We have all heard the expression: “Feed people, not landfills.”
But, what exactly does this mean and what’s wrong with landfills?
What do we do with the food that we are not going to eat?
The reality is that most people do not realize just how much food they throw away each and every day. And, the Environmental Protection Agency (EPA) tells us that about 95 percent of the food we throw away ends up in landfills or combustion facilities. In 2013, we disposed more than 35 million tons of food waste. That’s TONS of food waste. Once this food reaches the landfills, it breaks down to produce methane. Methane is a potent greenhouse gas that contributes to climate change.
The most important thing we can do is to reduce food waste in the first place. But there is avoidable waste and unavoidable waste. This “college” will deal with what to do with the waste – both avoidable and unavoidable.
Instead of sending food to landfill, we MUST (when possible) send food waste to compost.
Click the arrows to learn more about composting.
What is Compost?
The U.S. Environmental Protection Agency (EPA) tells us that compost is organic material that can be used as soil amendment or as a medium to grow plants. Mature compost is a stable material with a content called humus that is dark brown or black and has a soil-like, earthy smell. It is created by: combining organic wastes, like food wastes and yard trimmings and manure, in proper ratios into piles, rows, or vessels; adding bulking agents like wood chips as necessary, to accelerate the breakdown of organic materials. This allows the finished material to fully stabilize and mature through a curing process.
Natural composting, or biological decomposition, began with the first plants on earth and has been ongoing ever since. Composting, therefore, has been around long before any of us. As vegetation falls to the ground, it slowly decays, providing minerals and nutrients needed for plants, animals, and microorganisms. Mature compost, however, includes the production of high temperatures in order to destroy pathogens and weed seeds that natural decomposition does not destroy.
What are the Benefits of Composting?
- Turns wasted food into nutrient-rich soil that can be used as a new food source.
- Reduces or eliminates the need for chemical fertilizers.
- Serves as a marketable commodity and is a low-cost alternative to standard landfill cover and artificial soil amendments.
- Avoids methane and leachate formulation in landfills.
- A cost-effective method of remediating soils contaminated by hazardous waste.
- Promotes higher yields of agricultural crops.
- Provides cost savings of at least 50% over conventional soil, water, and air pollution remediation technologies, where applicable.
- Facilitates reforestation, wetlands restoration, and habitat revitalization efforts by amending contaminated, compacted, and marginal soils.
- Reduces the need for water, fertilizers, and pesticides.
What do I do if I Want to Compost at home or on-site? What are the Basics?
Onsite composting or even backyard composting can be conducted quite easily. A few helpful tips and pointers will enable you or your program to ensure that you are performing it correctly. There are five primary variables that must be “controlled” during composting. These include the following:
- Feedstock and nutrient balance.
Controlled decomposition requires a proper balance of “green” organic materials (e.g., grass clippings, food scraps, manure), which contain large amounts of nitrogen, and “brown” organic materials (e.g., dry leaves, wood chips, and branches), which contain large amounts of carbon but little nitrogen. Obtaining the right nutrient mix requires experimentation and patience and is part of the art and science of composting.
- Particle size.
Grinding, chipping, and shredding materials increase the surface area on which the microorganism can feed. Smaller particles also produce a more homogeneous compost mixture and improve pile insulation to help maintain optimum temperatures. If the particles are too small, however, they might prevent air from flowing freely through the pile.
- Moisture content.
Microorganisms living in a compost pile need an adequate amount of moisture to survive. Water is the key element that helps transport substances within the compost pile and makes the nutrients in organic material accessible to the microbes. Organic material contains some moisture I varying amounts, but moisture also might come in the form of rainfall or intentional watering.
- Oxygen flow.
Turning the pile, placing the pile on a series of pipes, or including bulking agents such as wood chips and shredded newspaper all help aerate the pile. Aerating the pile allows decomposition to occur at a faster rate than anaerobic conditions. Care must be taken, however, not to provide too much oxygen, which can dry out the pile and impede the composting process.
Microorganisms require a certain temperature range for optimal activity. Certain temperatures promote rapid composting and destroy pathogens and weed seeds. Microbial activity can raise the temperature of the pile’s core to at least 140 degrees Fahrenheit. If the temperature does not increase, anaerobic conditions (i.e., rotting) occur. Controlling the previous four factors can bring about the proper temperature.
Let’s Really Get Down to the Nitty-Gritty of Composting
Composting is good for everyone. It will save money for your program and is a great way to “go green” and help us to be environmentally friendly. Now, let’s get a little more technical and see what all this means and how we can all make a difference in ending food insecurity and helping the environment at the same time.
Anaerobic Digestion – What is this?
The U.S. Environmental Protection Agency tells us that if 50 percent of the food waste generated each year in the U.S. was anaerobically digested, then enough electricity would be generated to power 2.5 million homes for one year. That sounds impressive. But, what, exactly, is anaerobic digestion?
This is going to be technical, but very important if we want a firm understanding of different types of composting.
Anaerobic digestion is a process where microorganisms break down organic materials, such as food scraps, manure, and sewage sludge, in the absence of oxygen. Recycling food waste through anaerobic digestion produces biogas and a soil amendment, two valuable products.
Biogas, made primarily of methane and carbon dioxide, can be used as a source of energy similar to natural gas. The solid residual should be land applied or composted and used as a soil amendment.
Food can either be digested at facilities specifically designed for the organic portion of municipal solid waste, or co-digested at wastewater treatment plants and manure digesters.
So, what is co-digestion? Well, that is a process whereby additional, energy-rich organic materials like food scraps or fats, oils and grease, are added to dairy or wastewater digesters with excess capacity.
What do I do if I want to compost in my backyard or at my site? Can I?
You sure can. However, you must be aware of certain considerations and options before you get started on your own composting. Let’s talk about what can and cannot be composted in your own backyard or at your program site.
Backyard or onsite composting is suitable for converting yard trimmings and some food scraps into compost that can be applied on site. This method should not be used to compost animal products or large quantities of food scraps.
Climate or seasonal considerations
Climate and seasonal variations do not present major challenges to backyard or onsite composting because this method typically involves small quantities of organic waste. When conditions change, for example, if a rainy season approaches, the process can be adjusted accordingly without many complications.
Improper management of food scraps can cause odors and also might attract unwanted insects or animals. This is very important and must be taken into serious consideration when deciding to compost in your own backyard or onsite.
Backyard or onsite composting requires very little time or equipment. The most critical aspect of this type of composting is education. You must become familiar with every aspect of composting and what it means and how to do it correctly.
The conversion of organic material to compost can take up to two years, but manual turning can hasten the process considerably. If you can perform manual turning, the process might even take between 3 and 6 months. The resulting natural fertilizer can be applied to lawns and gardens to help condition the soil and replenish nutrients. You might be able to grow fruits and vegetables from what was your own food waste. What a wonderful idea.
Please note that compost should not be used as potting soil for houseplants because of the presence of weeds and grass seeds that may be in the compost.
Let’s talk about different kinds of composting
This method of composting uses red worms. Through the use of red worms – and remember, this is not about using nightcrawlers or field worms found in gardens – are placed in bins with organic matter in order to break it down into a high-value compost called castings. Worm bins are not that difficult to construct and they are also commercially available. The bins can be adapted to accommodate the volume of food scraps that you generate.
Worms will eat almost anything you would put in a typical compost pile, such as food scraps, paper, and plants. Vermicomposting can be ideal for those who live in small spaces such as apartments. Very often, vermicomposting is used in schools to teach children about the usefulness of composting.
Worms are sensitive to variations in climate. Extreme temperatures and direct sunlight are not healthy for the worms. The optimal temperatures for vermicomposting range from 55 degrees Fahrenheit to 77 degrees Fahrenheit. In hot, arid areas, the bin should be placed under the shade. By vermicomposting indoors it is much easier to avoid those problems posed by hot or cold climates. The primary responsibility, then, is to keep the worms alive and healthy by providing the proper conditions and sufficient food.
So, let’s review the basic requirements of vermicomposting: worms, worm bedding (for example, shredded newspaper or cardboard, and a bin to contain the worms and organic matter. Then you must maintain the proper bedding and burying of garbage and then separating worms from their castings.
Approximately 800 to 1,000 worms can eat up to half a pound of organic material per day. It typically takes three to four months for these worms to produce harvestable castings, which can be used as potting soil. There is also something called “worm” tea that is a high-quality liquid fertilizer for houseplants or gardens that is produced through vermicomposting.
Aerated (Turned) Windrow Composting
Windrows are long piles that are formed by organic waste and then aerated by turning the pile periodically by either manual or mechanical mechanisms. The ideal pile height, which is between 4 and 8 feet, allows for a pile large enough to generate sufficient heat and maintain temperatures, yet small enough to allow oxygen to flow to the windrow’s core. The idea pile width is also quite large- anywhere between 14 and 16 feet.
Why this method of composting
This method can accommodate large volumes of diverse wastes, including yard trimmings, grease, liquids, and animal byproducts (fish and poultry waste), but only with frequent turning and careful monitoring. This method is suited for large quantities, such as that generated by entire communities and collected by local governments, and high volume food-processing businesses such as restaurants, cafeterias and packing plants.
Climate or seasonal considerations
In a warm, arid climate, windrows are sometimes covered or placed under a shelter to prevent water from evaporating. In rainy seasons, the shapes of the pile can be adjusted so that water runs off the top of the pile rather than being absorbed into the pile. Also, windrow composting can work in cold climates. Often the outside pile might freeze, but in its core, a windrow can reach 140 degrees.
Leachate is liquid released during the composting process. This can contaminate local ground water and surface-water supplies and should be collected and treated. In addition, windrow composting is a large-scale operation and might be subject to regulatory enforcement. Samples of the compost should be tested in a laboratory for bacterial and heavy metal content. Odors also need to be controlled. The public should be informed of the operation and have a method to address any complaints about animals or bad odors.
Aerated Static Pile Composting
In aerated static pile composting, organic waste is mixed together in one large pile instead of rows. To aerate the pile, layers of loosely piled bulking agents such as wood chips and shredded newspaper, are added so that air can pass from the bottom to the top of the pile. The piles also can be placed over a network of pipes that deliver air into or draw air out of the pile. A timer or temperature sensors might activate air blowers.
Aerated static piles are suitable for a relatively homogenous mix of organic waste and work well for larger quantity generators of yard trimmings and compostable municipal solid waste such as local governments, landscapers, or farms. This method does not work well for composting animal byproducts or grease from food processing industries.
Organic materials are fed into a drum, silo, concrete-lined trench, or similar equipment where the environmental conditions-including temperature, moisture, and aeration- are closely controlled. The apparatus usually has a mechanism to turn or agitate the material for proper aeration. In-vessel composters vary in size and capacity.
In-vessel composting can process large amounts of waste without taking up as much space as the windrow method. In addition, it can accommodate virtually any type of organic waste (meat, animal manure, biosolids, food scraps). Some in-vessel composters can fit into a school or restaurant kitchen while others can be as large as a school bus to accommodate large food processing plants.
In-vessel composting can be used year-round in virtually any climate because the environment is carefully controlled, often by electronic means. This method can even be used in extremely cold weather if the equipment is insulated or the processing takes place indoors.
The good news about in-vessel composting is that it produces very little odor and minimal leachate. However, in-vessel composters are expensive and might require technical assistance to operate properly, but this method uses much less land and manual labor than windrow composting.