AWWA ACE56191

This paper explores the process selection decisions and design considerations that have to be addressed when installing membrane filtration processes at an existing treatment works. To illustrate these considerations, examples are drawn from recent Black & Veatch projects ranging from simple treatment of groundwaters subject to contamination with surface waters to multi-barrier, multi-stage processes. Design considerations include necessary pre-treatment, hydraulic design, interface with existing control systems, impact on upstream and downstream processes including dosing systems, integrity testing and finding and repairing damaged membranes, process optimization, commissioning and waste disposal. The need for meaningful pilot testing is also discussed, again with reference to recent projects. The reasons behind the increase in use of membrane technology are also reviewed. Factors considered include regulatory drivers, Cryptosporidium oocyst removal, asset renewal, automation, future-proof technology, minimizing use of chemicals and reduced footprint to minimize construction cost and land use. Selection of the correct type of membrane is also paramount to the success of a project. The merits of micro, ultra, nano and tighter membranes are discussed with their advantages and disadvantages. Similarly, the relative benefits of submerged and encased membranes is described with reference to recent projects. The lower capital cost of submerged membranes needs to be evaluated carefully against the higher cost of pressure driven systems with the need for other supporting infrastructure so that a holistic appraisal is made. The increased cost and attention to the design of civil works and assessing the suitability of using existing structures such as clarifier basins and rapid gravity filter shells is discussed and how this can impact on existing works operation during construction. Includes 3 references, table, figure.

Product Details

Edition:

Vol. - No.

Published:

06/16/2002

Number of Pages:

9

File Size:

1 file , 320 KB