Michigan

Overview of foundry sand reuse rules

The Michigan Department of Environmental Quality (MI DEQ) is working to revise its requirements that address beneficial use of industrial byproducts.  Currently, wastes can be classified as inert, low-hazard, or compostable. Criteria for an inert designation are further broken down for general use, use in a specific location, and use instead of a virgin product.

Michigan’s Solid Waste Management Act outlines a process for designating wastes as inert material or low-hazard industrial waste, thereby allowing beneficial reuse. Designation as either type of waste involves petitioning the Michigan Department of Environmental Quality (DEQ). The petitioner must provide a description of the beneficial use and demonstrate that the waste does not contain constituent concentrations exceeding primary or secondary drinking-water standards. Once the waste classification is granted, the petitioner must conduct annual tests and submit the results to DEQ.

What reuse options are acceptable?

The rules for solid waste management specify standards and requirements for the following general categories of reuse:

  • Nondetrimental material managed for agricultural or silvicultural use;
  • Inert materials appropriate for general reuse;
  • Inert materials appropriate for reuse at a specific location;
  • Inert materials appropriate for specific reuse instead of virgin material; and
  • Industrial waste classified as low-hazard industrial waste appropriate for general reuse.

Types of prior approvals for foundry sand reuse projects (X indicates a need for prior approval, while other uses can be done with no approval):

  • X: Landfill daily cover
  • X: Landfill – other
  • X: Feedstock for Portland Cement manufacture
  • Aggregate for Portland cement concrete
  • X: Aggregate for Asphalt
  • Aggregate for CLSM/Flowable Fill
  • X: Aggregate for pre-cast concrete/bricks/blocks/etc.
  • X: Structural fills & building bases
  • Road bases
  • Highway embankments
  • Manufactured soils
  • Composts & mulches
  • Nursery soils
  • Other: (list)

What restrictions apply?

The suite of relevant constituents and their thresholds varies, depending upon the type of reuse (e.g., agricultural use, substitute for virgin material). Solid waste designated as inert material appropriate for general reuse, use at a specific location, or a specific reuse instead of virgin material must meet a different set of constituents of concern and standards, depending on the waste classification. Because each combination of waste classification and reuse category will have its own set of requirements, the discussion from this point forward focuses on the criteria for the designation of low-hazard industrial waste originating from primary metals or fabricated metal industries (SIC codes 33 or 34).

For wastes classified as low-hazard industrial wastes, Michigan has established leachate thresholds for the following constituents: metals, halogenated volatile organics, nonhalogenated volatile organics, aromatic volatile organics, phenolic compounds, and formaldehyde.

The thresholds for metals, in mg/L, include:20

  • Arsenic - 0.5
  • Barium - 10.0
  • Cadmium - 0.10
  • Chromium - 0.50
  • Copper - 10.0
  • Lead - 0.50
  • Manganese - 0.50
  • Mercury (inorganic) - 0.02
  • Nickel (soluble salts) - 1.0
  • Selenium - 0.10
  • Silver - 0.50
  • Zinc - 50.0

For uses where the wastes may present an inhalation or direct contact hazard, the petitioner must provide the total concentration of each of the following chemical constituents:

  • hazardous constituents listed in 40 CFR Part 258, Appendix II;
  • constituents that have primary or secondary drinking-water standards
  • (established under 40 CFR Parts 141 and 143), including total chloride, total nitrogen, total iron, total manganese, and total sulfates;
  • total molybdenum and total sodium; and any indicator parameters that may be useful in establishing a ground-water monitoring program for the waste.

Do I need a permit?

A facility may petition the director of DEQ to designate solid waste as inert material, compostable material, or low-hazard industrial waste, thereby qualifying it for reuse.

The petition to classify waste involves completing DEQ's application form, which requires a general description of the material to be classified, including: (1) a description of the process used to produce the material; (2) a schematic of the process and list of raw materials; (3) maximum and average amounts of materials generated monthly and annually; (4) documentation that the material is not hazardous waste; and (5) a description of the proposed use or disposal method for the material. Compostable material classification is not relevant to spent foundry sand, and significant crossover exists between inert material and low-hazard industrial waste.

What steps do I need to take to reuse my foundry sand?

Inert Material. Facilities may petition to designate solid waste as inert material appropriate for general reuse, for reuse at a specific location, or for specific reuse instead of virgin material. Inert materials range from rock and excavated soil to chipped tires and low-hazard industrial waste (i.e., low-hazard industrial waste used as aggregate, road, or building material, ultimately stabilized or bonded by cement, limes, or asphalt).

Low-hazard industrial waste. Solid waste may be determined to be low-hazard industrial waste if: (1) it is a by-product of a production process from primary metals or fabricated metal industries (i.e., standard industrial classification (SIC) Code 33 or 34), and (2) the waste meets leaching.

The rules for solid waste management specify standards and requirements for the nondetrimental material managed for agricultural or silvicultural use; inert materials appropriate for general reuse; inert materials appropriate for reuse at a specific location; inert materials appropriate for specific reuse instead of virgin material; and industrial waste classified as low-hazard industrial waste appropriate for general reuse.

What testing do I need to perform?

The petition for reuse requires a description of the techniques used to sample and analyze waste. DEQ requires that the sampling and analysis be conducted in a manner consistent with EPA's Test Methods for Evaluating Solid Waste, SW-846, 3rd edition. To be representative of the waste, DEQ requires a minimum of four samples be collected. For constituents that are present in the material at potential levels of concern, their leaching potential must be determined using any of the following tests: (1) toxicity characteristic leaching procedure (TCLP), EPA method 1311; (2) synthetic precipitation leaching procedure (SPLP), EPA method 1312; or (3) other test methods that are approved by DEQ and more accurately simulate conditions at the site. If a hazardous substance is reported present in a sample at concentrations above the waste classification criteria, a facility may demonstrate  that the data are not statistically significant.

Approved materials classified through this process must be re-tested at least annually, with test results submitted to DEQ. The director has the discretion to specify more frequent testing if the characteristics of the material vary significantly.

Where can I get testing performed?

List test regional labs.

What reporting and recordkeeping requirements must I meet?

Once the waste classification is granted, the petitioner must conduct annual tests and submit the results to DEQ.

What other requirements must I meet?

None identified.

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