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Locally Delicious Kids Worm Bin

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Abstract

Locally Delicious and Humboldt State University's Engr215 Introduction to Design class came up with a worm bin design that utilizes a small scale worm bin system to allow children of ages 8-12. The bin can be constructed by kids without the help of their parents following the instructions we developed. This bin enables kids to get hands-on experience with composting and sustainable living. The final design consists of small water-resistant milk cartons that are easily accessible, recycled, and inexpensive.

Fig 1: Team Onychophora

Background

Locally Delicious is an organization run through Humboldt County, California, designed to better the community as well as raise awareness on certain issues. The design of the Kids only worm bin is a branch of this group's work with Humboldt State University's Engr215 students, designing sustainable and easily reproducible project for a system of schools in the area. After the projects have been finished and released, material regarding the details of the various projects will be published as a compilation in a book tentatively due out in the fall of 2011. The design outlined below is a product of Onycophora, a group of the aforementioned Engr215 students.

Problem statement and criteria

Criteria Weights Description
Cost 10 The cost of the project was geared towards being very minimal to fit the budget of kids. Most of the material to be used can be acquired at no cost to the child.
Maintenance 4 The amount of time related to upkeep of the worm bin will be minimal and sustainable for an estimated time of six to twelve months.
Materials 7 Materials apart from the worms themselves will not be difficult to obtain for the targeted age group or their parents, i.e. outside of the home, local hardware stores, or local grocery stores.
Efficiency 9 Within two months the worm bin will be able to produce castings provided that the worm bin is properly cared for and is given an adequate amount of food waste.
Build Time 8 Build time should be minimal, i.e. able to be completed over the course of one weekend by the targeted age group.
Educational Value 5 The worm bin design will enable the targeted age group to both learn about the general design of a worm bin and to help them understand the concepts of waste and consumption.
Durability 8 The worm bin design will be able to withstand the effects of child contact and weather for six to twelve months provided that the worm bin is being properly maintained.
Safety 5 The materials used in the design of the worm bin will not be harmful to the targeted age group’s health or well being.
Reproducibility 10 The design of the worm bin will be easily reproducible by the targeted age group, given adequate parental help and supervision.

Description of final project

Our Project is composed of empty half gallon milk or juice cartons. Inside of the cartons is a migration hole that allows worms the access to both cartons. Worms are fed on one side of the bin while castings can be removed from the other carton. This process will be repeated as the worms will migrate towards the food and leave castings behind. Each time the food is digested new bedding is inserted.

Costs

Our cost was very minimal because most the materials were reused materials, the table to the right shows of our costs and total for the project. The worms are the highest expense for the project.


Breakdown of the materials needed and associated costs.

Testing Results

To test the cardboard milk/silk/juice carton worm bin, we placed a cut off strip of the carton in a glass of water. This test was meant to determine how well the material of the carton would react to extreme weather conditions over a period of time when cut. We also placed a cut up strip of the carton which we had taped back together in the glass of water to determine how well the tape would hold up. After leaving both tests in the glass of water for two weeks now, the strips of carton and tape have taken on little to no damage. Because of these promising results, we have determined that cardboard milk, silk, or juice cartons are a good material to use for the Kids Worm Bin design.


When testing with children at Alice Birney School in Eureka, California, the results were positive. Three nine year old children constructed the bins with the help of two Onycophora team members, and appeared to enjoy the process. The most difficult steps for the children were those involving poking holes. It was found that not only do pencils work better than pens, but milk cartons are easier to penetrate than the provided Dole brand juice cartons. In addition, the cartons became structurally unsound after the cutting of the migration holes, making it more difficult to poke holes for aeration and for the top flaps.The favorite part of the project for the children we tested with was filling the bins with bedding. They enjoyed shredding the newspaper and picking grass and leaves to make a comfortable "home" for their worms.

Instructions for Making The Worm Bin

Discussion and next steps

The overall design of the kid's worm bin is such a simple one that it allows for various small changes of material and location. The "bin" itself could be constructed of any waterproof, easily accessible material, not just milk or juice cartons. The design works well both inside and outside, and can be easily placed in any area due to its small size. Though working for a variety of ages, testing results led us to believe that children eight to twelve years of age will be fully capable of building a "Wormland" bin if provided with adequate instruction.

Once implemented, it would therefore be important to take into account not only age and ability but adult supervision and help. Though this is a kid's project, it is recommended an adult assists with implementation and instructions to ensure proper building and safety.

The next steps of the project will be the publishing of the designs and findings in the book compiled by the organization Locally Delicious, and its implementation by students. We hope that anyone who attempts this project is satisfied with their results and learns something about red worms and waste in the process.

Reference