Above Ground Oil Water Separators

10 gpm - 30 gpm  (2 - 7 m3/h)

Our "low flow" series offers an industrial-duty design in a compact size.  This separator series is ideally suited for smaller vehicle wash stations.  These separators are also well suited for wastewater from small sumps, small stormwater treatment applications, groundwater pump and treat systems, and various other applications.  Our "low flow" series incorporates the same features in our standard sized separators that have helped Mercer build its sterling reputation--in a compact design.

50 gpm -100 gpm  (10 - 25 m3/h)

A step above the "low-flow" series, is our 50-100 gpm family of units.  This separator series features a true "V-shaped" coalescer which incorporates a full-width Chimney-Zone™ (zero velocity solids settling area) designed to process solids down and out of the coalescer.  A coalescer design which processes the solids out of the coalescer, instead of simply filtering the solids through, will produce cleaner effluent and for much longer intervals between required maintenance.  This family of Compliance Master separators is designed for a broad range of applications including the Food and Chemical industries (that require high efficiency while properly handling the solids present in the wastewater).

This is truly where the Mercer advantage shines.  Here, the actual field performance approaches the "theoretical" calculations produced during the design and engineering stage.  It's all about solids removal and a separator's ability to handle and process solids well; allowing very long, efficient run times between routine maintenance requirements.

150 gpm - 300 gpm  (35 - 70 m3/h)

This series bridges the gap between "small" separators and "large" separators.  It is with these "in-between sized" separators that the materials of construction become an important consideration based on performance and price.  Whether it is an environmental engineer that understands the complexities when dealing with certain applications, or a concerned maintenance professional trying to avoid the past problems of corrosion,the choices are very important in the long-term "cost of ownership".  Mercer International builds separators of various materials of construction, including epoxy-painted carbon steel, marine-grade aluminum, 304L and 316L stainless steel, as well as other metal alloys.   We also offer heavy-duty, reinforced plastic tanks, such as polypropylene to help combat corrosion in extreme conditions.

400 gpm - 600 gpm (90 - 140 m3/h)

As flow rates become larger, the inherent design advantages of the Multi-Pack coalescer become vital for maintaining high efficiencies within reasonable maintenance intervals.  With oil water separators of this size, it quickly becomes apparent how the Multi-Pack flat-plate, herringbone design enhances performance.  Why is this important?  Simply stated, large units have large coalescers which are difficult to lift and maneuver for cleaning.  Removable, flat-plate coalescers with a herringbone coalescer plate configuration and built-in Chimney Zone settling features need to be cleaned much less often; saving both time and money. This greatly reduces th overall "cost of ownership".  The unique design was first embraced by the Electric Utility marketplace over 20 years ago.  At the 400-600 gpm size range the ability to process solids out of the coalescer, instead of simply trapping them in the coalescer (like a coarse "filter"), is a system benefit that both the environmental and maintenance departments continue to appreciate. 

We are often called upon by the Electric Utilities and their Consultants to provide our separators in a "plug and play" skid, pre-assembled and pre-wired, ready for immediate operation.

750 gpm - 1000 gpm  (175 - 225 m3/h)

As the flow rates become larger, the importance of dedicated settling (solids) and rising (oil) zones become critical to obtain a truly non-fouling design.  Not only do the Chimney Zones process oils and solids out of the coalescer, they naturally create an break in the coalescer plate, providing shorter plate widths in the flow direction.  Shorter plate widths yield a lower "equivalent diameter" which is a measure of how a coalescer plate configuration will perform with solids present.  In a large separator with a standard-type coalescer, solids particles entering the coaleser, say at the upper left-hand portion of the coalescer (in the entry area view), will have to slide down the coalescer plate for up to 6-10 feet (or more) until the solids finally exit the plate pack at some lower left portion of the coalescer, where theoretically the solids are to be processed out of the coalescer.   However, with plate lengths that long in most typical coalescer designs (with lots of nooks and crannies) the likelihood of solids actually being processed out of the coalescer is quite low. Therefore fouling increases dramatically.  Our short plate-width design reduces the fouling problems significantly. 

Over 1,000 gpm (225 m3/h)

Mercer supplies shop-fabricated units as large as can be shipped (up to 5,000 gpm or more).  These are typically custom designed units with various sizes and shapes to best meet our client's field conditions. 

We also supply various flow configurations to maintain high efficiency and aide in maintenance procedures.  Units in this size range are typically designed to have the wastewater internally split into two flows within the unit.  Our "split flow" design feature best utilizes the separator tank to reduce the velocity in half through the coalescers.  This is done in order to maintain our stringent design criteria even at very large flow rates.  Our "split flow" design also offers the end user the ability to shut half of the separator down for maintenance while still allowing the other half to remain in operation.

For our largest separators, we design a "double-split flow" system allowing the most efficient use of coalscers and tank volume, enabling the end user to obtain maximal results (as shown on photo on left).