用法律、用技术征服二氧化硫的污染（续二）

顾名思义，烟气脱硫是一种用物理或化学的方法对燃料燃烧后的烟气进行处理而除去二氧化硫的方法；英文缩写名为FGD。这种方法的研究始于一百多年前的1850年。烟气中的硫主要是以二氧化硫的形态存在，脱硫看似简单，但因其烟气量极大，而二氧化硫浓度又非常低(大多在0．5％以下，如25万     

煤浆催化氧化法烟气脱硫研究

基于液相催化氧化原理,以煤浆做洗涤介质进行烟气脱硫。此法起催化作用的Fe2+/Fe3+离子通过SO2、O2和煤中的黄铁矿作用而现场产生。实验过程控制模拟烟气中的SO2摩尔分率和O2浓度范围分别为760×10-6￣3200×10-6和3%￣20%。实验表明,反应温度约在40℃以上时,脱硫率即达90%以上。二氧化硫浓度增大,脱硫率呈下降趋势,与石灰/石灰石脱硫过程类似。在实验范围内,pH值和氧气浓度对脱硫率基本没有影响,实际烟气中的O2浓度完全满足催化氧化反应的需要。随烟气脱硫过程的进行,脱硫浆液中的总铁含量不断增加,说明煤中黄铁矿被不断浸出,故此法在脱除烟气中的二氧化硫的同时也降低了煤中的黄铁矿硫。     

全球规模最大的烟气脱硫设备

英国最近在欧洲共同体的政治压力下,建立了一套用于功率为4亿瓦发电站的烟气脱硫设备,其规模是目前世界上最大的。该设备的第一期工程将于1993年开始运行,于1995年全部峻工投产,预计在1993年该发电站的二氧化硫排出量将削减90％。该脱硫设备每年耗用约66万t石灰石,使二氧化硫转变为石     

转炉除尘水用于烧结烟气脱硫的实验

在实验室进行转炉除尘水脱除模拟烧结烟气中二氧化硫的模拟实验。考察风速、入口二氧化硫浓度、液气比、反应接触时间、温度等因素对脱硫率的影响。研究表明,在设计的实验条件下,通过对实验参数的控制,用转炉除尘水可以取得很好的脱硫效果。     

微生物法烟气脱硫技术研究

采用微生物（氧化亚铁硫杆菌，简称TF菌）法脱除烟气中的二氧化硫。在相同操作条件下，比较了传统的工业化 方法稀硫酸吸收法（千代田法）与本法的优劣，研究了液气化、二氧化硫浓度、三价铁离子浓度等因素对吸收效率的影响；分析了脱硫反应前后吸收率pH值、三价铁离子浓度的变化。研究结果表明：适宜的液气比（12.5L/Nm^3 以上）、二氧化硫浓度（1000－5000ppm)和三价铁离子浓度（0.6g/L以上）能使该法具有较高（＞98％）的脱硫率。在常温常压操作条件下，微生物法的脱硫率远优于千代田法，具有一定的工业化价值。     

影响可再生烟气脱硫法的再生因素分析

可再生烟气脱硫法具有吸收剂可重复使用、二氧化硫可回收且不产生二次污染、原料消耗量小等很多优点,但仍然存在吸收剂再生问题。本文综述了几种典型的可再生烟气脱硫法的反应原理、存在的问题以及解决方法,并重点讨论了亚硫酸根氧化生成热稳定盐(HSS)导致可再生吸收剂再生能力降低、硫资源回收减少的影响因素以及应对策略,同时指出其主要影响因素是烟气含起催化作用的杂质、反应温度以及副反应的发生,应对策略主要有采用吸收剂脱硫前除尘、适当控制反应条件、加入有效添加剂和对已生成的热稳定盐进行处理等。该研究可为吸收剂再生问题研究提供参考。     

旋流水膜脱硫(RFD)技术在循环流化床锅炉烟气治理中的应用

采用旋流水膜脱硫技术，烟气经过电除尘器除尘后，从脱硫塔底部进入塔内，循环吸收液则从脱硫塔上部进入。烟气自下而上流动过程中，进行充分的气液接触，烟气中的二氧化硫与循环吸收液中的氢氧化钙发生反应而将二氧化硫除去，脱硫效率高，对烟气进行脱硫治理，取得良好效果。     

轮窑烧砖烟气元二次污染治理工艺研究

对轮窑志烟气处理的石灰乳水溶液吸收过程和百渣的固化过程进行了理论分析，探讨了该系统的工艺条件和设施。结果表明，采用喷射鼓泡瓜器自理含氟、含烟气，氟化物平均浓度从９４．７ｍｇ／ｍ＾３降至７．２ｍｇ／ｍ＾３，二氧化硫从６２５．５ｍｇ／ｍ＾３降至１１５．８ｍｇ／ｍ＾３，平均去除率氟化物为９２．４％，二氧化硫为８１．５％；吸收排渣可固化于主产品内而又不影响产品质量，消除了二次污染。     

工业用煤气燃烧装置二氧化硫减排方式的讨论

工业用煤气是工业生产中普遍采用的气体燃料,煤气燃烧过程会产生二氧化硫,减少煤气燃烧过程的二氧化硫排放可采用煤气脱硫和烟气脱硫两种方式。本文通过对煤气脱硫工艺及烟气脱硫工艺原理及参数进行对比的方式,讨论工业用燃气燃烧装置的两种二氧化硫减排方式的优缺点,为该类装置脱硫设计提供参考。     

新型文氏除尘脱硫洗涤器的研究

新型文氏除尘脱硫洗涤器是一种复合净化机理的燃煤烟气除尘脱硫一体化设备 ,其特点是体积小、阻力低、除尘脱硫效率高。实验研究和工业试验表明 :该洗涤器可使燃煤烟气二氧化硫和烟尘浓度达标排放     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.