STRUCTURED DECISION MAKING TO EVALUATE WASTEWATER TREATMENT ALTERNATIVES

With the many recent additions to air emission regulations governing wastewater treatment plants, it is becoming more challenging to evaluate wastewater treatment technology comprehensively. It used to be possible to select technology based strictly on cost and performance requirements to comply with the Clean Water Act. Now, with the publication of various amendments to the Clean Air Act, regulatory considerations have become prominent in the decision-making process. The Hazardous Organic National Emission Standards for Hazardous Air Pollutants (NESHAP) (HON), Miscellaneous Organic NESHAP (MON), and Subpart YYY Performance Standards regulate volatile organic compound (VOC) emissions from wastewater streams. If the site in question falls under one of these regulations, the process of selecting a wastewater treatment technology is complex. During the preliminary evaluation phase and selection of wastewater treatment upgrades, all the regulatory impacts must be factored into the decision-making process. Proper presentation of the operational risks, regulatory issues, and capital costs in a concise manner is critical to selecting the best option. A work flow process that generates the necessary information in a timely fashion is essential for efficient use of resources during this assessment phase. This process must be designed into the project at the outset to order work flow and deliver the necessary data when needed.At an integrated chemical manufacturing site in Texas, CH2M HILL performed a technology assessment to select a pretreatment system that met several objectives. Low capital cost, minimized plant operational risk, and minimizing current and future regulatory impacts were identified as critical success factors. In addition to these challenges, there was a critical timing issue to develop responses for the Texas Commission of Environmental Quality (TCEQ).One of the first steps was to break down the work flow into a process that had decision points. The decision points allow evaluation of the selected technologies based on the critical success factors. A parallel approach was used to develop regulatory understanding at the same time the technology evaluation was being performed. Data were summarized in tabular format to easily compare the options and allow informed decision making by the client.This paper describes the successful work flow process used showing the project as a case study in the application of this process. This process applies to industrial facilities that are faced with changing their wastewater treatment system. By using a structured approach, the cost of investigating options can be reduced and the risk of overlooking viable options can be mitigated.