Use of electrochemical oxidation process as post-treatment for the effluents of a UASB reactor treating cellulose pulp mill wastewater.

The main purpose of this study was to evaluate the performance of the electrochemical oxidation process as a post-treatment for the effluents of a bench-scale UASB reactor treating simulated wastewater from an unbleached pulp plant. The oxidation process was performed using a single compartment cell with two plates as electrodes. The anode was made of Ti/Ru0.3Ti0.7O2 and the cathode of stainless steel. The following variables were evaluated: current density (75, 150 and 225 mA cm(-2)) and recirculation flow rate in the electrochemical cell (0.22, 0.45 and 0.90 L h(-1)). The increase in current density from 75 to 225 mA cm(-2) did not increased the color removal efficiency for the tested flow rates, 0.22, 0.45 and 0.90 L h(-1), however the energy consumption increased significantly. The results indicated the technical feasibility of the electrochemical treatment as post-treatment for UASB reactors treating wastewaters from pulp and paper plants.     

A case study of regional catchment water quality modelling to identify pollution control requirements.

There are four ecologically important river catchments that contain candidate Special Areas of Conservation (cSACs) under the Habitats Directive in the Lake District National Park located in the North of England. These are the rivers Ehen, Kent, Derwent and Eden. For each cSAC, there are defined ecological criteria that include water quality targets to protect the designated species. Stretches of the riverine cSACs in each catchment are failing to meet these and other water quality targets. The Environment Agency commissioned a study of each catchment to provide the underpinning scientific knowledge to allow it to deliver its statutory obligations under the Habitats Directive. SIMCAT river water quality models were produced and used to predict the water quality impacts resulting from a number of water quality planning scenarios aimed at achieving full compliance with the Habitats Directive and other national and EEC water quality targets. The results indicated that further controls on effluent discharges will allow the majority of targets to be met but other sources of pollution will also need to be controlled. The outcome of the study also recognised that water quality improvements alone will not necessarily produce the required improvement to the ecological interest features in each cSAC.     

Disc filtration for separation of flocs from a moving bed bio-film reactor.

A Discfilter with 10 and 18 microm filter openings, respectively, was placed in parallel to a flotation plant for separation of biological flocs from a post-denitrifying Kaldnes Moving Bed Process, the last treatment step at the municipal wastewater treatment plant at Sj?unda, Malm?, Sweden. The effluent concentrations from the 10 and 18 microm filter were 2-5 and 2-8 mg SS L(-1), respectively, which is comparable to, or better than, the flotation plant. Comparison with experiences from activated sludge plants shows that the Discfilter works especially well after the Kaldnes process. Particle size distribution (PSD) studies show that particles larger than the filter openings of 10 and 18 microm are separated with approximately 90% efficiency, whereas most of the smaller particles pass the filter. This fact indicates that the major particle separation mechanism is physical blocking. These findings point to the possibility of improving the prediction of the separation efficiency by combining measurements of turbidity and suspended solids with particle size analysis.     

Modelling biological processes under anaerobic conditions through integrating titrimetric and off-gas measurements-applied to EBPR systems.

An innovative method for modelling biological processes under anaerobic conditions is presented and discussed. The method is based on titrimetric and off-gas measurements. Titrimetric data is recorded as the addition rate of hydroxyl ions or protons that is required to maintain pH in a bioreactor at a constant level. An off-gas analysis arrangement measures, among other things, the transfer rate of carbon dioxide. The integration of these signals results in a continuous signal which is solely related to the biological reactions. When coupled with a mathematical model of the biological reactions, the signal allows a detailed characterisation of these reactions, which would otherwise be difficult to achieve. Two applications of the method to the enhanced biological phosphorus removal processes are presented and discussed to demonstrate the principle and effectiveness of the method.     

Foreign Factor Ownership and Optimal Tariffs

In the presence of foreign factor ownership tariffs change not only the terms of (goods) trade but also income flows between countries. Assume that only the home country owns factors abroad. Then the optimal tariff is negative if and only if foreign factor ownership entails trade-pattern reversals. Trade-pattern reversals are neither a necessary nor a sufficient condition for a negative optimal tariff if the foreign country owns factors in the home country. Changes in the home country's tariff shift the foreign country's offer curve. This adds a new dimension to optimal tariff analysis.     

MANAGERIAL INCENTIVES AND CORPORATE DIVERSIFICATION STRATEGIES

Because the break-up of conglomerates typically produces substantial increases in shareholder wealth, many commentators have argued that the conglomerate form of organization is inefficient. This article reports the findings of a number of recent academic studies, including the authors' own, that examine the causes and consequences of corporate diversification. Although theoretical arguments suggest that corporate diversification can have benefits as well as costs, several studies have documented that diversified firms trade at a significant discount from their single-segment peers. Estimates of this discount range from 10–15% of firm value, and are larger for “unrelated” diversification than for “related” diversification. If corporate diversification has generally been a value-reducing managerial strategy, why do firms remain diversified? One possibility, which the authors label the “agency cost” hypothesis, is that top executives without substantial equity stakes may have incentives to maintain a diversification strategy even if doing so reduces shareholder wealth. But, as top managers' ownership stakes increase, they bear a greater fraction of the costs associated with value-reducing policies and are therefore less likely to take actions that reduce shareholder wealth. Also, to the extent that outside blockholders monitor managerial behavior, the agency cost hypothesis predicts that diversification will be less prevalent in firms with large outside blockholders. Consistent with this argument, the authors find that companies in which managers own a significant fraction of the firm's shares, and in which blockholders own a large fraction of shares, are significantly less likely to be diversified. If agency problems lead managers to maintain value-reducing diversification strategies, what is it that leads some of these same firms to refocus? The agency cost hypothesis predicts that managers will reduce diversification only if pressured to do so by internal or external mechanisms that reduce agency problems. Consistent with this argument, the authors find that decreases in diversification appear to be precipitated by market disciplinary forces such as block purchases, acquisition attempts, and management turnover.     

Contemporary ethical issues in labor-management relations

Numerous labor-management issues possess ethical dimensions and pose ethical questions. In this article, the authors discuss four labor-management issues that present important contemporary problems: union organizing, labor-management negotiations, employee involvement programs, and union obligations of fair representation. In the authors view, labor and management too often view their ethical obligations as beginning and ending at the law's boundaries. Contemporary business realities suggest that cooperative and enlightened modes of interaction between labor and management seem appropriate.Robert S. Adler is Associate Professor of Legal Studies at the Kenan-Flagler Business School, University of North Carolina at Chapel Hill. He teaches courses in Business Law, Business Ethics, and Regulation. Prior to coming to UNC, Professor Adler served as Counsel to the Subcommittee on Health and the Environment of the Committee on Energy and Commerce of the U.S. House of Representatives.William J. Bigoness is Professor of Business Administration and Director, Center for Management Studies at the Kenan-Flagler Business School, University of North Carolina at Chapel Hill. His professional interests include organizational behavior, human resource management, and labor-management relations. Dr. Bigoness was Visiting Professor of Business Administration at the International Institute for Management Development (IMD) located in Lausanne, Switzerland from 1985 to 1987.