Thursday, November 29, 2012

Waste Water Pre-treatment

Change of pace for the beer blog, this is just something I've been up to lately:

Filling a tote with trub/hops from the whirlpool
Currently at New Holland, we are in the process of some important expansions. Ranging from a new mill, a boiler, filler and several other key pieces of equipment that will help us continue to produce the exemplary beer that we are known for. However, those upgrades are not the point of this post. Currently, I’m spending time researching methods behind dealing with industrial waste, specifically the waste derived from the brewing process. The waste up until now has been stored in 25-30 three hundred gallon totes (usually found holding petroleum oils) which are emptied by a tanker truck weekly/bi-weekly. This method is proving to be far to costly and inefficient for us to continue down that road much longer. So I’ve taken the opportunity to put my un-claimed environmental degree to work by researching different methods to managing and purifying our brewery’s waste. By waste I do not mean radioactive slurry or very toxic chemical. I’m simply talking about the raw ingredients that go into beer. Our grain is picked up by a farmer, but that still leaves us with boat loads of yeast, spent hops and trub (or protein - from the boil - hot breaks). This all gets blended and put into totes to be collected and shipped off. To my knowledge, a lot of breweries in the Chicago area don’t have to do this and leave the processing for the municipal facilities. Here in Michigan, however, we get slapped with large fines and pre-treatment costs if we let any  organic (trub, yeast, grain...crap) or inorganic (detergents, acids... tested often by pH) go down the drain. So in an effort to reduce these costs, improve processes and save the environment, we are looking for alternative plans to dealing with this waste.
To give a brief outline, we have tanks available for storage and it is with these tanks that will determine what how we manage this waste. We have a large 300+ bbl tank and two 75 bbl tanks that are ready to use. It is their purpose that is the source of research. In either course of action, one will be a digestion tank, whether that is Aerobic or Anaerobic. 

The potential aerobic digester, next to the grain silo
Obviously getting an up and running pre-treatment system going is still a ways away (I’m only in the research phase) but I’m still learning a great deal. 

Not to give too much away, here are some Pros and Cons of aerobic vs anaerobic digestion tanks and what goes on within:

Aerobic: Microorganisms metabolize non-settleable organic solids/materials and produce settleable inorganic solid byproducts. Byproducts are heat, CO2 and water. Starting material include nitrogen, sulphur and phosphorus and result in oxidized forms of Nitrate (sodium, potassium and calcium salts), Phosphate and Sulphate.
  • Low construction costs
  • Safer (no combustables)
  • Better quality supernant (byproduct i.e. good waste)
  • Farms can use just about everything
  • High energy consumption (aeration and solid separation)
  • Effected more severely by temperature
  • More sludge produced for disposal
  • Odor

Anaerobic: Microorganisms digest organic solids in the absence of oxygen. End products are typically alcohols, aldehydes (toxic) and organic acids...50-70% Methane, 30-40% CO2. The rest is solid matter called bio solids
  • Waste produced can be used for electricity or fuel (for boilers)
  • Odor is less of an issue
  • Dairy farmers are often an easily accessible resource for information
  • Generates a lot of heat
  • Costly equipment (testing, monitoring, generators, gas cleaning equipment)
  • Still left with some toxic byproducts
  • More dangerous - combustable gas produced.

That’s a brief summary of what will be considered when the decision to tackle this project is made, but for now....more research!

No comments:

Post a Comment