FM Modules - UF

Rochem – FM modules (Flat-Membranes) have been developed especially for the seperation of bacteria, viruses and fine solids from water and wastewater with a high fouling potential. Most importantly the modules exhibit low specific energy consumption at high and steady state fluxes.

Rochem membrane filtration plants are compact and based on a standardized design. The combination of a hydrodynamically optimised module with a standardized and steadily improved plant design guarantees a high and stable productivity.
Princilple of Ultrafiltration

Ultrafiltration membranes form for bacteria and viruses and a stable operation for long periods without use of chemical cleaning agents. In addition the wide spectrum of commercially available flat sheet membranes for ultra-filtration (UF) allows the optimal selection of a membrane for each individual application.

Module advantages

Ultra Filtration Membrane

  • Safety barrier for pathogenic microorganisms like viruses and bacteria.
  • Seperation of colloids and dissolved organics of high molecular weight.
  • Long service lifetime of membranes since internal pore blocking is unlikely in case of UF.
  • High availability of Units.

Low operating cost

  • Low specific energy consumption.
  • Fully automated operation.
  • High water recovery rates up to 98%
  • Simple pant-assembly
  • Simple membrane replacement.

Low Investment cost

  • Standardized plant design
  • Optimum material selection(low cost plastic where possible)
  • Minimum number of sealings.
  • Simple system design by modular construction

Open feedside channel

  • Long operation intervals between flushing/ cleaning because of the high module loading capacity for separated solids.
  • Straight through flow without dead zones.
  • No prefiltration required.

High Degree of flexibility

  • Adaptation of feedside clearance (Distance between membrane cushions) to feed concentration
  • Wide choice of membranes. (UF,MF,NF)
  • Dead end and cross flow operation possible.

Environmental Aspects

  • Construction material can be recycled.
  • Minimized chemical consumption
  • Minimized concentrate disposal bacause of the high water recovery rate.

Simple Cleaning

  • Feedside airbubble flushing: high shear stresses of the two phase system air/water.
  • Permeate backflushing possible.


Low concentration Solids (Dead End Operation)
In case of low ssolids concentrations in the feed, for example in the production of drinking water from surface water, the distance (free path) between the membrane cushions can be rather small. The resulting high packing density in combination with the energy saving dead end operation guarantees a cost efficient operation of the system.

The separated and deposited solids are removed from the membrane surface by intermittent air bubble injection. Feedside air injection creates a two phase system and in turn very high shear stresses at the membrane surface. As a result the membranes are scrubbed. In addition to this very efficient feedside cleaning permeate backflushing can be applied.

  • Pathogens and phosphates removal from sewage.
  • Pretreatment for Reverse osmosis units.
  • Disinfection of Drinking and Surface Water
  • Treatment of Filter backwashing effluents.
  • Water recycling in the paper industry
  • Replacement for multilayer filtration systems.

High solids Concentration (Cross-flow operation)

In case of high solid concentrations in the feed, for example separation of water from the effluent of actyivated sludge bioreactors, a larger distance between the membrane cushions is optimal in combination with cross-flow operation.

The hydrodynamic shear stresses of the feed flow control efficiently the formation of the gel layer (deposit layer) on the membrane the module can be operated with high steady-state fluxes.

  • Treatment of biological effluents
  • Chemical wastewater treatment
  • Grey water treatment on ships
  • Classic ultrafiltration applications
  • Seperation of emulsions.



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