water membranes

One of the most efficient biocides for microorganism control in membrane systems is chlorine dioxide. High purity Solution 3000 removes and controls slime that blocks filter cartridges and membranes.

  • High purity chlorine dioxide at low doses does not damage membranes
  • Effective over a wide pH range (6-9) while chlorine is less effective at pH > 7.5
  • Quickly kills bacteria, viruses, algae, protozoans at very low dose
  • Chlorine dioxide penetrates slime to quickly kill microorganisms and remove biofilm.
  • Very low corrosivity
  • Solution 3000 ready-to-use chlorine dioxide


Solution 3000 ready-to-use chlorine dioxide

  • Safe; minimal chemical exposure to operators
  • Requires no chemical mixing
  • Easily controllable for precise intermittent or variable dosing
  • Very low capital; low maintenance
  • Reliable operation

Every membrane system is different. For help with Chlorine dioxide please contact us.

Biofilm in Membranes

One of the biggest problems plaguing the fast-growing field of membrane-based water purification is bio-fouling. Bacteria and other microorganisms secrete a polysaccharide “glue” that forms a slimy layer on the surfaces of membranes, filters, pipes and other components of a membrane system. This layer protects and nurtures bacteria and other microorganisms. Biofilm formation is especially problematic in water containing high levels of nutrients such as wastewater effluent streams. Biofilm blocks the flow of water through membranes and filters and necessitates frequent shut-down for off-line cleaning or replacement of elements. Off-line cleaning often results in damage to expensive membranes. Biofilm usually forms most quickly on the feed side of the membrane, but it can also form in the permeate stream or even within the membrane. Chlorine, hypochlorite, and related chemicals are not effective at controlling biofilm and can quickly damage membranes. Some disinfectants are only partly effective against biofilm in part because the disinfectants cannot penetrate the polysaccharide matrix. Therefore, when membrane performance is compromised by biofilm, the membrane must be taken off-line for mechanical cleaning and disinfection. During the shutdown for off-line cleaning the total system must be shut down, causing loss of production, or a secondary set of membranes must be provided, often at substantial cost. Off-line disinfectants never remove 100% of the biofilm so biofilm re-seeds itself and grows back faster after every cleaning. Published test results demonstrate that pure chlorine dioxide supplied in ready-to-use aqueous solution can remove bio-fouling and prevent its regrowth on Thin Film Composite (TFC) membranes and filters in reverse osmosis or ultra-filtration system without damage to membranes. Previous results showing membrane damage from chlorine dioxide are believed to be caused by impurities such as chlorine or chlorous acid in chlorine dioxide made at the point of use. These impurities are not present in CDG Environmental products. Chlorine dioxide can be fed at low doses either continuously or intermittently upstream of cartridge filters and membranes. Properly applied, very low doses of chlorine dioxide will control biofouling in feedwater passages, cartridge filters, both sides of the membranes, permeate water, and reject water.