Questions and answers about Aeromaster Composting Equipment (ACS)

What is the importance of drum speed to the process?

All Aeromaster turners offer variable drum speeds in the 150-300 rpm range. Some composting paradigms call for 650 rpm or faster drum speeds. We believe a variable drum speed in the lower range offers a spectrum of benefits:

  • Decomposition of varying feedstocks may benefit from specific rpm.
  • Differing time frames (number of days along) during the composting cycle may suggest differing speeds.
  • Equipment does not make compost, microbes do. The optimum drum speed and tine shape can provide the ideal environment for beneficial microbes to flourish.
  • Drum speed and tine shape should lift, blend, and aerate compost feedstocks rather than cut, shred, and pulverize.
  • High drum speeds retard, rather than accelerate, the composting process.
  • Aggregation for crumb structure and humus development are limited when high drum speeds or a pulverizing approach are used.
  • A perfect turn should move center materials to the perimeter and perimeter materials to the center of the windrow. Aeromaster turners do this rather than bouncing them off a hood or curtain.
  • A perfect turn should get oxygen into the windrow and most carbon dioxide out. Respiration tests in front of and behind an Aeromaster turner will demonstrate the quality of this exchange.
  • Lower drum speeds reduce maintenance costs as stress is reduced throughout the turner.
  • Safety is enhanced as the risk of projectiles flying from the pile is largely eliminated.

As always, if a company or operator wishes to compare the quality of our equipment or the ACS process, we simply ask them to submit finished compost samples for the broadest array of tests to examine the quality of the finished product for its soil and plant benefits. We are happy to evaluate similar feedstocks under their current system/equipment paradigm with the Midwest Bio-Systems/Advanced Composting System approach to see which best succeeded.


How durable is the Aeromaster?

In February of 2002 our office received a call from a composter who said he needed to make a repair on his PT-120. He’d had his turner for seven years and this was its first breakdown.

Aeromaster turners have been built to last. In fact, they have been described as “overbuilt.” This is important because decomposing feedstocks do not wait for the operator’s convenience. When they need aeration, they need it today.

Grover Landscaping in Modesto, California has described their SP-155 (since replaced by the larger SP-170 self propelled turner) as “virtually indestructible.” They are especially pleased that they never need worry about becoming stuck in wet ground. They say their Aeromaster has “exceeded all our expectations.”

Per hour operating and maintenance costs for the self-propelled turner have been demonstrated to be less than one-half the industry standard. A combination of building durability into the equipment along with a different composting paradigm make this possible.


What are the advantages of a retractable drum?

Firstly, at any point in the composting process the operator can stop, raise the drum, and walk into the middle of a row to examine the windrow Aeromaster PT-170 Compost Windrow Turner from Midwest Bio-Systemsprofile. Such an examination reveals the extent of mixing and blending of feedstocks, windrow stratification, the presence of molds, and the extent of feedstock decomposition.

Watch this video of a rectractable drum.

Also, if after beginning turning, the operator discovers the row is too wet, he can cease immediately and drive on rather than needing to complete the row or use a loader and shovels to dig himself out.

Finally, the drum can be locked in place for transportation from one site to another.


What are the tractor requirements for an Aeromaster pull-type turner?

Horsepower: Generally, 80-100 for model PT-120 and 90-120 for model PT-130. However, lower or higher horsepower may be suitable depending on your feedstocks, additional demands on the tractor (i.e. loader attachment) and site conditions. For assistance in determining tractor horsepower requirements for your Aeromaster turner, contact your local Midwest Bio-Systems representative.

540 PTO

Two remote hydraulic outlets

Creeper gear or hydrostatic drive

The tractor needs to travel slowly at a range of 20-50 feet per minute (.2 mph at rated PTO speed), depending on the stage of the composting cycle.