Brownfield Redevelopment versus Greenfield Development: A Private Sector Perspective on the Costs and Risks Associated with Brownfield Redevelopment in the Greater Toronto Area

This paper examines the nature of the economic costs and risks involved in brownfield versus greenfield redevelopment in the Greater Toronto Area (Ontario, Canada) from a private sector perspective, and assesses the potential effectiveness of different policies and programmes designed to attenuate associated costs and risks. Through interviews, case-studies and an analysis of hypothetical development scenarios, it has been found that the perception that brownfield redevelopment is less cost-effective and entails greater risks than greenfield development, on the part of the private sector, is true for industrial projects in the province, but not for residential ones, which were found to be feasible, given the assumptions of the present study. Furthermore, the study has found that the attractiveness of residential brownfield projects can increase considerably with minor policy changes, but that promoting industrial redevelopment will require a more vigorous approach that employs a variety of environmental policy and economic development measures.     

Using non-equilibrium biosorption column modelling for improved process efficiency

An unsteady-state biosorption column model in one space variable is considered in this paper. The theoretical study is motivated by the need for predicting the dependent variables of biosorption columns for removal of heavy metals from wastewater, which is potentially an important technology in cleaner production. Pollutant concentrations in the bulk phase, in the liquid filling the pores and in the solid biomass along the axial coordinate of the column were evaluated for a wide range of physical and chemical parameters of the global process. In particular, the assumption of instantaneous chemical reactions is replaced by a more realistic expression taking into account chemical kinetics and fluid advection time scales separately. The resulting system of partial differential equations was solved by means of a reliable numerical algorithm based on the method of lines. The data obtained using the model described in this paper are compared with published experimental data and an estimation of the increased efficiency is made.     

Clean catalytic technology for liquid phase hydrocarbon oxidation

 Liquid phase hydrocarbon oxidation is one of the principal routes towards industrial organic chemicals. However, low product selectivity and associated by-product formation are major problems in several oxidation processes. As a result of the increasingly stringent environmental regulations, the development of oxidation catalysts has been a major challenge in the last decade. An overview of novel selective and clean oxidation catalysts and processes is presented. Received: 27 July 1998 / Accepted: 8 September 1998