Cheese making is by and large a clean industry. However the process of cheese making produces a great deal of whey. And this is the greatest waste management issue a small dairy will face.
What is Whey?
Whey is composed of 97% water, plus ash, residual lactose, and whey protiens. So it is not a very nasty waste product. However, whey has a reasonably high BOD level (bio-oxygen demand levels required for organic breakdown) so it does need to be “digested”. Many ask why small dairies don’t harvest the whey to make whey protiens or ricotta. The short answer is that the cheese making process creates too much whey for small dairies to be able to harvest all of it. Many dairies will give the whey away to local pig farmers. Some have spread it on sub-par land. Drying whey is an option—but only for very large scale processors as the equipment to dry a liquid like whey to extract a few protiens requires significant capital and the volume to make it worth while (Did you ever wonder why most of the whey protiens sold in health food stores comes from New Zealand? A country where 20% of their GDP comes from the dairy industry?)
How FT decided to Handle Whey
First, we explored several options. Spreading was a possibility but only light spreading and on land with enough soil to absorb and digest it safely. You also cannot spread in the winter time as the soil cannot absorb it when frozen. The other option was to see if a pig farm would be interested. No one was in our area. We explored bio-digestors. However, there is not a lot of energy in whey to create the desired methane. We would need over 2M litres per year of whey to even think about using that technology in its smallest form! And on average, we only produce about 160 000L per year. Not nearly enough. Finally we explored simply trucking it to a treatment plant. But that is inconsistent with our philosophy. So the research continued until we determined that a bio-wetland was the ideal way for us to process whey.
Essentiall, the effluent if pumped through a 3-cell filtering system. Each pond is filled with alternating layers of gravel, clear stone, recycled wood chips and peat moss. The ponds are then planted with cattails, grasses and wild flowers. The resulting physical, chemical and biological processes combine in the wetland to remove contaminants and digest the whey. It also creates a new habitat for birds and butterflies! The system uses less than 12-20 cents of electricity per day and operates year round.