Spent Coolant Waste Disposal
What is Spent Coolant?
Machining coolants, also known as cutting fluids or antifreeze, are used to cool the tool and the part being fabricated to minimize overheating during machining and grinding applications. The most common type of coolant is made up of water-soluble oils, but water-soluble synthetics or semi-synthetics, and straight oils are also used.
Coolant Solutions are collected in sumps, are periodically regenerated with neat (fresh pure coolant) coolant, and continuously re-circulated through the tool. Eventually the batch of coolant will break down or get too dirty, become less effective and need to be changed. The coolant is now "spent", creating antifreeze waste.
Using an ENCON Evaporator for Spent Coolant Disposal
Spent coolant or waste coolant wastewater is one of the more common applications for ENCON Wastewater Evaporator systems. The wastewater cannot be simply flushed down the drain even if the neat antifreeze is advertised as biodegradable. That is because the spent biodegradable coolant is contaminated with oils and metals
Many companies choose to avoid the headaches of labor-intensive wastewater treatment technologies such as chemical treatment or filtration and simply pay to haul the wastewater. This can be very expensive.
Many satisfied customers have found that using an ENCON Evaporator to greatly minimize the amount of wastewater needing to be hauled is both simple and cost effective. The antifreeze waste is automatically fed to the evaporator and heated to a boiling temperature. The water is driven off as water vapor to the atmosphere and contaminants that boil at higher temperatures such as metals and oils will concentrate in the evaporator tank. Typical reduction percentages for spent coolant applications are 92-94%. The dramatically reduced volume of concentrated coolant, oils, and metals are then hauled for disposal.
ENCON Evaporators use 316L stainless steel as the standard material of construction for wetted parts in our Thermal and MVC product line. This material of construction is appropriate for most coolant applications. Higher alloys may be considered in an atypical and more corrosive application of low pH and relatively high inorganic chlorides.
Improving Cost Effectiveness Through Evaporation
Antifreeze wastewater often contains water soluble oils which are emulsified with water to make a homogeneous mixture. These oils will break out of the solution or emulsion upon heating in the evaporator and will float to the surface once the boiling stops. This oil can easily be decanted in the ENCON Thermal Evaporator either manually using the oil weir or automatically by using the optional auto-decant package. It is often the case that this decanted oil can be sold or used as waste fuel further improving the cost effectiveness of evaporation as a spent coolant minimization method.
How do I determine if my wastewater is appropriate for evaporation?
The centerpiece of our consultative approach is the wastewater qualification process. Not all waste streams are good candidates for evaporation. We believe it’s better to find that out in our laboratory than on your factory floor.
This analysis also helps determine materials of construction and allows us to determine operating procedure recommendations. If more detailed analysis of specific parameters is needed, ENCON can prepare appropriate samples and send them for outside lab analysis for a nominal cost (prices for analytical tests vary).
Once the analysis is complete, your ENCON Sales Engineer will deliver a report detailing the results to you. This report includes material of construction and pH adjustment recommendations, if needed. This allows you to make an informed decision if an ENCON evaporator is right for you.