Foundry Sand Reuse in South Carolina

Planning to reuse spent foundry sand in South Carolina? This guide covers the rules that apply, the tests that decide how the sand can be managed, and what DES 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. South Carolina law handles reuse through its definition of “recovered materials.” Recovered materials are not solid waste.

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.

South Carolina’s recovered materials rule

South Carolina’s Solid Waste Policy and Management Act sets the framework. Under S.C. Code § 44-96-40, solid waste does not include recovered materials. A recovered material must meet all of these conditions:

1. it has known use, reuse, or recycling potential;
2. it can be feasibly used, reused, or recycled;
3. it has been diverted or removed from the solid waste stream for sale, use, reuse, or recycling; and
4. at least 75 percent by weight of the material received in the previous calendar year was used, reused, recycled, or transferred to another site for those purposes.

A recovered materials processing facility handles only recovered materials. It must keep records of the weight it receives and the weight it uses, recycles, or transfers. It must also record where the material finally went, and show DES these records on request. Solid waste it generates stays regulated.

Material that does not qualify is solid waste. A solid waste management facility needs a DES permit under S.C. Code § 44-96-290. That includes facilities that store, process, recycle, or dispose of solid waste.

Structural fill has its own limits. R.61-107.19 limits structural fill to land-clearing debris, hardened concrete, cured asphalt, bricks, blocks, and other materials DES names by regulation. Materials contaminated by hazardous constituents or petroleum products may not be used.

Working with DES

• Before shipping: confirm with the receiving facility that it meets the recovered materials conditions. The receiving facility keeps the weight and destination records.
• What to show: the known use, how the sand is kept separate from other waste, and the receiver’s 75 percent turnover.
• Processing: a facility that processes solid waste needs a permit under R.61-107.6. That regulation does not apply to recovered materials processing facilities. It also exempts facilities processing waste generated on property under the same ownership or control.
• Landfill disposal: the landfill class depends on a waste characterization report submitted to DES (R.61-107.19, Part I, Section C).
• Special waste: industrial process waste, generated directly or indirectly by making a product, is a special waste. A municipal solid waste landfill must give prior written approval, under DES requirements, before accepting it (S.C. Code § 44-96-390).

Use DES’s permitting contacts to reach the solid waste and landfill programs. DES main line: (803) 898-3432, info@des.sc.gov.

Hazardous waste determination

South Carolina’s hazardous waste rules are Regulation 61-79. Its parts follow the federal numbering, such as R.61-79.261 for identifying hazardous waste and R.61-79.262 for generators.

South Carolina reporting differs from the federal rules. Under R.61-79.262.41, a large quantity generator that ships hazardous waste off site files a quarterly report with DES. The report is due within 30 days after each quarter ends.

Under R.61-79.262.11, 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, DES, 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.

For landfill disposal, R.61-107.19 compares TCLP results with South Carolina drinking water limits (MCLs) to decide which landfill class may take the waste. Use a laboratory certified by DES and follow EPA SW-846 sampling procedures.

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.

Reuse turns on the recovered materials conditions. Check any destination and proposed use with DES before scheduling delivery.

Confirm the receiver meets the recovered materials conditions, including the 75 percent turnover. 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.

SC OSHA runs South Carolina’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. Plan volumes so the receiver can use, recycle, or transfer at least 75 percent of what it receives each year.

Keep the waste determination, lab reports, DES correspondence, and the receiving site’s acceptance together. Record tonnage shipped, dates, and destinations. 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.
3. Choose a destination and get its material specifications.
4. Confirm with DES that the sand and receiver meet the recovered materials conditions, or get the needed permit or landfill approval.
5. Get written acceptance and arrange pickup.

Common questions

Rules and guidance

• S.C. Code Title 44, Chapter 96: Solid Waste Policy and Management Act
• DES: Solid Waste
• DES: Consolidated Solid Waste Landfill Regulation
• R.61-107.19: Solid Waste Landfills and Structural Fill
• R.61-107.6: Solid Waste Processing Facilities
• DES: Laws and Regulations – Hazardous Waste
• R.61-79.262: Standards Applicable to Generators of Hazardous Waste
• 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
• SC OSHA