What are Ultrafiltration systems?
Ultrafiltration (UF) is a membrane filtration method that uses hydrostatic pressure, to drive water through a semi-permeable membrane, similar to reverse osmosis. UF is a pressure-driven barrier that generates highly pure water, with low silt density against suspended particles, bacteria, viruses, endotoxins, and other pathogens.
What is the procedure for ultrafiltration?
Ultrafiltration treatment works by passing water through a semi-permeable membrane, and capturing larger particles and minerals on the other side.
Naturally, this membrane filter has a wide range of applications. As a result, many ultrafiltration system configurations are possible.
A: Configuration of Flow
The direction of the influent raw water in reference to the membrane orientation, can alter the operation of this system process.
Raw water rushes inward from the outer portion of a cylindrical membrane, towards the central axis. In contrast to inside-out flow, this flow pattern works well in greater total suspended solids (TSS) circumstances.
Raw water is influenced as it flows into the central space of a membrane tube, and then radially outward. This flow pattern is best when consistent hydrodynamics are required, however, it does not perform well in higher TSS situations.
The influent flow parallels the length of the membrane, but the pressure gradient across the membrane, pushes water through to the other side, and particles accumulate in a thin layer on the membrane.
- Dead-end flow
In this type of flow, the flow is perpendicular to the surface of the membrane. Filtered water travels through the membrane, but particles cling to the membrane's surface, in a thick coating.
Producing dead-end flow requires little energy, but the solid layer forms much faster, making this configuration more useful for lower contaminant concentrations, in the source water.
B: Configuration of the System
The vessel type and how the membranes are aerated are the two primary concerns, for how the system as a whole should be set up.
Most ultrafiltration treatment systems are technically submerged in the sense, that the membrane is totally surrounded by fluid, but this phrase specifically refers to systems built of enormous tanks, filled with raw water into which many membranes are lowered. The tank is equipped with the required inlets and outlets.
When a membrane is contained within a pressurized housing unit, multiple vessels are frequently joined in parallel to form systems.Each vessel has its own inlet and exit, which connects to a header, collecting the treated effluent from all of the vessels into a single stream.
Everything in an integrated system is contained within a single unit.
The raw influent is aerated in a separate tank, before being pumped to the membrane-containing tank or vessel.
C: Configuration of Membrane
The size and design of the membrane have a big impact on how the system works.
Consider a straw bundle tied together with a thin membrane folded up inside each straw. Because, the tubes are permeable, when the influent is pumped in, it begins within the semipermeable membrane, and flows across it before entering the vessel cavity.
The cavity's resulting permeate is then sent to the next treatment stage. Tubular systems normally operate only on inside-out flows, preventing the membrane from collapsing within the tube.
- Hollow fiber
This structure is comparable to a tubular system, but it lacks the membrane support that a tube vessel provides.
These systems can be used either inside-out or outside-in, but the thin, flexible fibers can break.
- Frame and Plate
It is made up of a spacer between two flat membranes that are stacked on top of one another, with some space in between. The feed water flows through the neighbouring membranes, while the filtered permeate water flows through the membranes to the spacer, which includes channels that transport it to the permeate (treated) water exit.
- Spiral wound
The feed channel transports raw water to the permeate channel, which filters it through the membranes. The permeate then spirals to the center, and exits through the outlet.
Ultrafiltration treatment is a form of membrane filtration for separating solid particles, from the liquid influent source. It can be used as a prefilter for other treatment processes, or as a tertiary polishing filter in drinking water and wastewater treatment systems.
How can we assist?
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