Water Oil Separation 101

Emerson Paynode
March 11, 2013 — 1,843 views  
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Industrial pollutants in rainwater runoff and storm sewer systems have degraded the environment so much that the Environmental Protection Agency (EPA) has issued the National Pollution Discharge Elimination System (NPDES) Regulations for Storm Water Discharge (40 CFR 122) for industrial facilities discharging storm water. Industrial facilities must find a way to separate grease, oil, and other pollutants out of water runoff to meet federal, state, and local requirements.

Engine and lubricating oils, as well as machinery coolants, can be separated from water, not only to comply with federal requirements, but also to protect other equipment and to recover and reuse the liquids, thereby increasing cost savings. Oil in washwater and coolant reservoirs can also be removed to extend the life of these liquids.

For companies that generate oily wastewater from the use of petroleum products, a water-oil separator can be a practical and effective way to treat wastewater to an acceptable level of discharge to a sewer system. Because water and oil do not mix well, and as oil floats because it's less dense than water, effective treatment can be achieved if the correct water-oil separator is installed, and routine maintenance is practiced.

A standard water oil separator is a large-capacity, underground cement vault installed between a drain and the connecting sewer pipe. The vaults are designed with baffles to trap sediments and retain floating oils. The large capacity of the vaults not only makes for convenient storage, but also slows down the wastewater, allowing oil to float to the surface and solid material to settle.

Be careful, however, when handling water oil separators. They can be costly to maintain, and if not properly managed, can pollute the surface and ground water and lead to costly violations. To make sure your water oil separator works properly, make sure to eliminate contaminants, wash without detergents, and minimize loading. Do not rely on your water oil separator to handle wash water from fuel, coolant, solvent, oil, or paint spills. Instead, clean up spills when and where they occur.

If you do not have the resources for a water oil separator, you can try to install water quality inlets instead. Water quality inlets (sometimes referred to as oil and grit separators) are underground multi-chambered tanks designed to remove sediments, and to a lesser degree, floatable liquids. The main advantages of water quality inlets lie in their unobtrusiveness, compatibility, and easy access.


Emerson Paynode