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CO2 and spent wash


stillwagon

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A friend of mine working on his permits in Washington was recently asked by the Dept. of Ecology what he planned to do about the CO2 produced by the fermentation process. I have been doing some research and there is very little information for the small scale operation in CO2 capture and storage. So what is everyone doing about their CO2 emissions? I am working with a local brewer startup and our intention is to capture, scrub, compress or liquefy the gas for reuse or resale. Liquification requires high pressure, and that has been difficult to find appropriate equipment for a small scale system. Next question is, what is everyone doing with their spent wash? Most I have talked to pour it down the drain if they have sewer, others haul it or have it hauled by someone to the local waste treatment plant. A study I have been reading shows it to be a beneficial agriculture amendment once processed. Employment of a bio-digester creates methane useful for heating in the distillation process, and a nutrient rich effluent when diluted is beneficial in agriculture. So what do you do with your CO2 and spent wash?

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My CO2 is collected and becomes food for the trees and other flora on my property. The oxygen is then used to burn the wood, to fire the still and repeat the whole process.

couldn't help it......

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I am worried about the liability of the wash if someone takes it and pollutes the groundwater in an area they use it if not properly employed. I know in most industries you have to provide documentation of proper disposal of hazardous waste. Otherwise you are liable for its misuse. Spent wash has incredibly high BOD and COD requirements, classifying it as hazardous waste.

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I haven't really worried about my CO2 though I have heard that it has practical benefits for people who are more technologically savvy than me if you can find a cost-effective way to store it. Really, I suppose the CO2 my still produces is absorbed by a few decorative trees I have growing indoors, not far from where I keep it. As has been mentioned, waste grains are commonly sent to local farmers to use as feed and I've had some luck with making bread with mine.

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  • 2 weeks later...

I would respond that fermentation is carbon neutral; the CO2 emitted during alcohol production is produced by the fermentation of sugars which were produced by plant photosynthesis. There is a lot of work being done to make CO2 recovery economical on a small scale. Those economics vary by local situations, but in general you would need to be well over 10,000 cases per year to even consider the expense which is on the order of US$200,000+ for a small system. Spent wash disposal via farm land application is viable in many regions. The main exposure with land application is surface rain water runoff carrying the applied organics into a body of water endangering fish, etc. Ground water contamination is less likely. There is probably a pumper service in your area that can take the wash. This material is 100% organic and can be digested into methane in a bioreactor, these systems are extremely expensive ($millions). There is a company called verde environmental that is making a small scale filtration system to reduce BOD/COD so you can send this type of material to your city sewer, maybe an alternative.

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