Novel fry-drying method for the treatment of sewage sludge

The purpose of this study is to introduce an efficient drying method named “fry-drying technology” for the treatment of sewage sludge. The basic principle of this method lies in the rapid escape of moisture from sludge material through its pores into the oil medium driven by the strong pressure gradient formed between sludge and oil media. This beneficial pressure distribution for moisture transfer can be established by the subtle combination of the difference of physical properties of specific heat and boiling temperature between water and oil. In order to determine the physical characteristics of this fry-drying technology, a series of experiments were performed in which important parameters, such as heating oil temperature, drying time, oil type, and sludge size, were varied. Numerical calculations using a single solid spherical particle model without any porosity were used to resolve the particle size effect associated with sludge drying.     

Fecal source tracking based on fecal coliform concentration and bacterial community structure in the Bong stream,Korea

Environmental Science and Pollution Research - Fecal source tracking of the Bong stream, a representative inland pollutant around the drainage basin of Gangjin Bay (an area where shellfish are...     

Study of anaerobic co-digestion on wastewater treatment sludge and food waste leachate using BMP test

Journal of Material Cycles and Waste Management - The study conducted basic component analyses including three component analyses, elementary analysis and heavy metal content and BMP test according...     

Environmental policy innovations in China: a critical analysis from a low-carbon city

The Chinese state is squarely ‘back’ in the business of environmental governance with an increasing number of policy innovations or experiments to resolve environmental issues. These have been mostly enacted through the ‘experimentation under hierarchy’ framework, undergirded by compensation-for-performance incentive structures for local agents. Based on on-site ethnography in local China, a critical analysis is presented of low-carbon city policy experiments – one of the most prominent environmental policies introduced in the past decade. Using lessons from the agency theory, it is hypothesized that outcomes of these policy innovations are contingent on different policy dimensions. Although a number of positive outcomes have been achieved in output-oriented dimensions, the fundamental difficulty of specifying all aspects of complex, multidimensional work tasks involved in low-carbon city development has frequently led to policy unmaking. The findings raise important questions about China’s tendency to rely excessively on compensation-for-performance structures to promote environmental policies.     

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.     

Correlation study of hazardous waste characteristics among various chemical processes in Republic of Korea

To harmonize with international standards, the Republic of Korea is in the process of converting its current hazardous waste classification system and setting up regulatory standards for all toxic substances present in hazardous waste. Detailed characterization of each form of hazardous waste belonging to five chemical processes and their correlations were studied. In the present work, the concentrations of 13 heavy metals, F^?, CN^?, 7 PAH compounds, total PCDD/F and 7 PCB isomers present in the hazardous waste generated among chemical processes such as synthetic rubber (SR), man-made fibers (MF), organic dyes and pigments (DP), pharmaceuticals and cosmetics were analyzed along with their leaching characteristics. Comparing all the processes, most of the heavy metal concentrations were high in SR waste. Naphthalene was the dominant PAH in most of the chemical process waste. PCDD/F concentrations of the samples were in the range of 0.001–0.003 ng I-TEQ/g. PCB isomer-101 and isomer-118 were found to be slightly higher than the permissible limit in the SR filter cake sample. SR process wastes doesn’t show any resemblance with the other process waste in either the heavy metals and PAH trend. Each sample from DP and MF were suitable only for hazardous waste landfill.     

Understanding American and Korean Students’ Support for Pro-environmental Tax Policy: The Application of the Value–Belief–Norm Theory of Environmentalism

By using the value–belief–norm theory of environmentalism, this study investigates American and Korean college students’ support for pro-environmental tax policy as a way to address global climate change. The results indicate that environmental concern and the perceived severity of climate change were significant predictors of one's tax policy support. Perceived individual responsibility for addressing climate change mediated the relationship between environmental beliefs (i.e. environmental concern and perceived severity) and tax policy support for Koreans. Such relationship was not observed among Americans. This study also examines whether political ideology functions as a predictor of tax policy support. For Americans, political ideology was a significant factor in predicting one's tax policy support and that it remained significant even after the inclusion of more proximal predictors—environmental concern and perceived severity. For Koreans, however, political ideology was not a significant factor. Theoretical and practical implications are discussed.     

1H-NMR-based profiling of organic components in leachate from animal carcasses disposal site with time

Leachate, generated by the decomposition of animal carcasses, presents many environmental, sanitary, and food safety hazards. However, research on the characteristics of leachate is lacking. In this study, we performed biochemical profiling of leachate from two animal species (pig and cattle) in two soil types (sandy loam and sandy soil) using ¹H-NMR-based profiling, followed by multivariate data analysis. The leachate was collected from a well-controlled artificial burial site over a 31-week period. Principal components analysis (PCA) of the NMR data showed similar patterns between species and soil types. Organic components, including organic acids and phenols, predominated, and their levels increased with time. The methylamine level in leachate from pig carcasses 18 weeks following burial was significantly higher than that from cattle carcasses; leachate from cattle carcasses in sandy soil 1 week after burial contained unique components (specifically ethanol, formate, alanine, N-methylation, and taurine), in contrast with those from sandy loam soil. This study suggests that a NMR-based profiling approach is useful to characterize the organic components in leachate from animal carcasses over time.     

The effective control of major industrial accidents by the Major Industrial Accident Prevention Centers (MAPC) through the Process Safety Management (PSM) grading system in Korea

This paper examines effectiveness of a regulatory enforcement organization (Major industrial Accident Prevention Center, MAPC), and a grading system for implementation of the Process Safety Management (PSM) regulation in Korea. A lot of chemical installations have been built in Korea since the 1960s. The frequent occurrence of major industrial accidents had made people's concerns grow. The Korean government enacted PSM regulations in 1996 in order to curb these accidents.However, a key question is how to make sure companies comply with the PSM regulations. In order to improve company’ compliance with PSM regulations the Ministry of Employment and Labor (MOEL) responsible for the regulation introduced a grading management system in 2001 and then established special supervisory centers for enforcement of PSM regulations in 2005. This paper reviews the role and effectiveness of the system in term of PSM enforcement. The author found that the grade-based approach has encouraged employers to implement the requirements of the PSM regulations. MAPCs play an effective role in enhancing enforcement performance. Although the more chemical plants have been established in Korea, the fewer major industrial accidents have occurred since the introduction of the system. The results may be useful for the policy maker to build an effective and efficient enforcement system.