垃圾衍生燃料灰渣中主要元素变化的研究

以垃圾衍生燃料(RDF)为研究对象,在600~1100℃条件下灼烧RDF灰渣,对灰渣中的主要元素变化情况进行分析.研究结果表明,RDF灰渣中主要元素包括硅、氧、铝、钙、镁、钾、钠、碳、硫、氯、磷、钛、锌等;灰渣中的可溶盐倾向富集在≤0.3 mm的灰渣颗粒上;在600~1000℃范围内,其总量处于动态平衡,在1100℃则大幅度减少.随着温度的上升,碳转化为二氧化碳气体;硫元素转化为硫酸盐,随后部分再转化为二氧化硫气体;氯元素转化为以氯化钠和氯化钾为主的氯化盐,在达到一定温度时发生相变转化为气体.硅、氧、铝、钙、镁、磷等元素留存于废渣中,随着温度提高,发生复合化学反应,相互键接形成复合硅酸盐物质.     

化工污泥基轻质填料的制备研究

以化工污泥焚烧灰渣和粘土为原料,添加自制无机重金属稳定剂S01,经烘干、预热、焙烧等工艺过程,制备了粒径为10~20mm的水处理用填料。通过单因素实验考察了S01添加量、烧结温度、化工污泥焚烧灰渣添加量、烧结时间等工艺条件对填料性能(堆积密度、吸水率)的影响,确定了填料的最佳制备条件:S01无机重金属稳定剂添加量4%,化工污泥焚烧灰渣添加量40%,烧结温度1 150℃,烧结时间10 min。在此条件下,填料的堆积密度为844.1 kg/m3,吸水率为9.27%,重金属浸出浓度远远低于《危险废物鉴别标准浸出毒性鉴别》(GB5085.3-2007)中规定的浓度限值。采用扫描电镜观察了填料表面和内部孔隙特征,发现最佳制备条件下制得的填料表面粗糙多孔,内部具有发达的孔道结构。     

城市生活垃圾焚烧灰渣及其性质分析

2002年，上海有2座生活垃圾焚烧厂将点火运动。每年将产生约18万t左右的焚烧灰渣。在决定灰渣的最终处理处置方案前，应对焚烧灰渣的性质有全面的了解。详细介绍了国外城市生活垃圾焚烧灰渣甚至生位置的不同分类，并介绍了各类灰渣的物理化学性质和工程性质，以及其重金属的浸出特征。对灰渣处理放置或有效利用时需注意的问题作了分析。     

垃圾焚烧灰性质分析及控制方法

随着焚烧技术在垃圾处理方式中普遍采用,焚烧产生的灰渣数量也日益增加。灰渣与飞灰中有毒的重金属及有机物质会污染土壤与地下水,对人类健康造成极大的影响。本文对各类垃圾焚烧灰渣的物理化学性质及重金属浸出特性进行了详细的阐述,介绍了灰渣的毒性分析与控制方法。通过分析可知:为了避免灰渣二次污染应该重点控制铬、镉、铍、铅等重金属和二恶英、呋喃等有机物的污染;处置后的灰渣有害离子浸出能力降低,根据灰渣物理和工程性质,可以成为再生资源充当填充材料和混凝土与沥青路面骨料等。     

城市污水污泥焚烧过程中的重金属迁移特性

重金属是污泥对环境污染的一个重要方面，实验证明，焚烧是防止重金属污染的优选处理方法。通过分析重金属元素在污泥中的存在形式及对高碑店污水理处厂污泥焚烧前后重金属含量的变化进行检测，研究了重金属在焚烧处理过程中迁移特性。结果表明，重金属在焚烧过程中迁移特性因其种类和燃烧工况而不同。根据研究结果，提出了污泥灰渣处理的建议。     

城市生活垃圾气化熔融焚烧技术

近年来,新开发的气化熔融焚烧技术实现了垃圾处理能源化目标和与环境的协调发展,该技术被认为是解决垃圾处理和能源问题最有效的方法。文章结合传统焚烧+灰渣熔融技术、阐述了两步法气化熔融和直接气化熔融两种气化熔融焚烧技术工艺流程的特点。气化熔融焚烧技术能遏制二英的产生和排放,降低焚烧过程产生酸性气体(SOx,HCl,HF,NOx等)、挥发性有机物尤其是芳香烃类、多氯化联苯类和二英、呋喃类、以及重金属和危害性灰渣的排放。叶恶叶恶     

利用城市垃圾焚烧溶融灰渣制作透水性砖块

城市垃圾焚烧溶融灰渣，选择筛分不同粒径，混合配比添加木屑、烧结剂、淀粉等，烧结成透水性砖块，作性能试验考查弯曲强度和透水性能。本实验适用于垃圾焚烧灰渣、飞灰及下水污泥焚烧灰渣等的有效处理及资源化再利用。     

医用玻璃及医疗垃圾灰渣的结渣特性研究

医疗垃圾的特性和成分是改善焚烧装置设计、运行及控制性能的重要参数.为了研究医用玻璃对医疗垃圾焚烧炉的影响,从医疗废物处置中心采集了玻璃和灰渣样品,分析了其化学组分和熔融温度.与煤灰成分相比,医用玻璃中的SiO2和碱金属氧化物含量较高.通过不同玻璃间的比较,总结了化学组分对熔融温度的影响.软化温度随着SiO2、CaO含量的增加而升高,但随B2O3、Na2O含量的增加而迅速降低.改变不同玻璃的混合比例.研究了混合玻璃的熔融特性.利用煤灰结渣指数对医疗垃圾灰渣的结渣倾向进行了判定.结果显示,仅沾污指数能够对灰渣得出适宜的判别.     

水泥厂废旧除尘布袋热重分析及其形态特征

采用综合热重分析法,对水泥厂3种不同工段的废旧除尘布袋及相对应的同型号新布袋进行了热重(TG)分析实验研究.结果表明,废旧除尘布袋热重分析的升温过程中主要有3个失重峰,前两个失重峰与涤纶纤维的燃烧析出相对应,第3个失重峰主要是碳酸钙分解的结果.采用积分法(Coats-Redfern方程)计算得到各阶段燃烧反应的机理方程及相应的活化能参数.分析表明,在低温段废旧布袋中的灰尘对燃烧反应影响不大,而在高温段废旧布袋中的灰尘导致燃烧反应活化能升高,阻碍燃烧反应进行.从电镜扫描和能谱分析可知,废旧除尘布袋中的涤纶纤维几乎被焚烧殆尽,剩下的少量焚烧灰渣由C、O、Si、Ca等主要元素,以及Ti、Al、Mg、Mn、Fe等次要元素组成.这种灰渣与水泥成分类似,具有较高的回收利用价值.     

污泥热处理灰渣制砖的实验报告

报道了用广州大坦沙污水处理厂污泥热处理(焚烧或热解)灰渣制作无填料烧结普通砖的试验情况。     

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.     

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.     

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.     

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.     

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

ＲｅｍｏｖａｌｏｆｈｅａｖｙｍｅｔａｌｓｆｒｏｍｓｅｗａｇｅｓｌｕｄｇｅｂｙｌｏｗｃｏｓｔｉｎｇｃｈｅｍｉｃａｌｍｅｔｈｏｄａｎｄｒｅｃｙｃｌｉｎｇｉｎａｇｒｉｃｕｌｔｕｒｅＷｕＱｉｔａｎｇ，ＮｙｉｒａｎｄｅｇｅＰａｓｃａｓｉｅ，ＭｏＣｅｈｕｉＦ...     

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.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Alterations of organ histopathology and metallolhionein mRNA expression in silver barb, Puntius gonionotus during subchronic cadmium exposure

Common silver barb,Puntius gonionotus,exposed to the nominal concentration of 0.06 mg/L Cd for 60 d,were assessed for histopathological alterations(gills,liver and kidney),metal accumulation,and metallothionein(MT)mRNA expression.Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae,vacuolization in hepatocytes,and prominent tubular and glomerular damage in the kidney.In addition,kidney accumulated the highest content of cadmium,more than gills and liver.Expression of MT mRNA was increased in both liver and kidney of treated fish.Hepatic MT levels remained high after fish were removed to Cd-free water.In contrast,MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water.The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.