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Upon publication of an honorary Desalination issue for Prof. David Hasson, a group of eleven former students, judged this as a good occasion to acknowledge his contribution to scientific aspects of the water treatment industry and membrane technology. Based on his focus on equilibria, deposition and inhibition of scaling species in heat exchangers and reverse osmosis as well as in remineralization applications, this publication provides highlights of how his contributions have promoted innovation in the water industry. The tribute also highlights his influence as an educator on the authors who conducted studies, in these three areas under his coaching and supervision at the Technion–Israel Institute of Technology over the past 50 years.

A Study is made of the mechanism of CaCO3 scale deposition on heat exchanger surfaces, occurring in the turbulent flow of water containing dissolved scale constituents under non-boiling conditions. A general rate model is presented which takes into account physical and chemical steps involved in scale deposition. Controlling mechanisms are elucidated by examining the dependence of scale growth rate on the pertinent basic parameters: flow velocity, scale surface temperature and water composition. Scale growth-rate varies with (Reynolds number)0.68and is only slightly dependent on surface temperature. This result signifies that CaCO3 scale deposition is diffusion controlled within the range of surface temperatures (67 to 85°C) and Reynolds numbers (13,000 to 42,000) covered by this study. The experimental data conform to the proposed model and suggest that in certain cases CO2 formed during the reaction remains in solution, while in others, it escapes as a gas on the reaction surface.

In this work a mathematical model for preliminary engineering design and economic evaluation of electrodialysis plants is developed. The model has been adapted for performing all the necessary calculations by computer. Sample calculations for the Mashabei Sade plant, currently under construction, are presented.