The first question you will probably ask is, "Why should I buy the Hydrasep® oil water separator?" The answer is that the Hydrasep® has the capability, dependability, and versatility to meet your needs, and is no longer "one of the best-kept-secrets on the market today" (as described by an official after witnessing the Hydrasep® in operation). Its performance is unsurpassed on the market today, and Hydrasep, Inc. wants to provide you with any information you need in deciding if you would benefit by installing a Hydasep® oil water separator.

An oil water separator is a primary treatment device. It is usually the first device, short of a sediment basin, to receive the waste water. Therefore, it can be exposed to a flow that will vary in rate and in oil concentration. In most applications the separator will be of the non-mechanical gravity type. Criteria for good design of oil water separators should include: effectiveness, proper inlet design, solids handling capability, enhanced separation, separate oil removal section, and clean water section.

Effectiveness:

The separator should be able to maintain its effectiveness at separating the liquids even when subjected to sudden variations in flow rate and concentration. It should be designed to handle the anticipated flow rate and contaminant concentrations under normal operation. It should also be capable of accepting flow rate increases up to 125% of rated capacity for a short duration without causing remixing of the oil/water interface. In addition, it should be capable of treating an upset where the quantity of pure oil may be 10% of the volume of the separator.

Proper Inlet Design:

The inlet to the separating section should be configured to uniformly distribute the flow and to prevent disturbing the oil/water interface.

Solids Handling:

Liquid mixtures introduced into the separator may contain entrained settleable solids. The design should allow these solids to settle prior to the introduction of the mixture into the separating section.

Enhanced Separation:

The separating section should be configured to accelerate separation. Enhanced separation may be achieved by reducing turbulence and controlling the velocity profile. It should not only prevent remixing at the oil/water interface and, but also stabilize it. This may be achieved by keeping the water flow parallel to the interface, i.e., never inclining it upwards.

Separate Oil Section:

The separator should be equipped with a separate compartment where oil may be removed without disturbing the interface in the separatiing section, and where the flow within the separator will not disturb the oil removal operation.

Clean Water Section: A final compartment that is isolated from the other sections should be provided in the separator to receive the clean water and to prevent any possible remixing of the separated components. This section should be designed to control the system hydraulics and regulate effluent discharge.

An API (American Petroleum Institute) separator is designed using Stokes' Law to determine the residence time required for particle rise. API recommends that turbulence should be controlled and that the horizontal flow velocity should not exceed 3 ft/s. It recommends a channel depth of 3 to 8 ft and a channel width of 6 to 20 ft with a depth to width ratio of 0.3 to 0.5. API also recommends a minimum channel length of 5 times the width. Based on API's recommendations, the minimum design Reynolds number for flow through the separator is in the range of 400 000. This is 40 times the transition to fully turbulent flow through a tube.

In the inclined plate separator depicted above, the oily water mix enters from the left and flows through the plate bundle. The plates in the bundle are usually set at an angle around 45°. As oil builds up in the separator, it fills the upper passages in the bundle causing higher velocities through the lower plates. As the liquid exits the plates, it is directed at the interface. Directing the water at the interface causes remixing of the oil, especially if there is a rag layer, with the exiting water. This remixing becomes more pronounced as the oil layer gets thicker. Dirty water will have less passages to go through, increasing its velocity and remixing ability.

Filter media are used in all aspects of liquid and gas treatment to remove low concentrations of particulate matter from the carrying fluid. All filter media are similar, in that particle removal is accomplished by preventing a particle of a given size from passing through a screen, or mesh, of a given opening. The filter opening size is usually defined in micrometers, µm, often referred to as microns, where a micron equals 0.001 mm which converts to an opening of 0.000 039 in. A human hair averages 0.003 inches in diameter, or 76.2 µm. Most filters are sized to remove particulates ranging in size from 40 to 150 µm and are considered as tertiary treatment devices. Rapid clogging occurs if high concentrations of particulate matter are introduced into the filter. Therefore filter media are best used for polishing the stream.

The Hydrasep® Advanced oil water separator is unsurpassed in its reliability of operation for the removal and recovery of all types of oils from process and waste water. Design features include a partitioned inlet section that prevents solids from entering the separator section, a vertical plate separator section that is inherently non-clogging, a partitioned oil removal or pumping section, and a sealed clean water compartment. The Hydrasep® does not require the use of filter meshes, which eliminates maintenance and replacement costs. The Hydrasep® can easily be incorporated as an in-line separation device in a multitude of applications.

Yes. The Hydrasep® is designed to allow for automatic and/or manual pumping of recovered oils from the unit, without water. The automatic operation uses state of the art programmable controllers with a surface mounted pump.

Extensive testing of the Hydrasep® has proven that the increase in moisture content is less than 5% in the recovered oils. In many applications, recovered oils or fuels will remain within ASTM allowable moisture content limits for that particular petroleum product, and can be sold or recovered. Hydrasep has separated crude oil from produced water from an ESP equipped well whereas the recovered crude met pipeline quality requirements without further treatment.

It is recommended that recovered oils, such as diesel fuel, be analyzed prior to re-classification. In many instances, however (referring to related codes), recovered oils can be reused, recycled or burned for heating purposes.

As previously stated, the Hydrasep® is designed specifically as an in-line separation device. It is versatile and is adaptable to treatment of any mixtures regardless of their source whether it be storm water runoff, waste from petro-chemical, metal processing, crude oil and mining, food processing, and/or transportation industries. The Hydrasp can, in many instances, be incorporated into a process with minimal modifications and using existing piping, pumps, and other resources.

Yes, Hydrasep, Inc. also offers the Hydrapass® Bypass Basin for large area surface run-off applications such as parking lots, airport tarmacs, and equipment storage. Facilities that have a low probability of oil spills will gain the economy of design and installation when the collected oils are washed off with the first flush. The separator can be sized to handle the first flush event, and all run-off greater than that may be safely by-passed.

Our definition of maintenance free refers to the fact that the Hydrasep® has no internal moving parts or filters that must be serviced on a periodic basis. In most applications equipped with a GN series controller, we recommend a monthly inspection of the control unit only, and an annual visual inspection of the separator. This annual inspection requires the removal of three manway hatches and observation of the liquids within these sections. The annual inspection should take 30 to 60 minutes, depending on the type and location of the installation.

We believe Hydrasep® provides the operator with the most dependable and lowest maintenance separator unit manufactured to date. It offers combines reliability with ease of maintence.

The Hydrasep® continues to efficiently remove oily components from water even when up to 50% of the separator's liquid volume is filled with oil. This feature allows the operator time to schedule removal of the captured oil without shutting down operations.

Hydrasep recognizes that the separation and recovery of immiscible liquids such as oils from water requires the application of specific technologies that are not readily available. In many industrial processes, field testing must be conducted. Hydrasep provides rental equipment for on-site testing and evaluation.