H2O2∕UV-C and Fe2+∕H2O2∕UV-C versus TiO2∕UV-A Treatment for Reactive Dye Wastewater

This study investigated the advanced oxidation of commonly used reactive dyestuffs in exhausted dye-bath effluents in homogeneous (H2O2∕UV-C and photo-Fenton) and heterogeneous (TiO2∕UV-A) media. Photocatalytic treatment efficiencies of two different TiO2 powders (PC 500 and Mikroanatas) and the platinized Degussa P25 were compared with that of the more well-known Degussa P25 in varying pH media. Treatment performance was strongly affected by the initial H2O2 concentration for H2O2∕UV-C and photo-Fenton oxidation systems, whereas for the TiO2∕UV-A process only PC 500 TiO2 powder, an anatase crystal phase of the semiconductor, exhibited a significantly pH-dependent reaction efficiency. The decolorization rate followed the order of Fenton∕UV-C > Pt-P25∕UV-A > Mikroanatas∕UV-A > P25∕UV-A > PC 500∕UV-A > H2O2∕UV-C, whereas the decreasing order for total organic carbon reduction was Fenton∕UV-C > H2O2∕UV-C > Mikroanatas∕UV-A > Pt-P25∕UV-A > P25∕UV-A > PC 500∕UV-A for the studied reaction conditions. Removal of optical density at 254-nm wavelength ranged between 75 and 96%.     

First Public-Private-Partnership Application in Taiwan’s Wastewater Treatment Sector: Case Study of the Nanzih BOT Wastewater Treatment Project

Taiwan has been promoting public-private-partnership (PPP) projects in the wastewater treatment sector with the aim of improving its sustainable environment and increasing its wastewater treatment rate. The Nanzih Wastewater Treatment Project is the first PPP application in Taiwan’s wastewater treatment sector. It provides important experiences and lessons for both the public and private sectors. This paper presents a detailed study of its tender process, concession agreement, financial structure, payment mechanism, and risk management. It explains the key features of the project and provides conclusive findings on the lessons learned. These observations should be useful for practitioners and academia who are interested in the development of future PPP wastewater treatment projects in Taiwan.     

Pyrolysis-GC∕FID Test for Biogenic Interference in Contaminated Soil

“Biogenic interference” is that portion of natural organic matter in soil that cannot be distinguished from petroleum in a standard test for contamination. Biogenic interference is normally a small fraction of total natural organic matter. In organic soils, however, biogenic interference alone can exceed “petroleum” limits set by regulatory agencies. A test using a pyrolysis-gas chromatograph∕flame ionization detector (GC∕FID) was developed to quantify biogenic interference in soil samples from northern Alaska. The samples had no known history of contamination, so all measured “petroleum” was derived from biogenic interference. The pyrolysis test was found to predict biogenic interference in soil samples more accurately than any combination of standard soil tests, including C:N ratio, pH, percent organic carbon, extractable carbon, humic acids, fulvic acids, low molecular weight acids, hydrophobic neutrals, and hydrophilic neutrals. Analysis of samples contaminated in the laboratory confirmed that the pyrolysis test could quantify biogenic interference in soils recently contaminated by petroleum.     

Web-Centric Framework for Secure and Legally Binding Electronic Transactions in Large-Scale A∕E∕C Projects

Typical architecture∕engineering∕construction (A∕E∕C) projects are technically, socially, and economically complex in terms of planning, management, and execution. In order to conduct day-to-day operations within the project (allocating funds and resources), the organizations involved in large-scale A∕E∕C projects participate in contractual transactions. Currently, these transactions are primarily conducted in the form of paper-based contracts, but there is a need to automate them, leveraging the advancements in information technology. Due to the legal weight of these contracts, electronic transactions need to be as secure and binding as paper-based transactions; the absence of a framework to achieve this has prevented large-scale automation, in spite of the presence of a host of web-based project management services. In this paper, we address the security concerns in conducting legally binding electronic transactions in large-scale A∕E∕C projects by developing a framework for conducting secure and legally binding electronic transactions. We also discuss the issues related to the implementation of such a framework at the decade-long $13.6 billion Central Artery∕Third Harbor Tunnel Project in Boston, Massachusetts.     

Fate of Anionic Surfactants in a 38?ML/Day UASB-Based Municipal Wastewater Treatment Plant: Case Study

The outcome of a 15-month monitoring study (August 2004–October 2005) on the anionic surfactants (AS), at the 38?ML/day up-flow anaerobic sludge blanket (UASB)-based sewage treatment plant (STP) is described. The average removal of AS was only around 57%. Appreciable concentration of AS was being discharged to the watercourse (average 2.41?mg/L; range 0.63–5.16?mg/L). On an average dried sludge contained 1,560?mg?AS?kg?1 dry weight. Mass balance indicated that, AS load of the orders of 23 and 33% is removed by adsorption in UASB reactors and polishing ponds (PP), respectively. Biodegradation of AS under anaerobic conditions in UASB reactors and PP does not seem to take place. In the sludge stream, appreciable biodegradation ( ≈ 70%) of adsorbed AS under aerobic conditions on the sludge drying beds takes place. If influent AS mass flux is normalized to 100?units, than 43 and 7?units are discharged with treated effluent and dried sludge, respectively, whereas 33 and 16?units are adsorbed/settled in PP and aerobically biodegrade on sludge drying beds, respectively.     

Numerical Simulation for Induction Refining Process of Metallurgical-Grade Silicon in Vacuum Furnace

The temperature and velocity distribution of melting pool fields is very important effect to the silicon purification in vacuum induction furnace.A numerical model for the electromagnetic-thermal-hydrodynamic coupling fields have been developed by using the f’mite element method(FEM)and a 2D numerical simulation for electromagnetic、temperature and velocity fields of metallurgical-grade silicon melting in vacuum induction furnace were performed with a software Multi-physics Comsol 3.5a in this paper.The results showed that the temperature field was dependent observably on input power of coils and induction heating times and the maximum temperature gradient in melting pool was 215K in holding time.With the silicon molted gradually a clockwise vortex was come into being for electromagnetic stirring in the smelting poor.The variation of velocity field in melting silicon is mainly influenced with the change of the current intensity and power frequency.The numerical predications of temperature distribution are in good agreement with experiments.     

Calculating Method for Influence of Material Flow on Energy Consumption in Steel Manufacturing Process

 From the viewpoint of systems energy conservation, the influences of material flow on its energy consumption in a steel manufacturing process is an important subject. The quantitative analysis of the relationship between material flow and the energy intensity is useful to save energy in steel industry. Based on the concept of standard material flow diagram, all possible situations of ferric material flow in steel manufacturing process are analyzed. The expressions of the influence of material flow deviated from standard material flow diagram on energy consumption are put forward.     

Broadside Compensation Rolling Model for Plan View Pattern Control in Wide and Heavy Plate Rolling Process

On the basis of a 5 m plate mill, a 3D rigid-plastic finite element （FE） model was developed to investigate changes of plate plan view patterns during hot rolling process. By analyzing the simulation results of conventional rolling processes, it was found that the plate plan view pattern was closely related to broadside rolling ratio. Then, the prediction models for plate plan view patterns were formulated by nonlinear regressive analysis of the simulation results and modified for high accuracy. Based on these models, the broadside compensation rolling method perform- ing at the last pass of broadside rolling phase was designed to decrease plate end crops. Comparing the plate plan view patterns with and without broadside compensation roiling, reduced plate end crops indicate that the broadside compensation roiling model is effective for plate plan view pattern control.     

Growth Rate,Microstructure and Phase Composition of Oxide Scales for Three Typical Steels in Simulated Continuous Casting Process

Growth rate,microstructure and phase composition of scale layer formed during oxidation in 56%H2O-9%O2-N2 and following continuous cooling in ambient air were experimentally investigated by means of optical microscopy,scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS)and X-ray diffraction(XRD)for45,20 CrMnTi and TTS443 Msteels respectively,to examine the effects of strand surface temperature and steel composition on the scale formation in simulated continuous casting process.The growth rates were found to be approximately parabolic and the calculated activation energy of TTS443 Msteel is much higher than those of the two other steels.For 45 and 20CrMnTi steels,the scale layers were looser and a distinct gap formed at the scale-substrate interface at higher strand surface temperature.The dominant phases within the scale were iron oxides except for FeO·Cr2O3phase simultaneously existing in the oxide scale of 20 CrMnTi steel.On the other hand,the scale layer formed on TTS443 Msteel was compact and tightly attached to the steel surface.At both lower and higher strand surface temperature,iron oxide was main phase in external layer of the scale,while chromia was dominant in inner layer with an appreciable Cr enrichment.     

Understanding the Initial Solidification Behavior for Al–Si Alloy in Cold Chamber High-Pressure Die Casting (CC-HPDC) Process Combining Experimental and Modeling Approach

Metallurgical and Materials Transactions A - In the cold chamber high-pressure die casting (CC-HPDC) process, alloy solidification in the shot sleeve due to heat loss leads to the formation of...