浅议公路工程项目施工技术与安全

技术管理是项目在施工过程中的一项重要工作,如何进行技术管理,很多资料中都有叙述,但大都是从编制技术文件、拟定方案、方案报批或开专家评审会、技术交底、技术创新、技术总结等方面进行管理。而施工技术与施工安全有着必然的联系,由于施工技术管理不到位造成的事故时有发生。笔者将从施工技术与安全的角度介绍技术管理的内容。     

声音

“咱们都是家里的顶梁桩,上有老下有小,出个事昨办？一个班里的工友就是亲兄弟,在井下,我们不仅要自保,更要互保、联保,在安全生产上如果班长不严、不管、不问,那才是对大家不负责任。” 这是中国平煤神马能源化工集团七星公司开拓四队班长白国周在生产过程中经常对工友说的话。白国周不断探索班组安全管理的新方法,并坚持把这些管理方法运用到生产实践中去,创造了22年没有出现任何生产安全事故的奇迹。     

短程硝化控制条件研究现状与应用分析

通过介绍短程硝化的机理,分析了温度、pH、DO浓度、SRT、游离氨浓度、实时控制技术及有机物浓度6个方面对于短程硝化的影响,探讨如何控制这些影响因素来达到亚硝酸盐的积累以及应用于实际所面临的困难,并展望了研究的发展方向     

二氧化碳变碳有望成真

英国《新科学》杂志日前载文介绍了德国化学家的最新发现,科研人员通过使用一种新型催化剂,以实现从二氧化碳中分离碳的目的,也就是模仿植物光合作用的过程,实现碳的循环利用.     

Transformations of particles, metal elements and natural organic matter in different water treatment processes

Characterizing natural organic matter （NOM）, particles and elements in different water treatment processes can give a useful information to optimize water treatment operations. In this article, transformations of particles, metal elements and NOM in a pilot-scale water treatment plant were investigated by laser light granularity system, particle counter, glass-fiber membrane filtration, inductively coupled plasma-optical emission spectroscopy, ultra filtration and resin absorbents fractionation. The results showed that particles, NOM and trihalomethane formation precursors were removed synergistically by sequential treatment of different processes. Preozonation markedly changed the polarity and molecular weight of NOM, and it could be conducive to the following coagulation process through destabilizing particles and colloids; mid-ozonation enhanced the subsequent granular activated carbon （GAC） filtration process by decreasing molecular weight of organic matters. Coagulation-flotation and GAC were more efficient in removing fixed suspended solids and larger particles; while sand-filtration was more efficient in removing volatile suspended solids and smaller particles. Flotation performed better than sedimentation in terms of particle and NOM removal. The type of coagulant could greatly affect the performance of coagulation-flotation. Pre-hydrolyzed composite coagulant （HPAC） was superior to FeCl3 concerning the removals of hydrophobic dissolved organic carbon and volatile suspended solids. The leakages of flocs from sand-filtration and microorganisms from GAC should be mitigated to ensure the reliability of the whole treatment system.     

Denitrification potential enhancement by addition of external carbon sources in a pre-denitrification process

The aim of this study is to investigate the denitrification potential enhancement by addition of external carbon sources and to estimate the denitrification potential for the predenitrification system using nitrate utilization rate （NUR） batch tests. It is shown that the denitrification potential can be substantially increased with the addition of three external carbon sources, i.e. methanol, ethanol, and acetate, and the denitrification rates of ethanol, acetate, and methanol reached up to 9.6, 12, and 3.2 mgN/（g VSS.h）, respectively, while that of starch wastewater was only 0.74 mgN/（g VSS,h）. By comparison, ethanol was found to be the best external carbon source. NUR batch tests with starch wastewater and waste ethanol were carried out. The denitfification potential increased from 5.6 to 16.5 mg NO3-N/L owing to waste ethanol addition. By means of NUR tests, the wastewater characteristics and kinetic parameters can be estimated, which are used to determine the denitrification potential of wastewater, to calculate the denitrification potential of the plant and to predict the nitrate effluent quality, as well as provide information for developing carbon dosage control strategy.     

竹笋壳为生物膜载体的废水处理技术研究

采用室内实验装置,研究了以农业废弃物竹笋壳为反硝化碳源和生物膜载体的生物反应器对于污水中硝酸盐的去除效果,并另设以聚丙烯惰性填料球为生物膜载体的生物反应器作为对照实验。实验结果表明,以天然竹笋壳作为反硝化碳源和生物膜载体的反应器启动时间短,对污水中硝酸盐氮的去除效果较好;装置对进水DO和pH值变化有一定抗性,DO在2.0~4.0mg/L,pH值在6.8~7.2之间变化时,反应器硝酸盐的去除率变化很小,缓冲能力较强;反应器稳定性强,出水硝酸盐的去除率在80%以上。     

水产品加工废水氨氮去除异常的分析研究

针对水产品加工废水处理工程运行过程中出水氨氮过高的问题.通过实验分析研究了该处理工程的硝化反硝化程度.实验结果显示,该处理丁=程的硝化反硝化程度过低(对TN的去除率仅为22.7%),硝化细荫和反硝化细菌含量较少,且活性较差.经分析其主要原因为进水水质、水量突变,而硝化细菌和反硝化细菌抗冲击能力较差,造成系统中硝化细菌和反硝化细菌含量减少,影响出水水质.     

颗粒化序列间歇式活性污泥反应器工艺处理化粪池污水

在序列间歇式活性污泥反应器(SBR)中成功培养出适应化粪池污水水质的好氧颗粒污泥.并将其应用于化粪池污水的处理.在好氧颗粒污泥培养的第15天左右,SBR中开始出现细小的颗粒,然后微生物在其上繁殖生长使颗粒逐渐增大而成熟;在第24天时,SBR中絮状活性污泥已基本实现了颗粒化.培养出的好氧颗粒污泥对化粪池污水有稳定的处理效果,在进水完全为化粪池污水时,COD、NH_4~+-N、TN的平均去除率分别为77%、61%、47%.但是,由于化粪池污水COD较低,因此无法维持较高的生物量,在后期的稳定运行过程中MLSS始终维持在2 500 mg/L左右.好氧颗粒污泥的同步硝化反硝化作用是其稳定脱氮的保证.     

DO对好氧颗粒污泥短程同步硝化反硝化脱氮的影响

以模拟城市污水为处理对象,研究了不同溶解氧下序批式活性污泥反应器（SBR）的短程同步硝化反硝化过程特征及处理效果。试验结果表明,溶解氧浓度是实现短程同步硝化反硝化的一个重要控制参数。在亚氮积累阶段,控制温度为28～32℃,pH值为7.5～7.8,当进水NH⁺₄-N为30 mg/L左右,COD为250 mg/L左右时,亚硝酸盐氮的积累率达到96%～98%。在试验阶段,常温下控制溶解氧在0.5～1.0 mg/L,可保证氨氮的去除率达到95%～97%,总氮的去除率达到82%～85%。