Oil Skimming Questions and Answers from the Experts

Do you have a question about oil skimming?

Ask Skimmerman, and your question will be answered on this page or in a private e-mail message. Read below to see Skimmerman’s answers to other questions. Check back here often to see answers to new questions.

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Paul Edwards asked: How can I check to see if the oil I need removed will adhere to your belt materials?

Skimmerman says: Abanaki has various belt materials that give customers the best pickup rates possible; an easy test to see what belt material is the most effective is to simply take a piece of pvc and/or metal pipe and run it through the oil that is floating on the surface. If the oil sticks to either one or both, then we know our belt materials will work as well.

George Perkins asked: I have a Tote It oil skimmer with a cr steel belt. Is there supposed to be a bearing inside the lower pulley?

Skimmerman says: The cr steel belts are actually driven by the upper magnetic drive pulley. The lower tail pulley functions by “floating” on the axle and stainless steel washer provided; applying weight on the belt and keeping it in place. No bearing is needed.

Anonymous asked: How do you set the timer on a Mighty Mini?

Skimmerman says: Turn the time dial to the time of day, set the desired switching program by pushing the switch actuators towards the center of the dial. Each segment equals 15 minutes.

Christopher Hollis asked: My belt is slipping on my Mighty Mini, how can I fix it?

Skimmerman says: Check to make sure there are no obstructions on the belt as it passes through the wipers. Check to make sure that the tail pulley (bottom roller) turns freely and is free from obstruction. Sometimes the coolant/oil combination in the application can be extremely slippery, making the belt slip. Try adding a 1/2″ spacer between the stabilizer bar spring and the mounting base plate to provide extra tension on the belt. The added resistance should keep the belt from slipping.

Dave Clarkson asked: What is the amp draw on the 110v Mighty Mini motor?

Skimmerman says: .5 amp

Dan Smith, Mech. Engineer at Cornerstone Engineering asked: For a Model 4, with a 12′ long poly type belt running continuously in a sump with water-oil mix at ambient temperature, with a pH between 8 and 11 and about 2500 ppm oil-to-water ratio,using the ceramic wiper blades, what can be expected to be the life of a) the belt b) the wipers, c) motor and d) gear box?

Skimmerman says:

  1. The Polybelt for this particular application should last a year or more. Certain factors can reduce the life of the belt however; fine particles and/or grit in the liquid or the head pulley not being level causing bad tracking of the belt to name a couple. Belt life expectancy is determined more by the application and the process than by the belt material!
  2. Your ceramic wipers should last close to forever. The only thing that will hurt these wipers is physical abuse.
  3. Your motor is a ¼ hp industrial strength TEFC motor and should last for many, many years of trouble-free operation.
  4. The gear box (gear reducer) is designed to slow down the number of revolutions to approximately 12rpm of the head pulley. About every 6 months or so the gear oil in the reducer should be changed. This unit, like the motor, should provide many years of service.If you are ever experiencing abnormal failure rates of any Abanaki equipment contact the factory for possible solutions.

Bryan Irving, Project Manager at Handex – NY asked: Do any of the skimmers work on gasoline recovery, they seem to be mostly for heavier oils.

Skimmerman says: For many years, due to the available technology, belt skimmers were efficient with removal of reasonably heavy oils only. This is because belt skimmers work on the scientific principle of surface tension. The amount of product recovered was therefore dependent on two factors: viscosity of the product and surface area of the belt. Some equipment manufacturers would speed up the belt hoping to recover more, but this led to emulsification and less efficient coating of the belt. Recently, Abanaki has developed a belt specifically for light fuel oils such as gasoline and diesel. We call it our LFO Polymer belt and recovery rates are astounding. A 1″ belt can remove 3 gph, a 2″ belt 6 gph and a 4″ belt 12 gph of fresh-from-the-pump gasoline! As the viscosity increases the removal rates increase as well. What we have done is to develop a belt with incredible surface area while only increasing the profile slightly. Use of Abanaki’s Oil Concentrator is strongly recommended while utilizing the LFO Polymer belt for recovery to ensure practically water free removal. If you have further questions, feel free to contact one of our technical support representatives at the factory.

Alejandro Alcala, Environmental engineer at GALVAK SA DE CV asked: We have a wastewater treatment plant for removing oil and grease. The wastewater comes from a cleaning section of strip (we’re a galvanizing and coil coating facility) and is pumped to equipment for adding sulfuric acid for break emulsion and free grease. I need you to recommend which skimmer to use. The flow of the wastewater is 24 GPM and o/g concentration is about 5000-7000 mg/L. The tank where it is released o/g has only 60 cm depth. Sometimes we have grease and not oil, this causes more problems when removing it. What do you recommend?

Skimmerman says: Considering what is known about the application the most appropriate Abanaki skimmer would be the Oil Grabber Model 4. This unit satisfies the calculated capacity requirements of approximately 58 LPH (15 GPH), and unless the grease is non-flowing will offer efficient discharge. I would recommend the skimmer be mounted on a 122cm (24″) stand to allow gravity discharge into a container such as a 55 gallon drum. I would recommend the belt be made of our standard Polymer material, and the wiper blade inserts be the hybrid ceramic-impregnated UHMW (Ultra High Molecular Weight) polypropylene. Also, I would recommend the submerged components (tail pulley, yoke & chain assembly) be made of 316 SS depending on the concentration of the sulfuric acid. Another consideration depending on the nature of the grease, would be silicone strip-heaters placed on the underside of the troughs to aid in discharge by keeping the grease liquefied. Therefore, based on the information you have supplied on the application, I would recommend an Oil Grabber Model 4 complete featuring a 4″ x 5′ 6″ (1.7 m) center to center poly-belt, 60hz 1 or 3-phase TEFC motor, 316 SS tail pulley, hybrid wiper inserts, 316 SS yoke & chain assembly, a 48″ mounting stand and possibly strip heaters for the troughs. Please, contact my International Sales Manager, Simon Bennett, at this e-mail address sb1@abanaki.com for pricing and any additional information.

Daniel Cross, Biochemist/Consultant at Biochemical Products and Services asked: Oil and grease tends to become solid in the surface of separation tanks in food industry. How do the skimmer works in this situation?. Are they provided with a heater?. Thanks for your answer

Skimmerman says: An oil skimmer can be used effectively in this application by utilizing a Mat Buster to break up the solids. As the skimmer picks up the oil and grease it is discharged into a heated trough or hopper (depending on the model selected), liquefied and discharged to a tramp oil container. As happens so often here at Abanaki, the Mat Buster grew out of the needs of our clients – such as you!

Randy Sears, Sr. Engineer at Westinghouse Savannah River Corp. asked: I’ve got a 4′ x 4′ x 4.75′ sump that receives condensate waste water from two air compressors in one of our facilities. Oil is migrating from the compressors and is getting into the its condensate waste stream causing an oil sheen on the sump’s contents. Normal discharge of the sump contents is to the Storm Sewer, but due to the oil residue it is being drummed. Do you have a recommendation?

Skimmerman says: You can approach this application two ways. You can skim the surface oil from the sump as long as the skimmer has sufficient time to remove the oil, or you can skim the oil from the drums. Air compressor oil is tough oil to skim because it is so thin. It tends to mix easily with the water and does not have the viscosity to be picked up quickly. If you decide to skim from the sump, let me know how long the water is retained before it is pumped to the storm sewer. A light sheen will take some time to pick up. Also, let me know the distance from floor level to the water surface at its lowest level. Keeping in mind that these skimmers discharge by gravity, you should take into account how high off of the floor the skimmer needs to be to discharge into your disposal container.

Pierre McKenzie, Subsurface Program Manager at GA Environmental Services, Inc asked: I have a need to recover #6 fuel oil from fractured bedrock. We are proposing to install a 12-inch diameter recovery well, 40 feet deep, cased from surface to 16 feet (soil/bedrock interface) open borehole to depth. GW at 18 FBG. Which system do you recommend. My experience with skimmers is that they don’t function well in #6. Wipers don’t tend to clean off the oil, especially during cold weather.

Skimmerman says: I recommend a 4″ PetroXtractor with the standard Polymer belt, heated troughs, 24-hour timer, tail pulley support rods and drum shutoff switch. The Polymer belt retains a minute amount of oil that actually helps draw the oil in the well to the belt on subsequent passes. The heated troughs help maintain discharge flow and the tail pulley support rods keeps the tail pulley from becoming neutrally buoyant in the viscous oil. While it is true that during cold weather #6 fuel oil does get quite viscous, it should not be a problem to wipe off of the belt. If too much is being left on the belt, adding enough heat to keep the unit above the freezing mark should solve the problem.

Karen Sohlberg, Environmental Engineer at R&C Industries asked: My oil skimmer isn’t picking up oil from my coolant sump like it did a few days ago. What is going on?

Skimmerman says: Your coolant may contain rust inhibitors that are coating the metal belt causing a barrier between the the belt and the oil. Try changing to a synthetic belt material such as Elastomer or Polymer. Rust inhibitors do not affect them.

CARLITO. SANTOS, JR., WASTEWATER TREATMENT DESIGNER CONSULTANT at UNIKLEEN INTERNATIONAL CORP. asked: Can you discuss applicability of your product to kitchen waste coming from a group of Chinese food restaurants. Do you have price ranges where I can select from, with its corresponding capacities?

Skimmerman says: The grease traps of restaurants are a perfect place for an Abanaki skimmer. As city, state and federal governments become stricter about water discharge from the food industry, restaurants will surely come under closer scrutiny. Depending on the size of the grease trap and flow of wastewater, various units will fit the bill. Don’t forget to ask about heaters as some fats and greases congeal quickly!

James Kilbane, Senior Engineer at BKC&E Consultants asked: I’ve used skimmer pumps in the past. Not only do they pick up a lot of water, they emulsify the oil and water. How is your skimmer different?

Skimmerman says: Abanaki does not use pumps to skim product and therefore the oil and water are not emulsified during the skimming process. As the belt passes through the oil/water interface, the oil sticks to the belt and is carried to the skimmer head where it is wiped off and gravity discharged to a collection/disposal tank. All Abanaki units are designed to pick up very little water. However, if there is little or no oil to coat the belt some water pickup is inevitable. To solve this problem, Abanaki has accessories such as timers and Oil Concentrators that will keep water collection to the minimum.

Sandy Lahtola, Geologist at BT Environmental asked: What is the recovery rate I can expect from a 4″ well?

Skimmerman says: Recovery rates are based on many factors including: speed of the belt, viscosity of your product, refresh rate of your well, size and material of your belt. Abanaki customizes each unit to ensure maximum product removal with minimum water pickup. For example: if your well had gasoline – a 2″ PetroXtractor with LFO Polymer belt running at 30 rpm would recover about 3 gph (assumes a reasonable refresh rate); if this well had #6 fuel oil a different setup would be used – a 2″ PetroXtractor with Standard Polymer belt, tail pulley support rods, timer, running at 12 rpm can recover over 6 gph (most wells can not recover this fast).

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