Anaerobic Treatment Alternatives for Industry - How to Evaluate and Select Best Alternative

Anaerobic treatment technology is being evaluated and implemented on numerous industrial wastewater projects, particularly in the food and beverage industry. The key advantages of the anaerobic treatment technology compared to aerobic treatment are: lower sludge production, lower power costs, smaller footprint and potential use of the methane gas for energy. There are several anaerobic treatment technology providers and a variety of project delivery approaches being used in the market place. The challenge for industry is how to evaluate and select the best technical process solution as well as the best project delivery alternative and team to design, build and startup the plant. The anaerobic treatment technology is typically a part of an overall treatment solution which includes subsequent aerobic treatment to meet permit limits as well as additional technology for water reuse or additional permit parameters such as color. This paper presents an overall approach for industry to use to develop the best technical and project delivery alternative. Case studies will be presented to demonstrate how the approach has been used. The paper also summarizes the variety of anaerobic treatment technologies available on the market, the process design parameters and how they are developed, and the project delivery alternatives. The advantages and disadvantages of the various technologies and project delivery approaches will be presented. The paper will also summarize along with case studies how anaerobic treatment feasibility and process design information is developed in bench-scale laboratory and on-site pilot studies. Guidance will be provided on deciding what level of treatability testing is needed to select the anaerobic technology and develop the process design information. One case study will discuss how an anaerobic treatment process followed by aerobic treatment and color removal has higher initial capital costs but lower life cycle costs with payback of less than 3 years. Anaerobic treatment was selected as part of the overall solution. Another case study will discuss the anaerobic treatment alternatives being considered by an industry moving into a city. The industry has to decide whether to build it's own plant or work with the local POTW on a potential solution which may benefit more than one industry. This case study will discuss and compare separate industrial pretreatment versus combined pretreatment at the POTW. Advantages and disadvantages and cost comparisons will be presented. A third case study will show how pilot studies were conducted for a group of pharmaceutical companies, first screening the feasibility of the process for assorted fermentation wastes, and then large-scale piloting of alternate anaerobic configurations. A unique aspect of the pilot study was the control of sulfides in re-circulating gas.