by F. Scott Davis
Membrane technology continues to undergo improvements and refinements, increasing its usefulness to municipal and industrial users alike. At the same time, the steadily decreasing cost of membranes has made the technology all the more attractive. Because of these factors, a growing number of municipalities and industries engaged in treating water, wastewater, or both can benefit from membranes.
For utilities or industries looking to do just that, a critical factor involves establishing a relationship with an architecture and engineering (A&E) firm that is experienced with membrane technology and the process of developing specifications for membrane-based treatment systems.
For industrial users that require high-quality water supplies, membranes offer a proven means of ensuring such requirements are met. When it comes to municipal drinking water, the capacity of membranes to facilitate the use of previously unusable water sources, including brackish groundwater and seawater, is facilitating new options to help meet the growing demand for water in many urban areas. Within the field of municipal wastewater, membranes continue to attract interest, particularly in applications involving membrane bioreactor (MBR) treatment systems.
Technological Expertise
Membranes differ from conventional treatment approaches in certain key ways, both historical and technical. Conventional treatment systems such as filtration or ion exchange link unit processes whose designs have been in use for decades. Over the years, the various aspects of such systems have undergone improvements in terms of their controls, media types, and internal components. However, the basic operational concepts have been around for a long time.
Membrane applications, on the other hand, date back only to the 1970s. Not only are membranes newer than their conventional counterparts, but they are more complex. Moreover, the science of membrane technology followed a novel developmental path, conforming entirely to neither the water nor wastewater industries. As a result, the membrane field has developed its own unique terminology.
Although complex, membranes offer unparalleled benefits in terms of better water quality. Given this complexity, municipalities and industries that are considering membranes as a means to meet their water and wastewater needs would do well to seek out an A&E firm that has significant prior membrane experience.
People Make the Difference
Recognizing the complexities and the promise of membranes, many A&E firms have hired technical staff with considerable expertise in the field. When evaluating A&E firms, potential clients should carefully consider the extent to which a firm's staff are knowledgeable and experienced in membrane technology.
Judging the capabilities of an A&E firm requires a certain amount of savvy on the part of potential clients to ensure that they hire the company most qualified to meet their membrane needs. To this end, end users should look beyond a mere list of membrane projects to which a particular firm has contributed. Ultimately, the people working for an A&E firm are what make the difference.
As in any business, personnel come and go at A&E firms, changing jobs and positions to better themselves. End users, therefore, must inquire about the experience of the individuals at the firm who would be involved with their project. When told by a prospective firm that it has designed or built a certain number of membrane plants that are producing so many millions of gallons of flow per day, end users should ask if the same staff who worked on these highlighted efforts would also work on their own projects.
Objectivity and Optimized Designs
In addition to their personnel, A&E firms offer an independent viewpoint that may be absent if a client were to deal directly with an original equipment manufacturer (OEM). Whereas OEMs are necessarily dedicated to their own technologies, A&E firms offer an unbiased assessment of a client's needs, considering all potential options to address the requirements of a given situation.
Beyond this benefit, however, is the ability of A&E firms to ensure proper coordination between the design requirements of a vendor and those of the end user. In other words, an A&E consultant looks at the “big picture” associated with a project, rather than evaluating simply the membrane component. For example, regulatory compliance is critical for municipal users, and proper disposal of concentrate plays a key role in ensuring compliance. Although they face a somewhat less stringent regulatory environment, industrial users likewise must ensure that they remain in compliance. A qualified A&E firm will offer a solid understanding of the regulatory process pertaining to both municipal and industrial membrane users.
In addition, A&E firms offer expertise in auxiliary components—including chemical-delivery systems, storage facilities, pretreatment processes, and biological treatment processes—that likely need to be accounted for during the design and construction of a membrane system. In short, a good A&E company will work to ensure that a membrane system is fully optimized so as to provide the maximum benefit to the client.
For example, A&E firms help to ensure that treatment applications are properly configured so as to optimize membrane performance. For drinking water applications in particular, pretreatment systems play a critical role, one that must be carefully understood if municipalities are to reap the greatest benefits from their investments in membranes. Similarly, the growing success of MBRs rests to a large extent on the ability of the design team to work with the product vendor to ensure that the system's biological and physical processes are properly integrated.
Common Features of Water Markets
The extent to which membranes are used in industrial settings continues to grow, ranging from food production to the manufacturing of semi-conductors. Given this assortment of applications in which membranes may be employed, industrial users can benefit significantly from A&E firms that have a solid grounding in the science underlying membrane technology and significant experience in designing and installing such systems.
Municipal and industrial membrane applications share certain commonalities. Although industrial users sometimes use raw water supplies, such users typically rely on higher quality water, including recycled water or water that has been treated to drinking water standards. These water supplies, then, are what industrial users seek to cleanse further in their membrane systems.
For their part, A&E firms have significant experience in designing and installing the systems that are used to treat water for such purposes as drinking water or recycled water. As a result, consulting firms have expertise that can benefit industrial users in terms of developing the pretreatment processes necessary to ensure the proper operation of their membrane systems. Conversely, an A&E firm that has worked in industrial settings is well suited to address the membrane-related needs of water and wastewater utilities.
Whether municipal or industrial in nature, entities looking to install or upgrade membrane treatment systems should carefully consider using the services of a qualified A&E firm. Before selecting such a firm, potential clients should evaluate its experience in designing membrane systems and its expertise in ancillary components and treatment processes. An organization that chooses the proper A&E firm will be rewarded with a partner that provides a total-system approach to designing membrane treatment systems. —m
About the Author:
F. Scott Davis, P.E., is a senior project manager in the Phoenix office of PBS&J. Davis' particular areas of expertise include reverse osmosis membranes and concentrate disposal.