Anthropogenic (human generated) waste materials are a source of great concern. The amount of space on the planet is finite, and as the human population expands, available space decreases. There are few truly wild regions left in the world due to the growth of the human race. With this growth comes serious problems. Where do we live? Where can we grow food? What about the by-products of human existence? The latter represents perhaps the greatest dilemma. Everyday human life produces a staggering amount of waste material. Much of this waste is carted off to landfills, where it can be left to decompose over a period of years.
Certain human waste products, such as plastics and metals, do not decompose readily, and must be left in the landfill for hundreds or thousands of years. Others decompose rapidly, breaking down in just a few weeks. Most often, these short-lived wastes are organic in nature, mostly leftovers from your dinner and grass clippings, weeds and sticks from your yard. That’s right, food and grass.
The United States Environmental Protection Agency estimates that food and lawn clippings account for nearly 60% of all wastes placed in landfills. Total landfill additions in the United States in 2000 were about 232 million pounds of waste, which means that about 140 million pounds were created by people discarding food scraps and lawn clippings. You can imagine how much space this must occupy.
Each person in the United States accounts for about 5 pounds of solid waste each day, of which, about 3 pounds is food or lawn waste. There are many ways to help reduce the amount of solid waste placed into landfills each day. Recycling plastics, glass, paper, and metals, redesigning industrial procedures to produce less waste, and composting of food and lawn materials have all helped to ease the load of solid waste.
Composting is a process by which certain organic waste materials are broken down into useful products by the action of soil microbes and terrestrial invertebrates. Backyard composting piles have grown in popularity among home owners with gardens, providing them with a good source of nutrient rich soil for their plants, as well as a way to reduce their trash output. Composting piles work through a series of biological activities to speed the breakdown of organic wastes into dark, rich soil that is a very good growth medium for plants. Typically, the waste materials are buried in the pile, kept moist and allowed to decompose over a period of a few weeks. The actual amount of time needed varies, depending on the type of material buried.
Certain food wastes, such as breads, will decompose rather quickly, while others, such as egg shells, will take much longer to break down. The pH, temperature, and moisture level of the pile can influence the speed of the breakdown as well. After a sufficient period of time, the castings, or excretions, created by the worms can be harvested and mixed with soil for planting. The castings are rich in nitrogen and phosphorus, two nutrients that are critical to the growth of plants.
The actual process of composting is mostly based on bacterial action. The bacteria are known as primary decomposers, being the first in a series of steps that leads to the breakdown of organic materials to simple end products. The bacteria initiate the decomposition, and serve as a food source for the secondary decomposers, such as worms. The worms eat the bacteria, and move about the pile, creating small passageways that serve to promote aeration. This is important because it allows aerobic bacteria to thrive, and prevents the elevation of temperature and production of toxic by-products that would be caused by anaerobic respiration.
Red wiggler worms are the most popular worm used for home composting bins. They are easy to culture and thrive in shallow (6-18”) soil. They are found in the upper layer of soil in nature, and reproduce rapidly when conditions are right. They are extremely light sensitive, and prolonged exposure to a light source will kill them. For this reason, opaque bins are recommended for home composting use. The worms will lay tiny lemon- shaped egg sacs throughout the bin, which can be removed and used to start another bin if so desired.
Did you know?
- The trash production in the United States has almost tripled since 1960. This trash is handled in various ways. About 27 percent of the trash is recycled or composted, 16 percent is burned, and 57 percent is buried in landfills.
- Composting is an ancient technology. There are Roman and biblical references to composting as well as numerous accounts of farmer composting practices in subsequent millennia.
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Vermi Composting Kit - Investigate the biological breakdown and remediation of human food waste in this stimulating semester-long exercise. Using this process, the degradation will occur much faster than composters based on microbial degradation. Students will use red wiggler worms to efficiently degrade household wastes and create a nutrient-rich soil.- Composting Investigations Lab Activity - Students can observe the effects of biological degradation safely and conveniently with this kit. Three investigations are featured in the manual supplied, including measuring temperature increases in the composting bin during the microbial degradation process. The compost you produce can also be used in a plant-growth study.
School Composting Investigations Lab Activity - Take your indoor composting activities outside by composting waste materials in a large outdoor bin. Teacher’s and students’ manuals are included to guide your class through a variety of investigative projects designed to create an efficient composting system. Along with the bin, you’ll also receive starting inoculum and our comprehensive instructions for setup. You’ll learn how to keep microbes alive so they can continue to degrade your carbon source (leaves, paper, etc.).
