Types of Solid Waste Recycling

We’ve been talking a bit about solid wastes recently. You may recall us mentioning that there are three categories for recycled materials, each with its own regulatory definition. Today we are going to look a little closer into what those three types are. When it comes to disposing of solid wastes via recycling the EPA currently regulates the three separate ways; use constituting disposal, burning waste fuels, and reclamation. The first step you have to go through when recycling a solid waste is to determine what kind of material you are dealing with.

Once you’ve determined what type of secondary material you are working with (spent material, sludge, or scrap metal, etc.) the way in which it is recycled will be the determining factor in whether or not the material is a solid waste and, as such, potentially regulated as a hazardous waste. There is a fourth type of recycling called direct use/reuse which is not regulated under RCRA. But let’s look at the RCRA regulated recycling options before we talk about that.

Use Constituting Disposal

According to §261.2, when wastes or products containing wastes are placed directly on the land it is considered to be use constituting disposal. That said, if direct placement of a Commercial Chemical Product on the land is consistent with its typical use, like pesticides, then the material is not regulated as a solid waste. A good example is heptachlor which can potentially be a P-listed waste. When it is used as a pesticide though, it is not regulated as a solid waste.

Burning Waste Fuels

“Burning hazardous waste for energy recovery and using waste to produce a fuel are both covered under burning waste fuels (§261.2). CCPs that are themselves fuels are not considered solid wastes when burned, however, since burning is consistent with the product’s intended use. For example, off-specification jet fuel is not a solid waste when it is burned for energy recovery because it is itself a fuel.”


We’ve talked about reclamation before but never in much detail. According to the EPA, “reclamation is the regeneration of wastes or recovery of usable materials from wastes (e.g., regenerating spent solvents in a solvent still). Wastes are regenerated when they are processed to remove contaminants in a way that restores them to their usable condition.”


Direct reuse of a secondary material, with no reclamation involved beforehand, is the last form of recycling we’re going to discuss. 40 CFR §261.2 provides exclusions from the definition of solid waste for those materials which are reused in one of the following three ways:

Use as an Ingredient

If a secondary material is directly used as an ingredient in a production process without first being reclaimed…then that material is not a solid waste.

Used as a Product Substitute

If a secondary material is used as an effective substitute for a commercial product without first being reclaimed…it is exempt from the definition of solid waste.

Returned to the Production Process

When a material is returned to the original production process from which it was generated, it is not a solid waste. This exclusion only applies if the material is used as a raw material or feedstock in the production process and if it is not reclaimed prior to its reintroduction into the system. The material does not have to be returned to the exact unit, but may be returned to any unit associated with the production of a particular product.

All information for this blog post was gathered from the EPA Document, Definition of Solid Waste and Hazardous Waste Recycling. As always, this blog post is not intended to be comprehensive and it is always best to check with the EPA and local government for full rules and regulations.

What is a Solid Waste?

When you hear the term “solid waste” you probably think it means exactly what it sounds like, a waste that is solid as opposed to liquid or gas. Interestingly enough though that is not what it means at all. The legal definition of “solid waste” actually has nothing to do with physical form. Rather, it deals with whether or not the material is a “waste.”

RCRA §1004(27) defines a solid waste as, “any garbage, refuse, sludge from a wastewater treatment plant, water supply treatment plant, or air pollution control facility, and other discarded material, including solid, liquid, semisolid, or contained gaseous material, resulting from industrial, commercial, mining, and agricultural operations and from community activities.”

The definition found in 40 CFR §261.2 is a little less extensive. §261.2 defines a solid waste as any material that is discarded by being abandoned, inherently waste-like, recycled, or a military munition identified as a solid waste. These four categories are explained further below.

What is an “abandoned waste?”

As you might have guessed, an abandoned material is simply one which has been discarded or thrown away. Under §261.2 a material is considered abandoned if it is disposed of, burned, or incinerated. Additionally, any material that is stored before or in place of disposal, burning, or incineration is considered abandoned.

What does it mean for a material to be “inherently waste-like?”

Regardless of whether or not they are recycled in some way, there are some materials that are always considered solid wastes under §261.2. Because the materials may still pose danger to human health or the environment after recycling, they are considered inherently waste-like and do not qualify for any type of recycling exemptions. According to the EPA, “examples of inherently waste-like materials are the dioxin-containing listed wastes F020, F022, F023, F026 and F028.”

What kinds of materials are recycled?

The EPA has three categories for a “recycled material.” According to §261.1 a material is recycled if it is used, reused, or reclaimed. Each of the three categories has a specific regulatory definition. So, a material is reclaimed if it is processed to recover a usable product or if it is regenerated. An example would be regeneration of spent solvents. A material is used or reused if it is either used as an ingredient in an industrial process to make a product, such as distillation bottoms from one process being used as feedstock in another process, or if it is employed as an effective substitute for a commercial product. For example, spent pickle liquor can be used as a sludge conditioner in wastewater treatment.

How and when do military munitions become solid waste?

RCRA in relation to military munitions was a somewhat controversial topic until February 12, 1997, when the EPA finalized a rule that specified when unused and used military munitions are considered discarded and become solid wastes (62 FR 6622). It was decided that unused military munitions would be considered solid wastes once they were removed from storage for disposal or treatment, when they were leaking or in any way deteriorated so they could not be recycled or reused, or when they were declared a solid waste by an authorized military official.

Unused munitions that are repaired, recycled, or reclaimed, are not considered solid wastes, nor are they considered solid wastes while in storage in demilitarization accounts (e.g., scheduled for treatment or disposal). Only when these munitions are finally removed from storage for the purposes of disposal do they become solid wastes.

Used military munitions become solid wastes when they are buried or landfilled onsite, or when they are removed from their landing spot for subsequent management (storage, reclamation, treatment, or disposal) off-range.

All information for this blog post was gathered from the EPA Document, Definition of Solid Waste and Hazardous Waste Recycling. As always, this blog post is not intended to be comprehensive and it is always best to check with the EPA and local government for full rules and regulations.

The Hazardous Waste Identification Process

The cornerstone of a successful hazardous waste management system is the proper identification of hazardous wastes. RCRA regulations at 40 CFR 262.11 require that any person who produces or generates a waste must determine if that waste is hazardous. 262.11 also provides four steps for generators to utilize in the process of hazardous waste identification. These are:

  • Is the waste a “solid waste”?
  • Is the waste specifically excluded from the RCRA regulations?
  • Is the waste a “listed” hazardous waste?
  • Does the waste exhibit a characteristic of hazardous waste?

So, in order to properly identify hazardous waste, it stands to reason that we should work our way through those four points.

Is the waste a “solid waste”?

As with many things, the first step in hazardous waste identification is pretty intuitive. We must first determine if the material is a waste. After all, if it is not a waste it can’t be a hazardous waste. That said, determining whether or not something is a waste can get tricky. Take glass bottles for example, one person could see them as something to discard while another may see them as valuable due to their ability to be recycled.

Because of this ambiguity, the EPA developed a set of regulations to assist in determining whether or not a material is a waste. RCRA uses the term “solid waste” in place of “waste. Under RCRA, the term “solid waste” means any waste, whether it is a solid, semisolid, or liquid. The first section of the RCRA hazardous waste identification regulations focuses on the definition of solid waste and is a good place to look if you are confused about this step.

Is the waste excluded?

While solid wastes are rather abundant, just a small percentage of them qualify as hazardous wastes. You might think that distinguishing between hazardous and nonhazardous wastes is a simple matter of chemical and toxicological analysis. This, however, is not the case. We must first consider other factors before evaluating the hazard posed by the chemical composition of a waste.

Due to the fact that regulating some wastes may be impractical, unfair, or otherwise undesirable, the EPA has created exclusions. Household waste, for example, can contain dangerous chemicals, like solvents and pesticides, but making households subject to the strict RCRA waste management regulations would create a number of practical problems. Congress and EPA exempted or excluded certain wastes, like household wastes, from the hazardous waste definition and regulations.

Determining whether or not a waste is excluded or exempted from hazardous waste regulation is the second step in the RCRA hazardous waste identification process. Only after determining that a solid waste is not somehow excluded from hazardous waste regulation should the analysis proceed to evaluate the actual chemical hazard that a waste poses. Check 40 CFR to see if the waste you generate is excluded for any reason.

Is the waste a “listed” hazardous waste?

The EPA has studied hundreds of different waste streams and listed the wastes accordingly. Listed wastes are described or listed on four different lists that can be found at 40 CFR 261, Subpart D. These four lists are:

  • The F list — The F list designates particular solid wastes from certain common industrial or manufacturing processes as hazardous. Because the processes producing these wastes can occur in different sectors of industry, the F list wastes are known as wastes from nonspecific sources. The F list is codified in the regulations at §261.31.
  • The K list — The K list designates particular solid wastes from certain specific industries as hazardous. K list wastes are known as wastes from specific sources. The K list is found at §261.32.
  • The P list and the U list — These two lists are similar in that both list pure or commercial grade formulations of certain specific unused chemicals as hazardous. Both the P list and U list are codified in §261.33.

The third step in hazardous waste identification is determining which (if any) of these lists your waste belongs on.

Does the waste exhibit a characteristic of hazardous waste?

We’ve talked about the characteristics of hazardous waste before. There are four different characteristics; ignitability, corrosivity, reactivity, and toxicity. If you need a refresher on the definitions of these characteristics check out our “Characteristics of Hazardous Waste,” post or our infographic depicting them.

The final step in the hazardous waste identification process is determining if your waste displays any of the four hazardous waste characteristics.