Commercial worm composting has been around since the early 1900s. Variations of it have been adapted to meet the needs of compost tea users at local farmers markets to the largest United States Facility, American Resource Recovery (AAR), which employs an estimated 500,000 worms to produce 75,000 tons of materials annually. Before embarking on the raising of worms for a large scale worm composting check your local and state regulations for restrictions or conditions that may be applied. Available feedstock is always an issue and there are certain climates that are more conducive to composting than others. You will need a lot of space for the production. AAR has 320 acres, 70 of which are dedicated to worm composting.
The biggest challenge in large scale worm composting is heat generation. There is always heat generated from decomposing materials and when done on a large scale the process needs special management. Control methods include fans blowing air across the material, adding water and when absolutely necessary reducing the amount of feed stock.
Feed stock can be any green or vegetable waste. It needs to be free of fats and animal products. Coffee grounds, tea bags, and broken egg shells are also welcome. Some large scale worm composting operations receive the waste straight from the public and charge a tipping fee when it is delivered. Shredded paper and cardboard form the bedding that worms need to survive. You should add some dirt and sand to provide a little grit for them The worms love the paper products and it helps to keep the proper pH in their environment. The layout and the process of large scale worm composting will vary from site to site depending on local conditions.
Large scale worm composting is done in a windrows system, the wedge system, beds and bins system,or a reactor system. These systems can be labor intensive and require a lot of attention or with modern technology can be completely automated. The future of large scale worm composting is bright. Over the years there have been many failures but we see more and more successes as time goes on. The failures are brought on by poor management, lack of adequate capital, lack of understanding on the part of regulatory agencies, unstable markets, and in some cases misrepresentation of technology by the developers. Oregon State University has provided a lot of education in the field for both production and utilization of product. In the future we will see greater demands for blended vermicompost and compost and the use of vermicompost tea for direct application to gardens and farm crops.