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Item Non-destructive approaches for assessing biofouling of household reverse osmosis membranes(2018-09) Markwardt, Stephan D.; Ronnie, Nirmala; Camper, Anne K.This study determined economic non-destructive methods to assess biofouling in point of use reverse osmosis (RO) membrane treatment systems. Three parallel household RO membrane units were operated under controlled feed water conditions to promote biofouling, inorganic fouling and a combination of both. Operational and biological parameters were monitored throughout the systems’ lifespan. Membrane autopsies assessed the degree and type of fouling. Statistical models determined statistically relevant parameters for fouling types that were validated with membrane autopsies. Permeate flow rates decreased differently with biofouling vs inorganic fouling. Large increases in permeate conductivity were noted in membranes suffering from biofouling and not in inorganically fouled membranes. The concentration of cell clumps from detached biofilm in the retentate increased in membranes experiencing biofouling and no increase was seen for inorganically fouled membranes. A combination of these methods could be used to conveniently assess the types of fouling experienced by RO systems.Item Challenges and Opportunities for Tribal Waters: Addressing Disparities in Safe Public Drinking Water on the Crow Reservation in Montana, US(2018-03) Doyle, John T.; Kindness, L.; Real Bird, James; Eggers, Margaret J.; Camper, Anne K.Disparities in access to safe public drinking water are increasingly being recognized as contributing to health disparities and environmental injustice for vulnerable communities in the United States. As the Co-Directors of the Apsaálooke Water and Wastewater Authority (AWWWA) for the Crow Tribe, with our academic partners, we present here the multiple and complex challenges we have addressed in improving and maintaining tribal water and wastewater infrastructure, including the identification of diverse funding sources for infrastructure construction, the need for many kinds of specialized expertise and long-term stability of project personnel, ratepayer difficulty in paying for services, an ongoing legacy of inadequate infrastructure planning, and lack of water quality research capacity. As a tribal entity, the AWWWA faces additional challenges, including the complex jurisdictional issues affecting all phases of our work, lack of authority to create water districts, and additional legal and regulatory gaps—especially with regards to environmental protection. Despite these obstacles, the AWWWA and Crow Tribe have successfully upgraded much of the local water and wastewater infrastructure. We find that ensuring safe public drinking water for tribal and other disadvantaged U.S. communities will require comprehensive, community-engaged approaches across a broad range of stakeholders to successfully address these complex legal, regulatory, policy, community capacity, and financial challenges.Item Community Engaged Cumulative Risk Assessment of Exposure to Inorganic Well Water Contaminants, Crow Reservation, Montana(2018-01) Eggers, Margaret J.; Doyle, John T.; Lefthand, M. J.; Young, Sara L.; Moore-Nall, Anita L.; Kindness, L.; Medicine, R. O.; Ford, Tim E.; Dietrich, E.; Parker, Albert E.; Hoover, J. H.; Camper, Anne K.An estimated 11 million people in the US have home wells with unsafe levels of hazardous metals and nitrate. The national scope of the health risk from consuming this water has not been assessed as home wells are largely unregulated and data on well water treatment and consumption are lacking. Here, we assessed health risks from consumption of contaminated well water on the Crow Reservation by conducting a community-engaged, cumulative risk assessment. Well water testing, surveys and interviews were used to collect data on contaminant concentrations, water treatment methods, well water consumption, and well and septic system protection and maintenance practices. Additive Hazard Index calculations show that the water in more than 39% of wells is unsafe due to uranium, manganese, nitrate, zinc and/or arsenic. Most families’ financial resources are limited, and 95% of participants do not employ water treatment technologies. Despite widespread high total dissolved solids, poor taste and odor, 80% of families consume their well water. Lack of environmental health literacy about well water safety, pre-existing health conditions and limited environmental enforcement also contribute to vulnerability. Ensuring access to safe drinking water and providing accompanying education are urgent public health priorities for Crow and other rural US families with low environmental health literacy and limited financial resources.Item Evaluation of regulations for monitoring the microbial quality of drinking water(1998) Camper, Anne K.; Hamilton, Martin A.Item Development and structure of drinking water biofilms and techniques for their study(1999-12) Camper, Anne K.; Burr, Mark D.; Ellis, B. D.; Butterfield, Phillip W.; Abernathy, Calvin G.Item Effects of substratum topography on bacterial adhesion(1998-12) Scheuerman, Teresa R.; Camper, Anne K.; Hamilton, Martin A.The effect of substratum topography on bacterial surface colonization was studied using a chemically homogeneous silicon coupon. “Grooves” 10 μm deep and 10, 20, 30, and 40 μm wide were etched on the coupon perpendicular to the direction of flow. Flow (Re = 5.5) of a bacterial suspension (108cells/ml) was directed through a parallel plate flow chamber inverted on a confocal microscope. Images were collected in real time to obtain rate and endpoint colonization data for each of three strains of bacteria:Pseudomonas aeruginosaand motile and nonmotilePseudomonas fluorescens.A higher velocity experiment (Re = 16.6) and an abiotic control using hydrophilic, negatively charged microspheres were also performed. Using a colloidal deposition expression, the initial rates of attachment were compared.P. aeruginosaattached at a higher rate thanP. fluorescensmot+ which attached at a higher rate thanP. fluorescensmot−. For all bacteria the rate was independent of groove size and was greatest on the downstream edges of the grooves. Only the motile organisms were found in the bottoms of the grooves. A higher fluid velocity resulted in an increase in the initial rate of attachment. In contrast, there was no adhesion of the beads. Attachment of the bacteria appears to be predominated by transport from the bulk phase to the substratum.Item Attachment and fate of carbon fines in simulated drinking water distribution system biofilms(1997-03) Morin, P.; Camper, Anne K.Concern over the release of colonized carbon fines from filters has increased with the interest in operating granular activated carbon filters optimized for biological activity. These fines may transport bacteria to the distribution system and become entrained in biofilms. The capture and release of carbon fines of two size ranges (1.2–50 μm and 1.2–8 μm) in biofilms and their impact on the biomass was studied using a bench-scale simulated drinking water system. Size of the particles was important, with large carbon fines (1.2–50 μm) remaining in the biofilms while the small ones (1.2–8 μm) were entrained and then detached. The presence of carbon fines did not influence the number or activity of bacteria present in the biofilms. Disinfection assays on biofilms containing particles were performed with chlorine (0.5 mg/L) and monochloramine (1 mg/L). Even in the presence of substantial numbers of carbon fines, the effect of the disinfectants on the biofilms as determined by destructive analysis and direct microscopic observation was limited. Carbon fines were released from the biofilms during disinfection.Item Spatial distribution and coexistence of klebsiella pneumoniae and pseudomonas aeruginosa in biofilms(1997-01) Stewart, Philip S.; Camper, Anne K.; Handran, S. D.; Huang, Ching-Tsan; Warnecke, Malcolm R.The heterotrophic bacteria Klebsiella pneumoniae and Pseudomonas aeruginosa stably coexisted in laboratory-grown biofilms, even though the growth rate of K. pneumoniae was twice that of P. aeruginosa under planktonic growth conditions. The failure of K. pneumoniae to displace P. aeruginosa from the biofilm could not be attributed to concentration gradients of the limiting nutrient (glucose) arising from the interaction of reaction and diffusion. Comparisons of the growth rates of the two species in mono- and binary-population biofilms suggested partial segregation of the two species in the latter. We used a fluorescently labeled monoclonal antibody to examine the spatial distribution of K. pneumoniae in frozen cross sections of biofilm to confirm this segregation. K. pneumoniae microcolonies resided on top of, or intermixed with, a base film of P. aeruginosa. We hypothesize that microscale structural heterogeneity and differing rates of bacterial attachment and detachment of the two species are responsible for coexistence in this system.Item Colonization and disinfection of biofilms hosting coliform-colonized carbon fines(1996-12) Morin, P.; Camper, Anne K.; Jones, Warren L.; Gatel, D.; Goldman, J. C.Item Colonization and disinfection of biofilms hosting coliform-colonized carbon fines(1996-12) Morin, P.; Camper, Anne K.; Jones, Warren L.; Gatel, D.; Goldman, J. C.