TSJ 3000 - a Composting Toilet

Introduction: TSJ 3000 - a Composting Toilet

Hi! Our names our Tiffany, Jenna and Sacha and we're a group of college students interested in sustainability. Our group was interested in creating an innovative toilet to be used in a Tiny House. In thinking sustainably, we wanted to shift the idea that humans are completely separate from nature. In fact, we have a strong relationship with nature and our ecosystem. In order to ensure the efficiency of the tiny house, we need to ensure that the dynamics of the system can take advantage of the resources that are available to us. A step further would be taking advantage of the resources that we, as humans, produce ourselves. The epitome of this concept is reflected in the product we are striving to make - a toilet that makes use of our waste and turns it into fertilizer for any garden that may be available.

The toilet design involves an indoor component, the toilet itself, the pipe that will connect the indoor and outdoor components, and the outdoor component, which is a basin with three different compartments. This design allows the product to be used in tiny houses that are on wheels, as the basin will be accessible underneath the house. The design could be modified for use in housing other than a tiny house, but our design focused on the tiny house. The basin portion of the toilet design involves three differently functioning compartments: one which stores the waste, one in which the thermophilic composting process takes place, and one that involves user input in making the soil pods. Our product only deals with the treatment of solid waste because it is urine-diverting. It is urine-diverting for two main reasons: to eliminate the foul odor that comes with mixing urine and feces, and the different processes to make each usable for recycling. In a future model, the urine could be filtered through greywater filtration systems and recycled into usable water for growing plants. However, for the purposes of our model, we only focus on the treatment of solid waste.

The process takes about three weeks, at which point the user will test the waste for coliform using an included test strip. To do this, the user will remove the second compartment cover by unscrewing the cover. If the test results come back negative, that there is no coliform present, the user will slide out the second plexiglass screen, allowing the waste to fall into the third compartment. The third compartment is a drawer, and once the waste is in the third compartment, the user may slide out the drawer and use the included soil cuber to make the waste into fertilizer pods. The pods are now safe and ready to use in a garden.

Step 1: Materials!

Materials to set-up composting toilet

4 x 6 inch Plywood

5 17 inches x 20 inches Sheets of plywood

2 sheets of 15 inches x 12 inches Plexiglass
2 sheets of 12 inches x 7 inches Plexiglass

15 inches x 8 inches Wooden Drawer

11 inch Plastic Black Piping

Toilet seat


20 screws

Two wing nuts

2 bolts







Drill Saw

Power Saw

Step 2: Making the Box

  1. Using the drawer as a base, measure the plywood and cut the plywood into 5 17 x 20 inches pieces of plywood
  2. Assemble the pieces of plywood around the drawer as to form a box shape, leaving a gaping space so that the drawer is retractable from the box
  3. Drill the pieces of woods together using drills and screws
  4. Drill a hole that is 4 inches in radius or 8 inches in diameter on the top of the box using the saw
  5. Using a power saw cut four slits into the open side of the box
  6. Measure the length and the width of the box using the ruler to divide the box into three sections
  7. Using this measurement, cut the plexiglass into two rectangular shapes that could slide into the box with the slits so as to form three separate section of the box
  8. Using more plexiglass, measure the height and length of the top half of the box. This plexiglass will act as a guard for both the first section of the box
  9. Cut the plexiglass into 2 12 inches x 7 inches so as to make the plexiglass guard using the drill saw
  10. Using the drill, make 4 holes on the sides of the plexiglass guard. This will be where the screws will be.
  11. Screw in plexiglass on the first section of the box (Caution, make sure the plexiglass does not go against the sliding plexiglass)
  12. Repeat steps 8 to 9, for the plexiglass that will act as the plexiglass guard for the second section of the boss
  13. Once this is completed, drill in two holes, one on each side, of the plexiglass
  14. Screw in one bolt per hole, using the drill, so as to attach the plexiglass guard to the second section of the box
  15. Using the wingnuts, secure the plexiglass guard by screwing in the wingnuts onto the bolts. This will allow the second plexiglass guard to be detachable when necessary.
  16. Measure the second section of the box.
  17. Using the saw, cut the styrofoam according to the dimensions of the second section of the box
  18. Line and insulate the second section of the box with styrofoam, by fitting in the two pieces of styrofoam on the sides of the second section of the box and screwing it in.
  19. Drill 6 holes on the side of the box for the second section of the box, drilling into the styrofoam so as to act as insulation for the box

Step 3: Making the Toilet Top

  1. To make the toilet portion of the composting toilet, acquire a bucket
  2. Drill a small hole in the bottom of the bucket that will be same dimensions as the hole on top of the box. The bucket will act as the toilet
  3. Measure the curve of the top of the bucket
  4. Acquiring the plywood and using a marker, draw a curve on the 4x6 inch plywood
  5. Using the buzzsaw, cut the curve of the plywood. The plywood should fit neatly along the curve of the bucket
  6. Drill two holes, vertically, on the curved plywood 6 inches apart. This should be where the two screws from the toilet seat should be.
  7. Reset the curved plywood along the top of the bucket
  8. Using the drill and screws, drill three holes through the bucket into the curved plywood. The curved plywood should, now, be connected to the bucket
  9. Take the toilet seat, and place it on top of the bucket, the two screws that connect to the toilet seat should go through the two holes of the curved plywood
  10. Seal the toilet seat by securing the bolts around the screws of the toilet and the curved plywood

Step 4: Connecting the Toilet With the Box

  1. To connect the toilet and the box, we will utilize the plastic piping
  2. Acquire plastic piping, and then using the buzz saw cut the plastic piping so that it is 11 inches long
  3. Turning the box sideways, place the piping within hole on top of the box until it hovers midway above the first section of the box
  4. Using the drill and three screws, drill three holes through the piping and into the box so that the pipe is connected to the box
  5. Once this is completed, place the toilet bucket over the piping
  6. There you go! You've made your composting toilet

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