TRANSVERSE-FLOW MODULE FABRICATION DEVELOPMENT
931/1/01
July 2001

Executive summary

Introduction

Membranes are incorporated into devices referred to as modules to allow them to be engineered into a process. In the case of capillary membranes, there are two conceptually different module designs available. The one design, by far the most commonly encountered, is the so-called axial flow device. In this design, which resembles a tube-within-tube arrangement, the feed flow is directed either axially along the lumen of the membranes, or axially along the outside of the membrane. Depending on the design of the membrane, filtration may occur either from the inside to the outside, or from the outside to the inside.

In transverse-flow modules, the flow is directed perpendicular to the membrane axis. The feed flow is directed along the central channel, and the permeate is collected in the four permeate manifolds at the edges of the module. This project involves the development of techniques to produce transverse flow membrane modules and methods to characterise such modules.

The incorporation of membrane technology to complement biological treatment of industrial and municipal effluent is one of the most rapid areas of membrane technology development. RSA once had the edge with their anaerobic digestion ultrafiltration (ADUF) process that was developed in the late 1980s. This project considered the development and characterisation of a special housing for capillary membranes (the transverse-flow bioreactor) for use in laboratory scale experimentation with bioprocessing.

Project aims

The programme had the following objectives:

• The development of transverse-flow membrane bioreactors (MBRs) useful for the small-scale point-source treatment of biodegradable effluents, the production of enzymes for the treatment of non-biodegradable noxious effluents or contaminated soil, or the biotransformation of objectionable species in effluents into useful products.
  • The work will concentrate on the development of MBR fabrication technology that will enable MBRs of different design to be manufactured without incurring expensive retooling costs.
  • The fabrication approach adopted will enable membranes of various diameters and materials of composition to be incorporated into the module.
  • The fabrication approach developed must lend itself for the large-scale production of both laboratory and larger sized modules.
  • The MBR end product must be simple, reliable, low in cost, robust, leak-proof and sterilisable.