How to Manage Lubricant Waste and Disposal
Across industry, great emphasis is placed on the handling and application of lubricants from the moment they arrive at a facility to the time they are introduced into service. However, proper handling techniques do not end when the oil has been put into service. Once the life of the oil has been exceeded, you must ensure the lubricant is captured and disposed of both safely and in an environmentally friendly way.
Waste Oil
Before beginning a discussion on waste oil, it is important to first understand exactly what it is. A common term that is used interchangeably with waste oil is used oil. According to the U.S. Environmental Protection Agency (EPA), the definition of used oil is any oil that has been refined from crude oil, or any synthetic oil that has been used and as a result of such use is contaminated by physical or chemical impurities. This is the technical description for the oil that is drained out of your equipment.
Although most used oil alone is considered non-hazardous, if it has been contaminated by a hazardous substance, then it must be handled as hazardous waste. This encompasses an entirely different set of protocols. Just because most mineral and synthetic fluids by themselves are considered non-hazardous does not mean that all risks associated with handling them have been eliminated.
Care should be taken during the handling of both new and used oils to avoid any potential risks associated with the fluids. Some oils have been known to cause dermatitis, while others are considered to be toxic. When handling these fluids, exercise caution and avoid prolonged contact with your skin. If you have cuts or sores on your hands, wear gloves to keep the fluid from being introduced into the bloodstream.
Biodegradability
As industry increasingly becomes more environmentally conscience, great strides have been made in the area of lubricant management and disposal. Lubricants are now being formulated to meet even the most stringent environmental regulations. Lubricant biodegradability is often tested and referenced when selecting a lubricant for certain environments. For example, the equipment used in open-pit mining is often very large and holds hundreds of gallons of engine oil, hydraulic oil, gear oil and fuel. In the event of a leak, you would want these oils to be environmentally safe. This is where biodegradability or eco-friendly lubricants come into play.
The biodegradability of a lubricant refers to how fast the lubricant can be converted to carbon dioxide and water by naturally occurring micro-organisms. There are a few main tests to determine the biodegradability of a lubricant. The first is the primary biodegradability test (CEC-L-33-A-93). In this test, the candidate oil is contaminated with sewage waste and left for 21 days at 77 degrees F (25 degrees C). At the end of the three-week cycle, the mixture is analyzed. The oil is considered to pass if only 20 percent of the original oil remains intact.
Guidelines for Bulk Storage Spill Protection
The Code of Federal Regulations’ guideline on overfill prevention instruments (40 CFR 280.20 (C)) states that tanks must:
- Automatically shut off the supply flow when the tank is 95 percent full,
- Alert the operator when the tank is more than 90 percent full, or
- Reduce flow 30 minutes prior to overfilling and alert the operator with a high-level alarm one minute before overfilling.
Containment capacity must equal or exceed maximum volume of the largest tank or 10 percent of the total stored volume, whichever is greater.
The ultimate biodegradability test is similar to the primary test. For this test, the oil is contaminated with micro-organisms and then left to sit for four weeks at 72 degrees F (22 degrees C). With this test, the amount of carbon dioxide produced is measured and compared against a standard. To pass this test, 70 percent of the candidate fluid must be degraded at the end of the four-week period.
A new biodegradability test method (CEC-L-103-12) was recently developed. It measures the loss of oil and oil-soluble metabolites over 21 days in a nature-like aqueous environment. See the article on page 22 for a more detailed explanation of this new method.
When comparing environmentally friendly lubricants, one must consider that much of a lubricant’s biodegradability depends on the base oil with which it is formulated. Higher refined mineral oils (Group III) tend to degrade better than Group I oils. Group IV polyalphaolefins, which are perhaps the most common synthetic oils, score poorly in biodegradability, while polyolesters and diesters are among the best for breaking down naturally. However, if you are looking for the best oil in terms of biodegradability, you would pick a vegetable base oil (natural esters).
| Lubricant Type | Primary Biodegraded Quantity |
|---|---|
| Vegetable Oils | 70 - 100% |
| Polyols and Diesters | 55 - 100% |
| White Oils | 25 - 45% |
| Mineral | 15 - 35% |
| PAG | 10 - 20% |
| PAO | 5 - 30% |
| Polyether | 0 - 25% |
Vegetable oils are gaining popularity not only because of their inherent environmentally friendly nature but also because they are able to match the performance characteristics of their mineral counterparts. While governmental agencies focus on what happens to mineral and synthetic lubricants after use, they aren’t nearly as concerned with lubricants that are derived from animals or vegetables. This can be a benefit in the disposal of vegetable-based lubricants, as expensive reclamation of these oils (due to environmental regulations) may not be required. Of course, this does not mean you can simply pour vegetable oils into a ditch and walk away from them. They just don’t fall under the same jurisdiction as used mineral or synthetic oils. Many companies purchase used vegetable oils and recycle these base fluids as bio-diesels and other fluids.
Leakage
Aside from the actual task of draining waste lubricant from a system, there is the risk of oil leakage, which can introduce used oil into the environment. Leakage is common in all industrial facilities, although some plants do a better job of mitigating it than others. Leakage is what causes most facilities to use more oil than what they actually need. Remediating leakage-prone equipment not only can save the company money from wasted oil but also help lessen potential environmental problems.
There are several ways to find the source of leakage, including using ultrasonic equipment. By listening to pipe fittings, valves and pump interfaces on circulating systems, you can often pinpoint internal leaks and fix them. Another common method introduces dye into the system. The dye will bleed through leakage points with the oil and can be identified with the use of an ultraviolet light source.
Once oil leaks from a piece of equipment, the first action must be to control the spill to prevent it from spreading. Several products are available that can help with this problem. Many of the plants I visit use oil “pigs” or super-absorbent mats to quickly soak up and contain the spills. If the oil has any hazardous materials, the area must be isolated and documented before clean-up procedures can begin.
Depending on the severity of the leak and the fluid in question, the reclamation technique may range from simply washing down the leak to full soil reclamation for decontamination. Always consult your company’s environmental policy as well as any local governmental regulations to determine the most appropriate course of action.
Removal
The best practice for the removal of waste oil from a machine is to keep oil from ever being introduced to the environment. The rise in popularity of portable filter carts has made this process even easier. With a waste oil drum nearby and a filter cart hooked to the system’s drain, oil is pulled out of the reservoir and introduced into the waste oil container. For this procedure, it is recommended to bypass the filters on the cart. After all, there is no need to filter the waste oil, which not only would slow down the pump but also cost more money for the purchase of new filters.
If filter carts are not available in your facility, having an appropriate waste oil container is a necessity. The container should be labeled for waste oil only and have adequate volume to hold all of the oil in the system from which it is being drained. Although 5-gallon buckets are often used to capture waste oil and then emptied into used oil drums or totes, this practice offers many opportunities for spills by the constant transfer of oil from one vessel to another.
If waste oil is to be stored in large volumes or for extended periods in a single location, it is best to have spill-containment protocol in place. By using spill-containing pallets or building underground spill-containment reservoirs, you can ensure that leaks or spills are captured and greatly reduce the risk of environmental impact. The rule for spill containment is that it must be able to house the largest volume of oil for the container or 10 percent of the total volume of all oil stored in it, whichever is greater.
There are benefits to housing waste oil and repurposing it for other applications. One popular use for waste oil is to capitalize on the inherent energy contained in the oil. By burning the oil, you can harness the BTUs and use it as a fuel source not only for heat but also for power generation in some instances.
The re-refining of waste oil into a reusable oil source is becoming both increasingly popular and economical. These oils are cleaned of contaminants, re-additized and considered like-new oils. Several automotive oils on the market are re-refined oils.
As industry continues to become more eco-friendly, there will be an added emphasis on waste oil disposal and reclamation in the near future. By reviewing your current procedures and implementing some of the ideas in this article, you can put your facility ahead of the curve and realize the benefits of managing your waste oil with a best-practice mentality.
