The New Belgium Brewing Company recently evaluated the effectiveness, reliability, and robustness of submerged anaerobic membrane bioreactor (AnMBR) technology at their Fort Collins, Colorado craft brewery. The pilot study drivers were the performance limitations of Upflow Anaerobic Sludge Blanket (UASB) digesters, space constraints and a desire to maximize recovery of energy resources. While effective in removing (65-85%) of soluble COD, UASBs are limited in their ability to handle and remove total suspended solids (TSS) and other brewery waste flows such as trub, spent hops, and spent yeast. Additionally, the chemical oxygen demand (COD) and TSS in the effluent from UASBs are typically above POTW surcharge discharge limits resulting in additional levied surcharge costs or the need for energy and space intensive downstream aerobic treatment. With changes in consumer preferences resulting in a higher%age of hops being used in the brewing process, UASBs and other conventional brewery pre-treatment systems have struggled to digest their waste streams due to spent hops-related microbial inhibition impacts to the biota1. This market shift has also forced breweries to haul and dispose of more solids at landfills. New Belgium Brewing sought to find a more dependable and sustainable solution for treatment of brewery waste and implemented a pilot project to assess the effectiveness of the AnMBR technology to treat brewery waste including the high COD spent hops and spent yeast – high strength residual streams with high biomethane potential. The pilot evaluation included assessing the biogas quality and biogas quantity generated from the digestion of the various brewery waste flows to identify any quality impacts from increased COD loading from spent hops and spent yeast. The project sought to identify appropriate technology and determine the feasibility of conditioning the recovered biogas with membranes to increase the options for utilization of the recovered carbon source. Energy recovery options evaluated included direct pipeline injection of the highly purified and compressed biomethane (“green” gas) and compared these costs with more traditional biogas utilization options such as boiler make-up, combined heat and power (CHP) cogeneration, and microturbine fuel. The relatively small scale of the proposed full size biogas conditioning system would make this project notable in the US, possibly putting the system within grasp of numerous new breweries and other industries using anaerobic digestion as pre-treatment for their process waste flows.
This presentation is available to AMTA Members only.
- Tim Rynders, PE
- CDM Smith Inc.
- AMTA/AWWA Membrane Technology Conference, Long Beach, CA
- AMTA/AWWA Membrane Technology Conference
- Ultrafiltration, Design, Pretreatment, Energy, MBR, Pilot, Biogas Conditioning