PCDD/PCDF reduction by the co-combustion process

A novel process, termed the co-combustion process, has been developed and designed to utilise the thermal treatment of municipal solid waste (MSW) in cement clinker production and reduce PCDD/PCDF emissions. To test the conceptual design; detailed engineering design of the process and equipment was performed and a pilot plant was constructed to treat up to 40 tonnes MSW per day. The novel process features included several units external to the main traditional cement rotary kiln: an external calcinations unit in which the hot gas calcined the limestone thus making significant energy savings for this chemical reaction; the lime generated was used in a second chamber to act as a giant acid gas scrubber to remove SOx and particularly HCl (a source of chloride); an external rotary kiln and secondary combustion unit capable of producing a hot gas at 1200 degrees C; a gas cooler to simulate a boiler turbogenerator set for electricity generation; the incorporation of some of the bottom ash, calcined lime and dust collector solids into the cement clinker. A PCDD/PCDF inventory has been completed for the entire process and measured PCDD/PCDF emissions were 0.001 ng I-TEQ/Nm(3) on average which is 1% of the best practical means [Hong Kong Environmental Protection Department, 2001. A guidance note on the best practicable means for incinerators (municipal waste incineration), BPM12/1] MSW incineration emission limit values.     

Uptake and depuration of the anti-depressant fluoxetine by the Japanese medaka (Oryzias latipes)

The selective serotonin reuptake inhibitor (SSRI) class of anti-depressants is among the most widely prescribed groups of pharmaceuticals. Consequently, aquatic ecosystems impacted by municipal wastewater discharges are predicted to receive substantial annual loadings of these compounds. Although SSRIs have been detected in fish tissues, little is known of their uptake and depuration in freshwater fish species. In this study, Japanese medaka (Oryzias latipes) were exposed to fluoxetine at a nominal concentration of 0.64 microg L(-1) for 7d and subsequently allowed to depurate in clean water over a 21d period. Fluoxetine uptake by medaka was observed within the first 5h of exposure and the biologically active metabolite, norfluoxetine, was also detected in medaka tissues during this timeframe. A maximum fluoxetine concentration was measured in medaka by the third day of the uptake phase, yielding an uptake rate constant (k(1)) of 5.9+/-0.5 (d(-1)). During the depuration phase of the experiment, a half life of 9.4+/-1.1d was determined for fluoxetine. Using these data, bioconcentration factor (BCF) values of 74 and 80 were estimated for fluoxetine and a pseudo-BCF (the ratio of the concentration of norfluoxetine in medaka and the aqueous fluoxetine concentration) of 117 was calculated for norfluoxetine. These results indicate longer persistence and greater potential for the bioaccumulation of fluoxetine and norfluoxetine in fish tissues than would be predicted from prior half life estimates derived using mammalian species.     

Fe/C微电解-超声波/Fenton氧化-活性炭吸附处理仲丁灵农药废水

采用Fe/C微电解-超声波/Fenton氧化一活性炭吸附处理高色度、高COD、高盐分、高毒性的仲丁灵农药废水.试验结果表明:(1)Fe/C微电解处理仲丁灵农药废水的最佳条件:pH为4,铁屑投加量为0.5 mol/L,Fe与C摩尔比为2:1,反应时间为4h.(2)Fenton氧化的最佳条件:pH为4,FeSO4·7H2O投加量为0.03 mol/L,H2O2投加量为0.4 mol/L,反应时间为2 h.(3)在Fenton氧化的最佳条件下,超声波/Fenton氧化对COD去除率最高(平均约为80%).(4)当吸附时间为2 h、PH为6、活性炭投加量为20 g/L时.COD去除率可达90.5%.(5)采用Fe/C锻电解-超声波/Fenton氧化一活性炭吸附处理后,COD、色度均可达到<污水综合排放标准>(GB 8978-1996)中的一级标准.     

Triton X-100在土壤颗粒上的吸附特征研究

采用平衡振荡法,研究了砂土对非离子表面活性剂Triton X-100的吸附特征。结果表明,砂颗粒对Triton X-100的吸附能力总体较低,单位吸附含量均＜1.1 mg/g;砂颗粒吸附Triton X-100过程中存在显著的吸附剂浓度效应,砂颗粒上Triton X-100含量随着固液比（吸附剂浓度）的增大而减小;吸附容量q_m与平衡常数K_L值随固液比变化而变化,Langmuir方程适用范围是起始浓度C₀相对较小的固液吸附体系;0.5～1 mm石英砂的吸附能力略＞0.2～0.5 mm石英砂,0.5～1 mm和0.2～0.5 mm石英砂吸附Triton X-100变化特征具有显著的一致性,采用高斯拟合模型可以反映出石英砂吸附Triton X-100的变化规律,相关系数R²均＞0.98。     

新型MnOx/CNTs催化剂低温选择性催化还原NO

采用等体积浸渍法制备了MnOx/CNTs催化剂,用于低温NH3选择性催化还原(SCR)NO的实验.使用BET,FT-IR,TEM和XRD对催化剂进行表征,结果表明:碳纳米管经混酸超声分散,增加了羧基活性基团,锰氧化物颗粒分布较均匀.在模拟烟气条件下,考察了催化剂的MnOx负载量、煅烧温度及质量和烟气流速比(W/F)对NO脱除率的影响.煅烧温度为773 K,MnOx负载量为10%时,NO脱除率达到98.56%;W/F为2～3 mg/(mL·min-1)时NO的脱除率更高.     

上海浦东垃圾焚烧发电厂飞灰性质研究

研究了上海浦东新区垃圾焚烧发电厂烟气净化系统飞灰的物理和化学性质 .结果表明 :飞灰为含水率很低的灰色粉末 ,主要由Si,Al,Ca,Na ,K ,Mg ,Fe ,C和S组成 .飞灰中Pb的浸出浓度高于危险废物鉴别标准 ,为危险废物 .矿物组成主要为SiO2 ,Al2 SiO5,Na Cl,KCl,CaAl2 Si2 O8,Zn2 SiO4,CaCO3和CaSO4等 ;溶解盐含量高达 1 7 9%— 2 2 1 % ,酸中和能力约为 3 0meq·g- 1 — 6 0meq·g- 1 ,对环境pH变化的抵抗能力强 .     

Inhibition of metamorphosis in tadpoles of Xenopus laevis exposed to polybrominated diphenyl ethers (PBDEs)

Tadpoles of the African clawed frog, Xenopus laevis were exposed, beginning at stage 50, to a commercial pentabromodiphenyl ether mixture (DE-71) through the diet. Subsequent experiments were conducted using a single intraperitoneal injection at stage 58 with limited quantities of two purified brominated diphenyl ether (BDE) congeners, BDE47 and BDE99 and DE-71 to determine the relative potency of these BDE congeners within the commercial mixture. Significant inhibition of tail resorption, delayed metamorphosis and impacts on skin pigmentation were observed in Xenopus exposed to DE-71 in the diet at nominal doses of 1000 and 5000 microgg(-1) of food. The estimated time required for 50% of the tadpoles to complete metamorphosis was significantly lengthened in Xenopus exposed to a dietary concentration of 1 microg DE-71 per gram of food. Analysis of PBDEs (sum of 32 congeners) in Xenopus from the treatment with 5000 microgg(-1) of DE-71 indicated that the frogs accumulated an average of 1030 microgg(-1) (wet weight) of PBDEs. In the intraperitoneal injection trials, similar inhibitory responses were observed in Xenopus injected with DE-71 at a nominal dose of 60 microg per tadpole, or injected with BDE47 at a nominal dose of 100 microg per tadpole. No responses were observed in Xenopus injected with BDE99 at doses up to 100 microg per tadpole. Complete inhibition of metamorphosis was observed only in the highest DE-71 dietary treatment. The results of this study are consistent with a mechanism of action of PBDEs involving competitive inhibition of binding of thyroid hormones to transporter proteins, although the mechanism cannot be definitively determined from this study. The observed effects may have occurred through other mechanisms, including sublethal toxicity. The doses used in this study are greater than the levels of PBDEs to which anurans are exposed in the environment, so further studies are required to determine whether exposure to PBDEs at environmentally relevant concentrations can affect frog metamorphosis.     

Quantification and modelling of 2,4-dinitrotoluene reduction with high-purity and cast iron

Cast iron has been used as a reactive material in permeable reactive barriers (PRBs) for site remediation. While reactions are generally believed to occur on the iron (oxide) surface, a recent study by [Oh, S.Y., Cha, D.K., Chiu, P.C., 2002a. Graphite-mediated reduction of 2,4-dinitrotoluene with elemental iron. Environ. Sci. Technol. 36 (10), 2178-2184] showed that graphite inclusions in cast iron can also serve as reaction sites for 2,4-dinitrotoluene (DNT). These authors also found that graphite-mediated reduction of DNT has a regioselectivity that is different from that for iron surface. In this study, we quantified the observations reported by Oh et al. and examined the role of graphite in cast iron through numerical modelling. Models containing one and two reaction sites were developed to evaluate the mass transfer, sorption and reaction rates for DNT reduction in batch systems containing high-purity and cast iron. Our simulations showed that the regioselectivity, defined as the ratio of the ortho- and para-nitro reduction rate constants, was 0.37+/-0.04 S.E. (S.E.=one estimated standard error) for iron surface and 3.59+/-0.76 S.E. for graphite surface. In the cast iron-water system, we estimated that at least 66+/-2% S.E. of the DNT was reduced on graphite surface, despite the low graphite content and the lower DNT reduction rate with graphite than with iron. Graphite played such an important role because of the rapid adsorption of DNT to graphite. In the batch experiments conducted by Oh et al., external mass transfer was not rate limiting. Surface reaction was the rate-limiting step for DNT reduction on the graphite surface in cast iron, whereas internal mass transfer and/or adsorption and surface reaction were important for high-purity iron.     

不同基质对马尾松容器苗及其菌根的影响

以10种培养基质，对马尾松进行容器育苗研究．结果表明：以竹叶为基本材料配制基质，比纯黄心主基质培育的马尾松百日苗，干物质重增加对2％；与蛭石基质相比，增加43.9％；与松树皮基质相比，增加25.0％以松针为基本材料配制的基质效果近似于竹叶．两者对苗木生长的影响，与各处理相比较，均达到了极显著水平．培养基质理化性质与苗木生物量相关的矩阵分析表明，容器基质的客重和孔隙度对苗木生长影响最大;基质内有效养分含量，特别是磷含量的多少很重要．竹叶和松针作为基质，表现了良好的理化性质，促进了马尾松苗木早期菌极化，百日苗面根感染率分别比黄心土基质的百日苗提高12.9％和17.0％同时加快了苗木生长．     

鸡毛微波水解制备复合氨基酸螯合铜的实验研究

利用微波,以鸡毛为原料提取复合氨基酸,并制备复合氨基酸铜.分别通过正交实验分析出提取复合氨基酸的最优条件为:固液比为1:10,所用硫酸浓度为3 mol/L,水解时间为3 h,水解反应所需的微波功率为360 W;制备复合氨基酸螯合铜的最优条件为:物料比为1:2,反应的pH为6,反应的温度为60 ℃,反应的时间为80 min.