|Filling a tote with trub/hops from the whirlpool|
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|
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
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!