Aerated Static Pile Composting Explained

  • By: composthq
  • Date: March 12, 2023
  • Time to read: 5 min.

What is ASP Composting? 

Aerated static pile composting uses airflow to reduce the time it takes to compost large amounts of waste and lessening unpleasant odors.

Composting is a great way to help the environment and produce richly fertilized soil.

But if you have more questions than answers about composting, we can help. First, you’ll need to decide on the type of composting that will work for you. 

One of the most economical, time-saving composting syles is aerated static pile composting. What is aerated static pile composting, you may ask. 

ASP is a hot composting method that uses the purposeful movement of air through waste materials to make them compost rapidly, even in a small space.

Compost materials are piled on top of ridged or flexible perforated pipes. The piping is connected to fans that circulate oxygen through the pile. 

Air is circulated through the compost with either positive or negative air pressure, speeding up compost time by balancing the oxygen and moisture needs of the mixture.

Negative pressure, where air is pulled through the compost rather than pushed, is primarily used in larger operations. 

Aerated static pile composting does not require turning, so it is not as physically demanding as traditional composting for individuals.

No need for physical labor makes it a good option for large operations such as farms.   

ASP Composting Cost

Cost is one of the main factors in determining the type of compost system that is right for you – or whether you want to begin composting in the first place. 

Compared to traditional “backyard composting,” ASP composting is a little more expensive.

You can build or buy a compost bin for less than $100, but you’ll end up putting a lot of work into this system because it will need to be turned every few weeks but monitored daily. 

For around $200, you can purchase everything you’d need to set up your own ASP composting system at home.

Once it is in operation, your ASP compost will do its job without any effort from you.

 A large-scale operation with a multi-pile system can cost upwards of $100,000. A large factor in this cost is leveling and preparing an area to place the system. 


There are several clear benefits of aerated static pile composting: 

  • faster biodegration
  • can handle wetter compost than traditional composting
  • can compost large amounts of compost in a small area
  • easy to maintain moisture and oxygen levels, and, therefore, the temperature of compost
  • greatly reduces compost odors


When compared to other composting techniques, ASP has its disadvantages as well: 

  • dry out faster than other compost methods and require careful monitoring
  • depend on electricity
  • requires extra materials (finished compost, compost fleece, or mulch)
  • materials must be mixed, not layered

How an ASP Composting System Works 

Surprisingly, only a few supplies are needed to build a simple ASP composter, and these same components are found in systems of any size. All ASP systems work exactly the same way. 

Materials Needed

Once you understand what each part of the system does, its operation is quite intuitive. The following components are needed for a home or industrial aerated static composting pile system: 

  • Manifold  The mainfold is the piping that delivers the air. In homemade systems, this is PVC pipe with holes drilled in it. Multi-pile systems need ball valves so each pile can be aerated independently. 
  • Blower – The blower is attached to either a timer or a temperature sensor in most cases, but you’ll still need to keep an eye on it. You can purchase a blower for a home system online or in any home improvement store. 
  • Plenum layer – This layer can be wood chips or any other semi-permiable substance that will gently diffuse the air from the holes in the piping. This prevents air from going straight up or diverting to the sides of the pile, taking the path of least resistance. 
  • Active layer – The active layer is the compost material, which needs to maintain a carbon-to-nitrogen ratio (C:N) of around 25:1 and reach a temperature of 131 degrees Fahrenheit for a minimum of 3 days. 
  • Bio layer – Your bio layer can be mulch, compost, or more expensive options. The bio layer discourages pests, reduces odors, and reduces the amount of heat that is released into the atmosphere.  

How it Works 

  1. First, the blower sends air through the manifold. This is usually done on a schedule such as 30 seconds of air on, then 30 minutes with the air off. 
  2. The air passes through the plenum layer, diffusing it to the entire pile. 
  3. Compost begins aerobically composting within the active layer. 
  4. The bio layer stalls heat and odor produced by the composting process. 

What Can Be Composted with ASP Systems? 

Anything you would add to a backyard compost bin can be added to an ASP composting system. This includes all manner of organic waste and food waste that is high in nitrogen. 

ASP composting is particularly effective for farms where manure has a tendency to build up. Livestock and equine farms have seen great success using ASP systems.

Horse manure takes a long time to decompose because it is usually mixed with bedding materials such as shavings, giving it a carbon-to-nitrogen ratio of around 75:1. 

ASP Composting Versus Other Methods

There are 3 main types of composting: 

Aerobic – Aerobic composting uses air to facilitate composting. ASP is an aerobic composting technique. Tumbler composters are another way to achieve this. 

Anaerobic – Anaerobic composting does not require the addition of oxygen, nor does it requre turning. It can take a year or more, it stinks, and it increases the risk of producing bacteria. 

Vermicomposting – This method uses worms to degrade materials. It can be combined with aerobic composting to speed up the process even more. 

Aerated systems are normally found in large-scale operations, including farms and composting facilities.

However, they are easy to assemble and offer a hands-off option for individuals as well. 

Large composting operations use computerized systems to monitor the temperature of the compost and to manage the airflow to the compost materials.

But you can monitor your ASP system manually or with a simple thermostat. 

Aerated static pile composting is good for colder climates where you might not otherwise be able to do year-round outdoor composting. 

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