Foundry Sand Reuse in Rhode Island

Planning to reuse spent foundry sand in Rhode Island? This guide covers the rules that apply, the tests that decide how the sand can be managed, and what DEM 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. In Rhode Island, DEM approves each reuse through a beneficial use determination (BUD). A BUD covers a specific solid waste, for a specific purpose, at a specific location.

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.

Rhode Island’s beneficial reuse law

Rhode Island’s beneficial reuse law is R.I. Gen. Laws § 23-18.9-16. DEM may approve environmentally beneficial reuse of solid waste in a municipality. It may weigh the waste’s physical and chemical characteristics, the proposed use, and the location.

Beneficial reuse material must be a processed, nonhazardous solid waste that is not already defined as recyclable material (§ 23-18.9-7). No one may process, store, transport, dispose of, or otherwise use solid waste for beneficial reuse without a written BUD from DEM. Every approved proposal must include:

1. public notice in a newspaper of general circulation;
2. notice to the manager or mayor and council of the municipality; and
3. a hearing held in the affected municipality.

DEM’s BUD guidelines (Policy WM-SW-2007-01) treat a BUD request as part of an application for a variance from the solid waste regulations. Uses that apply material to land are presumed low-utility. DEM looks closely at whether they are reuse or simply another way of disposal.

Applying to DEM

• Who files: usually the facility that will accept the sand and turn it into a saleable product. A foundry may apply if it also recycles the sand and makes it directly available for reuse.
• Before filing: DEM recommends a meeting to discuss the proposal. It strongly recommends sending a material characterization plan for comment before any sampling.
• Application: apply in writing. Answer each of the guidelines’ considerations, including hazard controls, the raw material the sand replaces, the end market, and why the use is not disposal.
• Controls: state the quantity received and the most stored at one time. Name the source and generator, and describe the process that makes the sand, with a diagram.
• Municipal copy: if you propose reusing more than three cubic yards in one location, send a copy of the application to that municipality.
• Notice and hearing: before DEM decides, the applicant posts newspaper notice and holds a public hearing. The applicant pays these costs.
• Review: DEM first checks the application for completeness. Its guidelines estimate about three months to one year for the review.
• Term and renewal: an approval expires one year from issue unless it says otherwise. It may be renewed for three years. Request renewal in writing at least 60 days before it expires.
• Financial assurance: DEM may require assurance that the project will be completed and unused material removed.
• After approval: DEM may deny, suspend, or revoke an approval. It may refuse or revoke a BUD where the applicant or a facility involved has existing violations.

DEM Office of Land Revitalization and Sustainable Materials Management, 235 Promenade Street, Providence, RI 02908: (401) 222-2797. Current and past BUD approvals are posted on DEM’s Beneficial Use Determination page.

Hazardous waste determination

Rhode Island’s hazardous waste rules are 250-RICR-140-10-1. They incorporate 40 CFR Parts 124, 260–261, 263–265, 266 (except Subpart H), 270, and 273 from the July 1, 2013 CFR. Rhode Island’s own generator rules in § 1.7 apply in place of 40 CFR Part 262.

Rhode Island sets its own testing rules. Test with the approved methods in 40 CFR Part 261, Subpart C; equivalent methods are not allowed. To rely on product knowledge instead, show in writing clear and convincing scientific evidence of the waste’s characteristics and the process that made it. Rhode Island also lists state hazardous wastes, such as PCB waste at 50 ppm or more.

Under 250-RICR-140-10-1.7.3, the foundry must decide whether its spent sand is hazardous:

1. Check whether the waste is excluded from the hazardous waste rules.
2. Check whether it matches a listed hazardous waste.
3. Check for hazardous characteristics, including toxicity. Test the waste, or apply knowledge of the materials and processes used.

Rhode Island requires generators to keep determination records for at least 3 years.

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, DEM, 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.

DEM’s guidelines ask for a characterization plan covering sample collection, analyses such as TCLP, variability, the number of samples, and health and ecological risks. If the sand will become a manufactured soil product, show the use meets the residential direct exposure criteria for soils in DEM’s remediation regulations.

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.

DEM decides reuse case by case. Check any destination and proposed use with DEM before scheduling delivery.

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.

Storage and records

Store spent sand on a defined pad or in bins, control dust and runoff, and keep other foundry wastes out. The BUD application must state the most sand stored at the site at any one time. It must also describe storage, handling, runoff, and erosion controls.

Keep the waste determination, lab reports, DEM approvals, and the receiving site’s acceptance together. Record tonnage shipped, dates, buyers, and destinations, and follow the record period in the BUD. Generators keep test results for waste determinations for at least three years under § 1.7.7.

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. Get a written DEM BUD for that sand, use, and location, after notice and a hearing.
5. Get written acceptance and arrange pickup.

Common questions

Rules and guidance

• R.I. Gen. Laws § 23-18.9-16: Beneficial reuse of solid waste
• R.I. Gen. Laws § 23-18.9-7: Definitions
• DEM Guidelines on Beneficial Use Determinations (Policy WM-SW-2007-01)
• DEM Beneficial Use Determination program
• 250-RICR-140-10-1: Rules and Regulations for Hazardous Waste Management
• 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