Foundry Sand Reuse in Alaska

Planning to reuse spent foundry sand in Alaska? This guide covers the rules that apply, the tests that decide how the sand can be managed, and what DEC 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 Alaska, “beneficial use” of solid waste needs DEC approval before it begins, and the rule names wastes DEC may not approve.

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.

Alaska’s beneficial use rule

Alaska’s beneficial use rule is 18 AAC 60.007. Beneficial use of solid waste is allowed only with prior DEC approval. The use may not begin until DEC approves the proposal. The rule allows two kinds of use:

1. structural fill, under 18 AAC 60.008; or
2. an ingredient in a manufactured product or a similar use, under 18 AAC 60.009.

DEC may approve wood waste, coal ash, crushed asphalt, and other similar solid wastes for these uses. Structural fill must replace natural or raw materials. Fill placed below the ground surface must sit at least five feet above the seasonal high water level of the uppermost aquifer.

How the rule treats foundry waste

Under 18 AAC 60.007(d), some solid wastes may not be beneficially used under 18 AAC 60.008 or 60.009. The list includes hazardous waste and industrial solid waste.

Alaska defines industrial solid waste in 18 AAC 60.990. It is non-hazardous solid waste from a manufacturing or industrial process. The definition names iron and steel manufacturing waste, and waste from nonferrous metals manufacturing and foundries.

Treated waste

Under 18 AAC 60.005(e), a person who treats a waste may ask DEC to manage the treated waste as inert or exempt waste. The person must show that treatment eliminates the potential release of hazardous constituents. DEC approval comes first, and the treatment operator keeps records showing each load was treated as approved.

Working with DEC

• Start with classification: ask DEC how it classifies your sand under 18 AAC 60.990 before you prepare a beneficial use proposal.
• Who files: the person who wants to beneficially use the solid waste submits the proposal. For fill on land you do not own, include proof of the landowner’s consent.
• Structural fill: use DEC’s “Beneficial Use of Solid Waste as Structural Fill” application. A project under 23,000 cubic yards is small; a larger one is large. The fee is set in 18 AAC 60.700, Table E-3: $685 for a small fill authorization and $1,595 for a large one.
• Fill content: show the site’s value before and after, the waste types and volumes, the specifications the waste meets, an operations plan, and construction drawings.
• Manufactured product: compare the product made with and without the waste. Show the waste stays bound in the product. Describe handling controls and, for a new product, its market.
• Review time: DEC approves a structural fill proposal within 30 working days of a complete proposal when the rule’s conditions are met.
• After approval: cover fill with at least six inches of exempt earthen material when the project ends. Other cover, such as pavement, needs prior DEC approval.

DEC Solid Waste Program: Anchorage (907) 269-7802, Fairbanks (907) 451-2108, Juneau (907) 465-5318.

Hazardous waste determination

Alaska adopts the federal hazardous waste rules by reference in 18 AAC 62, section by section. For example, 18 AAC 62.221 adopts the 40 CFR Part 261 characteristics of hazardous waste.

Alaska adds a yearly filing. Small and large quantity generators must submit EPA Form 8700-12 to DEC by March 1 each year, covering the prior calendar year (18 AAC 62.301).

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, DEC, 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 a large structural fill project, DEC requires metals and volatile organic compound results by EPA Method 1312 (SPLP), plus any other parameters DEC requests. For a large project lasting more than a year, DEC may require yearly retesting.

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.

DEC approves each beneficial use before it begins. Check any destination and proposed use with DEC before scheduling delivery.

When you talk to DEC, first confirm how it classifies your sand under 18 AAC 60.990. Then describe the proposal as structural fill or as a manufactured product ingredient. 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.

Alaska Occupational Safety and Health (AKOSH) runs Alaska’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. Do not store waste in a way that causes polluted runoff, a health hazard, or access by animals. DEC can act if a site storing more than 50 tons of material for reuse causes a nuisance or risk. It can require removal or limit storage to one year (18 AAC 60.010).

Keep the waste determination, lab reports, DEC approvals, 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. Ask DEC how it classifies your sand under 18 AAC 60.990.
4. Choose a destination and get DEC approval for that sand and use before it begins.
5. Get written acceptance and arrange pickup.

Common questions

Rules and guidance

• 18 AAC 60.007–.009: Beneficial use of solid waste
• 18 AAC 60.990: Definitions
• 18 AAC 60.010: Accumulation, storage, and treatment
• 18 AAC 60.700: Fee requirements
• DEC: Beneficial Use of Solid Waste as Structural Fill application
• 18 AAC 62: 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
• Alaska Occupational Safety and Health (AKOSH)