生物膜填料塔净化低浓度有机废气研究

研究了入口 中甲苯浓度，气体流量，液体喷淋量，填料层高度，操作方式等因素对生物膜填料塔净化低浓度甲苯废气性能的影响，研究结果为生化法净化低浓度为机废气的工业应用提供了依据。     

用生物填料塔处理三甲胺废气

为解决废气中有机胺类物质的恶臭污染问题,采用自制生物填料塔处理三甲胺废气,考察了生物填料塔运行的主要影响因素及对三甲胺废气的净化效果。实验结果表明,在进气中三甲胺质量浓度为80.00mg/m3、气体流量为0.3m3/h(停留时间不小于30s)、循环液喷淋密度为0.5m3/(m2.h)的条件下,三甲胺去除率达99.9%,净化后气体能达到国家二级排放标准;生物填料塔对三甲胺的总去除量与容积负荷呈直线关系,相关系数达0.9949,表明三甲胺废气的生物净化效果显著。     

生物滴滤塔处理甲苯废气

分别以生物陶粒和聚氨酯泡沫为生物滴滤塔填料,对甲苯废气进行处理,考察不同生物滴滤塔挂膜启动时间以及气体流量和甲苯质量浓度条件下生物滴滤塔对甲苯废气的去除效果。实验结果表明：生物陶粒为填料的生物滴滤塔所需要的挂膜启动时间更短;在气体流量为450L/h时,以生物陶粒为填料的生物滴滤塔甲苯去除率稳定在72%左右,聚氨酯泡沫为填料时甲苯去除率稳定在65%左右。以聚氨酯泡沫为填料时,随甲苯质量浓度提高,甲苯去除率下降幅度较小,甲苯质量浓度为1.80g/m3时,甲苯去除率仍在72%以上。     

陶粒填料生物滴滤塔处理二甲苯废气

以两种不同的陶粒作为生物滴滤床填料净化二甲苯废气,研究了喷淋液量、气体流量、进气负荷、喷淋液中氨氮浓度及填料层高度对净化效率的影响,并对两种填料的使用效果进行了对比。结果表明：二甲苯废气进气流量越小、进气负荷越低,净化效果越好;充足的氮源是高净化率的保证;对于较高浓度的废气,需要适当增加填料层高来达到净化要求;使用具有比表面积大的陶粒作为填料,可以使设备挂膜时间更短、能耗更低,净化效率更高。     

活性炭填料塔FeSO4液相催化氧化脱硫

对活性炭及瓷拉西环两种填料用自来水进行脱硫对比实验,证明无论是等宏观表面积还是等填料层高度,活性炭填料的脱硫率均高于瓷拉西环。在活性炭填料塔中进行了FeSO4液相催化氧化脱硫实验,考察了液气比、空塔气速、吸收温度及SO2进口浓度对脱硫率的影响。综合实验结果表明,连续运行500min时,脱硫率及吸收液pH分别稳定在93．5％以上及4．6左右,且两者的变化趋势基本一致。     

用生物滴滤塔净化苯乙烯废气

用内部填充有陶粒的生物滴滤塔净化苯乙烯废气,考察了气体流量、液体喷淋量及氮源对苯乙烯废气净化效果的影响。,进口苯乙烯质量浓度为300～4500mg／m^3时,气体流量和进FI苯乙烯质量浓度对苯乙烯的去除率影响显著,当气体流量为0．3m^3／h时,苯乙烯去除率达87％以上。实验结果表明：在气体流量为0．9m^3／h时,液体喷淋量对苯乙烯废气的净化效果影响不明显;降低进口苯乙烯质量浓度和增大生物滴滤塔的有效传质面积,有利于苯乙烯的净化;用浓度为0.0017mol／L的NaNO3作氮源时苯乙烯的去除效果优于用NH4Cl作氮源时苯乙烯的去除效果。     

生物填料在废水处理中的研究进展

综述了生物膜废水处理工艺中常用生物填料的研究进展。针对无机生物填料和有机生物填料的不同特点，分别介绍了二者在生物膜反应器中的应用现状。重点介绍了有机生物填料在亲水改性、表面带电改性、生物亲和改性和磁改性方面的研究进展。在此基础上，结合生物填料的使用现状，提出了未来生物填料的研究方向和发展趋势。     

生物膜填料塔启动及烟气脱硫研究

进行了生物膜填料塔挂膜启动及烟气脱硫实验研究。循环液的Fe2+的氧化速率与吸光度有明显的相关性,同时,压力损失和pH也是挂膜启动完成的重要指标。通入低浓度SO2气体驯化后,脱硫率可达到90%以上,Fe2+氧化速率维持在0.2g/(L.h)左右,连续保持7d,挂膜启动完成。脱硫实验结果表明,在SO2入口质量浓度小于2 000m g/m3、喷淋液中Fe2+浓度大于或等于0.06m o l/L、喷淋率约为12L/(m3.h)、空塔气速约为0.15m/s的条件下,脱硫率可达96%以上。当喷淋液循环使用7次后,必须补充新鲜营养液,以保证较高的脱硫率。     

生物滴滤法处理喷漆废气

采用生物滴滤系统处理喷漆废气,在研究了混合气体中甲苯与二甲苯之间相互作用的基础上,对生物滴滤系统净化喷漆废气的稳定性进行了研究。实验结果表明:在挂膜启动阶段,进气流量为22.5 m3/h、空塔停留时间为33.9 s、进气甲苯质量浓度为400~1 500 mg/m3的条件下,最终甲苯去除率可稳定在97%以上;在总进气质量浓度为1 000 mg/m3的条件下处理甲苯和二甲苯混合气体,混合气体中甲苯与二甲苯存在相互抑制作用,且甲苯对二甲苯的抑制作用更强;在进气流量为20.0 m3/h、空塔停留时间为38.0 s、进气中总挥发性有机物(TVOCs)质量浓度为300~900 mg/m3的条件下处理喷漆废气,平均TVOCs去除率为90.84%,出口二甲苯质量浓度低于GB16297—1996《大气污染物综合排放标准》中规定的排放限值(二甲苯质量浓度为70 mg/m3),基本满足排放要求。     

悬浮填料在废水生物处理中的应用进展

综述了悬浮填料及反应性悬浮填料在废水生物处理中的应用。在曝气池中添加悬浮填料对传统活性污泥法进行改进，改造工程简单，并可使原有污水处理场的处理能力及脱氮能力大大提高；悬浮填料与活性污泥法的多种变型相结合，在市场上形成了多种新型反应器和新的商品处理工艺。反应性悬浮填料的使用也已取得一系列成功经验，但仍然要注意反应性悬浮填料本身在废水中的降解问题。     

A “convective” flow biofilter for the biofiltration of contaminants at sub‐low concentrations

Biofiltration of contaminants at concentrations below a certain level (sub‐low concentrations) is not as effective as at higher concentrations, which leads to incomplete removal of the contaminants, because of diffusive mass transfer of the contaminants inside the biofilm and insufficient carbon and energy sources to sustain biomass growth and maintenance. To overcome the limitation of diffusion, this article proposes the concept of convective flow biofilm in which contaminated air flows through the porous biofilm and thus carries the carbon and energy sources to the biomass. The innovative concept of convective flow biofilm was implemented in a convective flow biofilter (CFB), which was built from activated carbon‐coated ceramic monoliths by selectively blocking the channel openings. The CFB was tested for 11 weeks for the biofiltration of toluene at inlet concentrations below 100 ppmv. The CFB performed consistently better than the conventional diffusive flow biofilter (DFB), as indicated by the higher removal efficiencies and the higher CO₂ productions. The CFB demonstrated up to 30 percent higher removal efficiency and an up to 100 percent higher elimination capacity than the DFB. © 2007 Wiley Periodicals, Inc.     

Separation of plastic waste via the hydraulic separator Multidune under different geometric configurations

The recovery of high-quality plastic materials is becoming an increasingly challenging issue for the recycling sector. Technologies for plastic recycling have to guarantee high-quality secondary raw material, complying with specific standards, for use in industrial applications. The variability in waste plastics does not always correspond to evident differences in physical characteristics, making traditional methodologies ineffective for plastic separation. The Multidune separator is a hydraulic channel allowing the sorting of solid particles on the basis of differential transport mechanisms by generating particular fluid dynamic conditions due to its geometric configuration and operational settings. In this paper, the fluid dynamic conditions were investigated by an image analysis technique, allowing the reconstruction of velocity fields generated inside the Multidune, considering two different geometric configurations of the device, Configuration A and Configuration B. Furthermore, tests on mono- and bi-material samples were completed with varying operational conditions under both configurations. In both series of experiments, the bi-material samples were composed of differing proportions (85% vs. 15%) to simulate real conditions in an industrial plant for the purifying of a useful fraction from a contaminating fraction. The separation results were evaluated in terms of grade and recovery of the useful fraction.     

Use of rubble from building demolition in mortars

Because of increasing waste production and public concerns about the environment, it is desirable to recycle materials from building demolition. If suitably selected, ground, cleaned and sieved in appropriate industrial crushing plants, these materials can be profitably used in concrete. Nevertheless, the presence of masonry instead of concrete rubble is particularly detrimental to the mechanical performance and durability of recycled-aggregate concrete and the same negative effect is detectable when natural sand is replaced by fine recycled aggregate fraction. An alternative use of both masonry rubble and fine recycled material fraction could be in mortars. These could contain either recycled instead of natural sand or powder obtained by bricks crushing as partial cement substitution. In particular, attention is focused on the modification that takes place when either polypropylene or stainless steel fibers are added to these mortars. Polypropylene fibers are added in order to reduce shrinkage of mortars, stainless steel fibers for improving their flexural strength. The combined use of polypropylene fibers and fine recycled material from building demolition could allow the preparation of mortars showing good performance, in particular when coupled with bricks. Furthermore, the combined use of stainless steel fibers and mortars containing brick powder seems to be an effective way to guarantee a high flexural strength.     

Pyrolysis of municipal plastic wastes: Influence of raw material composition

The objective of this work is the study of pyrolysis as a feedstock recycling process, for valorizing the rejected streams that come from industrial plants, where packing and packaging wastes are classified and separated for their subsequent mechanical recycling. Four real samples collected from an industrial plant at four different times of the year, have been pyrolysed under nitrogen in a 3.5 dm³ autoclave at 500 °C for 30 min. Pyrolysis liquids are a complex mixture of organic compounds containing valuable chemicals as styrene, ethyl-benzene, toluene, etc. Pyrolysis solids are composed of the inorganic material contained in the raw materials, as well as of some char formed in the pyrolysis process, and pyrolysis gases are mainly composed of hydrocarbons together with some CO and CO₂, and have very high gross calorific values (GCV).It has been proved by the authors that the composition of the raw material (paper, film, and metals contents) plays a significant role in the characteristics of pyrolysis products. High paper content yields water in the pyrolysis liquids, and CO and CO₂ in the gases, high PE film content gives rise to high viscosity liquids, and high metals content yields more aromatics in the liquid products, which may be attributed to the metals catalytic effect.     

Converting waste expanded polystyrene into polymeric azo dyes containing the sulfonamide group

Using waste expanded polystyrene as raw materials, a series of polymeric azo dyes containing the sulfonamide group were prepared by chlorosulfonation, amidation, hydrolysis, diazotization and coupling reactions in this study. The main influence factors of each step reaction were discussed and the proper reaction conditions were obtained. The polymeric azo dyes prepared showed good thermal stabilities, and their 5 % weight loss temperatures were all higher than 350 °C. These polymeric dyes could solve in toluene at the room temperature. They showed different maximum absorption wavelengths in the ultraviolet–visible region and gave various colors. The relationships between colors and molecular structures of polymeric dyes were investigated. These polymeric azo dyes prepared have potential applications in dyeing polymer materials, such as plastic and fiber.     

Comparison of the weight-loss degradability of various biodegradable plastics under laboratory composting conditions

Eight kinds of biodegradable plastics were compared for their degradability in controlled laboratory composting conditions. A thin film of each plastic was mixed into the composting material, and weight-loss degradability was calculated from the weight changes of the film during composting. It was found that weight-loss degradability strongly depended on the specific kind of biodegradable plastic; two were very high, four moderate, and the remaining two very slight. The most easily degradable plastic degraded by as much as 81.4% over 8 days of composting. By comparing the weight-loss degradability with ultimate degradability, which is defined as a molar ratio of carbon loss as CO₂ to the carbon contained in the biodegradable plastic, the order of the ease of degradation of the biodegradable plastics differed. Received: February 7, 2000 / Accepted April 14, 2000     

PREPARATION OF CERAMIC MEMBRANE FILTERS,FROM WASTE FLY ASH,SUITABLE FOR HOT GAS CLEANING

The preparation and performance of ceramic membrane filters made from fly ash from coal-fired power stations were investigated. The porous and crack-free ceramic composite membrane was prepared by dip-coating a stainless steel mesh in a slurry of fly ash. Membrane properties investigated included pore structure, permeability and mechanical strength. The ash membrane filter shows great potential for the filtration and microfiltration of high-temperature gas-particulate streams, and re-uses waste fly ash composed of multiple oxides with a wide size distribution. The median pore size of the tested membrane was 2.3μm and the differential pressure gradient was 0.9 kPa l⁻¹min⁻¹, which is comparable to fabric filters currently in use in some New South Wales power stations. The high mechanical strength of the membrane was caused by fusion of the glassy material in the fly ash. Since the membrane consists of metal and ceramic composities, it also shows good flexibility.     

制药废水硝化-反硝化除氮研究

含高浓度氮的制药废水经好氧生化处理后,虽然出水的ＣＯＤ,ＢＯＤ５均可达到行业排放标准,但ＴＮ仍高达约１７０ｍｇ／Ｌ。本研究在曝气池中设置填料,利用生物膜外层好氧,内层缺氧厌氧的条件,使硝化－反硝化脱氮在同一构筑物内进行,ＮＨ３－Ｎ和ＴＮ去除率分别可达约９０％和７０％。在本试验条件范围内,温度越高,负荷越低,硝化和反硝化作用越完全,ＮＨ３－Ｎ和ＴＮ去除率越高。