慢的速率直接分解;随着乙酸浓度的增大,生物释磷速率增快,同时随之增加的PHA含量能促进污泥的水解酸化.上清液中PO43--P和Mg2+浓度在达到最大值后出现了下降的现象,其可能形成鸟粪石等沉淀.根据试验数据,本文提出了从富磷污泥中回收磷的策略,即可在厌氧消化开始前向污泥中投加一定量碳源,并在发酵24h内分离上清液进行磷回收,这样不仅可以快速大量地从上清液中回收磷并减少沉淀引起的管道堵塞等问题,还可消除高浓度磷酸盐对厌氧消化的影响.     

沸石负载对叔丁基杯[4]芳烃乙酸对铀的吸附行为

以对叔丁基杯[4]芳烃与溴乙酸乙酯为主要反应底物合成了对叔丁基杯[4]芳烃乙酸,然后将其负载在沸石上,红外光谱显示合成物具有杯[4]芳烃乙酸的特征结构,扫描电镜分析表明对叔丁基杯[4]芳烃乙酸成功负载于沸石之上,且分布均匀,分散性良好.通过静态吸附实验,结果表明在pH值 4,对叔丁基杯[4]芳烃乙酸/沸石的负载比0.025/1,吸附剂用量0.5g,铀初始质量浓度10mg/L,吸附时间30min时,沸石在负载了对叔丁基杯[4]芳烃乙酸后,对溶液中铀的吸附率从30%左右提高到93%.沸石和负载沸石吸附动力学行为均符合准二级动力学模型,但负载沸石对铀的吸附速率明显高于沸石.沸石和负载沸石吸附等温式都符合Langmuir吸附等温线,说明都为单分子层吸附;由此推导出的最大吸附量Qm从16.8919提高到32.5733mg/g,这主要是因为沸石负载了对叔丁基杯[4]芳烃乙酸增加了吸附点位.吸附铀前后的红外光谱表明,负载沸石对铀的去除主要依靠对叔丁基杯[4]芳烃乙酸与铀的强络合作用和Si—O和Al—O的吸附作用,两种作用的协同加快了吸附速率,增加了吸附容量.     

铝箔复合膜集气袋对有机废气的适用性研究

通过在不同的时间段,测定存放于铝箔复合膜集气袋和玻璃注射器的丙酮,醋酸乙酯,苯,异丙醇标准气的浓度,气体浓度与贮存时间的关系,本次试验结果表明,丙酮,醋酸乙酯,苯,异丙醇在铝箔气袋中的稳定性明显优于在玻璃注射器中,应尽可能在８－２４ｈ内测定。     

农业区氨氮流失模型

定量分析了农田降水、产流,下渗,排水,蒸散发,灌溉之间的关系并提出相应的数学方程式,采用Ｌａｎｇｍｕｉｒ等温线动态描述土壤中氨氮吸附与两相平衡状态,在此基础上,建立了一个模拟随农业排水和产沙的充失数学模型,并以江苏省锡澄农业区为例说明了这一模型的应用。     

Acid aerosols in the Pittsburgh Metropolitan area

This article presents data on ambient concentrations of selected acidic aerosols at four existing monitoring sites in the Pittsburgh PA metropolitan area. The data were collected by staff of the Allegheny County Health Department, Division of Air Quality during the summer and fall of 1993. The sampling protocol was focused on obtaining 24 h-average ammonia, ammonium, acidic sulfates, and particle strong acids data on a 2 to 3 day cycle. The data were obtained using Harvard University School of Public Health's “Short-HEADS” annular denuder sampling train. The Pittsburgh area is of interest because it is downwind of a major regional source of sulfur and nitrogen emissions from coal-burning power plants: the Ohio River Valley. The data presented here indicate that ground-level concentrations of acidic aerosols in Pittsburgh are highly correlated spatially and that many pollutants are higher on days when ground-level wind direction vectors indicate that wind is coming from the southwest rather than from the Pittsburgh source area itself. The monitoring site that is most upwind of the Pittsburgh source area – South Fayette – has particle strong acid levels about twice those of sites closer in to the Pittsburgh central business district.