Transport of Sewage Sludge in a Mixed Water Column

Sewage sludge from four publicly-owned treatment works was sampled and characterized in terms of parameters affecting transport at the 106-mile deep ocean disposal site as part of the US Environmental Protection Agency's site monitoring programme. Samples from treatment plants in Passaic Valley, Rahway, and Elizabeth, New Jersey and New York City were characterized in terms of dynamic size distribution, suspended solids and density. the transport characteristics of sludge particles were measured using a 2 metre computer-interfaced laboratory settling column. Experiments were conducted at constant salinity (35 ppt) while varying hydrodynamic mixing, sludge type and concentration using a modified factorial experimental design. Hydrodynamic power dissipation was varied so that the vertical dispersion and rms fluid shear rate ranged between 0-6 cm²S^-1 and 0-30s^-1 respectively. Results indicate that at least 80% of suspended sludge particles will eventually settle under mixed conditions. the average settling velocities ranged between 0.05-4.05 × 10^-3 cm ^s-1. Shear rates above 15 s^-1 inhibited sludge settling due to aggregate breakup and boundary effects, but at a lower shear rate, differential settling and fluid shear were the dominant transport mechanisms. Sludge dilution (1/500-1/5000) had a limited effect on the settling rate. Results from this study can be used to calibrate particle transport models to determine the fate of sludge disposed at an ocean disposal site.     

Large-scale effects on resistivity index of porous media

The estimation of humidity in the unsaturated zone of soils and NAPL saturation in contaminated aquifers may be based on the interpretation of electrical resistivity index logs. In the present work, concepts of the theory of the two-phase flow in pore networks are employed to interpret the form of the equilibrium and dynamic resistivity index curves of large porous samples. A resistivity cell is constructed to measure the capillary and electrical properties of large samples of unconsolidated porous media. The drainage capillary pressure and resistivity index curves of a sand column are measured by using the micropore membrane (porous plate) method, where a 0.5% wt/vol NaCl aqueous solution is displaced by n-dodecane. The dynamic resistivity index curves are measured by using the continuous injection technique for various orientations of the sand column. Based on concepts of the two-phase flow theory, concerning the dominant displacement growth pattern in a pore network and arising from the cooperative effects of capillary, buoyancy, and viscous forces, approximate relationships are developed for the resistivity index and saturation exponent as functions of the water saturation. The saturation exponent decreases as the displacement advances and the fluid distribution across the sand column tends to be homogenized after oil breakthrough. Both the resistivity index and saturation exponent increase as the displacement pattern tends to become compact and stable. In the destabilized flow pattern, as the Bond number decreases, the resistivity index may increase respectably within a narrow range of values of the Bond number. This happens when the thickness of the unstable capillary finger exceeds the lateral dimension of the porous sample and becomes a fractal percolation cluster. The saturation exponent becomes almost constant and independent of water saturation only over the destabilized displacement pattern at high values of the Bond number.     

A multi media load model for the Baltic Sea

The background of this work is the international decision process with regard to the selection of chemicals to be assessed with priority. In order to stress the precautionary principle, mass flows were analysed rather than concentrations, threshold values, etc., as preferred by the chemical legislation (which still excludes the marine area). Lindane, hexachlorobenzene (HCB), trichloroacetic acid and its sodium salt, medium-chained chlorinated paraffins and tributyltin (TBT) were selected due to their great relevance for the marine area. Trichloroacetic acid is an interesting model compound on account of its accidental formation by degradation of volatile chlorinated hydrocarbons and during chlorination processes. In addition, a hypothetical compound was modelled, representing a highly water-soluble substance with low vapour pressure. The balancing area is the Baltic Sea and its catchment area. In order to model the substance flows, the 'Input/Output-load model' has been developed. The model quantifies the shift and the distribution of a yearly load of the substance investigated from the terrestrial-limnic into the marine compartment (Baltic Sea). Water-soluble substances, which are usually considered to be of no concern, may enter the sea in great amounts and, if not degradable, remain there. It turned out to be necessary to take into account remobilisation, unintended formation and point as well as line-sources.     

油田作业区生活污水处理设计与运行

倒置A2/O悬浮填料生物膜处理工艺,能有效解决生物脱氮除磷工艺中的泥龄矛盾。其工艺简单、运行低耗、处理高效、抗冲击能力强的特点在宣汉采气作业区的生活污水处理工程中得以应用,适合油田作业区生活污水的处理。在来水波动较大时,出水也可达到《城镇污水处理厂污染物排放标准》(GB18918-2002)一级B标准。     

三高气田钻完井重大事故现场监测数据采集管理系统的设计与实现

把信息化技术用于油气田安全领域,用采集的现场数据评估安全生产环境,实现油气田安全信息化是近年来的新课题。为了有效地监测和预防油三高气田（高含硫、高产量、高压力）井喷事故造成的灾害,讨论了基于网络架构的重大事故现场监测数据采集管理系统软件的研究与设计,包括气象数据,传感器数据,监测设备GPS数据与视频信息的实时采集、处理、分析与显示,并且分段说明了该系统各部分的设计和实现的重点.该系统具有友好的人机界面,并且引入了流媒体技术、无线传感器技术等多种先进技术,能够最大程度地得到全面的表征油气田安全的数据与信息;该系统已经在研究实例龙岗油气田的实验中证明了具有安全生产方面的现实意义。     

室内空气污染的来源及控制措施

随着经济的发展和人们生活水平的提高,室内空气污染逐渐成为人们关心的环境问题之一。室内空气污染物包括悬浮固体污染物和气体污染物,其中可吸入颗粒物对人体呼吸系统有极大危害;气体污染物主要包括有机气体污染物、无机气体污染物和放射性气体污染物,它们可以引起病态建筑综合症（SBS）、化学物质过敏症等相关病症。本文分析了各种室内空气污染的来源,并据此提出室内空气污染的防控措施。     

石化废水深度处理及脱盐的中试研究

针对石化行业污水回用处理设施很快失效的现状,开发了“集成式悬浮载体生物氧化－砂滤－臭氧活性炭处理－超滤反渗透”的组合工艺对炼油厂外排水进行深度处理.连续7个月的中试结果表明,处理后外排水中COD、NH3-N、BOD5、油和浊度等均优于回用水标准,可作为工业循环冷却水、绿化用水和办公等用水;常规深度处理的出水经过超滤反渗透处理后,电导率稳定在35~40μS/cm,可作为动力车间的新鲜水,不会发生膜污染和堵塞问题.尽管外排水的水质波动很大,但是组合工艺运行稳定、可靠,具有突出的抗冲击性能.     

Invertebrate community characteristics in biologically active carbon filter

Biologically active carbon (BAC) system was set up in a water plant of South China during January to December 2007,to study the invertebrate community characteristics of BAC filter.Thirty-seven invertebrate species were found,of which 28 belonging to rotifers.Filter operation could lead to an output of invertebrates in high abundances with the filtrate,and the maximum density could reach 5608 individuals/m 3.Average abundances in the effluent water increased in 27-33 folds in comparison to the influent water during the sampling period.Invertebrate community succession had the following trend:filter-feeding animals → small benthic invertebrates → large benthic and resistant invertebrates.Abundances of large-sized invertebrates (copepod adult and oligochaete) at bigger-media column were significantly higher than that at small-media column.The results implied the abundant species diversity of invertebrate in BAC filter.The relationship between invertebrate and biofilm still remain to be studied in detail.     

Contributions of biofilm and suspended sludge to nitrogen transformation and nitrous oxide emission in hybrid sequencing batch system

Hybrid system combines the nature of suspended growth and attached growth has been widely applied to wastewater treatment. In this research, the contributions to N transformation and N2O emission by biofilm and suspended sludge in the hybrid sequencingbatch reactor for a simultaneous nitrification, denitrification and phosphorus removal process were investigated. For the hybrid system, nitrification occurred mostly in the suspended sludge, while the biofilm played the major role in denitrification. The interaction of the biofilm and the suspended sludge in the same reactor resulted in a better overall nitrogen removal performance with simultaneous nitrification and denitrification. However, N2O emission was the main end product of nitrogen removal for the hybrid system; while it was N2 for the biofilm. The relative low N2O emissions from the pure biofilm and the pure suspended sludge corresponded to the relatively high nitrate at the end of the aeration period compared with the hybrid system.     

沸石滤料曝气生物滤池处理水产养殖废水的工艺特性

采用上流式沸石滤料曝气生物滤池(ZBAF)对水产养殖废水进行处理.结果表明,沸石的高效吸附作用可使系统获得快速启动,异养菌和硝化菌生物膜的成熟分别只需7d和25d;系统在水力负荷0.25m/h及气水比20∶1工艺条件下运行效能最佳,COD和NH+4-N去除率分别稳定在85%和70%左右.通过对ZBAF滤柱沿程水质、微生物等指标分析,异养菌和硝化菌主要聚居区分别在滤料层下端和上端,DO值的低谷位置可作为其聚居区分界线;生物量(磷脂-P)和生物活性(好氧速率)沿高程的分布大体一致,其最大值均出现在滤柱底部,分别为114.12 nmol/g和0.67 mg/(g.h).