Dissolved Air Flotation Clarifier (DAF) or Oil-Coalescing Separator (OCS)?
Previously, M.W. Watermark posted a blog topic discussing the differences between a Dissolved Air Flotation Clarifier (DAF) and a Slant Plate Clarifier (SPC), and the types of applications best suited for each.
Click here to read, “Slant Plate or Dissolved Air Flotation (DAF) Clarifier?” on our blog.
We’ve heard that our customers also are interested in a comparison between DAFs and Oil-Coalescing Separators (OCS).
The M.W. Watermark Oil-Coalescing Separator is very effective in removing non-emulsified oils, grease, diesel, gasoline and fuels from a waste stream. The DAF removes those contaminants as well as suspended solids, metals and non-soluble BOD from a waste stream. Both have a compact design, which is one of the reasons why they are so popular with engineers and end users.
Oil Coalescing Separators
The M.W. Watermark OCS is designed to remove free and non-emulsified oils, grease, diesel, gasoline and fuels from a waste stream, resulting in an effluent quality of 10 mg/l or less of contaminants 20 microns and larger. The OCS operation is based on closely-spaced oleophilic (oil attracting) media that promotes the impact and formation of larger oil particles. As the oil droplets increase in size their rise rate to the water surface also increases.
How it works
The influent water enters the separator and flows through a tightly stacked bundle of M.W. Watermark media. The media expands the surface area of the separator giving the oil more room on which to combine (coalesce). As the oil droplets accumulate on the media and coalesce they develop into larger droplets that flow up the surface of the media, detach and rise to the water surface. Surface oil decants by gravity into a segregated oil reservoir where it can be removed from the tank. Heavier solids (solids having a specific gravity higher than that of water) will slide down the surface of the media into the sludge chamber at bottom of the tank for periodic removal. Virtually oil-free water travels under an oil reservoir baffle, over an adjustable weir and into a clean water effluent chamber. The water is discharged to sewer from this chamber.
Oil-Coalescing Separators are used in a variety of applications, including wash racks, airports, automotive, bilge water, chemical processing treatment, groundwater remediation, oil production and spill recovery, parking lots, power plants, processing plants, pulp and paper mills, railroads, steel mills and utility companies.
Dissolved Air Flotation Clarifiers
The M.W. Watermark Dissolved Air Flotation (DAF) Clarifier is designed to remove suspended solids, oils, grease, metals and non-soluble BOD from a waste stream. Clarification rates as high as 97% removal, with proper chemical pretreatment, are common. The DAF operation is based on small air bubbles attaching themselves to the contaminants in the water and floating them to the water surface for removal.
How it works
Clean water is processed through a recycle system that creates 20-30 micron bubbles. The bubbles are mixed with the incoming wastewater and attach themselves to the contaminants, which gives them buoyancy and floats to the surface. A counter current skimming mechanism continuously scrapes the “float” from the water surface and into an isolated chamber. Heavier solids that do not float settle into a sludge chamber located at the bottom of the unit. Sludge outlets are located in the sludge chamber for intermittent removal. Clean water travels under a baffle wall, over an adjustable weir and into a clean water effluent chamber. The water is discharged to sewer from this chamber.
Dissolved Air Flotation Clarifiers are used across a wide range of industries for a variety of applications, including automotive, chemical processing plants, food and beverage, fracking applications, mining and minerals, petrochemical, petroleum and gas, and manufacturing.
The M.W. Watermark Oil-Coalescing Separator uses a unique media to assist in ascending the oils and grease to the water surface for removal, while the Dissolved Air Flotation Clarifier uses flotation via small micron air bubbles to “float” the contaminants to the water surface for removal. Both have compact footprints with user-friendly designs.
M.W. Watermark offers a full line of DAF Clarifiers. We have nine DAF models available, with increasing capacities, to cover a wide range of design flow needs. Our DAF models range from a treatment surface area of 30 to 500 square feet. Our OCS models range from 10 gpm to 5,000 gpm. Each of our high-quality DAF and OCS models are assembled in the U.S.A.
Contact us today to discuss your application. Our team of experts can help assess the best equipment option for your solids separation needs.
About M.W. Watermark
M.W. Watermark wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference in the water business, and as a result, make a positive difference to our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. We also specialize in rebuilding used water treatment equipment. Together, we can make a difference.
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