Membrane technology

Membrane processes are processes in which ultrafine filtration in the submicron range is carried out using a membrane. They are used for drinking water, industrial water and wastewater treatment. Depending on the filtration requirements, the following processes are distinguished:

Reverse osmosis (RO)
Filtration spectrum: divalent and higher-valent ions, can be used in drinking water for softening or sterilisation (germ barrier) 

Nanofiltration (NF)
Filtration spectrum: divalent and higher-valent ions, can be used in drinking water for softening or sterilisation (germ barrier)

Ultrafiltration (UF)
Filtration spectrum: organic molecules, colloids, salt 

Microfiltration (MF)
Filtration spectrum: bacteria, particles, suspensions

The different filtration ranges are due to the use of different membranes. The most commonly used process is reverse osmosis. Membrane processes are project-based systems that require thorough clarification of technical requirements and consultation.

A water analysis is required for the technical configuration of the system.

Please contact us to discuss your problem.

Reverse osmosis systems utilise the biological process of osmosis, i.e. the equalisation of solutions with different concentrations via a semi-permeable membrane. The process is reversible. In the reverse osmosis process, water is forced through a membrane by means of a high-pressure pump. The substances dissolved in the water (ions, particles, organic compounds, etc.) are too large to pass through these membranes. This results in permeate (pure water) on one side of the membrane and concentrate (with particles enriched in the source water) on the other side of the membrane. The desalination rates are at least 97% based on 1000 mg/l salt content of the feed water, with a standard yield of 75%. Further improvement of the permeate can be achieved by using multi-stage systems, downstream mixed bed cartridges or electrical deionisation cells. The yield can be improved to approx. 90% by using a concentrate stage to process the concentrate. Reverse osmosis systems require pre-treatment of the feed water to protect the membranes used. Water softeners, antiscalant dosing and ultrafiltration systems are often used for this purpose.

System data for our reverse osmosis systems

• 30 l/h - 40,000 l/h
• Salt retention > 97.0%
• Yield 75% - 93%
• Pre-treatment
• Softening, antiscalant dosing, ultrafiltration
• Residual hardness control via Testomat