Aerated static pile (ASP) composting refers to any of a number of systems used to biodegrade organic material without physical manipulation during primary

composting Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical and biological properties. It is commonly prepared by decomposing plant, food waste, recycling organic materials and manure. The resulting m ...

. The blended admixture is usually placed on perforated piping, providing air circulation for controlled

aeration Aeration (also called aerification or aeriation) is the Systems engineering process, process by which air is circulated through, mixed with or solvation, dissolved in a liquid or other substances that act as a fluid (such as soil). Aeration proces ...

. It may be in

windrows A windrow is a row of cut (mown) hay or small grain crop. It is allowed to dry before being baled, combined, or rolled. For hay, the windrow is often formed by a hay rake, which rakes hay that has been cut by a mowing machine or by scythe into ...

, open or covered, or in closed containers. With regard to complexity and cost, aerated systems are most commonly used by larger, professionally managed composting facilities, although the technique may range from very small, simple systems to very large, capital intensive, industrial installations. Aerated static piles offer

process control An industrial process control in continuous production processes is a discipline that uses industrial control systems to achieve a production level of consistency, economy and safety which could not be achieved purely by human manual control. I ...

for rapid

biodegradation Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegrada ...

, and work well for facilities processing wet materials and large volumes of feedstocks. ASP facilities can be under roof or outdoor

windrow composting In agriculture, windrow composting is the production of compost by piling organic matter or biodegradable waste, such as animal manure and crop residues, in long rows (''windrows''). This method is suited to producing large volumes of compost. T ...

operations, or totally enclosed

in-vessel composting In-vessel composting generally describes a group of methods that confine the composting materials within a building, container, or vessel. In-vessel composting systems can consist of metal or plastic tanks or concrete bunkers in which air flow and ...

, sometimes referred to tunnel composting.

Aeration

The

system uses fans to push and/or pull air through the composting mass. Rigid or flexible perforated piping, connected to fans, delivers the air. The pipes can be installed in channels, on top of a floor, or included throughout the pile during buildup. In large-scale systems, forced aeration is accompanied with a computerized monitoring system responsible for controlling the rate and schedule of air delivery to the composting mass, although meters and manual monitoring techniques may also be used in smaller scale operations. Advantages of this composting method include the ability to maintain the proper moisture and oxygen levels for the microbial populations to operate at peak efficiency to reduce pathogens, while preventing excess heat, which can crash the system. Aerated systems also facilitate the use of

biofilter Biofiltration is a pollution control technique using a bioreactor containing living material to capture and biologically degrade pollutants. Common uses include processing waste water, capturing harmful chemicals or silt from surface runoff, and ...

s to treat process air to remove

particulate Particulates – also known as atmospheric aerosol particles, atmospheric particulate matter, particulate matter (PM) or suspended particulate matter (SPM) – are microscopic particles of solid or liquid matter suspended in the air. The ter ...

s and mitigate

odor An odor (American English) or odour (English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is caused by one or more volatilized chemical compounds ...

s prior to venting. However, aerated systems can dry out quickly and must be monitored closely to maintain desired moisture levels. In Thailand this system has been used by 470 farmer groups. (May, 2008).Agricultural and Food Processing Wastes Composting In Thailand by Aerated Static Pile System
The process required 30 days to finish without turning, with 10 metric tons of compost (10 piles) obtained each time. A 15-inch squirrel-cage blower was used to force the air through 10 static piles of compost, one at a time, for 15 minute periods twice a day. The raw materials consisted of agricultural wastes and animal manure in the ratio of 3:1 by volume.

References

{{Reflist Composting Industrial composting

Aeration

See also

References