Frequently Asked Questions


Q: Who invented VSEP?
A: VSEP was invented in 1985 by Dr. J. Brad Culkin. The original prototype used loudspeakers to generate vibration for the membrane disc stack as shown in the photo below.

Q: What promted Dr. Culkin to invent the VSEP technology?
A: Dr. Culkin developed the idea for the VSEP while working as a scientist at Dorr-Oliver in the area of separation techologies. He saw the advantages of membrane-based separations over other traditonal methods, but the membrane media tended to foul rapidly.

Q: Do you make your own membranes?
A: No, New Logic buys membranes from all of the leading manufacturers and modifies them for use in the VSEP system. We currently use over 200 different membranes.

Q: Can you use ceramic or steel membranes in a VSEP system?
A: No, VSEPs employ only polymeric membranes.

Q: What comes with a VSEP system?
A: The standard VSEP system comes with the VSEP vibratory base system, filter pack, feed pump(s), clean-in-place system, automated air-actuated valves, all interconnecting piping within our system, and a programmable logic controller (PLC) with a touch-screen interface. All of this is skid-mounted and tested on water prior to shipment to ensure an easy plug-and-play installation on-site..

Q: What is the throughput for each 84” VSEP module?
A: As a general rule of thumb:

RO = 20-50 gpm
NF = 35-70 gpm
UF = 50-100 gpm
MF = 50–150

Q: How much membrane area is in each 84” module?
A: About 1500 square feet (120 square meters)

Q: How tall is the i84 VSEP unit?

A: The overall height is about 17 feet. The recommended minimum ceiling height is 20 feet.

Q: What is the footprint of a single VSEP unit?
A: The footprint of a single module is about 4’ square. The overall footprint of a single VSEP system (with the pump/control/CIP skid) is about 16’ x 4’. To ballpark an installation size, add an additional 5’ for each VSEP module, and an additional skid for each six to eight modules.

Q: What type of floor is required for the installation?
A: A level, structural slab is sufficient. If the slope of a floor is more than 1/4 “ over the four feet of space the VSEP will sit on, we would recommend a level “housekeeping slab” be poured on top of the grade.

Q: What flow rate can be processed with VSEP?
A: VSEP systems are modular, can be arranged in parallel, and as such can theoretically process any flow rate. The feed stream is hooked up to a manifold (header) and the feed is distributed evenly over the array.

Q: What membrane type is good for what?
Reverse Osmosis = Dissolved metals, salts removal, high purity water
Nano-Filtration = BOD/COD reduction, dissolved metals, wastewater
Ultrafiltration= Suspended solids removal, product dewatering
Microfiltration = Large suspended solids removal, dewatering

Q: What is the maximum operating temperature of a VSEP?
A: The maximum temperature is determined by the membrane. Maximum temperatures range from about 60°C to 130°C (140°F to 266°F). High temperature VSEP systems can operate at 130°C with a Teflon membrane.

Q: What pH can the membranes tolerate?
A: Again, this is always membrane-dependent. Generally speaking, the more open the membrane, the better it is at extreme pH tolerance. We have filtered 54% phosphoric acid with a nanofilter and we’ve filtered 50% sodium hydroxide with Teflon.

Q: Can your membranes tolerate chlorine and/or other oxidizers?
A: This is another membrane-dependent factor. Some can take a little, others can take a lot. Most nano and RO membranes can’t tolerate much at all. Where a membrane’s tolerance to oxidizers is low, we can easily overcome this problem by dosing the feed with a small amount of a reducing agent such as sodium metabisulfite.

Q: Can the VSEP system tolerate free oil? How much can it take in an RO system?
A: VSEP systems are very tolerant of oily feed. We have filtered used crankcase oil and numerous oily wastewater streams. With an RO membrane, VSEP can handle about 10% of free oil without significant flux loss.

Q: How often do you have to clean the membranes?
A: This is a question that is nearly impossible to answer without some operating data from the particular stream in question. Anywhere from once a day to once a month is possible, with one or twice a week being the average. Pilot testing will help determine the necessary cleaning frequency.

Q: How high can you concentrate to in a VSEP system?
A: The record is 74% solids, which has been done on TiO2 and CaCO3. The real limitation is the pumpability of a given feed material at its gel point (suspended solids) or where the osmotic pressure is too high to overcome at 1000psi (dissolved solids).

Q: What is the maximum suspended solids level (TSS) you can feed to a VSEP system?
A: About 50% starting

Q: What is the pressure drop across the VSEP filter pack?
A: The answer is about 1 psi, however the question is really not relevant to our system. The reason people ask this question is because it’s important in a cross-flow membrane filtration system, as this is the major source of pump energy loss. In a VSEP system, the shear comes from the vibration, not the pump. 99% of the pressure drop occurs at the concentrate exit valve, which we can control to be whatever we want.

Lab Testing FAQ

Q: What do I get for my lab test?
A: 5-day test (membrane selection, pressure study, concentration study, cleaning study) a complete report, some basic analytical and samples of the resulting permeate and concentrate. Extensive analytical testing is available for an additional charge.

Q: How much sample do you need?
A: A bare minimum of 15 gallons. We would prefer to get 20-55 gallons.

Q: What about shipping?
A: Customers are responsible for all shipping costs. If a sample is biologically active, the sample should be chilled and shipped overnight to New Logic. In such cases, you must closely coordinate the shipping date with the New Logic Lab staff to ensure a machine and technician are available upon arrival of the sample.

Q: How long does all of this take?
A: There is typically about a one-week wait from the time the sample arrives and the start of testing. The test takes about five days to complete. After the testing is completed, the report is generated about one to two weeks later. It’s about a month from start to finish.

Q: I can’t send my sample to your facility for testing. Can we do a lab test here at my plant?
A: Yes. It’s considerably more expensive, however, as you have to lease a pilot machine.

Pilot Testing FAQ

Q: How long will it take to get a pilot machine on site?
A: Typically within a month. We have to coordinate the machine as well as the technician.

Q: Do you have explosion-proof pilot machines?
A: Yes, we have Class I Div II machines available.

Q: What is the footprint of the pilot system?
A: Approximately 3’ x 6’.

Q: What are the electrical requirements for the pilot system?
A: 208, 3-phase.

Q: What is the size of the pilot system piping?
A: ½ inch

Q: What is the pressure limitation of the pilot system?
A: 1000 psi

Q: What is the temperature limitation of the pilot system?
A: 100°C (membrane dependent)

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