Full Description

Particulate adsorbents, such as powdered activated carbon (PAC), can be used in conjunction with ultrafiltration (UF) or microfiltration (MF) membrane processes for the removal of dissolved contaminants that are not rejected by the membrane alone. In this process, dissolved contaminants transfer to the adsorbent, which is too large to pass through the membrane. The resulting hybrid system joins the outstanding microorganism and particle removal capabilities of MF/UF membranes with the ability to remove targeted dissolved contaminants by adsorption. No additional tankage is required, because adsorption can take place in the membrane reactor. Thus, the hybrid sorption-membrane process expands the scope of MF/UF treatment to encompass a broad range of water quality goals in a single process that is both compact and cost-effective. Up to now, most of the attention in hybrid sorption-membrane processes has focused on adding PAC to MF or UF membrane reactors, which is often referred to as the PAC-UF process. There have been many bench and pilot-scale studies that have looked at various aspects of the PAC-UF system including demonstrating and modeling process performance, and optimizing operational parameters. There have also been a few full- scale plants built with the PAC-UF process. These studies demonstrate the benefits of the PAC-UF process and provide some insight into how to improve system performance from an operational perspective. Another approach to improving the hybrid sorption-membrane processes is to identify and characterize the performance of novel adsorbents that offer advantages over conventional PAC, which is the predominant adsorbent used in research and industry today. A hybrid sorption-membrane process is a unique treatment situation for an adsorbent and provides some special challenges. In particular, hybrid sorption-membrane processes typically allow only a short amount of adsorbent residence time (ART) and hydraulic residence time (HRT). With an understanding of the unique conditions of contemporary hybrid sorption-membrane process, it is possible to select advantageous properties for novel adsorbents that mitigate current process limitations. Hybrid sorption-membrane treatment conditions also provide an impetus for new adsorbent characterization tests to quickly and accurately identify adsorbents that are well suited for a sorption-membrane process. In particular, the flow-through nature requires supplemental testing to augment the information provided by conventional batch test characterization. This paper introduces a relatively simple adsorbent characterization test used by the authors to screen adsorbents for sorption-membrane processes. Some results from the new test are provided where it was used to screen novel adsorbents for the removal of a common earthy-musty odor compound (2-methylisoborneol, 2-MIB) from a Lake Michigan source water. Includes 17 references, figures.

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Edition: Vol. - No. Published: 01/01/2001 Number of Pages: 8File Size: 1 file , 250 KB