Rational pricing of groundwater with a growing population

When population is increasing, characterizing the optimal water consumption path is complicated by the fact that the underlying dynamics of the water stock is contingent on the level of the stock itself. We propose a method of constructing the optimal path in this case. Since population is increasing, the optimal consumption path may involve refraining at times from consuming the totality of the surface water flow in order to restock in groundwater for future consumption. The aquifer then serves as a means to achieve welfare increasing intertemporal transfers of surface water. Therefore the aquifer itself, as distinct from the stock of water it serves to store, may have value and the marginal valuation of water when groundwater stocks are being drawn upon should, for this reason, differ at times from the marginal valuation of water when it is drawn strictly from surface water.     

Resource conservation in the pulp and paper industries—rational-use-of-energy approach

Sharp rises in energy prices have generated an interest in the pulp and paper industries in cogeneration and heat pump applications. However, the institutional and industry-specific barriers to their implementation, despite economic viability, indicate the inadequacies of the energy conservation and energy saving approaches to minimise energy costs. A systems approach, referred to as rational-use-of-energy, is proposed to overcome some of the barriers and to highlight the conservation potential of other resources, such as chemicals and water at appreciably low effluent loads.     

The effects of corona electrode geometry on the operational characteristics of an ESP

Experiments were run in a pilot scale electrostatic precipitator (ESP) to determine the effects of corona wire-to-wire spacing on the operating conditions. Tests were run, using a reentrained low sulfur fly ash at both hot- and cold-side conditions. The effects of varying wire-to-wire spacing were determined. Results are given which show that varying wire spacing at cold-side conditions has little operational effect on the ESP while improved efficiency can be obtained at hot-side (low resistivity) conditions by reducing wire spacing. The increased efficiency results from a higher average operating voltage. The effects of back ionization are clearly demonstrated by a set of experiments in which dust was selectively removed from the wires or plate. These tests show that the lower operating voltage caused by back ionization is a combined effect of high resistivity dust on both the wires and plate.     

Review and assessment of models for predicting the migration of radionuclides through rivers

The present paper summarises the results of the review and assessment of state-of-the-art models developed for predicting the migration of radionuclides through rivers. The different approaches of the models to predict the behaviour of radionuclides in lotic ecosystems are presented and compared. The models were classified and evaluated according to their main methodological approaches. The results of an exercise of model application to specific contamination scenarios aimed at assessing and comparing the model performances were described. A critical evaluation and analysis of the uncertainty of the models was carried out. The main factors influencing the inherent uncertainty of the models, such as the incompleteness of the actual knowledge and the intrinsic environmental and biological variability of the processes controlling the behaviour of radionuclides in rivers, are analysed.