Earth Tub Troubleshooting

This page describes the current status of problems or inefficiencies in the Earth Tub operation. Please contact me with any suggestions.

Plastic Bags

Problem: The degradable plastic bags wrap around the auger during mixing. This covers the auger and greatly reduces its mixing and shredding abilities
Background: We had decided to use degradable plastic bags to make transport of waste from collection to Earth Tub cleaner and easier. The bags are supposed to break down in standard composting conditions (similar ones advertise 60-90 days to complete degradation).

Possible Solutions:

1. Use bare cans (no bags) with the bottom lined with scrap paper or leaves to prevent caking on the bottom and absorb some moisture. Dump everything into the tub and rinse the can after each use.
   Tested: worked well and receptacle was no dirtier than with the bag. Do not lay paper flat on bottom of the can. Use crumpled balls of paper and form a layer. Bathroom hand towels would work well for this purpose.
2. Use paper collection bags. Dump all in tub.
3. Use hedge clippers to shred the plastic bags once they are in the tub.

Make a suggestion

Leachate Transport

Problem: Leachate must be drained from the Earth Tub must either be placed back inside or must be disposed of in a sanitary sewer

Background: Leachate (dirty water) is generated from the wastes in the Earth Tub. There is a spigot at the base of the Earth Tub that allows for the draining of leachate. It is about 3" off the ground. The sanitary sewer entrance is about 15' away from the spigot and stands 6-8" high.
Possible Solutions:

1. Run a hose from the spigot to the Earth Tub to the sanitary sewer and try to get the leachate to run uphill (hand pump?)
2. Empty leachate into a collection pan and then carry to Tub or sanitary sewer

Make a suggestion

Student Sorting Accuracy

Problem: When students separate trash, there is a small amount of error, resulting in non-compostable materials being misplaced with the compostable waste.
Background: Students separate their plate waste after each meal into three categories: compostables (food and untreated paper), recyclables (glass, aluminum, and clean paper) and non-compostables (waxed paper, plastics, styrofoam). Most non-compostable materials that are misplaced in the Earth Tub will not adversely affect the composting process, with the very notable exception of glass. Glass would have a high likelihood of shattering in the tub, spreading sharp glass shards throughout the batch, rendering the whole batch dangerous.
Possible Solutions:

1. Manually dig through the trash and remove non-compostables
2. Screen material before adding it to the Tub
3. Send a newsletter to student for further education and familiarity with the project
4. Build a sorting station with all waste types (compostable, glass, aluminum, clean paper, plastic, all else) deposited at the same location, designed for ease of use.

Make a suggestion

Cord Restrictions

Problem: The power cord for the auger gets wrapped around the Earth Tub, restricting the regular mixing process.
Background: The Earth Tub must be mixed regularly (~3x/week) with the auger running to mix the food scraps with the bulking agent (leaves). This is done by starting the auger and then rotating the tub for two complete rotations (one clockwise and the other counter-clockwise). During the rotation, the cord often gets wrapped around the side of the Tub and restricts further movement.
Possible Solutions:

1. Build a small tower in the middle of the tub with a swiveling top to guide the cord directly to the power source without wrapping around the side of the Tub.
2. Get a longer cord to allow for the cord to completely wrap around the tub.

Make a suggestion

 

Does this give you an idea? Then go to the Idea Bank and make it known.

Got questions? You can reach me at envintrn@rice.edu.

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Accessed times since 9-2-99