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- All Subjects: Toxicology
- All Subjects: Water--Purification--Organic compounds removal.
- Creators: Conroy-Ben, Otakuye
Description
Activated Carbon has been used for decades to remove organics from water at large scale in municipal water treatment as well as at small scale in Point of Use (POU) and Point of Entry (POE) water treatment. This study focused on Granular Activated Carbon (GAC) and also activated Carbon Block (CB) were studied.
This thesis has three related elements for organics control in drinking water. First, coagulation chemistry for Alum and Aluminum Chlorohydrate (ACH) was optimized for significant organics removal to address membrane fouling issue at a local municipal water treatment plant in Arizona. Second, Rapid Small Scale Column Tests were conducted for removal of Perfluorinated compounds (PFC), PFC were present in groundwater at a local site in Arizona at trace levels with combined concentration of Perfluorooctaneoic Acid (PFOA) and Perfloorooctanesulfonic Acid (PFOS) up to 245 ng/L. Groundwater from the concerned site is used as drinking water source by a private utility. PFC Removal was evaluated for different GAC, influent concentrations and particle sizes. Third, a new testing protocol (Mini Carbon Block (MCB)) for bench scale study of POU water treatment device, specifically carbon block filter was developed and evaluated. The new bench scale decreased the hydraulic requirements by 60 times approximately, which increases the feasibility to test POU at a lab scale. It was evaluated for a common POU organic contaminant: Chloroform, and other model contaminants.
10 mg/L of ACH and 30 mg/L of Alum with pH adjustment were determined as optimal coagulant doses. Bituminous coal based GAC was almost three times better than coconut shell based GAC for removing PFC. Multiple tests with MCB suggested no short circuiting and consistent performance for methylene blue though chloroform removal tests underestimated full scale carbon block performance but all these tests creates a good theoretical and practical fundament for this new approach and provides directions for future researchers.
This thesis has three related elements for organics control in drinking water. First, coagulation chemistry for Alum and Aluminum Chlorohydrate (ACH) was optimized for significant organics removal to address membrane fouling issue at a local municipal water treatment plant in Arizona. Second, Rapid Small Scale Column Tests were conducted for removal of Perfluorinated compounds (PFC), PFC were present in groundwater at a local site in Arizona at trace levels with combined concentration of Perfluorooctaneoic Acid (PFOA) and Perfloorooctanesulfonic Acid (PFOS) up to 245 ng/L. Groundwater from the concerned site is used as drinking water source by a private utility. PFC Removal was evaluated for different GAC, influent concentrations and particle sizes. Third, a new testing protocol (Mini Carbon Block (MCB)) for bench scale study of POU water treatment device, specifically carbon block filter was developed and evaluated. The new bench scale decreased the hydraulic requirements by 60 times approximately, which increases the feasibility to test POU at a lab scale. It was evaluated for a common POU organic contaminant: Chloroform, and other model contaminants.
10 mg/L of ACH and 30 mg/L of Alum with pH adjustment were determined as optimal coagulant doses. Bituminous coal based GAC was almost three times better than coconut shell based GAC for removing PFC. Multiple tests with MCB suggested no short circuiting and consistent performance for methylene blue though chloroform removal tests underestimated full scale carbon block performance but all these tests creates a good theoretical and practical fundament for this new approach and provides directions for future researchers.
ContributorsAshani, Harsh Satishbhai (Author) / Westerhoff, Paul (Thesis advisor) / Hristovski, Kiril (Committee member) / Conroy-Ben, Otakuye (Committee member) / Arizona State University (Publisher)
Created2017
Description
Human impact alters the natural environment via multiple pathways, including contamination from pollutants. This human activity may adversely impact an organism’s ability to respond to environmental change. Using Bisphenol-A (BPA), a common environmental contaminant, I examined how exposure affected behavioral strategies critical for survival in a changing environment. BPA is used during plastic manufacturing, and it enters aquatic systems from wastewater streams; however, it is an endocrine-disruptor that has broad health effects from metabolism to behavior at a wide exposure range. In this study, I specifically tested whether environmentally relevant concentrations of BPA impact maximum metabolic rate and boldness in zebrafish, Danio rerio. I also examined activity level, optomotor response, body mass, and standard length to see if I can mechanistically explain any underlying changes caused by BPA. I treated groups of adult zebrafish for 7 days and exposed them to either 0.1% dimethyl sulfoxide (DMSO, control), a low environmentally relevant concentration of BPA (0.02 mg/L), or a 1-fold higher BPA concentration (0.2 mg/L). I found that the low exposure group experienced a decrease in maximum metabolic rate and the high exposure group showed a decrease in boldness. In other words, these changes in metabolism were not dosage dependent while the boldness results were dosage dependent. BPA had no effects on optomotor response, body mass, standard length or activity level. These results suggest that no level of BPA is safe, environmentally relevant concentrations are having an effect on adult organisms’ behavior and health that could affect their survival.
ContributorsLopez, Melissa (Author) / Martins, Emilia P (Thesis advisor) / Suriyampola, Piyumika S (Thesis advisor) / Conroy-Ben, Otakuye (Committee member) / Arizona State University (Publisher)
Created2021