A composting pilot is a small, time-limited run of your own feedstock through the method you are considering, set up to answer specific questions before you commit to a full facility. A useful pilot runs at least two or three full batches, records temperature, oxygen, moisture and product quality for every batch, and ends with a written report that a board, a permit writer or a grant reviewer can read without having visited the site. Decide what you need to prove before you place the first load, because the questions set the layout, the instruments and the schedule.

Key takeaways

• Write the questions first. A pilot that only shows “it composts” does not help a permit application or a budget vote.
• Use your real feedstock, at the mix and the season you expect at full scale, and run more than one batch.
• Log temperature continuously. The federal biosolids standard for an aerated static pile, which California’s composting rule also uses, is 55 degrees Celsius or higher for three days, and a regulator will want to see the record.
• Pilot piles should be close to full-scale height and width. Shorten the length, not the cross-section, or the heat and airflow results will not transfer.
• Check whether the pilot itself needs a notification or permit. In California, a research composting operation needs an enforcement agency notification and has a volume cap.
• Some things do not scale from a pilot: traffic, peak-season receiving, staffing rhythm and product sales. Plan those separately.

Why run a pilot at all

Most composting methods are well documented, so a pilot is rarely about whether composting works. It is about whether it works with your material, on your site, under your rules, with your people. Four situations justify the effort.

The feedstock is new to you. A yard trimmings site that plans to add food scraps, a wastewater plant considering biosolids composting, or a digester operator with solid digestate each face a recipe question that published ranges only partly answer.

A regulator or neighbor needs evidence. Air districts, solid waste enforcement agencies and water boards respond to measured data from the proposed site far better than to brochures.

A board or funder needs confidence. Elected officials and grant reviewers want to see that the applicant has operated the method and has numbers to back the request.

The team has not composted before. A pilot is the cheapest training program available. Sustainable Generation’s profile of Mid Valley Disposal in Kerman, California quotes the company’s vice president saying that, with no composting experience, the demonstration project “greatly enhanced our understanding of food waste composting” and helped with the later expansion design.

A pilot is not always the right step. If you are expanding an existing operation with the same feedstock and the same method, operating records from the current site are better evidence than a new trial.

Step 1: Write the questions the pilot must answer

Put each question in a form that has a measurable answer, and name who needs the answer.

Question	What to measure	Who needs it
Does our mix reach and hold pathogen reduction temperatures?	Pile temperature at several depths, logged at least daily	Solid waste regulator, biosolids program
Which recipe works best?	Moisture, bulk density, carbon to nitrogen ratio, oxygen, time to stability for two or three mixes	Operations, design engineer
How much water does the process need or shed?	Water added, leachate collected, moisture at start and finish	Water board, design engineer
What are the air emissions?	Source test by a qualified contractor under a protocol the air district accepts	Air district
What does the product look like?	Lab analysis for maturity, stability, salts, nutrients, metals, pathogens, physical contaminants	Buyers, regulator
How much labor and equipment time does a batch take?	Hours by task for each batch	Finance, operations

Step 2: Check what approvals the pilot needs

A pilot is still a composting operation. Before you set up, ask each agency how it classifies a temporary trial.

In California, for example, the solid waste regulations cover research composting operations under 14 CCR 17862, which must meet the enforcement agency notification requirements. The operator may not have more than 5,000 cubic yards of feedstock, amendments, active compost and stabilized compost on site at any one time, must describe the research objectives and methods before starting, and must submit results within two years unless the enforcement agency grants an extension. Other states handle trials through a pilot or demonstration approval, an exemption below a size threshold, or a modification to an existing permit. Ask before you build, and get the answer in writing.

Step 3: Design the pilot so the results transfer

Feedstock and recipe

Use the material you will actually receive, collected the way it will actually be collected. Hand-picked clean loads produce flattering results that a full-scale tipping floor will not repeat. Record the contamination you see.

Build each batch to a written recipe. The Cornell Waste Management Institute describes a moisture content of 50 to 60% as generally optimum for composting, and notes that oxygen in the pore spaces starts at about 15 to 20% and that anaerobic regions develop when it falls below about 5%. Those ranges give you the targets to test against. If you are comparing recipes, change one variable at a time: the ratio of food scraps to bulking material, for instance, with everything else held constant. Our list of the best compost feedstocks covers typical properties by material.

Pile geometry

Heat retention and airflow depend on the pile’s cross-section. A pilot pile that is half the planned height loses heat faster and resists air differently, so its temperature curve says little about the full-scale pile. Keep height and width close to the full-scale design and reduce the length.

Method and equipment

Mobile and modular systems exist for this purpose. SG’s pilots and demos page describes a program built around the SG MOBILE® system, a covered aerated static pile that uses a GORE® Cover and positive aeration, intended for proof-of-concept testing, stakeholder education, and data collection for grant applications or permitting. SG describes SG MOBILE® as installed in days to weeks, depending on the site, and says the pilot uses the same core technology as its full-scale systems. The SG MOBILE system page says each unit comes with the SG COMPOST CONTROL™ System, which records temperature, oxygen and blower data and exports it for reporting. Whatever vendor you use, confirm that the pilot unit’s controls and sensors match what would be installed at full scale.

Instruments and records

At minimum, plan for:

1. Temperature probes at more than one depth and location in each pile, logged automatically.
2. Oxygen measurement, either continuous or by daily spot checks.
3. Moisture testing at build, at each move, and at the end.
4. A scale or a consistent bucket count so every batch has a mass balance.
5. A batch sheet that records recipe, build date, moves, water added, and anything unusual.
6. A complaint and observation log, including wind direction on the days of pile building and breakdown.

Step 4: Decide how long to run

The length of a pilot is set by the batch cycle of the method and the number of batches you need. One batch proves little, because a single run cannot separate the method from the weather or from one unusual load. Plan for at least two or three complete batches, and overlap them if the layout allows.

For a sense of batch length, SG’s How It Works page describes a 4 to 8 week treatment time versus 8 to 12 months for open windrow. A pilot of three covered batches therefore takes a few months with overlap, while a windrow comparison running beside it would still be in progress.

Season matters as much as duration. If the main worry is wet weather, a summer pilot does not answer it. If the main feedstock is seasonal (fall leaves, harvest residues), schedule the pilot when that material is arriving. Our guide to composting in wet, cold and arid climates explains what each season changes.

Step 5: Collect the data each audience needs

For a solid waste or biosolids regulator

The core record is time and temperature. Under 40 CFR Part 503, Appendix B, a Process to Further Reduce Pathogens using the within-vessel or static aerated pile method means the material is maintained at 55 degrees Celsius or higher for three days. For windrows it means 55 degrees or higher for 15 days or longer with a minimum of five turnings. EPA does not certify compost or composting systems. The operator demonstrates compliance with records, batch by batch.

State rules can repeat these numbers and add monitoring detail. California’s 14 CCR 17868.3, for instance, requires at least one temperature reading for every 200 cubic yards of active compost each day during the pathogen reduction period, and specifies the depth at which readings are taken. Set up the pilot’s probes to meet the rule you will be permitted under.

For an air district

Air permits in regulated districts turn on tested emission reductions. In the South Coast, Rule 1133.3 covers emission reductions from composting operations, and the San Joaquin Valley air district has its own rule, Rule 4566, Organic Material Composting Operations. If the pilot includes a source test, the report should state the feedstock mix, pile age at each sampling event, the test method and who conducted it. SG reports greater than 95% VOC control in third-party testing of its covered system. A district will still ask how any vendor’s test conditions compare with your proposed operation, which is the reason to test on site when the permit depends on it. Our compost facility permitting guide covers the three permit families.

For a board

Boards respond to plain comparisons: what went in, what came out, how long it took, what staff time it required, and what neighbors noticed. Invite members to see a pile built and a pile opened. Bring finished product and the lab sheet to the meeting.

For a grant application

Reviewers look for readiness. Pilot data supports the feedstock quantities, the method selected and the applicant’s capacity to operate. The U.S. EPA’s Solid Waste Infrastructure for Recycling program was funded for fiscal years 2022 to 2026. As of October 2026 the program page does not show an open application period, so check it and your state program for current rounds. Our list of grants for organics infrastructure has more.

Step 6: Scale the results honestly

Sort the pilot’s findings into two groups.

Transfers well: recipe and moisture targets, temperature curves at full-scale cross-section, time to pathogen reduction, water demand per batch, product quality, emissions per unit of material under the tested conditions, and operator familiarity with covers, probes and controls.

Needs separate analysis: truck traffic and queuing, receiving and mixing at peak daily volume, contamination from a full collection program, stormwater from the whole pad, the number and type of loaders, staffing through weekends and holidays, and the market for the full product volume.

The Kerman profile gives a concrete example of a finding that shaped a design. According to SG, the pilot showed the need for water addition in a hot, arid climate, and the permanent facility was designed with dedicated water piping as a result. SG’s profile of the Prince George’s County, Maryland organics facility describes a county that began with a pilot handling food scraps alongside yard trimmings, added mobile units as hauler demand grew, and later moved to permanent bunkers. Growth in stages is a legitimate outcome of a pilot, and so is a decision not to proceed.

Pilot report checklist

• Questions asked, and the answer to each
• Feedstock sources, quantities and contamination observed
• Recipes tested, with moisture and bulk density at build
• Temperature and oxygen records for every batch
• Mass and water balance
• Lab results for finished compost
• Emission test report, if performed, with test conditions
• Labor and equipment hours by task
• Complaints, visitors and regulator inspections
• What would change at full scale, and what was not tested

FAQ

How long should a composting pilot last?

Long enough for two or three full batches in the season that worries you most. With a covered aerated static pile, where SG describes a 4 to 8 week treatment time, three overlapping batches fit within a few months. Add time before the first batch for approvals and setup, and time afterward for lab results and the written report.

How much material does a pilot need?

Enough to build piles at close to full-scale height and width, since heat retention and airflow depend on cross-section. The length can be much shorter. Check the regulatory cap as well: California’s research composting rule limits the site to 5,000 cubic yards of all material on hand at any one time.

Does a pilot need a permit?

Often it needs a notification or a limited approval, and the answer differs by state and by agency. Ask the solid waste, air and water regulators separately how they treat a temporary trial. If you want emission data to count toward a later air permit, agree the test protocol with the air district before testing.

What if the pilot results are poor?

That is a useful result. Poor temperature performance usually points to recipe, moisture or pile size, and a second batch can test the fix. If the method cannot handle the feedstock or the site, learning that from a pilot costs far less than learning it from a completed facility.

Next step

If a pilot fits your project, start with the question list and the regulator calls, then choose equipment. SG’s pilots and demos page describes its program, and the consulting team can help plan a demonstration that a regulator will accept.

Related guides

• How to Start a Commercial Composting Facility
• Compost Facility Permitting Guide
• Compost Process Control: Oxygen, Temperature, Moisture and C:N
• Lease vs Buy Composting Equipment
• Composting in Wet, Cold and Arid Climates

← All commercial composting guides

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