The ABCs of solvents, solutes, and solutions
A solvent is a substance that dissolves a solute to form a solution. Water is the best example. In fact, it’s the most common solvent in the world. A solute, on the other hand, is the substance that’s getting dissolved. Sugar is the “solute” when you’re making a “solution” of simple syrup.
But we’re guessing you’re not reading this because you want to mix up a Brandy Old Fashioned. Instead, if yours is an industrial or manufacturing enterprise—big or small—there’s an excellent chance that you have solvents onsite that require hazardous waste removal.
Industrial/commercial solvents are generally considered under one of four categories
1. Halogenated solvent waste. A solvent is “halogenated” if it contains carbon and hydrogen, but where one or more of its hydrogen atoms have been replaced by a halogen. So what’s a halogen?
Halogens are a group of elements that share the same address on the periodic table. [We knew you’d ask. It’s VIIA (17)]. They are fluorine, chlorine, bromine, iodine, and astatine. Each is a reactive nonmetallic element that likes to hook up with hydrogen.
The key word here is reactive.
A substance is considered reactive if, for example, it explodes nearby another hazardous waste, which is incentive enough not to mix them. But more subtly, reactive wastes can become dangerously corrosive, toxic, or ignitable when too close & personal among themselves. Thus it’s crucial that you keep them separated during storage or transportation.
2. Non-halogenated solvent waste. Non-halogenated solvent wastes lack fluorine, chlorine, bromine, iodine, or astatine. Instead, they feature methanol, acetone, ethanol, ether, ethyl acetate, hexanes, or toluene.
As they’re relatively less dangerous, the cost for their hazardous waste disposal is less expensive. Thus, you should keep them apart from halogenated solvent wastes. Otherwise, if you mix the two, the entire quantity must be treated as a halogenated substance, which needlessly increases your hazardous waste management costs.
3. Heavy metals solvents. These contain things like arsenic, cadmium, barium, chromium, lead, selenium, mercury, or silver, which are heavy metals that hold the rapt attention of the EPA for causing gastrointestinal and kidney dysfunction, nervous system disorders, skin lesions, vascular damage, immune system dysfunction, birth defects, and cancer.
As if that’s not enough, heavy metals have an endemic tendency to bioaccumulate, meaning they increase in concentration inside people and animals over time (relative to their concentration in the environment). Obviously, you can’t pour this stuff down the drain. You need careful hazardous waste management.
4. Paint solvents and residues. These come from oil-based paints and thinners, which contain “volatile organic compounds” (VOCs), and so are seriously frowned upon by the EPA. This is because when oil-based paints dry, the VOCs vaporize, and wreak havoc on the ozone layer.
If you’re using industrial paints, check out your leftover drums. If they say acrylic, epoxy, polyester, polyurethane, or polytetrafluoroethylene, then they belong to a gaggle of resins, solvents, additives, and pigments that are of existential interest to the EPA.
Although any one of these chemical constituents mightn’t be a listed hazardous waste per the EPA, it could nonetheless be considered a characteristic waste if it possesses one or more noxious “characteristics” such as corrosivity, ignitability, reactivity, and/or toxicity.
The danger here is that it’s up to you to figure out whether your leftover industrial paint is a characteristic hazardous waste: a requirement you must meet within a specified timeframe so that the paint “characteristics” don’t change over time.
Again, you need to get expert advice.
A word about recycling
Most industrial solvents can be processed to render a percentage of their bulk into reusable product—typically as much as 80 percent. In the simplest scenario, these are returned to your facility for re-use in combination with their more-expensive virgin counterparts.
Thereby, you can realize savings across the entirety of your operation by reducing your need for virgin solvent by 80 percent, commensurately decreasing your disposal and regulatory costs, even though you might be dedicating more funds to “hazardous waste management” per se.
Or another way to look at it: if you’re an LQG disposing of 1 million gallons of spent industrial solvent per month, recycling that waste so that you can reuse 80 percent of it will effectively cut your hazardous-waste stream to only 200 thousand gallons.
As is understandable, the EPA takes a very dim view of discharging solvents down the drain and into the municipal sewer. So do its state & local counterparts. And they don’t care if the solvent is miscible vs. non-miscible with water; or flammable vs. nonflammable. It can’t go down the drain. Period.
Instead, solvents require strict hazardous waste management. They must be placed in suitable containers that are tightly-capped, properly labeled with red hazmat tags, and designed so that no vapors or liquid might escape. Knowing how to do this properly takes expert advice.
You must ensure that spent or unwanted solvents are transported to the correct category of waste disposal facility. The transporter must be legally “permitted” to do so. Likewise, the facility must be “permitted” to accept them.
Making sure that these exigencies are met is solely on your head. You’re responsible for a hazardous waste “from cradle to grave” in EPA parlance, which means that selecting a transportation and/or treatment company that meets EPA muster is your legal obligation.
Don’t take chances. Get expert advice.
The nuances of hazardous waste management—especially in the realm of solvent disposal—require diligence on your part and that of your employees. You need an onsite protocol for handling solvents. You can’t allow individual employees to be making ad hoc decisions about what to do with a chemical waste when it presents itself.
Once you’ve developed such a protocol—and ensure everyone’s trained about it—it’s much less likely that expensive mistakes will be made: the kind that might be litigable or even criminal.
As in all things involving the EPA—not to mention OSHA and a raft of state and local agencies—expert advice is crucial. And the best is available right here.
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