Removal of pollutants of landfill leachate by recirculation

SAfter leached from municipal solid waste landfill was treated by recirculation, the concentration of pollutants decreases greatly, and the moisture content of the solid waste in landfill site was increased and waste stabilization rate was accelerated. Compared with traditional treatment methods, this method offers more important practical values, including short investment, enhanced treatment efficiency and facilitated operation and management. The experimental results indicated that a 99.9% removal of ammonia nitrogen and an 80.5% removal of COD were obtained, when hydraulic power surface load is 15.92 L/m^2·d, and organic surface load is 25.54 g/m^2·d.     

Influence of the Plasma State on the Formation of Nano Crystalline SiC Films

The influence ofthe plasma state on the microstructure transformation from amorphousto nanocrystalline state is emphasized during the formation of the silicon carbide (SIC) films deposited by the plasma enhanced chemical vapor technique. The effect of two key parameters, the working pressure and hydrogen concentration in the gas flow, that perform the dependence by modulating the two essential factors of the plasma stateions energy and gas composition, is in-depth investigated. The experimental results showed that nanocrystalline SiC films fit for field emitters could be achieved under an appropriate ion energy flow density and gas components in the plasma.     

Fouling Characteristics and Prevention Techniques for Membrane Bioreactor

Membrane fouling is the main problem of membrane bioreactors (MBR), which seriously influences its wastewater treatment effect and running. The characteristics of microbiology and hydrodynamics concerning membrane fouling were investigated and the measure was put forward for optimum operation of MBR. The measure is that 1) the parameters of activated sludge concentration (X) and membrane flux should be lower than the critical values of X and membrane flux respectively, and 2) the activated sludge should be discharged periodically. The experimental results show that the combination backwashing of gas and permeated effluent is better than single gas backwashing or single permeated effluent backwashing. This technique can remove the cake layer deposited on the membrane surface, decrease the membrane fouling, and recover the membrane flux effectively. So it is effective for prevention of membrane fouling.     

Impact of artificial waterfall using reclaimed water to VOCs and its health risk assessment

To study the impact of an artificial waterfall using reclaimed water on volatile organic compounds （VOCs） in air, air samples around the waterfall sight and over the CASS pond of a wastewater treatment plant were collected and VOCs were analyzed by MC-MS with USEPA Method TO-14. The total volatile organic compounds （TOVCs） concentration of a background sample is 2112 μg/m^3, and the sample over the CASS pond has a TVOC concentration of 1858μg/m^3. The TVOC concentrations of air samples within 10 m of the artificial waterfall are between 3216 μg/m^3 and 6362 μg/m^3, which are 1.52 - 3.0 times that of the background sample. The VOCs in air sample impacted by reclaimed water or waste water exhibit a relatively high proportion of toluene but low proportion of benzene. B/T/E/X （ Benzene/Toluene/Ethylbenzene/Xylene ） ratio of the air sample around the artificial water fall is（O. 36/11.78/1/1.10）. Health risk assessment （HRA） was done with the USEPA four-step approach. The result indicates that the artificial waterfall using reclaimed water indeed leads to the increase of human risk value. The total risk value of the sample around the waterfall is 2. 8 - 1.6 times that of the background sample. However, the total risk value of the air sample around the waterfall （2. 8 × 10^-6 ） for common people is still lower,compared to the acceptable public risk level（ 10^-5 ）. For occupational workers of the wastewater treatment plant, the sum of lifetime non-carcinogenic and carcinogenic risk values （ 1.26 × 10^ -5 ） is higher than that of the acceptable public risk level.     

A preliminary study on total removal efficiency of organic pollutants in sewage by Harbin municipal sewage treatment plant

To evaluate the removal efficiency of organic pollutants in the sewage by Harbin municipal sewage treatment plant,the influent and effluent samples from the plant were pretreated by liquid-liquid extraction (LLE) under conditions of acidity,neutrality and alkalescence in sequence,and then were analyzed by gas chromatograph-mass spectrum (GC-MS) procedures.Results indicate that there are 70 species of organic pollutants in the influent sample of the plant,which mainly consist of alkyls,benzene series,esters,and heterocyclic compounds.Some of these organic pollutants are biotoxic and belong to persistent organic pollutants (POPs).Four species among them are on the list of Prior Pollutants of Environmental Protection Agency of USA (USEPA).However,7 species of organic pollutants appearing in the effluent sample mainly include alkyls of multi-carbons and phthalate esters.The removal efficiency of phthalates is poor because of their poor biodegradability.The sewage treatment technique is effective in removing most of organics pollutants.     

Influence of operation parameters on flash smelting furnace based on CFD

The influence of three important operation parameters in Jinlong flash smelting furnace, including the distributing blast speed, the oxygen enrichment rate of process air and the ratio of central oxygen to overall oxygen (Oc/Oo), has been investigated using a virtual simulation system on copper flash smelting furnace. The core of this virtual simulation system is a numerical simulation of CFD (computational fluid dynamics), and this system incorporates coupling momentum transport, heat transport, mass transport,reaction kinetics between gas and particles and chemical reactions between gas and gas. A set of numerical predicted data were obtained. The CFD simulation shows that there is a sensitive zone of the distributing blast speed, and the dust content ascends when thespeed exceeds 180 m.s^-1. Increasing the oxygen concentration of processing air benefits the efficient production of the flash smelting furnace.     

The Cement Solidification of Municipal Solid Waste Incineration Fly Ash

The chemical composition, the content and the leachability of heavy metals in municipal solid waste incineration （ MSWI） fly ash were tested and analyzed. It is shown that the leachability of Pb and Cr exceeds the leaching toxicity standard, and so the MSWI fly ash is considered as hazardous waste and must be solidifled. The effect of solidifying the MSWI fly ash by cement was studied, and it is indicated that the heavy metals can be well immobilized if the mass fraction of the fly ash is appropriate. The heavy metals were immobilized within cement hydration products through either physical fixation, substhtaion, deposition or adsorption mechanisms.     

Feasibility of Combustion of Petroleum Coke in 230t／h Circulating Fluidized Bed Boiler

In order to reuse the high sulfur petroleum coke, the waste in chemical industry, as fuel of power plant for energy recovery, the combustion property of petroleum coke was researched experimentally in circulating fluidized bed (CFB) boiler. The performance of the boiler in burning mixed fuel with different ratios of coal to petroleum coke is obtained. Based on the experimental data, Factors influencing the stability of combustion, thermal efficiency of boiler, and emissions and desulphurisation are discussed. This study demonstrates that the combustion of petroleum coke in CFB boiler is applicable, and has great significance on the design and operation of CFB boiler to burn petroleum coke.     

Natural Fresh Proteins Directed Hierarchically Porous Nitrogen-doped TiO_2 as with High Performance as Photocatalyts and Electrode Materials

Fresh EPF proteins from Liangzi Lake were employed as a template to synthesize hierarchically porous nitrogen-doped TiO_2 in a single process.The experimental results show that N-TiO_2 sample exhibits significantly enhanced visible-light photocatalytic activity in both chemical waste treatment and hydrogen production,and the visible-light photocatalytic activities vary with the concentrations of EPF proteins.The optimal concentration of protein is 600 mg·mL~(-1) and the degradation of RhB could be almost completed in just 25 min.Furthermore,the performance of as-synthesized TiO_2 as an electrode for Li-ion battery can be also regulated by the EPF proteins.Natural extrapallial fluid (EPF) proteins extracted from the same kind of mussels living in different regions have significantly different effects on the performances of TiO_2 as electrode materials for Li-ion battery.The present work highlights the unimaginable effects of natural organic matrix on the synthesis of advanced materials with optimized functional properties.     

Pretreatment of Corn Stalk by Steam Explosion

A steam explosion pretreatment,which is one of the best ways of pretreating plant stalk,is applied at various severities to corn stalk.It could effectively modify the super-molecular structure of com stalk and defibrat-ing corn stalk into individual components.The relationship between yield of reducing sugar and the operating con-ditions,including temperature,pressure of steam explosion pretreatment and acidity,is also established.Experi-mental results prove that the steam explosion substantially increases the yidld of reducing sugar,and the optimal condition for steam explosion is as follows;the pressure is 2.0MPa,the pressure-retaining time 300s,the initial acid concentration 1%and the acid treatment time 24h.     

生物膜填料塔净化低浓度CS2废气的实验研究

介绍了生物膜法净化低浓度CS2、H2S含硫废气的基本原理，采用生物膜填料塔进行了净化低浓度CS2废气的实验研究．结果表明：生物膜填料塔在最佳操作条件(进口气体浓度100mg／m^3、气体流量0．1m^3／h、循环液流量20L／h、pH=4．0)操作时，对CS2去除率可达到80％．表明生物膜填料塔净化低浓度的CS2废气是可行的．     

采用错流式生物滴滤反应器净化甲苯废气

为了解决生物滴滤塔有效降解空间低,压降高,易堵塞等问题,采用错流式生物滴滤反应器,以单一底物甲苯驯化的纯菌种恶臭假单胞菌为菌源接种,陶粒为填料,处理含甲苯废气.研究了反应器的挂膜启动、不同停留时间、不同体积负荷以及营养液温度对反应器甲苯处理能力的影响.反应器挂膜启动仅需要7d,挂膜成功后,停留时间为144、72、48和36s时,最大体积去除负荷为276.62g/(m~3·h),营养液最佳温度为28～34℃.结果表明,采用错流式生物滴滤反应器净化甲苯废气是一种可行有效的的工艺,设备结构和操作方式的改变提高了生物降解的有效空间,并可以有效调节反应器内的湿度,适于大气量挥发性有机废气的治理;停留时间的变化对反应器处理性能的影响较小,且可以迅速恢复;控制营养液温度可以调整反应器微生物生存的环境温度,从而提高反应器去除效率.     

规整填料内乙醇胺吸收CO2的计算流体力学模拟

为模拟规整填料单元内乙醇胺吸收烟气二氧化碳的过程,利用计算流体力学(CFD),考虑包含化学反应气液质量传递过程,建立伴有二级化学反应的气液两相流动模型.通过改变吸收过程的操作条件,如气液入口流量比、CO_2入口质量分数、乙醇胺入口摩尔分数、压强等,分析吸收塔规整填料单元内碳捕捉过程的影响因素.CFD模拟结果表明:CO_2吸收率随乙醇胺浓度与压强的增大而升高;随烟气CO_2浓度与气液流量比的增大而下降;对各影响因素影响定量排序,乙醇胺浓度对吸收效率影响最突出,其次依次是CO_2入口浓度、气液入口流量比、压强.模拟与试验结果相吻合,得出了相应的最优参数.     

地铁站板式蒸发冷却器叉流条件下传热传质特性

在气液叉流条件下,采用非接触式红外热成像测温方法,就不同气相雷诺数和液膜雷诺数对地铁站板式蒸发冷却器液膜传热传质特性影响进行了实验研究,结果表明：对于确定的被冷却水温,在液膜雷诺数增加的过程中,液膜厚度逐渐增加,进出口温差逐渐减小,削弱液膜换热,但雷诺数上升使得液膜湍动强度增强,强化了液膜换热,在这2个因素的协同作用下,存在最佳液膜流动雷诺数,使得液膜的换热热阻最小,传质最强,换热系数最大。     

生物滴滤池净化废气生物膜的培养过程研究

研究了处理甲苯废气的生物滴滤床生物膜的培养与驯化过程。在 2 0～ 2 5℃的温度条件下 ,以鲍尔环和阶梯环填料为载体 ,实现生物滴滤池的快速挂膜与驯化。接种污泥的性能、湿度和营养液的pH和循环量是影响生物滴滤池挂膜和驯化的主要因素。     

低浓度苯乙烯废气的生物法处理

采用生物膜填料塔进行了净化低浓度苯乙烯废气的实验研究及生物膜内微生物菌群分析.研究结果表明:进口气体中苯乙烯浓度为1 000 mg/m3以下、流量为200 L/h、循环液流量为10 L/h的操作条件下,废气中苯乙烯的去除率可达90%以上.依据实验结果数据,对相关的机理问题进行了分析探讨.     

生物滴滤塔去除废气中一氧化氮

采用生物滴滤塔反硝化去除废气中NO,分别以活性炭和陶粒作为填料,研究了碳源、喷淋液量、气体流量、进气浓度及氧气体积含量对去除效果的影响,并对两种填料进行了对比.结果表明:甲醇比乙醇和葡萄糖更适宜做反硝化去除NO的碳源.NO废气的进气流量越小,进气浓度越低,去除效果越好.在实验范围内,喷淋液的流量对滤塔的去除效果几乎没有影响.反硝化处理NO时,为保证较高的去除效率,氧气体积含量应控制在4%以下.从运行过程和去除效率来看,所使用的柱状活性炭填料要优于所用的陶粒填料.     

T型管内两相流分配特性数值模拟

T型管内气液两相流分配不均易导致换热器偏流和受热不均。为了优化T型管内气液两相流流动,以FLUENT为模拟软件,以流体流动参数和管子几何结构为研究变量,对T型管内流体流动进行数值模拟。发现流体入口液相体积分数越大,入口速度越小,液滴粒径越小,越利于流体均布;同时支管衔接处采取弯管结构较直管结构优越,其中入口速度对流体分布影响最明显,速度相差3个数值即可优化两个出口液相体积分数比差10%左右。结果表明,相应改变流体流动参数和管子几何结构能有效优化T型管内流体流动。     

液幕式烟气脱硫塔气液两相流动特性研究

针对液幕塔这一新型湿法烟气脱硫装置,从喷嘴的射流特点出发,对回落液幕分布规律、液滴的粒径分布和液幕塔内气液流动特点进行了分析,结合试验结果理论分析了顺流/逆流吸收塔内液幕床层高度并分别对烟气速度、液气比对床层压降的影响进行了试验研究。得到了液幕床层高度计算公式和床层阻力系数计算的关联式,为液幕塔的设计和优化提供了基础性试验数据。     

毛细作用气液分离过程的理论分析

针对分液冷凝换热器的毛细作用气液分离流动过程,建立了稳定流动情况下的一维数学模型.模型综合考虑了静压、重力、毛细压力、切应力的影响 ;考察了在稳定状态下孔径、孔数以及其组合方式对液膜高度的影响,同时还考察了入口干度和流量对液膜高度的影响;发现孔径和孔数对液膜高度影响基本相同,都是随着数值的增大而液膜高度减小.孔径为1.3 mm、孔数为8时液膜高度都分别为零,气液分离失效,但是干度和流量的对液膜高度影响趋势却相反.在干度为0.5、流量为0.058 kg/s时液膜高度也都分别为零,气液分离失效.