Composting Dairy Manure with Vermicomposting

Vermicomposting is the process of using worms to compost organic materials such as vegetation, cardboard, and kitchen scraps into vermicast fertilizer. The worms consume this material and then excrete that material into worm castings, which is a phenomenal organic fertilizer for all plants. A vermicomposting company, Worm Power, decided to take on a major problem as the result of animal production: dairy manure. When the company was deciding where to locate in the eastern US, they chose Avon, NY for a few reasons. It is a major agriculture area, focusing on grape and apple production, and dairy cattle. 675,000 cows are currently in production, making this the 3rd largest dairy producer in the nation. These cows are producing an excess of around 16 billion lbs of manure a year! Not only was there an excess of manure, but dairies are also located 5 miles away from two major shipping facilities to ship the finished compost product.

Dairy manure is a major issue that America is struggling to dispose of properly.  One cow can produce 82 pounds of manure per day per 1000 pounds live weight. The average Holstein dairy cow weighs 1300-1400 lbs and could potentially produce around 115 lbs of manure A DAY.

Manure lagoons

Manure lagoon where liquid manure is spread

Farmers typically use the traditional method of spreading manure on fields that need fertilizer (any production field). The problem is, cow manure is HOT from all the nitrogen which will burn the plants if too much is mixed in. A cow produces manure with approximately 210lbs of total nitrogen, 84lbs of phosphorous and 166lbs of potassium every year. Therefore, the manure must be distributed properly or it will have negative impacts on the plants. The liquid manure is separately distributed into dedicated “lagoons” to soak back into the ground.

Production process

Entire process showing how Worm Power converts manure to compost

logoWorm Power created a process to turn composted dairy manure first into worm food and then into a profitable fertilizer product. Typically, raw manure would not be fed to worms, but when it is composted and mixed with other materials it provides a good diet for worms. The building where the worms are housed is equipped with automatic ventilation, water, heated/insulated, and a direct lighting system to discourage the worms from crawling out.

aeration bays

The process begins in a covered facility where the raw manure is stored and then mixed with other materials in specific ratios using tractors. The manure mix is housed in aeration bays where the thermophilic composting phase begins. Thermophilic composting is the process of breaking down waste (grass clippings, wood chips, or sawdust) in a large pile using thermophilic bacteria. The material sits here for 14 days, being turned with machinery once. This ensures a few things: weed seed reduction, pathogen reduction, and stabilization of materials. During this process, oxygen and temperature are measure while continuously checking air flow-rate and volume controls to ensure the thermophilic process is working properly.

feeding

Diagram of how the worms are strategically fed

flow through system

Where the worms live in a flow through system

The red wiggler worms are housed in a flow through system as pictured above. They are strategically fed to ensure all the material is composted and harvested properly. If the worms are not happy and not in the correct habitat, they will not feed off the material or breed. Without these two actions, the material will never compost. Therefore, it is important to maintain the correct conditions for bedding, moisture, amount of food, etc.  The farmers taking care of these worms keep a log book with all necessary information and recommend using your nose to investigate, as the compost should not smell.

harvest

Diagram showing how the vermicompost is harvested

After six weeks it’s time to harvest the worm castings. The castings are carefully strained from the bottom layer using a hydraulic machine. These castings will be delivered through three product lines and packaged in bulk or for retail sales. The market focus is on a local and nationwide scale. Residential consumers (gardening/home use) and commercial farmers alike purchase these products with good success.

Worm Power has been awarded nine research grants from Federal and State agricultural agencies to continue developing vermicomposting techniques for large scale environmental challenges such as manure.  They partnered with multiple departments at Cornell University for a long-term project that researched the many ways vermicomposting can consume portions of the extensive amounts of waste generated in the US.

-Posted by Kelli

*All images are from Principles and Practices of Commercial Scale Vermicomposting and Earthworm Husbandry

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