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Using ozonation and alternating redox potential to increase nitrogen and estrogen removal while decreasing waste activated sludge production

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dc.contributor.supervisor Oleszkiewicz, Jan (Civil Engineering) en
dc.contributor.author Dytczak, Magdalena Anna
dc.date.accessioned 2008-09-10T13:34:20Z
dc.date.available 2008-09-10T13:34:20Z
dc.date.issued 2008-09-10T13:34:20Z
dc.identifier.citation Dytczak M. A., Londry K. L., Siegrist H. and Oleszkiewicz J. A. (2006). Extracellular polymers in partly ozonated return activated sludge: impact on flocculation and dewaterability” Wat Sci and Tech 54(9), 155-164 en
dc.identifier.citation Dytczak M. A., Londry K. L., Siegrist H. and Oleszkiewicz J. A. (2007). Ozonation reduces sludge production and improves denitrification. Wat Res 41, 543-550 en
dc.identifier.citation Dytczak M. A., Londry K. L. and Oleszkiewicz J. A. (2008a). Biotransformation of estrogens in nitrifying activated sludge under aerobic and alternating anoxic/aerobic conditions. Wat Env Res, 80, 47-52 en
dc.identifier.citation Dytczak M. A., Londry K. L. and Oleszkiewicz J. A. (2008b). Nitrifying genera in activated sludge may influence nitrification rates. Wat Env Res, 80, 388-396 en
dc.identifier.citation Dytczak M. A., Londry K. L. and Oleszkiewicz J. A. (2008c). Activated sludge operational regime has significant impact on the type of nitrifying community and its nitrification rates. Wat Res 42, 2320-2328 en
dc.identifier.uri http://hdl.handle.net/1993/3062
dc.description.abstract The effectiveness of partial ozonation of return activated sludge for enhancing denitrification and waste sludge minimization were examined. A pair of nitrifying sequencing batch reactors was operated in either aerobic or alternating anoxic/aerobic conditions, with one control and one ozonated reactor in each set. The amount of solids decreased with the ozone dose. Biomass in the anoxic/aerobic reactor was easier to destroy than in the aerobic one, generating approximately twice as much soluble chemical oxygen demand (COD) by cell lysis. Increased COD favoured production of extracellular polymers in ozonated reactors, enhancing flocculation and improving settling. Floc stability was also strengthened in prolonged operation in alternating treatment, resulting in declined solids destruction. Dewaterability was better in alternating reactors than in aerobic ones indicating that incorporation of an anoxic zone for biological nutrient removal leads to improvement in sludge dewatering. The negative impact of ozonation on dewaterability was minimal in terms of the long-term operation. Ozone successively destroyed indicator estrogenic compounds, contributing to total estrogen removal from wastewater. Denitrification rate improved up to 60% due to additional carbon released by ozonation. Nitrification rates deteriorated much more in the aerobic than in the alternating reactor, possibly as a result of competition created by growth of heterotrophs receiving the additional COD. Overall, ozonation provided the expected benefits and had less negative impacts on processes in the alternating treatment, although after prolonged operation, benefits could become less significant. The alternating anoxic/aerobic reactor achieved twice the nitrification rates of its aerobic counterpart. Higher removal rates of estrogens were associated with higher nitrification rates, supporting the contention that the nitrifying biomass was responsible for their removal. The alternating treatment offered the better estrogen biodegradation. Microbial populations in both reactors were examined with fluorescent in situ hybridization. Dominance of rapid nitrifiers like Nitrosomonas and Nitrobacter (79.5%) in the alternating reactor, compared to a dominance of slower nitrifiers like Nitrosospira and Nitrospira (78.2%) in the aerobic reactor were found. The findings are important to design engineers, as reactors are typically designed based on nitrifiers’ growth rate determined in strictly aerobic conditions. en
dc.format.extent 1912307 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US
dc.subject nitrification en
dc.subject denitrification en
dc.subject ozonation en
dc.subject sludge minimization en
dc.subject microbial ecology en
dc.subject activated sludge en
dc.subject wastewater treatment en
dc.subject flocculation en
dc.subject settling en
dc.subject dewatering en
dc.subject endocrine disruptors en
dc.title Using ozonation and alternating redox potential to increase nitrogen and estrogen removal while decreasing waste activated sludge production en
dc.degree.discipline Civil Engineering en
dc.contributor.examiningcommittee VanGulck, Jamie (Civil Engineering) Tenuta, Mario (Soil Science) Daigger, Glen (CH2MHill, Denver CO) en
dc.degree.level Doctor of Philosophy (Ph.D.) en
dc.description.note October 2008 en


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