Assessment of the ecodesign improvement options using the global warming and economic performance indicators

In this paper, an assessment method is proposed for ecodesign improvement options using global warming and economic performance indicators. A reduction in the GHG emissions in the entire life cycle stages of a product was chosen as the global warming performance of the product. The external cost which converts the external effect of global warming into a monetary value was chosen as the global warming performance indicator in order to measure the performance of the GHG reduction of the product. The life cycle cost (LCC) of the product was chosen as the economic performance indicator to measure the performance of the life cycle cost reduction of the product. The assessment method based on the two performance indicators was applied to the liquid crystal display (LCD) panel for a case study.     

Construction of a chemical ranking system of soil pollution substances for screening of priority soil contaminants in Korea

The Korean government recently proposed expanding the number of soil-quality standards to 30 by 2015. The objectives of our study were to construct a reasonable protocol for screening priority soil contaminants for inclusion in the planned soil quality standard expansion. The chemical ranking system of soil pollution substances (CROSS) was first developed to serve as an analytical tool in chemical scoring and ranking of possible soil pollution substances. CROSS incorporates important parameters commonly used in several previous chemical ranking and scoring systems and the new soil pollution parameters. CROSS uses soil-related parameters in its algorithm, including information related to the soil environment, such as soil ecotoxicological data, the soil toxic release inventory (TRI), and soil partitioning coefficients. Soil TRI and monitoring data were incorporated as local specific parameters. In addition, CROSS scores the transportability of chemicals in soil because soil contamination may result in groundwater contamination. Dermal toxicity was used in CROSS only to consider contact with soil. CROSS uses a certainty score to incorporate data uncertainty. CROSS scores the importance of each candidate substance and assigns rankings on the basis of total scores. Cadmium was the most highly ranked. Generally, metals were ranked higher than other substances. Pentachlorophenol, phenol, dieldrin, and methyl tert-butyl ether were ranked the highest among chlorinated compounds, aromatic compounds, pesticides, and others, respectively. The priority substance list generated from CROSS will be used in selecting substances for possible inclusion in the Korean soil quality standard expansion; it will also provide important information for designing a soil-environment management scheme.     

Feasibility of On-line Measurement of Sewage Components Using the UV Absorbance and the Neural Network

The objective of this study was to test the feasibility of a new method to improve the accuracy in the estimation of sewage components. Adding to the regression of sewage components with UV (ultraviolet) absorbance values, a proposed method considered an unclear but existing relationship among characteristic of sewage production. Sewage production showed very defined profiles due to the daily human activities. So the main idea was the combination of measuring the UV absorbance values and analyzing the characteristics of the sewage production. For this purpose, 446 sewage samples taken at every 2-h interval for 51 days at a wastewater treatment plant were statistically analyzed using neural network (NN). NN was trained with 350 data sets (about 29 days) of UV absorbance values, flow rate and time. And as a result, it could predict 96 data (12 days) as a validation, indicating that estimation accuracies were improved to higher level than those of the linear regressions. The proposed method could estimate concentrations of total nitrogen (TN) and total phosphate (TP) within practical accuracies as well as total suspended solid.     

Effect of CO on NO oxidation over platinum based catalysts for hybrid fast SCR process

The oxidation characteristics of NO over Pt/TiO2 (anatase, rutile) catalysts have been determined in a fixed bed reactor as a function of O2, CO and SO2 concentrations in the presence of 8% water. The conversion of NO to NO2 increases with increasing O2 concentration up to 12% and it levels off. This saturation effect is more pronounced over rutile-Pt/TiO2 (r-Pt/TiO2) than that of anatase-Pt/TiO2 (a-Pt/TiO2). The presence of CO increases NO oxidation significantly and this enhanced effect is more pronounced on a-Pt/TiO2 than that on r-Pt/TiO2 with increasing CO concentration at lower temperatures. The same effect is also observed on the catalysts with different Pt and tungsten oxide (WO3) loadings. With increasing Pt and WO3 loadings on TiO2 support (Pt-WO3/TiO2), formation of NO2 is high even at lower temperatures. The presence of SO2 significantly suppresses the oxidation of NO over both r-Pt/TiO2 and a-Pt/TiO2 catalysts but it is less pronounced due to low stability of sulfate on a-Pt/TiO2.     

电解法处理酵母废水的研究

对生化处理后的难降解酵母废水进行了电解氧化研究。研究了絮凝剂、电解质(NaCl)、电流强度、pH值对COD、色度去除率的影响,并对其作用机理进行了分析。     

Sorption of hydrophobic organic compounds onto organoclays

The behavior and fate of nonionic hydrophobic organic compounds (HOCs) in the environment are mainly controlled by their interactions with various components of soils and sediments. Due to their large surface area and abundance in many soils, smectites may greatly influence the fate and transport of the contaminants in the environment. In our experiments, HOC sorption by hexadecyltrimethylammonium (HDTMA)-modified smectite linearly increased with the amount of HDTMA added to the clay. However, tetramethylammonium (TMA)- and dodecyltrimethylammonium (DTMA)-modified smectites showed not only inferiority in their sorption of HOC compared with the HDTMA-smectite, but also a partially decreased HOC sorption at specific surfactant loading levels. This means that the sorption of organoclays for organic contaminants was significantly influenced by the amount and size of the surfactants added on the clay. In addition, it seems that the interlayer structure (e.g., pore size) formed at each surfactant loading level plays an important role to adsorb HOC in different amount.     

Utilizing a database to interpret leaching characteristics of lead from bottom ashes of municipal solid waste incinerators

This study focuses on evaluation and quantification of factors affecting leachability of lead from bottom ashes of municipal solid waste incinerators (MSWI) by utilizing a database. The database, which was constructed with data collected from sources such as research papers, questionnaires and reports, consists of 1149 data sets on 508 MSWI plants. Factors chosen as affecting lead leachability included: pH in the leachate, loss on ignition of bottom ash, total content of lead, and content of main elements such as Fe, Mn, Si and Al. The lead leachability was reduced to a minimum at neutral pH, increased with increasing pH and, especially, showed an abrupt increase at pH levels above 12. The main factor controlling the pH of the leachate appeared to be leachable Ca(2+) originating from portlandite (Ca(OH)(2)). Leaching concentration increased with increasing total contents of lead, and the relationship between leaching of lead and loss on ignition showed no distinct tendencies. The lead leaching ratio increased with decreasing total contents of Si, Mn and Fe. It is evident, therefore, that these numerous factors determine the leachability of lead in a simultaneous and complex manner.     

Longitudinal‐Vertical Hydrodynamic and Turbidity Simulations for Prediction of Dam Reconstruction Effects in Asian Monsoon Area1

Abstract: This research investigates possible impacts of enlarged water body according to dam reconstruction on the hydrodynamics and water quality of the reservoir using a laterally averaged, two‐dimensional hydrodynamic and transport model, CE‐QUAL‐W2. The lake was formed by the artificial dam in 1983 for agricultural water supply and is currently under consideration of reconstruction so as to expand the volume of reservoir for flood control as well as water supply in downstream areas. To calibrate and validate the model, field‐collected data were compared with model predictions for water level fluctuations and water temperature during the years of 2001 (from January to December) and 2003 (from March to November). The model results showed a good agreement with field measurements both in calibration and verification. Utilizing the model, impacts of dam reconstruction on the thermal hydrodynamics and turbid current were predicted. From the model results, dam reconstruction limited the depth of thermal stratification below 10 meter and formed steep temperature gradient between epilimnion and hypolimnion. The restricted thermal stratification persisted up to the end of September. This result indicated that thermal stratification would become stronger during summer and stay longer after dam reconstruction. In addition, the restricted thermal stratification caused vertical circulation of water mixing lower than 10 meter and isolated the upper water layer from the lower water layer which increased the volume of hypolimnetic water with low temperature. The vertical circulation near the surface also mitigated propagation of density plume within the depth of 10 m which would remain the hypolimnetic water clean.