Reverse osmosis

== Landfill leachate purification ==
{{Unreferenced section|date=May 2023}}
Treatment with RO is limited, resulting in low recoveries on high concentration (measured with [[electrical conductivity]]) and membrane fouling. RO applicability is limited by conductivity, organics, and scaling inorganic elements such as CaSO<sub>4</sub>, Si, Fe and Ba. Low organic scaling can use two different technologies: spiral wound membrane, and (for high organic scaling, high conductivity and higher pressure (up to 90 bars)), disc tube modules with RO membranes can be used. Disc tube modules were redesigned for landfill [[leachate]] purification that is usually contaminated with organic material. Due to the cross-flow, it is given a flow booster pump that recirculates the flow over the membrane between 1.5 and 3 times before it is released as a concentrate. High velocity protects against [[membrane scaling]] and allows membrane cleaning.

===Power consumption for a disc tube module system===
[[File:Disc tube module and Spiral wound module.png|alt=Disc tube module and Spiral wound module|thumb|Disc tube module with RO membrane cushion and Spiral wound module with RO membrane]]

{| class="wikitable"
! colspan="4" |Energy consumption per m<sup>3</sup> leachate
|-
|name of module
|1-stage up to 75 bar
|2-stage up to 75 bar
|3-stage up to 120 bar
|-
|disc tube module
|6.1–8.1 kWh/m<sup>3</sup>
|8.1–9.8 kWh/m<sup>3</sup>
|11.2–14.3 kWh/m<sup>3</sup>
|}