S. J. BURY (1), J. Carlock (2), S. J. Gluck (2), J. Earnest (3), B. Wagner (3); (1) The Dow Chemical Company, Midland, MI, U.S.A.; (2) The Dow Chemical Company, Freeport, TX, U.S.A.; (3) Saint Arnold Brewing Company, Houston, TX, U.S.A.
Saturday, October 10
River Terrace 2
Brewery wastewater discharge to publicly owned water treatment plants for BOD5 removal can be a significant primary cost for a brewery. The foreseeable trend is for these external treatment charges to increase coupled with stricter regulations and discharge limits that may force a brewery to curtail production or adopt an expensive in-house treatment. Indeed, production and sewer charge data compiled at many sites across the United States suggest that some areas with existing breweries have more costly fees than others. With the rapid growth of craft brewing, demand for simple systems to manage BOD5 discharge is growing and outpacing sewage treatment capacity. Therefore, to meet this growing need, a low-maintenance, easy-to-operate system for BOD5 removal is essential for economic and environmental sustainability. Recently we completed an intensive pilot study at Saint Arnold Brewing Company in Houston, TX, of such a wastewater treatment technology to quantify the BOD5 removal from the discharged wastewater. The unit consists of a holding tank, a pump for recycling from the tank, and an aboveground, passively aerated, attached growth biofilter. The skill set required to install and operate such a system exists within the maintenance staff of any craft brewer. The study consisted of 37 batches over 1,400 hr, including 3 detailed 24 hr studies collecting hourly BOD5 and TOC data. The unit was operated 24/7 in an unattended mode except for the batch changeovers and sampling. The feed stream was highly variable in organic content. We pulled each batch charge directly from the wastewater discharge line and did not employ equalization, as would occur in a permanent installation. Consequently the brewhouse operating schedule strongly influenced the wastewater pulled for each batch. In spite of the high variability, the system was extremely robust. Operating data and the configuration employed consistently achieved greater than 80% TOC and greater than 90% BOD5 removal. Batches that had lower removal were nitrogen limited. The detailed studies of the performance of the unit under a range of loadings from a low at 300 ppm BOD5 to a high at 5,200 ppm BOD5 demonstrated robust performance, even with uncontrolled pH, and dissolved oxygen demonstrating greater than 95% BOD5 removal. The results of this 2 month study indicate that this technology can be a low-cost solution for on-site treatment of brewery wastewater. We will present further analysis of the pilot data and examples of designs, capital, and operating expense estimates for different brewery sizes.
Scott J. Bury is a principal research scientist in the Process Optimization group of The Dow Chemical Company’s Engineering Sciences organization within Core R&D. He received his B.S. degree in biology/biotechnology from WPI and his Ph.D. degree in chemical engineering from Rice University. His research interests include process simulation and optimization of biological and chemical processes, using both continuous and discrete event technology and eliminating failure modes when implementing new process technology. He is an expert in wastewater treatment.