Sand filters, drum filters, disc filters

Filtration & Microsieving

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What is filtration and what is the decisive difference to micro-sieving


sand filter

Backwash or continuous filters? Which is better for my individual application? Where's the difference?



What can be achieved with the respective methods?



Filtration (also called filtration, filtering or filtering) involves the separation of solid particles, macromolecules, microorganisms, viruses or droplets from a fluid using a filter medium. The fluid can flow through the filter medium while the components of the fluid to be filtered that are to be separated are held back by the filter medium. The permeation of the fluid through the filter medium is associated with a pressure difference. The fluid to be filtered can be gaseous or liquid. It can be a solution, a suspension, an emulsion or an aerosol. Filtration is one of the mechanical separation processes. Since membranes are often used as filter media, there is a close connection with membrane technology. Classic filtration processes driven by pressure differences across the filter medium are usually distinguished from other membrane-based separation processes, such as reverse osmosis and pervaporation, and from chromatographic processes used for the preparative purification of mixtures of substances, such as column chromatography.

sand filtration

Chemische Wasseraufbereitung

Sand filters are used, among other things, for drinking water treatment (slow sand filters and/or quick filters) or for further cleaning of waste water by separating suspended matter. Sand filters are arranged as the final cleaning stage behind the systems for biological and chemical wastewater treatment. Sand filters as a post-cleaning stage after "technical" small sewage treatment plants are a very effective means of improving the flow before it is discharged into sensitive receiving waters. Their effect consists in the most extensive retention of suspended matter, a reduction in BOD, COD and ammonium nitrogen and in ferrous soil material in a certain phosphorus elimination. In addition, there is an equalization of the discharge, which is particularly desirable in the case of impounded aeration plants, and the certainty that short-term operational disruptions in the technical system do not immediately affect the receiving water. Post-cleaning sand filters are similar in structure to the filter chamber or the plant beds and, if they are open, are usually planted with reeds etc. or over time, over time, growth of different composition occurs due to seed accumulation.


Continuous operation has numerous advantages compared to traditional backwash sand filters. With conventional sand filters, the particles are collected in the sand bed. This leads to an increasing pressure drop until eventually the sand has to be cleaned by backwashing before cleaning can continue. The time between backwashes can be very short. This reduces the effective operating time. It was only with the development of DynaSand's continuous sand filter technology that an optimal solution for a continuous water and wastewater treatment process was found, which offers a constant filtrate quality even with a high surface load.


DynaSand improves the process
• No first filtrate, but always pure filtrate of high quality
• No shock loads during wash water treatment
• Tolerates high levels of suspended matter without pre-treatment
• Low pressure drop
• Low energy consumption
• Low monitoring and maintenance costs
• No downtime for backwashing
• Little need for space

DynaSand simplifies the system
• No backwash pumps required
• No flushing water tank required
• No collection tanks required for used rinse water
• No need for automatic backwash valves
• No scavenging air blowers required
• No nozzles in the filter that can clog
• Only one filter medium
• System that is easy to design and maintain
• Simple extension for biological treatment

Examples of industrial applications
• Metal processing
• Wash water recycling
• Process water
• Side stream filtration of cooling water
• Tinder residue
• Chemical processes
• Ideal for pre-treatment in place of gravity filters

Filtration and microsieving of water


Water is a vital resource that is vital to human beings. In order to ensure that water is clean and safe for consumption, various treatment processes must be used. Filtration and micro-sieving are two important processes used in water purification to remove contaminants and particles. In this paper, we will delve deeply into the concepts of filtration and microsieving of water and explain their importance in water treatment.

1. Filtering:

Filtration is a physical process of passing water through a filter media to remove unwanted substances. The filter medium can be made of different materials, including sand, activated carbon, gravel or special membranes. The choice of filter media depends on the type of contaminants to be removed from the water.

There are different types of filtration techniques including sand filtration, activated carbon filtration and membrane filtration. In sand filtration, water is passed through a layer of sand, removing larger particles and contaminants. Activated carbon filtration uses the adsorbing properties of activated carbon to remove organic contaminants and odors. Membrane filtration uses porous membranes to retain particles, bacteria and viruses to produce clear water.

Filtration plays a crucial role in removing suspended solids, turbidity, sediment and various contaminants such as pesticides, heavy metals and microorganisms. It is an important step in water treatment and is used both in large-scale waterworks and in smaller household appliances such as water filters.

2. Micro-sieving:

Microsieving is a process based on filtration technology, but specifically aimed at removing microscopic particles and microorganisms from water. It is often used in combination with other cleaning processes such as filtration and disinfection to ensure comprehensive water treatment.

Microsieving uses fine filter media, often in the form of membranes that have microscopic pores. This pore size can vary depending on the application and ranges from a few microns to nanometers. The water is forced through the membrane with pressure or vacuum, which means that particles, bacteria and viruses that are larger than the pore size are retained.

Microsieving is extremely effective in removing pathogens such as E. coli, Cryptosporidium