Table of Contents
  1. Introduction
  2. Installation
    1. Preparation
    2. Installation Instructions
    3. Starting your toilet
  3. Maintaining Efficiency
  4. Use and Care
  5. Troubleshooting
  6. Warranty

Use and Care

To ensure that your BioLet will operate at its peak potential and that the end product (Humus) will be hygienically safe to handle and to recycle on your property, pay close attention to the following directions.


  • Always observe good biohazard safety practices when working on the BioLet. Wear goggles, disposable rubber gloves and clothing to prevent contact with unprocessed human excrement. Unprocessed human excrement contains potentially dangerous human pathogens, which may cause illness.
  • NEVER put cigarettes or other burning or glowing materials into your BioLet!
  • Do not put sanitary napkins, food scraps, or animal excrement in your BioLet. Your BioLet is intended for the disposal of human urine, fecal matter and toilet paper ONLY. Introduction of other materials may hinder the composting process or decrease the capacity of your toilet.
  • Always unplug the toilet before working on it or emptying the tray.

Adding starter mulch

It is very important to add starter mulch to your toilet on a regular basis in order to promote aeration, add carbon and to improve the compost's ability to absorb liquid. During regular operation add a minimum of 1 quart of starter mulch per week per person. Therefore, one should make it a habit to add about 1/2 cup of starter material after each fecal use.

Approved mulches
Use of only BioLet approved starter mulches is recommended. Approved mulches will carry the BioLet logo. Using any other mulch may cause a decrease in the efficiency of your toilet and may void the warranty on mixer parts if their failure is determined to be caused by usage of unapproved mulch.

Homemade mulch
  • If you desire to make your own mulch you can use the following recipe for 10 gallons of starter mulch:
  • 6 1/2 gal Blond high fibrous, Canadian sphagnum peat moss (All peat moss is not the same)
  • 3 1/2 gal - Pine wood shavings (obtainable from nearly any livestock feed store as livestock bedding) Do not use sawdust, chainsaw chips, or cedar chips
  • 2 cups Good rich garden soil from first 6 layer of soil (Ensure from an area where pesticides are not used)
  • 1 pound Dry molasses.
  • 1 pound Hulls of buckwheat, wheat, peanuts or cocoa.
  • 1 pound Coarse Perlite
    Keep your mixture dry and allow it to breathe. Except for when starting your BioLet, do not dampen. The mulch will mix in and dampen with bathroom use.

BioLet USA cannot guarantee the operation of your unit unless you are using approved mulch.

Using the mixer

The function of the mixer is to mix paper and waste, increase aeration and to keep the compost porous and uniformly moist. This is necessary to transform the compost into humus, as well as to transport the compost into the collection tray.
When you lift the upper seat to its fully upright position the microswitch on the back of the toilet will be depressed and the mixing arms will turn for approximately 5 seconds. When you finish using the toilet, lower the upper seat. This will release the microswitch and allow the mixing arms to complete their cycle. The full cycle takes approximately 1 minute. If the seat is lifted to its fully upright position in the middle of the mixing cycle, the mixer will stop and then resume whenever the seat is lowered again. If you desire to use the unit again before the mixing cycle is complete, ensure the upper mixing arm did not stop directly below the seat.

Adjusting the thermostat

Since no two applications are exactly alike, the first month using your BioLet Composting Toilet is the most critical. Therefore, you will need to pay close attention to the liquid indicating tube on the right-hand side of the toilet (when facing toilet) and the consistency of the humus inside the toilet. To ensure your toilet is started properly and will provide you with years of trouble-free service, please pay close attention to the following, until your unit is running in a consistent state with the proper moisture content.

Things to watch

  • Glance at the indicating tube on the right-hand side (when facing toilet) before each use to see if there is any indication of liquid.
    • If liquid is indicated: increase the thermostat setting by 1
    • If liquid level continues to rise after subsequent uses, continue increasing the thermostat 1 number at a time until the level in the indicating tube becomes stable.
  • Occasionally press on the seat and look at the material inside the toilet. It should appear to be a moist loamy material.
    • If the material appears dry, decrease the thermostat setting by 1
  • Continue to watch the above conditions and make the appropriate adjustments until you reach a state where you have a moist, loamy material inside the toilet with no liquid indicated in the tube.

Emptying the humus tray

In a full-time residential setting, empty the humus tray when the compost reaches the upper mixing arm/ leveler or once every 6 months, whichever comes first. In a part-time cabin/cottage setting empty the humus tray when the compost reaches the upper mixing arm/ leveler or once a year whichever comes first.

  1. Switch off the electricity.
  2. Place newspaper or sheet of plastic in front of the toilet.
    1. Check the liquid level indicator tube, on the left hand side of the toilet (when facing toilet), to ensure that there is no liquid in the bottom part of the toilet.
    2. If liquid is present in the tube DO NOT open the tray door until it has been drained off.
    3. By placing a shallow tray under the indicating tube and removing the tube from its top connection excess liquids may be drained off.
    4. If you suspect the liquid has been building up for an extended period of time and there could be a substantial amount of liquid in the bottom of the toilet, move the toilet to a suitable place outside the building before draining off the liquid.
  3. Open the front cover by removing the 2 thumbscrews and detach the indicator tube from the tray. Bend the tube upwards and push its upper part into the toilet (behind the metal frame) making more room to pull out the tray.

  4. When pulling out the tray, you might want to use the metal frame supplied with your BioLet.
    1. Insert the mouth of a garbage bag through opening in frame.
    2. Drape top of bag over frame in a manner so the frame holds the bag open.
    3. Place holes on each side of frame over the bolts for the front cover.
    4. Replace the thumbscrews to hold the frame in place.
    5. Push in on the bottom of the bag and pull the tray into the bag.
    6. Remove the frame and bag and take outside.
    7. Empty the tray into the bag.
  5. Dispose of the humus, whenever possible, by adding it to an existing outside compost pile for finishing or when an existing compost pile is not available, by mixing it with soil or compost and trench it in around ornamental trees and plants and cover it with a minimum of 5" topsoil, or dispose of it in a manner approved by your local health authorities.
  6. Check whether any compost material has spilled onto the bottom of the toilet. If this is the case, while wearing rubber gloves, clean up the spilled material and empty it back into the toilet.
  7. Clean the tray thoroughly; particularly the area around the indicator tube nipple to ensure the flow of liquid is not being restricted.
  8. Insert the humus tray and reattach the indicator tube.
  9. Replace the front cover, ensuring the thumbscrews are hand tight.
  10. Rotate the mixer handle several times in the clockwise direction (10 Standard) or press the microswitch several times (20 Deluxe) until compost falls through the grate into the humus tray, thereby reducing the volume in the composting chamber.
Shutting down your toilet

If your BioLet is going to be idle and not used for periods of two days or more:

  • Add about one quart of humus starter per week that you will be away or one gallon (whichever is less) and mix it well into the compost.

  • Unplug the toilet and seal the opening by inserting the bowl cap supplied with the unit (white, boat-shaped cover with a rubber seal). This will prevent the compost from turning dry & hard and will stop insects from entering the BioLet.

In case of paper build up

If a build-up of toilet paper occurs, sprinkle a small amount of water over it to make it dissolve and mix into the compost.

Use a sponge or sponge style toilet brush and liquid soap or some other mild detergent when cleaning your BioLet. Never use scouring powder or other strong detergent that could scratch the surface.

Insect control
The presence of insects in and around your BioLet is frequently an indication of excess moisture. If there is excess moisture you will need to remedy this situation to be able to completely remove the insects from your toilet. Use of mulch not authorized for use in your BioLet may also introduce insect larvae into your toilet.
To rid your toilet of insects: Insert a Hot-Shot No Pest Strip (blue and white envelope type package), Spectracide Bug Stop Pest Strip (green and yellow envelope type package) or similar product containing Dichlorvos as the ONLY active ingredient inside the bottom of the unit but outside the tray. These items are readily available at you local hardware store or department store in their garden centers.

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