Inga's Food Waste Management System

At our house, we divert all food waste from the landfill and process all of it on site. We eat plenty of fried food, spicy food, processed food, along with healthy stuff of course. But, typically the rules of composting forbid putting these types of foods in compost or worm bins. By using Bokashi waste fermenting and composting with black soldier fly larva, we are able to efficiently and safely return ALL of our food waste back to the earth.  

In Bokashi, you ferment your food waste with anaerobic microbes in a sealed container -- usually a 5 gallon bucket with a tight seal (gamma seal or specially designed bokashi bin). It allows you to store your waste till you are ready to deal with it. Typically, people just bury their bokashi scraps after a 2-week fermentation period. Where I live, the ground is hard pan clay, and I have lived in places with limited space, so finding multiple places to bury scraps was not practical. I do Bokashi in the winter months and store my food scraps all winter till spring. No smell, no bugs.

Enter Black Soldier Flies - my favorite creature on earth. These clean insects are seasonal, warm weather creatures. You typically find them in your compost bin anyways. But, each spring, I seed a freshly made wire compost bin with 10 to 20K larva. The larva have a voracious appetite. They can eat all kinds of food (yes fried, spicy, sugar, processed, anything, including bokashi scraps). If you allow them to dominate a bin, other nasty flies stay away. When they are ready to pupate, they crawl out of their food source (bin) and find a dry place to turn into an adult fly. The adults live for only a week to mate and die. You never see them. Because soldier flies convert 95% of what they eat into themselves and leave when they are ready to pupate, then your bin level never gets overwhelmed. I do not clean out my bin till the end of the season (fall). I literally dump gallons and gallons of food scraps all summer long, including those winter food scraps from Bokashi bins. When, fall settles in, I switch back to Bokashi to store my scraps till spring.
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I have done this system at a townhouse, suburban backyard, and our new country property (2 acres).

During the fall and winter...

  1. Collect solid food waste in an air tight gallon-size container in the fridge over a week's time.
  2. Once a week, transfer refrigerator waste to a 5-gallon Bokashi bin A. Sprinkle with Bokashi bran.
  3. Repeat steps 1 and 2 until Bokashi bin A is filled. Set aside bin A.
  4. Start filling Bokashi bin B in same manner. It takes us about 1 month to fill a Bokashi bin with food waste. Set aside bin B.
  5. While filling Bokashi bin B, drain bin A in the sink (fluid builds up at bottom).
  6. If needed, top off bins A and B with more waste. Start another bin, if necessary.
Picture
These are my 2 bokashi buckets I use for storing winter food scraps. The bag at the bottom with brown stuff is the bokashi bran innoculated with the good anaerobic microbes. During the winter, after the scraps sit a couple of months, the level goes down with gravity half way, so I am able to top them off if needed. The spigot is for draining the leachate -- very strong smelling stuff, that I put down the drain. But, there is no smell to the buckets.

During the spring and summer...

  1. We order 10,000 compost-grade black soldier fly larva in the spring when the night time temperatures stay above 50 degrees F.
  2. Fill a wire compost bin with about a foot of dry leaves or spent guinea pig bedding (pine shavings and hay). 
  3. Create a pit in the center of the compost pile and dump in a filled Bokashi bin. Add the larva to the Bokashi waste. Consider topping with a layer of dry bedding.
  4. Cover the wire compost bin with insect screen or burlap for at least a week to allow the grubs to dominate the food.
  5. Eventually, allow at least a square foot size opening, so that native black soldier fly females can come to lay eggs. OR place an "egg trap" on top of the bin (corrugated cardboard).
  6. As the larva consume the food, add more Bokashi waste and fresh waste as needed.
Picture
This is my wire bin for soldier fly larva I set up for this year. I fill it with dry material, like chopped leaves or spent bedding from my guinea pigs. Then I mix into the middle of it the bokashi scraps from winter. I top it with more dry stuff. I keep it covered with burlap or insect screen till I seed it with 10 to 20K black soldier fly larva. I give it week till no other flies want to hang around. The dominating presence of black soldier flies keeps other flies away. The bowl with cardboard is an egg catcher. I filled the bowl with chicken feed and water. When it starts smelling, it will attract local female soldier flies. Since they only lay eggs ABOVE food waste, and not in it, they will use the cardboard holes to deposit eggs, while other flies cannot lay in the food. Then, I will transfer those eggs to the pile beneath. But, once soldier flies dominate, I will not need to use the egg catcher. The females will find the pile and lay eggs there, while other flies stay away.
These are my soldier fly larva. They are the fastest and least picky eaters. Voracious appetites. Here they are munching on greasy pizza crusts. In the summer, there is no time for food to go bad when transferred to the bin because the soldier flies eat it so quickly.