Different Filtration Methods

There are various methods of filtration. We’ve talked about Continuous-flow centrifugation, Nanofiltration membranes, and CFC+ViroCap. If you’re wondering about the differences between them, read on. You may find some of them helpful or even beneficial for your operation. We also discuss why each is important and which is better for your needs. You can also compare them to other methods of filtration. You can read more about this or contact your local filtration service provider like industrial process filters Virginia for example.

Candle filters

Candle Filters come in many different types, sizes, and styles. The significant types can contain as many as 250 filtering elements and cover 200 square meters of filtering surface. Larger Candle Filters also have a diameter of 2.5 to 3 meters and may have a pressure of six bars. They are relatively inexpensive and can be set up quickly, though they can only handle the lowest levels of turbidity and iron. Therefore, some manufacturers recommend using them for smaller families.

Ceramic candle filters are made of two different containers, the upper one having a flow rate of 1-2 L per hour. A typical candle filter treatment capacity is 8 L. The lower container has a tap and lid that enables safe water to be withdrawn. These filter units can work well for homes or small businesses but must be carefully monitored. In addition, because of the potential for contamination, candle filters must be disposed of properly to prevent a fire.

Continuous-flow centrifugation

Continuous-flow centrifugation has several advantages over conventional filtering methods. For example, it is less costly and has the potential to separate solid and liquid samples simultaneously. In addition, the centrifuge is designed to run slower than the filtrate stream, which is advantageous for the low-cost recovery of valuable P2O5.

The rotor is cleaned before sampling. The rotor is surrounded by a laminar flow cabinet and can be cleaned from the outside. This allows users to check the flow rates of effluent during sampling. For monitoring effluent, flow-through photometers are very useful. If possible, you should use titanium rotors. The rotor tubing should match the rotor tubing.

Nanofiltration membranes

There are various types of nanofiltration membranes, and each of these uses a slightly different membrane. The performance of a nanofiltration membrane depends on the retention of polyvalent ions and the permeability of the material. The retention of monovalent ions depends on the ion concentration, while the permeation of non-ionized substances is dependent on the surface roughness. For comparison, the surface roughness of a commercial membrane is around 45°.

The UF process is based on using a polyethersulfone or polysulfone membrane with a pore size of 0.01-0.2 mm. This membrane removes protozoan cysts and has a low water filtration rate. It can also eliminate particulate matter, including bacteria. Nanofiltration membranes for different filtration methods effectively eliminate pathogens and other particulate materials.


A recent study used a modified glass wool filter to separate the bacteria, viruses, and coliphages present in wastewater. The filtered samples were centrifuged to separate the elute, and aliquots were taken for bacterial and protozoan analysis. Coliphages were also extracted from filter eluates. The results showed high variability between filtration methods, and they differed significantly between the two processes.

When comparing the recoveries of MS2 coliphage and enterococci, glass wool filtration showed the lowest median recovery, and the CFC+ViroCap filter recovered the highest value. The recovery of both enterovirus and cryptosporidium was higher with the CFC+ViroCap filter, and the median concentration for both filters was below detection. The CFC+ViroCap filter had the highest recovery, with averages of 900 PFU/liter. Glass wool, on the other hand, had the lowest recovery, with a median of 420,000 CFU/liter.


The UF Filtration method is based on membrane separation, and the pore size of the membrane is in the range of 0.01-0.1 um. UF membranes are porous, with a dense skin layer, small pore size, and low surface porosity. Because of these properties, UF membranes have a higher hydrodynamic resistance than MF membranes. The operating pressure for UF systems is typically two to five bars.

One of the most significant limitations of UF is the high cost of replacement membranes. This process often requires additional feed water pretreatment to avoid damaging the membrane units. UF filters are generally used as the pre-filter stage of reverse-osmosis systems. The process begins with a selectively permeable membrane mounted in a centrifuge tube. Centrifugation forces a buffer through the membrane. The protein is deposited in the upper chamber of the filter.