Foundry Sand Reuse in Nevada

Planning to reuse spent foundry sand in Nevada? This guide covers the rules that apply, the tests that decide how the sand can be managed, and what the solid waste management authority 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 Nevada, reuse falls under the general solid waste rules. The solid waste management authority for the county reviews each use and any site that processes the sand.

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.

Nevada’s solid waste rules

How Nevada classifies foundry waste

Nevada defines solid waste to include solid or semisolid industrial waste (NRS 444.490). Hazardous waste managed under the state hazardous waste law is excluded.

Under NAC 444.585, industrial solid waste includes waste from making nonferrous metals, including the foundries that make them. It also includes waste from making iron and steel. Class III landfills accept only industrial solid waste.

Reuse and processing approval

Nevada’s solid waste rules are NAC 444.570 to 444.7499. Three solid waste management authorities enforce them:

• Southern Nevada Health District in Clark County;
• Northern Nevada Public Health in Washoe County; and
• NDEP in all other counties.

Under NAC 444.644, all solid waste must be stored, collected, used, treated, processed, and disposed of safely. None of those steps may create a health hazard, a public nuisance, or harm to the environment. Solid waste systems must not pollute the air or surface or ground water. No system for handling, processing, salvage, or disposal may operate until the authority approves it.

Under NAC 444.676, any other processing method needs approved plans, specifications, and design data before it starts. NDEP lists material recovery facilities and process facilities among the facilities that need a permit.

Working with the solid waste authority

• Who reviews: the solid waste management authority for the county where the sand will be used or processed.
• Contacts: NDEP Solid Waste Program, (775) 687-9462. Southern Nevada Health District, (702) 759-0600. Northern Nevada Public Health, (775) 328-2434.
• Processing sites: a site that processes the sand needs the authority’s approval of its location, design, and operating plans before it operates. Confirm its approval covers spent foundry sand.
• What a process facility submits: NDEP’s process facility guidance asks for a design report stamped by a Nevada professional engineer. It also asks for an operating plan that lists the materials recovered and their final use or markets.
• Facility permits: NDEP reviews a permit application for completeness within 45 days. A technical review and a 30-day public comment period follow.

NDEP Bureau of Sustainable Materials Management, Solid Waste Program: (775) 687-9462, solidwaste@ndep.nv.gov.

Hazardous waste determination

Nevada adopts the federal hazardous waste rules by reference in NAC 444.8632. It adopts 40 CFR Parts 260 through 270, 273, and 279, plus Subparts A, B, and G of Part 124. The adopted text is the version that existed on July 1, 2018. NAC 444.86325 to 444.8634 list Nevada’s changes.

Nevada’s definition of hazardous waste is broader. Under NAC 444.843, it also includes waste containing PCBs. It also includes waste brought into Nevada that its home state designates as hazardous, with limited exceptions. If you ship sand into Nevada, check how your home state classifies it.

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, the solid waste management authority, 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.

Ask the solid waste management authority which analyses it needs for the proposed use and site. Your data should show the use will not harm health or the environment or pollute air or water, as NAC 444.644 requires.

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.

The solid waste management authority for the county decides reuse case by case. Check any destination and proposed use with that authority before scheduling delivery.

Describe the sand, the casting process, the test results, and the planned use. 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.

Nevada OSHA runs Nevada’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. Under NAC 444.662, the industry is responsible for safe and sanitary storage of its solid waste until it is removed.

Recycling sites have limits. Under NAC 444.74763, a materials recovery facility may not store recovered materials for more than one year. It must sell and remove at least 75 percent of them in each 12-month period. Recovered materials stored longer are waste and must be disposed of properly.

Keep the waste determination, lab reports, authority approvals, and the receiving site’s acceptance together. Record tonnage shipped, dates, and destinations.

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 the use or processing plan with the solid waste management authority for that county.
5. Get written acceptance and arrange pickup.

Common questions

Rules and guidance

• NDEP: Solid Waste Permitting Authorities and Requirements
• NDEP: Solid Waste Application Forms and Guidance
• NDEP: Process Facility Guidance Document
• NAC Chapter 444: Sanitation
• NRS Chapter 444: Sanitation
• 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
• Nevada OSHA