Aerated Static Pile Composting

Aerated static pile composting, also known as forced aeration composting, is an efficient way to produce high quality compost. It is especially helpful for large volumes of organic waste.

It is also a good choice for colder climates where outdoor composting is not possible. This method uses perforated pipes and fans to push or pull air through the composting mass.

Aeration

Aeration in composting is a critical component of maintaining good composting conditions. It fulfills the stoichiometric demand for oxygen from aerobic decomposition, removes excess moisture and heat, and reduces odors. In addition, aeration increases decomposition rates. Aeration can be performed by using a water-fall or air diffusion method.

In aerated static pile composting, aeration is achieved by placing perforated pipes underneath the aerated base material (typically wood chips, chopped straw or other porous materials). The pipe runs lengthways beneath the ridge of the compost pile and is connected to a blower that either pulls or pushes air through the pile.

The aeration system is controlled by a time clock or temperature sensor and may be run continuously or periodically depending on the size of the pile and the dry weight of the raw materials. The choice of blower and aeration pipe depends on the operation, and piping is typically above grade, rather than below, to avoid clogging issues.

To achieve proper aeration, it is necessary to create a properly mixed raw material mixture and add the appropriate amount of water to the mix. This must be done without compaction of the material and without introducing too much air into the mix.

A properly mixed raw material mixture can be made up of a variety of feedstocks, including kitchen waste, sludge, grass clippings, animal waste, and more. These can be combined in any aerated static pile composting ratio and are often used in a mix with other types of composting materials, such as peat moss or straw.

ASP systems are a popular composting technology that can be used for a wide range of raw materials, including meat wastes, vegetable waste, seafood wastes, dairy manure and others. They require less space than other composting methods and can be operated in cold climates.

Aerated static pile composting is an efficient method for creating a high-quality, marketable product from a range of organic wastes. It requires minimal land, is odor-free, and can produce compost in about three weeks. However, it can also be expensive to install and operate. Nevertheless, it has been widely successful in many countries.

Temperature

Temperature is a key factor in determining the rate of decomposition. When composting piles become too hot (temperatures 131F or above), bacterial activity is inhibited, and pathogens and weed seeds are killed. To keep the temperature consistent, aeration is required to vent the excess heat and provide oxygen.

The size, type, and moisture of the feedstock influence how much it will heat up in a static pile composting system. Higher moisture material will generally heat up faster than lower moisture materials. Pile depth and the surrounding environment can also impact the temperature. Adding more moisture in the form of fresh greens, browns, or other waste can help maintain an adequate temperature range.

Composting materials with a high C:N ratio or containing large amounts of ash or mineral matter usually attain high temperatures more slowly than material that does not contain these components. Shredding or pulverizing feedstock also helps distribute the heat and decreases heat loss.

Aerated static pile composting can be performed with any kind of feedstock, including food scraps, yard trimmings, sewage sludge, and municipal solid waste. It produces a stabilized compost product that is used as mulch or soil conditioner. It is an excellent option for composting large quantities of organic waste from businesses, cities, and farms.

It is important to note that aerated static pile composting can be done indoors or out, depending on the type of aeration system. Typically, the aeration system is placed under the compost pile. A layer of wood chips is then placed over the compost mixture to facilitate the distribution of air in the system.

GMT offers a variety of aeration systems to meet the specific needs of your composting operation. These include positive, negative, and reversing aeration. They come in bunker-wall, mass-bed, and in-vessel configurations; and are sized and equipped to fit your site, feed stocks, and economics.

ASP aeration systems are designed to reduce emissions and control temperature by using an internal aerator to supply a constant flow of air through perforated pipes under each pile. Aeration can be conducted manually or automatically through timer motor controls.

Moisture

During decomposition, oxygen and moisture must be kept within a certain range to provide optimum conditions for microorganisms. If these conditions are not maintained, odors will be produced.

Aerated static pile composting is a simple, inexpensive method of achieving this goal. It uses ridged or flexible perforated pipes connected to a fan to distribute oxygen throughout the pile. It is used for a wide variety of composting feedstocks and can be operated with positive or negative air pressure, balancing the oxygen and moisture needs of the compost material to reduce the time it takes for the pile to become a finished product.

Negative aeration is most commonly used in larger operations while positive aeration is more common for small home compost systems. Both methods involve a blower connected to a timer or temperature sensor.

The aeration process in composting is designed to satisfy three primary aeration demands: oxygen demand from biological oxidation; moisture removal from decomposition of dry materials; and heat removal. The oxygen demand from biological oxidation calculates out to 1.44 g of O2 /g of dry solids; the moisture demand from decomposition of wet materials is 8.6 g of O2 /g of wet material; and the heat removal demand is 38.4 g of O2 /g of dried solids (Keener, 1997).

Composting facilities are increasingly accepting a wider variety of feedstocks, including yard trimmings and food waste, for compost production. Adding these materials to the composting process decreases the amount of waste that must be disposed and increases the quality of compost produced.

This process reduces energy consumption by reducing fuel consumption from waste haulers and the use of power for aerating the pile. aerated static pile composting It also helps to comply with SARA (40 CFR 355) and EO 12856, which requires that federal facilities reduce their use of electricity.

In addition, aerated static pile composting produces a higher quality product than outdoor composting, which makes it a good choice for large-scale facilities or farms. It also requires less land than other composting methods.

Aerated static pile composting can be a great solution for composters who have limited space or aren’t able to do year-round composting. It is also a popular option for colder climates where outdoor composting is not possible.

Turning

Turning is an important step in composting, as it allows the microbes to access oxygen. It also helps the pile maintain a temperature range and wards off weed seeds. The frequency of turning varies depending on the rate of decomposition and the materials used. In general, a hot compost pile should be turned once a week, while a cold pile should be turned every three to six weeks.

In aerated static pile composting, the material is piled on top of ridged or flexible perforated pipes that connect to fans that circulate air through the pile. Positive or negative air pressure can be used to balance the oxygen and moisture requirements of the mixture, speeding up the composting process.

The aeration system is controlled by timers and limit switches. This method can be used for large-scale composting operations, including farms, as it does not require a lot of physical labor.

Typical raw materials include animal waste, sludge, food scraps, and paper. Some of these can be mixed with peat moss, straw, or other bulking agents to help increase their decomposition rate. Other common additions are corn cobs, crop residues, and bark.

Once the raw materials are piled, they must be topped off with a layer of finished compost or bulking agent. This layer prevents drying, insulates the compost from heat loss, discourages flies, and filters out potential odours. It may also be necessary to add water, depending on the temperature of the pile and the material porosity.

A hot compost pile is usually ready to harvest in about four to eight weeks, while a cold pile is finished in about six to 12 months. The decomposition time is shorter for a cold pile because there is less need to constantly monitor and regulate the temperature.

In-vessel systems allow materials to be placed in bins that contain walls and roofs (Plate 8). They can eliminate problems caused by weather, odours, and provide better temperature control. They are often used to store large volumes of waste in a single location, as they can be easily stacked and protected from rain.