Engineering for Toxicity Removal: A New Set of Design Rules
The role of the environmental engineer in designing cost-effective wastewater treatment operations is changing as a result of recent regulatory initiatives.' The removal of "toxicity" from wastewater is becoming increasingly stated as an engineering objective. This objective, as opposed to the more traditional engineering goal of "pollutant" or even "toxicant" removal, brings with it a shift in the fundamental approach to evaluating treatment system performance and the design of new or upgraded facilities. While individual pollutant specific designs can be encountered in the toxicity removal design process, more commonly either a general chemical parameter such as total organic carbon or chemical oxygen demand or a biological effect parameter approach is required. This chapter discusses the limitations in the current methodology and identifies areas where traditional design rules may have to be modified or relaxed.