Electrostatic enhancement of moving-bed granular filtration

The electrostatic granular filter developed by Combustion Power Company combines a moving-bed filter with an electrostatic grid for high-efficiency collection of particulate. The coulomb charge occurring naturally on particulate from combustion or other processes in which tribocharging occurs is sufficient such that imposition of an electric field substantially enhances mechanical collection in the packed filter. A mathematical model is presented which accounts for the major parameters affecting electrostatic performance. Experimental data developed in an industrial unit retrofitted with electrostatic equipment and a pilot-scale filter demonstrates dramatic improvement in opacity and outlet loading; the industrial unit achieved 99% collection efficiency with less that 4 Iwd (1kPa) pressure drop. Data from the pilot-scale filter has shown that collection of micron-size particulate is especially enhanced with the electric field and has confirmed the 99% overall collection capability demonstrated in the industrial unit. The design of a 420,000 acfm (1200 m³/min) system being installed at Weyerhaeuser Company's Longview, Washington plant is also discussed.     

Secondary materials and international trade

The paper develops the international trade dimensions of recycling. It begins by outlining the sources of demand and supply that determine the volume, composition and direction of trade in waste materials. The model is intended to describe factors affecting international flows of any type of secondary material, although its usefulness in an empirical context is restricted in many cases by data limitations and complex lag structures on the supply side. Parts of the model are then applied to the case of waste paper, focusing on observed differences in national recycling rates and the role of trade in reconciling those differences.     

Applying a TQM framework to the public policy process: Part I—the framework

In Part I of this article, a TQM framework is described that can be used to analyze as well as manage the public policy process. Key elements of the framework include leadership, issues analysis, goal and policy development, strategic vehicles, implementation, indicators and outcomes, and stakeholder review. The framework can be used to analyze public policy cycles, predict future issues and outcomes, and develop more sustainable approaches to manage linked economic, environmental, and societal issues. In Part II, the framework is used to examine the effectiveness of management of environmental issues in the Great Lakes region over the past three decades and to demonstrate the need for a more integrated approach to regional management.     

Engaging your networks

The following is an excerpt form Grace Wever's new book Strategic Environment Management: Using TQEM and ISO 14000 for Competitive Advantage (John Wiley & Sons Inc., 1996). In this chapter entitled “Engaging Your Networks,” she shows how companies can “design-in” satisfaction through supply chain partnerships and join hands productively with customers and stakeholders to address EHS issues of mutual concern. Guidelines for value-added partnering are included as well as many illustrative company samples.     

New insights into the determinants of the total fertility rate,infant mortality rate and life expectancy

SUMMARY

Data on 127 countries from the World Development Report (1993) are examined with respect to associations between the total fertility rate (TFR), infant mortality rate, life expectancy, female primary education, GNP and domestic water supply. A marked negative association between quantity of domestic water and the total fertility rate, independent of infant mortality, GNP and women's education, was found. However, water was not significantly associated with infant mortality, after controlling for CNP, female education and TFR. Further research at the micro- (community and individual) and macro-level is suggested to understand why and how water plays such an important role in TFR. At the same time, development policies and programmes need to give high priority to the domestic water supply at community as well as national levels.     

What Is the Potential Measurement Error in Occupational Exposure Studies?

ABSTRACT

This paper demonstrates statistical methods that estimate measurement error from available industrial hygiene data. Errors in measuring a continuous exposure variable may arise when all individuals in a work area are assigned the same exposure. An example is when the mean of exposure measurements obtained on a sample of individuals is assigned to all workers with similar jobs. This may lead to inaccurate point and interval estimates in exposure-response modeling. A method of simulating the distribution of true (i.e., unobserved) individual exposures is described in order to estimate the mean and variance of measurement error. The minimum variance unbiased estimator approximates the mean of lognormally distributed exposure measurements. The distribution of true individual exposures is approximated by the distribution of simulated estimates of mean exposure. The methodology is illustrated by exposure data from work areas manufacturing refractory ceramic fiber (RCF) and RCF products. Results show that exposure is slightly underestimated in work areas with between 25 and 113 exposure measurements; measurement error variance averages about 1.3% of the total variance.     

Effectiveness of Photocatalytic Filter for Removing Volatile Organic Compounds in the Heating,Ventilation, and Air Conditioning System

Abstract

Nowadays, the heating, ventilation, and air conditioning (HVAC) system has been an important facility for maintaining indoor air quality. However, the primary function of typical HVAC systems is to control the temperature and humidity of the supply air. Most indoor air pollutants, such as volatile organic compounds (VOCs), cannot be removed by typical HVAC systems. Thus, some air handling units for removing VOCs should be added in typical HVAC systems. Among all of the air cleaning techniques used to remove indoor VOCs, photocatalytic oxidation is an attractive alternative technique for indoor air purification and deodorization. The objective of this research is to investigate the VOC removal efficiency of the photocatalytic filter in a HVAC system. Toluene and formaldehyde were chosen as the target pollutants. The experiments were conducted in a stainless steel chamber equipped with a simplified HVAC system. A mechanical filter coated with Degussa P25 titania photocatalyst and two commercial photocatalytic filters were used as the photo-catalytic filters in this simplified HVAC system. The total air change rates were controlled at 0.5, 0.75, 1, 1.25, and 1.5 hr^?1, and the relative humidity (RH) was controlled at 30%, 50%, and 70%. The ultraviolet lamp used was a 4-W, ultraviolet-C (central wavelength at 254 nm) strip light bulb. The first-order decay constant of toluene and form-aldehyde found in this study ranged from 0.381 to 1.01 hr^?1 under different total air change rates, from 0.34 to 0.433 hr^?1 under different RH, and from 0.381 to 0.433 hr^?1 for different photocatalytic filters.     

Errant corporations, diffuse responsibilities, and the environment: ethical issues in the Orica case study

The papers in this volume deal with various aspects of the HCB legacy at the Orica plant at Botany. Whether explicitly or implicitly, they are concerned with questions of ethics; with the just distribution of burdens and benefits; with just processes for disposing of dangerous industrial waste; and with a just custodianship of the Botany environment. These ethical issues illustrate the difficulty of securing corporate accountability, and the elusiveness of responsibility within organisations. This paper reflects on some of the issues for ethics raised by the Orica case and their significance for corporate ethics.