Small-Scale and On-Farm Composting Permit
Pennsylvania’s General Permit WMGM017 (“Source Separated Composting”) authorizes small-scale composting, including on-farm, of residual and municipal waste, whereas the WMGM042 (“Anaerobic Digestion”) permit is for anaerobic digestion of animal manures and food waste. While the previous WMGM017 permit (2012 – 2022) only covered on-farm composting, the renewed permit (2022-2032) expands coverage to include small-scale, non-farm composting facilities in addition to on-farm composting operations.
The renewed WMGM017 permit allows the composting, vermicomposting, and hermetiacomposting (using black soldier flies) of a variety of source-separated materials. Materials eligible for on-farm composting include manure, yard waste, source separated food waste from various sources, and source-separated newspaper and cardboard. Non-farm composting facilities are limited to composting yard waste and source-separated pre- and post-consumer food waste. Approved uses for finished compost include marketing or distribution as soil substitute, soil conditioner, soil amendment, fertilizer, or mulch.
In order to qualify for a general permit, the compost facility must meet the following criteria:
– “Does not exceed five (5) acres for on-farm composting, or two (2) acres for non-farm, small scale composting.
– “Does not store more than 500 tons or 1,000 cubic yards per year of source separated food scraps.
– “Does not store more than 3,000 cubic yards per acre of total materials at any one time.”
In addition, non-farm, small scale facilities accepting more than 3,000 cubic yards of material for processing per year must maintain a financial bond for a sum that “guarantees the removal and proper management of any feedstocks, compost, and finished products”.
Other provisions stipulated by the latest version (2022) of the WMGM017 permit include, but are not limited to:
A site plan of the compost facility along with a description of the procedures used to assure compost quality, as well as a plan for nuisance minimization so that activities do not negatively impact the quality of air, water, or public health. |
Composting methods must be via windrows, aerated static piles, or in-vessel. Windrows must maintain a minimum temperature of 55 degrees C for 15 days and turned in consistency with currently accepted science-based composting technology. Aerated static piles and in-vessel systems must maintain that same temperature for 72 consecutive hours. |
Incoming food scrap must be incorporated into the composting processes within 24 hours. Putrescible waste other than manure must be held in closed containers for no longer than 24 hours before incorporation into the composting processes. Incorporation of all other materials must occur within one week of receipt. |
The compost pad options include “a compacted mixture of select granular material with adequate fine-grained particles to bind it together and reduce permeability,” lime-stabilized soil blends, or paving with concrete, asphalt, or geosynthetics. All compost pads much be sloped at 2-4% to prevent ponding of liquids and storm water should be diverted away from the composting area. |
The compost operation cannot be within a 100 year floodplain, 300 feet of an “exceptional value wetland,” within 100 feet of a wetland other than an exceptional value wetland, within 300 feet from an occupied dwelling, within 50 feet of a property line, within 300 feet of a water source, within 3.3 feet of a ground water table, or within 100 feet of a perennial stream. |
As stated in the Pennsylvania Code § 287.101, parties are exempt from obtaining a permit if materials are generated as part of “normal farming operations”–which includes food processing waste or sludge that were generated as part of the farm’s operations and are not hazardous. Forms of material management on a farm that overstep or violate the law’s stated conditions may result in the Dept. of Environmental Protection (DEP) requiring the facility operator to obtain a solid waste permit (or take other action deemed appropriate) if the composting activity poses “a threat of harm to the health, safety or welfare of the people or the environment of this Commonwealth.” Of note is that, while mushroom composters may qualify to be exempt from obtaining a permit, they must follow best management practices (Document 254-5401-001) laid out by the DEP.
More Information
- Pennsylvania’s Compost Facility Regulations (PA Administrative Code, Chapter 281)
- Pennsylvania Department of the Environmental Protection – Composting Resources and Information
- Pennsylvania Department of the Environmental Protection – On-Farm Composting
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Original post from July 30, 2012
Updated March 31, 2023