Composting Facility Sizing Calculator

Pad area and windrow count are purely volumetric calculations based on how many cubic yards of material move through the system, not how much that material weighs. Feedstock Type only changes the density used to convert volume into tons, which is why it drives Annual Throughput instead of the physical footprint calculations.

For windrow and aerated static pile, Composting Method sets your Active Composting Time -- 12 weeks for windrow versus 8 for aerated static pile -- and a longer active time means more material accumulates on the open pad at once before it's finished, which directly increases the pad space needed to hold it all simultaneously. For in-vessel, the effect is even bigger: material composts inside enclosed vessels rather than on an open pad, so Required Pad Area and Number of Windrows/Piles both drop to 0 regardless of volume -- see Vessels Needed for how in-vessel systems actually scale instead.

Not in this calculator -- Turning Frequency is tracked for reference but doesn't currently factor into the process-time, sizing, or cost calculations. In real windrow operations more frequent turning can shorten active composting time by improving aeration, but that relationship varies too much by pile size, climate, and feedstock to model reliably here, so active time is held fixed by Composting Method instead.

Curing Time is added to Active Composting Time to get Total Process Time, which represents how long material sits in the system from intake to finished product, reflected in Volume in System at Once for every method. For windrow and aerated static pile, a longer total process time means more weeks' worth of material accumulates on the pad simultaneously, which increases Required Pad Area. In-vessel systems hold that same accumulated volume in enclosed vessels instead, so Required Pad Area stays 0 for in-vessel regardless of Curing Time -- see Vessels Needed for that method's real sizing driver.

It doesn't model site-specific factors like drainage, setback requirements from property lines or waterways, odor-control infrastructure, leachate management, or seasonal variation in feedstock volume -- all of which affect a real facility's footprint, permitting, and cost beyond the volume-and-method-based sizing this tool provides.