Aerated Static Pile

Product Description

The Aerated Static Pile is a modular composting technology for biological stabilisation of municipal organic waste under a controlled environment. The design can be used for over 500 kg of organic waste, with minimal leachate, to produce a soil enhancer for agricultural fields, gardens, and/or forest land. The process decreases the composting cycle time, is space-efficient, and can be used in cold climates.

Target SDGs

SDG 6: Clean Water and Sanitation

Market Suggested Retail Price

$1,212.00

Target Users (Target Impact Group)

Community, Small and Medium-sized Enterprises, Public Sector Agencies, NGOs

Distributors / Implementing Organizations

This technology is available as open-source but can also be acquired from organisations in India and the USA.

Competitive Landscape

Direct competitors include Rotary Drum Composting, Vermicomposting, and NADEP Composting.

Manufacturing/Building Method

The Aerated Static Pile is built on site which can be designed for large scale industrial compositing systems or for smaller scale operations.

Intellectural Property Type

Open-source

User Provision Model

This product can be constructed by the users or by contacting retailers.

Distributions to Date Status

Due to the open-source nature of this technology, the distributions to date are unknown.

Input requirement (volume and frequency)

500 kg and above

20% food scraps, 40% wood chip, 20% cow manure, 20% horse manure

Carbon: Nitrogen Ratio of 25-30:1

Additives

Wood chips

Production capacity (kg output per kg input)

0.5 to 0.67 kg output per kg input before screening. Can reduce down to 0.3 to 0.4 kg output after screening.

Production duration

30 to 60 days for finished bulk product, up to 6 months curing for a bagged product.

Percentage of nutrient recovery

Up to 60 % Nitrogen:50 % Carbon

Complementary treatment needed

None

Design Specifications

Aerated Static Pile is composting with airflow introduced into the composting system to control pile temperatures in order to yield high-quality compost that is effectively free of pathogens, parasites and weed seeds. Through this process, offensive odours and flies are controlled. This consists of five components.

A blower connected to a timer or temperature sensor that controls airflow in or into the system, depending on the oxygen requirements.
A ‘manifold’ to deliver air. Typically PVC pipes with holes.
A plenum layer to diffuse columns of air escaping the PVC pipes to ensure uniform distribution into the bottom of the composting pile.
An active layer with the material to compost. Air promotes aerobic composting in the active layer. Depending on the composting material, the Carbon-to-Nitrogen ration needs to be controlled (typically 25-30:1). Sometimes through the use of wood chips.
A biofiltration layer, typically comprised of mulch or compost to trap heat, odours, and protects the active layer from animals.

Product Schematics

Technical Support

There is no technical support provided as users are expected to maintain the product on their own.

Replacement Components

Replacement components include additives such as wood chips and the feedstock material to be composted.

Lifecycle

The lifecycle of the Aerated Static Pile is the time it takes for feedstock to be composted, approximately 30 to 60 days for a bulk product. The process can then be repeated for future composting products.

Manufacturer Specified Performance Parameters

Performance targets of the Aerated Static Pile include:

No flies/mosquitoes
No odour
Minimal leachate is generated
Can be used for 500 kg of organic waste and above
Sellable quality product

Vetted Performance Status

Testing by the University of Leeds evaluated hybrid Aerated Static Piles (suck and blow aeration) compared to sole blow aeration. Hybrid piles produced higher and even temperatures through the pile and increased pathogen inactivation compared to solely blow aeration. Hybrid piles presented higher sanitization due to the high temperatures but lower microbial activity and compost stability the the blow piles in the initial stages of composting.

Safety

Offensive odours must be controlled during the process through a thick bio layer. Monitoring the temperature is essential to ensure efficient eradication of faecal coliforms and salmonella bacteria while achieving a high quality composting product.

Complementary Technical Systems

The Aerated Static Pile can be extended as it is a modular system. Organic product can be used for agricultural fields, gardens and forest land soil enhancers.

Academic Research and References

Sikora, L. J., et al., 1981, Materials Balance in Aerated Static Pile Composting, Journal (Water Pollution Control Federation) 53: 1702-1707.

Robinson, J. J., Stentiford, E. I., 1993, Improving the aerated static pile composting method by the incorporation of moisture control, Compost Science & Utilization 1: 52-68

Sesay, A. A., Lasaridi, K.E., Stentiford, E. I., 1998, Aerated static pile composting of municipal solid waste (MSW): a comparison of positive pressure aeration with hybrid positive and negative aeration, Waste Management & Research 16: 264-272.

Notton, D., 2005, “Theoretical and experimental determination of key operating parameters for composting systems,” Ph.D. dissertation, Cardiff University, Cardiff, UK.

Isobaev, P. et al., 2014, An enhanced compost temperature sampling framework: Case study of covered aerated static pile, Waste Management 34: 1117-1124.

Brodie, H. L., et al., 2013, A comparison of static pile and turned windrow methods for poultry litter compost production, Compost Science & Utilization 8: 178-189.

Ott, N., Paris, B., McSweeney, J., 2016, Testing an aerated static pile (ASP) compost system for efficiency of time and space, SARE (Sustainable Agriculture Research and Education).

Compliance with regulations

The composting industry has adopted criteria for all organic waste materials to ensure that finished compost products are safe for use. The technical term is “Process to Further Reduce Pathogens” (PFRP), covered under the U.S. Environmental Protection Agency (EPA) 40 CFR Part 503. To ensure:

Pile temperatures shall be maintained at 55^oC (131^oF) or higher for a minimum of 3 days.
Faecal Coliforms must be less than 1000 MPN/g total solids.
Salmonella sp. Bacteria must be less than 3MPN/4g of total solids.

Evaluation methods

Evaluation criteria for Aerated Static Piles include pile temperatures shall be maintained at 55oC (131oF) or higher for a minimum of 3 days, and a Carbon-to-Nitrogen ratio of 25-30:1.

Other Information

The product can also be acquired from organisations in India and the USA. Aerated Static Pile Composting: An Introduction to ASP Compost 101 Science direct - Composting