Do I need a permit?
There are several Minnesota environmental permits that affect grain elevators, feed mills and fertilizer mixing plants.
You need an air permit if your potential air emissions exceed thresholds or if certain federal standards apply. Use the grain elevator air emissions calculator to figure this out.
Fertilizer mixing plants: use the grain elevator tab in the calculator to calculate emissions from granular fertilizer mixing and handling.
Generally, grain elevators that buy, sell, or market grain (SIC code 5153) are likely to be exempt from the industrial stormwater permit. "Storage only” facilities (SIC 4221), feed mills (SIC 2047 and 2048), and fertilizer mixing plants (SIC 2875) must obtain a permit.
Grain elevators that make most of their revenue from grain but also mix fertilizer do not need an industrial stormwater permit.
More information and application forms are on the industrial stormwater permit web page.
If you are constructing a new facility or are adding on to your current one, you need a construction stormwater permit if you will disturb more than one acre of land.
The 10 Steps to Compliance fact sheets on the Hazardous waste documents and forms webpage will help you determine if your wastes are hazardous. If they are, apply for a hazardous waste license online on the agency's e-Services webpage. Review the file below for instructions.
Additional fact sheets on the MPCA Hazardous waste documents and forms webpage provide guidance on managing specific wastes.
These regulations are independent of any permits you may need.
Federal air. You must follow the requirements of the New Source Performance Standard (NSPS) for grain elevators (40 CFR Part 60, Subpart DD) if your unloading stations, loading stations, grain dryers, or grain handling operations have been constructed, modified, or reconstructed since August 3, 1978, and your elevator has a permanent storage capacity of about 2.5 million bushels or more (or, for elevators located at a wheat flour mill, wet corn mill, dry corn mill for human consumption, rice mill, or soybean oil extraction plant, a permanent storage capacity of about 1 million bushels or more).
Animal and pet food manufacturers, cereal manufacturers, breweries, and livestock feedlots are exempt from this standard.
MPCA air quality fact sheet 8-14 provides a summary of the requirements.
Federal air. The National Emission Standard for Hazardous Air Pollutants (NESHAP) for prepared feeds manufacturing (40 CFR Part 63, Subpart 7D) may affect your feed mill if you use additives or premixes containing chromium or manganese. This EPA fact sheet summarizes the regulation and its requirements: Regulations for prepared feeds manufacturing (U.S. EPA).
Below is a brief summary of the Minnesota air rules affecting grain elevators:
- Preventing Particulate Matter From Becoming Airborne: 7011.0150
- Nuisance: 7011.1010
- Standards of Performance for Dry Bulk Agricultural Commodity Facilities: 7011.1005
- Control Requirements Schedule: 7011.1015
- Definitions: 7011.1000
You must prevent avoidable amounts of dust from becoming airborne, including dust from your driveway. See MPCA Air Quality fact sheet 4-01: aq4-01 for more information.
You cannot operate a grain elevator in such a way that it creates a public nuisance.
- clean up commodities spilled on the driveway and property
- maintain air pollution control equipment in proper operating condition
- utilize air pollution control systems as designed
- follow the requirements of the federal air requirements for grain elevators (Subpart DD) if it applies to you.
If the federal standard for grain elevators (Subpart DD) doesn’t apply to you, check 7011.1015 to see if your facility has "control required." If control is required, you must meet the following standards:
- <5% opacity for fugitive emissions from truck unloading stations, railcar unloading stations, railcar loading stations, or handling operations
- <10% opacity for fugitive emissions from truck loading stations
- <20% opacity for fugitive emissions from ship or barge loading or unloading stations, though no opacity standard applies during trimming or topping-off
- <10% opacity for particulate emissions from control equipment
- there must be no discharge of particulate matter from control equipment that has a collection efficiency of less than 80 percent.
If the federal standard for grain elevators (Subpart DD) doesn’t apply to you, and there is no control required under part 7011.1015, you must unload, handle, clean, dry, and load commodities in a way that minimizes fugitive emissions. If a capture system is used, the particulate matter must go through control equipment that has a collection efficiency of at least 80 percent by weight.
Column dryer screen perforations must be 3/32 inches in diameter or less. Emissions from a rack dryer must be filtered by a 50-mesh (or finer) screen enclosure before discharge to the atmosphere.
Best management practices
Common complaints about grain elevators are about dust and “bees wings” from the grain itself and dust from trucks driving on gravel roads. Whether or not you need any permits, the ideas and practices listed below can help you be a good neighbor by reducing dust. Less dust is better for you and your employees, too.
- Provide your community with contact information so they can contact you directly if they have a complaint.
- If you have had a wet fall or a bumper crop year, let your community know you will be running the dryer more than usual and what that will mean for them.
- Rural elevators, let your neighbors know when the harvest is about to start and what hours during the day you will be loading and unloading grain. Because the elevator is quiet most of the year, people may surprised by the increased noise and traffic – especially if they are new neighbors.
- Let neighbors know if you will be conducting particularly noisy operations and how long you expect it to last.
Grain unloading and loading (dump pits and loadouts)
- One of the main ways dust is generated is when a falling stream of grain hits the receiving pit. Allow the grain to form a cone around the receiving grate (known as “choke unloading”) to decrease the distance the grain falls.
- Dump pits with induced draft fans installed must use fans with a capacity of at least 50 cfm/sq. ft. of airflow at the effective grate surface, that is the area of the grate through which air passes when can be pulled through during unloading.
- Enclose the receiving area as much as possible. Aim for a receiving shed with closed doors at both ends. A receiving shed with no doors (or doors always open) may create a “wind tunnel” effect that is worse than no shed at all. Alternately, consider curtains or a shroud around the receiving pit.
- Prevent grain from falling as much as possible at loadout. Use dead boxes, socks, or drop-down spouts or sleeves that extend at least six inches below the sides of the receiving container to minimize grain free-fall distance.
- Restrict the flow of the grain when the receiving container is empty or only partly full.
- Consider wind speed and direction. Limit grain handling when the wind will cause neighbors to receive excessive amounts of dust or chaff. Winds are stronger and windy days are more common in the spring and fall – the same time of year when you will be handling more grain.
- Conduct grain oiling at the dump pit before transferring to bin storage. Check that the oil is dispersed well. As little as ½ gallon of oil per thousand bushels of grain can reduce dust by up to 80%.
- If storing grain in outdoor piles, store for the shortest amount of time possible and keep piles tarped.
Grain dryers – the source of many complaints
Inspect dryer screens before each dryer start-up.
- Do not exceed the manufacturer’s recommend capacity for the amount of grain passing through the dryer.
- Enclose grain inlets and outlets to dryers, and enclose as much of the dryer as is practical.
- Double-check that column dryers have screen perforations of 0.094 inch (3/32 inch) or less.
- Double-check that rack dryers have a maximum screen filter size of 50 mesh.
- If it is time to buy a new dryer, consider one that captures the “bees wings.” In general, cross-flow column dryers create less dust and “bees wings” than rack dryers. However, some rack dryers have only a couple of exhaust points, which means you could add pollution control devices there.
- Running your dryers cleanly and efficiently will also help you save energy and money. More information is in this bulletin from the University of Wisconsin Extension Office: Low Cost Energy Conservation: Grain Dryers.
Equipment such as bucket elevators or legs, scale hoppers, conveyors, turn heads, scalpers, cleaners, trippers, and headhouse and other structures.
- Keep grain handling equipment clean and in good condition.
- Enclose or seal grain handling equipment.
- Control the speed of grain handling equipment. Keep conveyor belts at the minimum speed necessary.
- Use aeration fans as little as possible when loading grain into storage bins.
- Locate and configure equipment so the building helps block windblown dust.
- When you buy new cleaning and processing equipment, choose dust-tight equipment, lip-type shaft seals for bearings on conveyors and other equipment housings, and flanged inlets and outlets for spouting, transitions, and miscellaneous hoppers.
Air pollution control equipment
Equipment such as quick-closing doors, enclosures, air curtains, wind deflectors, grain oiling equipment, loadout socks, drop-down spouts or sleeves, baghouses, vent filters, and cyclones.
- Operate air pollution control equipment whenever there is grain present.
- Check air pollution control equipment daily for proper functioning.
- Fix malfunctions immediately to minimize the amount and duration of excess dust.
- Schedule regular maintenance of control equipment.
- Keep equipment logs with information such as dates of inspections, maintenance procedures, and replacement of equipment.
- Choose baghouses (fabric filters) instead of cyclones. Cyclones often cannot contain the finest dusts.
General maintenance, upkeep, and repair
- Clean up indoor and outdoor areas such as floors, roofs, and decks to prevent accumulation of chaff and dust that can blow around.
- Clean up the yard, ditches, and curbs as needed to prevent accumulation of grain, chaff, and grain dust that can blow around.
- Clean up any grain spills on your driveway or access roads.
- Water unpaved roadways or traffic areas to minimize dust to the air.