Treatment Plant Design in an Era of Changing Regulations

Abstract

The 1986 amendments to the Safe Drinking Water Act (SDWA) have initiated a new era in drinking water treatment that will affect the thinking of design engineers. What is needed to upgrade existing plants to meet the new standards, particularly those associated with the Surface Water Treatment Rule, how might designers currently working on a proposed treatment plant project deal with the uncertainty, what to be looking at in terms of designing a plant with enough flexibility to be able to accommodate future by‐products standards while at the same time maintaining cost effectiveness are questions raised by the moderator of this discussion. One impact of the Surface Water Treatment Rule will be the need for existing plants to optimize their disinfection chemistry to comply with the CT (concentration time) requirement and, in some cases, to lower turbidity, perhaps by replacement of filter media. Emerging technology such as ozone, slow sand filtration providing filtration without the complexities of chemical treatment, use of granular activated carbon to remove organics, advanced oxidation, use of ultraviolet light or hydrogen peroxide to enhance the effectiveness of ozone, and membrane processes are highlighted in this discussion.