Basic Membranes an Operators and Owners Introduction to Membrane Bioreactors, sizing Criteria, Surrounding Systems and Expected Trends in the Industry.

While designing membrane bioreactor facilities over the past four years, I have listened to many presentations and toured numerous facilities. The presentations have focused on the membranes and its performance ability. The tours and design experience has given me the opportunity to see that the membrane process is more than just membranes. Critical to the membrane design is the site specific conditions and the numerous support systems that compliment and surround the membrane units.Different from the many papers and presentations that I have seen or heard, this paper provides the operator an introduction to membranes, critical site specific sizing criteria, and the many systems that compliment the performance of membranes and surround the actual membrane units. The paper has been prepared in the perspective of the Operator and Owner by breaking out each support system and its function. Operators, Owners, Engineers and the Manufacturers need to be more attentive to the surrounding systems of each design as membrane plants become larger and the application more varied. This paper provides an Operator and Owner a basic understanding of membranes, systems surrounding the membranes and the aspects of a membrane design.Initially, various membrane classifications and applications will be defined. From this point the focus will move toward Membrane Bioreactors. The reader is introduced to typical membrane process configurations and variations with respect to conventional activated sludge processes. Basic terminology is provided as well as the mechanics of flat plate and hollow fiber membranes.After providing the reader with a basic understanding of membranes, the membrane activated sludge process is placed in the overall plant. Preliminary treatment is discussed with the various types of equipment available for screening and grit removal. The importance of preliminary treatment before a membrane bioreactor and the critical design parameters of the equipment are reinforced. The next process, the membrane bioreactor is examined based on critical sizing criteria. Differences are discussed between NPDES permit sizing criteria, membrane activated sludge process sizing criteria and possible hydraulic configurations. Types of post treatment facilities are then presented. The membrane bioreactor impacts on the sludge process and sludge production completes the plant overview.The paper focuses next on the systems that surround and support the two leading membrane manufacturers, GE – Zenon and Enviroquip, a Division of Eimco Water Technologies. This comparison identifies the similarities and differences between the two types of membrane processes, since each are a different type of membrane, hollow fiber and flat plate respectively. Surrounding support systems include:the return activated sludge systems,aeration blower system,membrane blower system,membrane units,permeate system,maintenance system,chemical systems, andperformance monitoring systemsWhen appropriate, illustrations or schematics are provided of each support system with a summary of components, function and purpose.The paper is concluded with a general comparison between the membrane support systems, a general philosophy of each membrane manufacturer's approach to the process technology, a global design approach to assist the Operator and Owner during design and what is possibly on the horizon from the manufacturers.