.:: Ultrafiltration  System ::.

Ultrafiltration is used for the separation of suspended solids, colloids, bacteria and virus. This technique uses membranes with pore size between 1-100nm.

Types Of Membranes Used In Ultrafiltration:

There are 4 membranes geometries:

• Spiral wound module: this design tries to maximize surface area in a minimum amount of space.  It is the less expensive but more sensitive to pollution due to its manufacturing process. It consists of consecutive layers of large membrane and support material in an envelope type design rolled up around a perforated steel tube.
• Plate and frame module: it is normally used for bad quality water. They are set up with a stack of membranes and support plates.
• Tubular membrane: Generally used for viscous or bad quality fluids. These modules do not need a preliminary pre-treatment of the water. As the feed solution flows through the membrane core, the permeate passes through the membrane and is collected in the tubular housing.
  The main drawback is that the system is not very compact and has a high cost per m2 installed and it is not very compact. Diameter’s tube is generally between 4 and 25mm.
• Hollow fiber membrane: The modules contain several small (0.6 to 2 mm diameter) tubes or fibers. As the feed solution flows through the open cores of the fibers, the permeate is collected in the cartridge area surrounding the fibers. It can carry out the filtration in two ways, either “inside-out” or “outside-in”

The ultrafiltration plant uses hollow fibers to take particulate matter out of the water. The walls of the fibers are porous, letting water through and keeping the particles behind.

A cross section of an ultrafiltration vessel shows the thousands of hollow fibers packed inside.

A powerful microscope shows the tiny holes in the walls of a fiber. Like a kitchen sieve, they let water through and leave larger material behind.

While these fibers are tiny, there are plenty of them. About 9,600 fibers are in one vessel, and there are four vessels in one long module. The plant has 28 vessels on each ultrafiltration unit, and there are 40 of those units in the new plant. That means there are about 43,008,000 fibers cleaning the city’s water.

 Ultrafiltration plant for Low, Medium and High turbidities

High resistance, low fouling outside-in membranes

All equipment mounted on stainless steel 304 skid

Standard control with micro-controller and turbidity display

Advanced control with flow, pressure, differential pressure and turbidity transmitters for data monitoring,normalisation and SCADA.

Integrity test

The system includes:

  Feed pump with frequency control SS 316
  Self cleaning filter 50 -200 microns
  UF modules Hollow fiber outside / in in dead-end or   cross-f   flow configuration 
  Backwash pump
  Air blower
  Chemical dosing stations for chemically enhanced backwash
  Standard or advanced instrumentation .

Three UF plants type:

Low turbidity < 5 NTU
Medium turbidity < 20 NTU
High turbidity < 50 NTU

Ultrafiltration Units

One of the 40 water purifying units inside the Ultrafiltration Plant at Columbia Heights.



Altogether, these fibers create a surface area of 1,669,000 square feet. That’s larger than the area the Pentagon building covers. If put end-to-end, these fibers would stretch more than 40,000 miles, or about 1.6 times the circumference of the earth at the equator.

All of these fibers produce a lot of water. In just one day, the ultrafiltration plant can produce up to 70 million gallons of clean, drinkable water. At that rate, it could fill Lake of the Isles in a little more than four days.

The new water plant will take impurities as small as 0.03 micrometer (µm) out of the water you drink. To give you an idea of how small that is, the table below lists the size in microns of a number of familiar small items:

Ultrafiltration Plant will remove microns as small as 0.03 micrometers (µm)

Although ultrafiltration removes nearly all viruses from the water supply, a fraction of them cannot be completely screened out. However, the threats posed by these pathogens are mitigated by chlorine treatment.

Dissolved salts and minerals are also small enough to remain in the water after ultrafiltration. These compounds are desirable, since they contribute to the taste of our water. Mineral content is also added to the water to prevent pipe corrosion that would otherwise take place as the water makes it to customers.