Foundry Sand Reuse in Iowa

Planning to reuse spent foundry sand in Iowa? This guide covers the rules that apply, the tests that decide how the sand can be managed, and what DNR needs before the sand can be reused.

Key terms

Spent foundry sand

Foundries bond silica sand into molds and cores for casting metal. The sand is reused many times in the plant. Spent foundry sand is molding and core sand that can no longer make molds or cores.

Green sand and chemically bonded sand

Green sand is bonded with clay, usually bentonite, plus water and additives such as carbon. Chemically bonded sand uses resin binders. Most cores are chemically bonded. The binder system affects what the spent sand contains.

Beneficial reuse

Beneficial reuse puts a waste material to productive use instead of disposing of it. Iowa calls this beneficial use. DNR’s written decision or rule that a use is reuse, not disposal, is a beneficial use determination.

TCLP

The Toxicity Characteristic Leaching Procedure (EPA Method 1311) measures how much of certain contaminants can leach from a sample. It is one part of deciding whether a waste is hazardous.

What’s in your spent sand?

Spent sand carries what the casting process added: binder residue, metal fines, and burnt core material. The alloy matters most. Sand from iron, steel, and aluminum foundries is the most commonly reused. Sand from leaded brass and bronze foundries is often regulated as hazardous waste.

Keep each stream separate. Baghouse dust, shotblast fines, cupola slag, broken cores, and core room sweepings need their own evaluation. Mixing them into spent sand can change how the whole load is managed. Track the alloys cast, the binder system, and any process changes.

Iowa’s beneficial use rules

Iowa’s beneficial use rules are 567 IAC 102.300–102.308, in Chapter 102, Division IV. A solid by-product used under a beneficial use determination is not regulated as solid waste disposal.

Iowa defines foundry sand in 567 IAC 100.2. It is a solid by-product of molding, core-making, and casting cleaning that mainly contains sand, olivine, or clay. It must also be suitable for disposal as solid waste in a sanitary landfill.

Foundry sand uses approved by rule

Rule 102.303 lists uses approved by rule. Under 102.303(4), foundry sand from steel and ferrous casting may be used as:

1. leachate control drainage material at a sanitary landfill;
2. subbase for hard-surface pavement construction;
3. structural fill or fill material;
4. emergency flood control sandbags; or
5. sandblasting or other abrasive.

These uses need no further DNR approval unless DNR notifies you otherwise under 102.307. They must still comply with 102.305 and 102.306. Fill and subbase uses must meet the testing, placement, management plan, and reporting rules in those sections.

Landfill daily cover

Under 567 IAC 101.108(3)(d), a municipal solid waste landfill may use foundry sand as daily cover, mixed with soil at 50/50 by volume. The landfill must notify DNR and its DNR field office at least 30 days before first use, to amend its permit.

Other sand and other uses

Any use not approved by rule needs an individual determination under 102.304. That includes sand from nonferrous casting used for the 102.303(4) purposes. DNR may set conditions or issue a temporary determination on a trial basis. DNR denies proposals whose main purpose is land disposal.

Land placement of a solid by-product without a determination is presumed to be illegal disposal of solid waste.

Applying to DNR

• Who files: a generator, user, or proposed user of the sand may apply in writing. An application from anyone other than the generator needs the generator’s written consent for the proposed use.
• How: complete DNR Form 542-0056, Beneficial Use Determination Application. Mail it with attachments to DNR’s Land Quality Bureau, Solid Waste and Contaminated Sites Section, 6200 Park Ave Ste 200, Des Moines, IA 50321.
• Contents: contact details, a scaled site map, and a description of the sand, its use, and how it will be moved and handled.
• Supporting data: chemical and physical characteristics, proof of a market, a health and environment demonstration, and a solid by-product management plan.
• Site map: show zoning, land use, and homes and buildings within 750 feet, plus haul routes and their load limits.
• Testing: the health and environment demonstration may include TCLP and total metals testing of a representative sample. DNR may ask for more information.
• Engineer: DNR may require you to retain a professional engineer licensed in Iowa.
• Review: if an application is incomplete, DNR notifies you of the deficiencies and returns it within 30 days of that notice. You may reapply. DNR sends a written denial within 90 days of receipt, and you may appeal within 60 days.
• After approval: DNR may revoke a determination if its basis was wrong or is no longer valid, a violation occurs, or new information shows significant risk. Use outside the determination’s terms may be treated as illegal disposal.

DNR beneficial use program: (515) 201-8272.

Hazardous waste determination

Iowa does not administer the federal RCRA Subtitle C hazardous waste program. EPA Region 7 manages it in Iowa.

Iowa’s reuse routes depend on that determination. Under 567 IAC 100.2, foundry sand and other solid by-products must be suitable for disposal as solid waste in a sanitary landfill. Sand that is hazardous waste does not meet those definitions.

Under 40 CFR 262.11, the foundry must decide whether its spent sand is hazardous:

1. Make the determination at the point of generation, before mixing or dilution. Repeat it if the waste may have changed.
2. Check whether the waste is excluded from the hazardous waste rules.
3. Check whether it matches a listed hazardous waste.
4. Check for hazardous characteristics, including toxicity. Use knowledge of the materials and process, testing, or both. Test when knowledge alone is not enough.

Small and large quantity generators must keep records supporting the determination for at least three years after the waste was last sent for treatment, storage, or disposal.

TCLP testing and limits

Tell the lab the alloys cast, the binder system, and which streams the sample includes. Use representative samples. Agree on the sampling plan with the lab, DNR, and the receiving site before collecting.

A waste is hazardous for toxicity if its TCLP extract meets or exceeds any limit in 40 CFR 261.24. The limits for the RCRA metals are:

Passing TCLP addresses toxicity for the substances tested. It does not approve reuse or rule out other reasons a waste may be hazardous. See material testing for sampling basics.

Fill, pavement subbase, and soil stabilization uses must also meet 567 IAC 102.305(1). SPLP (EPA Method 1312) results must be at or below ten times the drinking water MCLs. Total metals must meet Iowa’s statewide soil standards or background levels, whichever are greater. DNR Form 542-0652 lists the limits; for lead, they are 0.15 mg/L SPLP and 400 mg/kg total. Management plan test results must come from a laboratory certified under 567 IAC Chapter 83.

Finding a reuse destination

EPA’s 2014 risk assessment found three uses protective of health and the environment for silica-based spent sand from iron, steel, and aluminum foundries: manufactured soil, soil-less potting media, and road subbase. EPA and USDA support those uses. The finding does not cover sand from brass or bronze foundries, olivine sand, or sand mixed with other foundry wastes such as baghouse dust or cupola slag. EPA defers to state programs, so the state rules on this page still decide each use.

Iowa’s rules name specific routes for foundry sand. Check any destination and proposed use with DNR before scheduling delivery.

• Fill, subbase, landfill drainage, or flood sandbags: approved by rule under 102.303(4) for sand from steel and ferrous casting. Fill and subbase placement must follow 102.305(1).
• Landfill daily cover: a municipal solid waste landfill may mix foundry sand 50/50 with soil under 101.108(3)(d), after its 30-day notice to DNR.
• Manufacturing ingredient: Division IV does not apply to a by-product directly incorporated into a manufacturing process to make a commercial product. The exception is a use that may cause harm similar to improper disposal (102.301(6)).
• Other uses: apply for an individual determination under 102.304.

Fill and subbase placement rules are strict. Keep sand out of waterways, wetlands, and waters of the state, and at least five feet above the high water table. Keep it 200 feet from sinkholes and from wells used, or usable, for human or livestock water. Keep it 100 feet from property lines unless the adjacent landowner consents in writing. Floodplain placement must follow local and DNR rules. The sand must meet the rule’s pH ranges and must not be putrescible.

Get the receiving site’s specifications and written acceptance. If reuse is not cleared, arrange disposal that fits the waste determination.

Worker protection

• Silica: foundry sand is mostly crystalline silica. OSHA’s general industry standard, 29 CFR 1910.1053, sets a permissible exposure limit of 50 µg/m³ of respirable crystalline silica as an 8-hour average. Exposure assessment starts at the 25 µg/m³ action level.
• Construction use: crews placing sand as fill or subbase fall under the construction silica standard, 29 CFR 1926.1153.
• Lead: brass and bronze foundries that cast leaded alloys also follow OSHA’s lead standard, 29 CFR 1910.1025.
• Dust: control dust during shakeout, storage, and loading.

Iowa OSHA runs Iowa’s OSHA-approved State Plan. For most employers, its standards apply in place of federal OSHA and must be at least as effective.

Storage and records

Store spent sand on a defined pad or in bins, control dust and runoff, and keep other foundry wastes out. Fill, subbase, and other land uses under 102.305(1) need a solid by-product management plan. So does any use approved under 102.304. The plan lists where the sand comes from and sets testing at least semiannually. It describes storage locations, maximum inventory, run-on and runoff controls, and dispersion controls. Storage may not exceed six months unless DNR authorizes more in writing.

Keep the waste determination, lab reports, DNR approvals, and the receiving site’s acceptance together. Record tonnage shipped, dates, and destinations. Keep all management plan records for at least five years after project completion. File the plan with DNR’s central office before reuse, whenever you revise it, and within 60 days of the end of the calendar year. For each land project, also report its location and the tons used. Keep determination records for at least three years.

Before pickup

1. Identify the alloys cast, sand and binder systems, separate streams, monthly volume, and plant location.
2. Make the hazardous waste determination and complete the required tests, including SPLP and total metals for land uses.
3. Choose a destination and get its material specifications.
4. Confirm the use fits rule 102.303(4) or 101.108(3)(d), or file DNR Form 542-0056 for an individual determination.
5. Get written acceptance and arrange pickup.

Common questions

Rules and guidance

• Iowa DNR: Solid Waste Programs (Beneficial Use)
• DNR Form 542-0056: Beneficial Use Determination Application
• DNR Form 542-0652: Beneficial Use Determination Analytical Testing Report
• 567 IAC Chapter 102: Solid Waste Management (Division IV, Beneficial Use)
• 567 IAC Chapter 101: Sanitary Disposal Projects (alternative cover, 101.108(3))
• 567 IAC Chapter 100: Definitions (100.2)
• Iowa DNR: Hazardous Waste and Contaminated Sites
• 40 CFR 262.11: Hazardous waste determination
• 40 CFR 261.24: Toxicity characteristic
• EPA Method 1311: TCLP
• EPA: Beneficial Uses of Spent Foundry Sands
• EPA: Risk Assessment of Spent Foundry Sands in Soil-Related Applications
• 29 CFR 1910.1053: Respirable crystalline silica
• 29 CFR 1926.1153: Respirable crystalline silica in construction
• Iowa OSHA