USCC Compost Operations Training Course

Systems and Methods Page 1

Composting Systems & Methods

Lyndell Pate

Ecoverse

Identify and quantify 

Feedstocks

Analyze Markets

Develop and adjust recipes

Collect or receive  feedstocks

Process:Grind, Mix, Compost, Cure, Screen, etc.

Market and distribute

Assess

Compost Facility Feedstock‐Process‐Market Feedback

Compost Facility

Start here or here

Feedstock receipt

Active Composting

Curing

Screening

Storage and packing

Feedstock preparation, mixing

Odor control

Dust control

Monitoring

Product analysis

Non‐compostablesRecycle or dispose

Collect Feedstocks

Product sales,distribution and use

“Overs”

Collect Feedstocks

Collect Feedstocks

1st Stage 2nd Stage

Flow of materials and activities at the compost facility

Compost facility activities

Feedstock receipt

Active Composting

Curing

Screening

Storage and packing

Feedstock preparation, mixing

Odor control

Dust control

Monitoring

Product analysis

Non‐compostablesRecycle or dispose

Collect Feedstocks

Product sales,distribution and use

“Overs”

Collect Feedstocks

Collect Feedstocks

1st Stage 2nd Stage

Flow of materials and activities at the compost facility

Compost facility activities

Recycle or dispose?

Water management

Methods

• Piles

• Turned windrow

• Aerated static pile

• In Vessel

• Anaerobic Digestion

• Hybrids

Descriptive Factors

• Open/freestanding    vs.

– Covered

– Bins

• Passive aeration vs.

• Negative aeration      vs.

• Static                            vs.

• Batch                            vs.

Enclosed

– Contained

– In‐vessel

Forced aeration

Positive aeration

Agitated or turned

Continuous

USCC Compost Operations Training Course

Systems and Methods Page 2

Static Piles

• Passive aeration

• Advantages– Low labor

– Footprint

• Disadvantages– Little process control

– Slow

– Watch out for fires with large piles

Static Pile (not aerated)

Assisted Passive Aeration Turned Windrow

• Most common method

• Many options to accomplish “turning”

• Advantages

– Breaks up clumps, homogenizes

– Size reduction

– Stimulates composting

– Flexibility, piles can be combined to save space

• Disadvantages

– Potential odor release during turnings

Turned Windrow

USCC Compost Operations Training Course

Systems and Methods Page 3

Turned Windrow

Turned Windrow

Turned Windrow Extended Windrows/Trapezoidal Piles

Trapezoidal Piles Aerated Static Pile

• Active Aeration (positive or negative or both)

• Covered or uncovered

• Advantages– Control

– Footprint

• Disadvantages– Power

– Drying

– Mixing

USCC Compost Operations Training Course

Systems and Methods Page 4

Aerated Static Pile Active Aeration

Air Intake

Air Outlet

Aerated Bins

USCC Compost Operations Training Course

Systems and Methods Page 5

Negative Aeration  Negative Aerated Static Pile

Covers

• Porous (ex. Compostex)

• Micro Porous (ex. MOR and Gore Cover)

• Impermeable (ex. ECS, Ag Bag, CTI, etc.)

Porous Covers

USCC Compost Operations Training Course

Systems and Methods Page 6

Positive Aeration/Micro‐porous Cover Negative Aeration/Impermeable Cover

Positive Aeration/Impermeable Bag“In‐Vessel”

• Wide range of technologies

• Advantages

– Increased control

– Minimizes weather impacts

• Disadvantages

– Cost

– Management

Trenches or Bunkers

NatureTech 

GMT Earth Tub

Hot Rot System 

Bins and Boxes

USCC Compost Operations Training Course

Systems and Methods Page 7

More Boxes: Batch Systems

ECS

Rotating Drums

In‐Vessel Negative Aeration

Anaerobic Digestion

• Uses microorganisms to break down organic materials and produce biogas

– Biogas is a mixture of methane and carbon dioxide

• Combusted to produce renewable electricity

• Cleaned to pipeline natural gas standards

• Further processed into compressed natural gas (CNG)

Anaerobic Digestion

• Goals of AD include:

– Divert organic materials from landfills and incinerators

– Generate clean, distributed, renewable energy

– Restore and maintain healthy soils using compost products

– Displace chemical fertilizers

USCC Compost Operations Training Course

Systems and Methods Page 8

Anaerobic Digestion

• Low Solids (Wet A/D)

– Best for pumpable slurries like manure, wastewater and pulped food scraps that are less than 20% solids content. 

– Materials are:

• Blended, Mixed with heated water and innoculum to kick‐start the digestion process 

• Pumped into the chamber(s) where digestion and biogas production occur

• After digestion solids are separated from the liquids and either composted or land applied

Anaerobic Digestion

• High Solids (Dry A/D)

– Also known as “dry fermentation”

– Best for stackable materials like food scraps and yard debris that have a solids content of 25% –50%. 

• Materials are mixed and loaded into digestion chambers using a wheel loader.

• After two weeks in the digestion system the partially degraded material can be aerobically composted.

•

Hybrids

• Use other methods at different points in system

– In‐vessel ASP Passive pile for curing

– ASP Turned windrow

– Digestion Turned windrow

Active Composting

Curing

1st Stage 2nd Stage

Putting the System Together

• Considerations

– Feedstocks

– Land

– Environment

–Goals

• Tradeoffs

‐ Location

‐ Budget

‐ Potential Growth

‐ Process Control