Building a school compost bin for a school garden
There are a number of designs for a compost bin. Your choice of design will depend on your climate, whether the compost bin is to be indoors or outdoors, the size of the project, the amount of food scraps being put into the compost bin, and the length of time you wish the composting to "work" before harvesting the soil
The Department of Crop & Soil Sciences Cornell University provides a number of health & safety guidelines for composting in a school setting.
A composting project in a school, either in the classroom or on the school property, can be a great opportunity for students to gain direct knowledge and experience with natural processes and a method of reducing and recycling biodegradable wastes. Although composting utilizes natural decay processes, these processes are occurring in a relatively small, concentrated area of a pile or bin. There is a potential for human exposure to the organisms involved and the products they produce. To make this educational experience a successful one, we should consider how we might reduce any potential risks. Providing an experience with composers is basically similar to bringing into a school other living things so that students can observe and interact with the living environment. Direct interaction with living organisms is not free of risk. We know that some people can experience health problems: for example, allergic skin reactions or asthma to bird or other animal dander, asthma to fungi, or infections from bacteria and fungi.
Composting is a controlled decay process which fosters the growth of bacteria and fungi, as well as other organisms. It can be a source of exposure to microorganisms, their spores, or their by-products. Exposure to these items could occur by: • Inhalation • Skin contact or absorption • Injection (exposure through the skin, such as through cuts, abrasions, or puncture wounds) • Ingestion (usually hand-to-mouth transfer). Children and adults are experiencing an increase in the incidence of asthma and may be immunocompromised from inherited or acquired conditions, or due to medication.
While most people do not experience any reaction to compost bins or compost, we need to minimize the risks so that we can protect susceptible people and provide a rich educational experience. Here are some thoughts and suggestions.
The Department of Crop & Soil Sciences Cornell University provides a number of health & safety guidelines for composting in a school setting.
A composting project in a school, either in the classroom or on the school property, can be a great opportunity for students to gain direct knowledge and experience with natural processes and a method of reducing and recycling biodegradable wastes. Although composting utilizes natural decay processes, these processes are occurring in a relatively small, concentrated area of a pile or bin. There is a potential for human exposure to the organisms involved and the products they produce. To make this educational experience a successful one, we should consider how we might reduce any potential risks. Providing an experience with composers is basically similar to bringing into a school other living things so that students can observe and interact with the living environment. Direct interaction with living organisms is not free of risk. We know that some people can experience health problems: for example, allergic skin reactions or asthma to bird or other animal dander, asthma to fungi, or infections from bacteria and fungi.
Composting is a controlled decay process which fosters the growth of bacteria and fungi, as well as other organisms. It can be a source of exposure to microorganisms, their spores, or their by-products. Exposure to these items could occur by: • Inhalation • Skin contact or absorption • Injection (exposure through the skin, such as through cuts, abrasions, or puncture wounds) • Ingestion (usually hand-to-mouth transfer). Children and adults are experiencing an increase in the incidence of asthma and may be immunocompromised from inherited or acquired conditions, or due to medication.
While most people do not experience any reaction to compost bins or compost, we need to minimize the risks so that we can protect susceptible people and provide a rich educational experience. Here are some thoughts and suggestions.
- Protect those likely to be most sensitive. Discover any potentially susceptible students in the class or school building. Determine who may have allergies, be immunocompromised or be prone to infections that could make them sensitive to potential risks. Control exposure of these individuals by restricting who actually comes in contact with the compost. Other students or the teacher could feed the compost bin or take samples. Do not stir or otherwise disturb the pile or bin when people susceptible to inhalation of allergens are nearby.
- Consider the type of compost bin. Most school compost bins are too small to undergo a thermophilic (hot) phase making the risk from the fungus Aspergillus minimal, but also failing to get hot enough to kill pathogens that might be contained in post-consumer food scraps. (See fact sheet on Health & Safey Guidance for Small Scale Composting at: http://cwmi.css.cornell.edu/smallscaleguidance.pdf. For information on worm composting, see Worm Composting Basics: http://compost.css.cornell.edu/worms/basic.html).
- Turning the compost. Turning of compost piles releases most of the airborne particles and gases that can cause symptoms in some people. So if a pile is turned, be aware of the wind direction and of the susceptibility of those nearby and those doing the turning. Susceptible children should not turn the compost.
- Where to put the composting activity? If outside, keep it away from air intakes and downwind, for the prevailing winds, of the building. Often, compost piles are placed in school courtyards with surrounding classrooms having unit ventilators; this may not be a good location as it places the air intakes for these units too close to the pile. If inside the building (such as a worm bin), consider hallways, areas near loading docks, or other areas which are drafty.
- There are other potential sources of molds such as carpets that should also be considered if air circulation is inadequate.
- Manage the compost well. Making compost requires a mix of feedstocks, some high in nitrogen (like food scraps) and others high in carbon (like leaves, sawdust and newspaper). Keeping food scraps covered with high-carbon materials will keep down flies and dispersal of fungal spores. Make sure you have a box of sawdust at hand (not cedar). It is advisable for people to handle only their own food scraps or only to use food scraps that have not been eaten to avoid sharing of germs.
- Practice good hygiene. Anyone coming in contact with the compost bin or compost should practice good hygiene by either effective washing hands well or wearing disposable gloves. Gloves should be available and users should know proper technique for removing gloves. Hands should be washed after gloves are removed. Anyone with cuts and abrasions should cover them with bandages and wear gloves.
- Recognize potential symptoms. If a student comes into contact with the compost and gets short of breath, wheezes, has irritation of the eye/nose/throat, experiences nausea, or headache, these symptoms might be associated with exposure to the compost. Consider modifying procedures as needed to protect everyonehttp://cwmi.css.cornell.edu/health.pdf
FOR SOME IDEAS ON HOW TO USE COMPOST AS AN EDUCATIONAL TOOL - This web site explains how to make compost either indoors or outside, and gives detailed information on the science of the composting process. It also includes articles about weird and unusual composting, frequently asked questions, and a composting quiz. View at: http://compost.css.cornell.edu/schools.html
Composting in the Classroom: Scientific Inquiry for High School Students - A manual for teachers interested in using composting as a topic for scientific inquiry by high school students. Includes example research topics, guidelines for directing student research, and instructions for a wide variety of techniques related to compost science. http://compost.css.cornell.edu/CIC.html
Nellie J. Brown, MS, CIH Director, Workplace Health & Safety Program Industrial Labor Relations, Cornell University FACT SHEET 2005http://cwmi.css.cornell.edu/health.pdfHealth & Safety Guidance for Composting in the School Setting2 Cornell Waste Management Institute2005http://cwmi.css.cornell.edu/compostbrochure.pdf.