Transmissivity Improvement

Membrane Technology for Transmissivity Improvement

undefinedRO Transmissivity


Membranes selectively remove dissolved species from a variety of sources including:

  • Surface water
  • Rinse water from fabric dyeing
  • Industrial wastewater
  • Landfill leachate


Demands for development of membranes with specific performance continue to increase as water quality requirements tighten and water treatment system designs become more complex. Such demands lead to development of new reverse osmosis (RO) and nanofiltration (NF)membranes with selective rejection characteristics for removal of the contaminants affecting the ability of the water to transmit light (transmissivity).  

Where UV is employed for disinfection the requirement for transmissivity improvement has become important at many facilities.

The NF membrane typically rejects only larger polyvalent cations and anions and as a result produces a very small volume of reject

Nanofiltration (NF) membranes have good selectivity for removal of naturally occurring organic compounds as well as iron. Organic material can be found in groundwater sources which have surface water intrusion, or groundwater sources which are influenced by decomposing vegetative materials. The contamination of these waters is measured in terms of color units.

Treated water from landfill leachate is another source of color in wastewater.   When this wastewater is discharged to a municipal treatment plant (POTW), color and the presence of certain organic acids affect the performance of the final ultraviolet treatment step, causing the receiving facility to require that these components be reduced or eliminated.

Dynatec has developed a number of options for color and organic acid removal.  Since each project requires different levels of removal and has different treatment requirements, treatability work is typically carried out to establish the required treatment process steps.  Typically, treatment requirements not only include color removal, but may also require the removal of COD, BOD, oil and grease, metals, etc. etc. The treatment steps may include:

  • metals and/or free floating oil
  • settleable materials removal
  • ultrafiltration for removal of suspended  colloidal materials
  • nanofiltration using several options that are available, depending on the requirements of the particular application
  • reverse osmosis for the  removal of color, dissolved solids and organics


Dynatec will carry out benchtop treatability work at their treatment lab or will provide small-scale pilot equipment that is shipped to the project site where longer term studies can be carried out.

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