I put it as an answer as it is a plate separator used for water and waste oil
Mainly used for sewerage plants, floor waste, and recycling.

Generally, In a short form:::::SOME! run a small charge through the plates to attract the molecules and retain them, then the plates are removed and cleaned. (No doubt the usual bunch will disagree) In my workshop I have to clean mine every month and fill out a report for the Government.

Reference information:
http://oilandgas.veoliawater.com/en/expertise/our_offering/D...

Wastewater treatment equipment, water purification systems and ...
The inclined-plate (lamella) style separator provides sedimentation of suspended solids in an area that's only a fraction as large as that required for a ...
www.mancorp.com/solids_separator.html - 23k -

Treatment Plants - Lamella Plate Separator, Clarifiers ...
We specialise in water and waste water treatment plants namely lamella plate separator, clarifiers, clarifloculators, and aeration systems.
www.idswater.com/water/india/swift_tech/wastewater_treatmen... - 30k -

Industrial Water Treatment: Refining, Petrochemicals, and Gas ... - Google Books Result
by François Berné, Jean Cordonnier, Ecole ... - 1995 - Technology & Engineering - 248 pages
2.5.2.3 Lamella oil separators The principle of separating oils by means ... or waste water thanks to the manufacture of one-piece plastic plate packages. ...
books.google.com.au/books?isbn=2710806738...

--------------------------------------------------
Note added at 2 hrs (2009-02-13 07:25:59 GMT)
--------------------------------------------------

Lamella Plates Explained,

Here are some practical principles you can possibly use.

The Lamella principle (based on an old Shell Oil patent) consists of closely spaced parallel plates. In a settling clarifier, the water flows evenly through the plates from the bottom to the top. In any system that uses gravity for separation, the downward settling rate must be greater than the upward flow rate. In the Lamella, this is enhanced by applying the principle of laminar flow. Simply put, the upward flow velocity is slowest where the water contacts the plates and greatest at the point between the plates. As the water containing solids passes between the plates, the solids will move toward the surface of the plate where the velocity is reduced. This lower velocity area allows the rising solids to reverse direction and fall downward along the surface to the bottom where they are removed.

The above explanation was provided to help you understand the importance of the following: The plates must have a smooth surface, well maintained to keep them clean, or the solids can't slide smoothly downward against them. In drinking water clarification, algae can grow on the surfaces and inhibit the separation process. The plates must be smooth and clean. Secondly, the plates must be evenly spaced. Sometimes, fiberglass plates will structurally fail after years of submersion and sag against each other. If this happens, the lamanar flow is destroyed and they no longer function properly. If the plates are unevenly spaced and have a rough surface from long submersion, they should be replaced.

The simple principles described above apply to both settling clarifies and DAF (dissolved air flotation) which often use laminar flow. Some people have removed the plates and tossed them aside, saying it works fine without them. That is somewhat true, but the flow capacity is greatly reduced when you do that.

Keep the plates clean and evenly spaced for best performance. After that, it is a matter of proper chemistry for floc formation, maximum settling rate of solids and keeping within the design flow parameters of the equipment.
In recent years a small mili voltage is applied to help with the collection /separation of the solids, depending on Manufacturers and uses.

--------------------------------------------------
Note added at 2 hrs (2009-02-13 07:27:47 GMT)
--------------------------------------------------

link to the above article..
http://www.waterandwastewater.com/cgi-bin/yabb/YaBB.pl?num=1...

--------------------------------------------------
Note added at 11 days (2009-02-24 13:25:00 GMT) Post-grading
--------------------------------------------------

Thank you