The laboratory setup shown here (top) was used to conduct multiple manganese capability experiments in parallel. The laboratory equipment (bottom) used in the experiments included a manganese solution reservoir, pump, media column, and tubing. 2010Collection of filter media cores. The majority of the filter media sample cores were collected during high-rate filter backwash. Typically, two cores were collected for each filter that was sampled using a media-coring device (2-in.-diameter clear schedule 40 polyvinyl chloride pipe) adopted from Soucie et al (2003). Samples from the Carno and Cantref water treatment works in South Wales were collected in a different manner, with the filters off-line and drained. A coring device was driven through the dry filter media, and the core was then removed from the filter intact. Media from the Stamford, Conn., water treatment plant automatic backwash traveling bridge filter were obtained by sampling a few inches into the top of a 12-in.-deep media cell.Media cores from all filters were divided into approximately 6-in.-deep subsamples. The media subsamples were kept wet in finished water from the utility and kept at 4ºC during transportation and storage. All media samples were air-dried at 30ºC and low (25%) humidity for long-term storage after receipt at the University of Massachusetts Amherst.Media samples were removed from the fluidized media bed using a filter sampling device.

Washington, District of Columbia, installed activated carbon‐based lead mitigation filters on all water fountains/sinks in break rooms, classrooms, and health suites located in public elementary schools. To investigate the impact of these point‐of‐use filters, 12 water fountains/taps with various filter ages, with and without sediment prefilters, spread across four schools were monitored weekly from July to December 2017, along with two unfiltered sources per school (n = 8). Within the first 100 days postinstallation, filtrate from filters in schools with high influent monochloramine and no prefilter temporarily increased nitrite concentrations, with concentrations of some filters exceeding 0.4 mg/L N. Subsequent decreases in filtrate nitrite for these filters coincided with increases in live cell counts. Microbial community “fingerprints” were determined with flow cytometry. Filtered and unfiltered water fingerprints differed, indicating selective microbial growth on, and release from, the filters into the filtrate.

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