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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The impact of a change in disinfectants on the water quality of a distribution system

Baek, Nak-hyun January 1994 (has links)
Chloramine is a widely used alternative disinfectant for chlorine in potable distribution water. This alternative was investigated and employed to show its effect for suppressing coliforms, trihalomethanes(THMs), disinfection by-products (DBPs), and corrosivity.Coliform analyses were performed with m-Endo(total coliform) and m-T7 agar(injured coliform) by using a standard Membrane Filtration method. Heterotrophic bacteria were monitored with HPC agar(PCA) and R2A agar (nutrient limited agar). EPA methods 502.2, 524.2, and 504 were used to determine levels of Trihalomethanes(THMs) and Disinfection by-products(DBPs).In our study, we observed no significant differences in coliform counts, that could be attributed to the switch in disinfectant. The most common coliform identified was Enterobacter cloacae. We also noted that m-T7 performed better than m-Endo in the detection of coliforms. We also observed a low level of corrosion (0.4-3.8 mils/year) in the distribution system (DS). Higher counts of heterotrophic bacteria were enumerated on R2A when compared to HPC. DBP values decreased two fold when compared with DBP values for the two previous years during which chlorine was used as the disinfectant. / Department of Biology
2

Assesment [sic] of water quality parameters in the West Fork of the White River in Muncie, Delaware County, Indiana / Assesment of water quality parameters in the West Fork of the White River in Muncie, Delaware County, Indiana / Assessment of water quality parameters in the West Fork of the White River in Muncie, Delaware County, Indiana

Asbaghi, Navid January 2007 (has links)
Water quality parameters including ammonia, nitrate+nitrite, phosphate, total suspended solids, Escherichia coli, and dissolved oxygen were statistically evaluated from sampling data collected by the Bureau of Water Quality (City of Muncie, Indiana) at five sampling locations in Delaware County over a five-year period (2002-2006). These data were also compared with water quality standards/guidelines to determine how sample values compared to acceptable levels of these parameters. Friedman's non-parametric test was used to study the differences between sites and seasons. Spearman's Rank Correlation was used to study the correlations between water quality parameters at each sampling site. Significant differences were observed for individual parameters when evaluated relative to sampling location based on pooled monthly collected data as well as data evaluated on a seasonal basis. These differences indicated the fact that different sources were responsible for observed concentrations at a particular location and that seasonal phenomenon such as precipitation, discharge and temperature also affected sample concentrations at individual sampling locations. Most notable were differences in geometric mean concentrations of ammonia, nitrate+nitrite, phosphate and E. coli upstream and downstream of the wastewater treatment plant (WWTP), with highest concentrations downstream, indicating the significant impact of the WWTP on water quality in the White River. Significant correlations observed among some study parameters suggested that sample concentrations may have been affected by similar sources. In comparison to water quality standards, concentrations of ammonia, nitrate+nitrite, phosphate, and E. coli were at unacceptable levels at most sampling locations. / Department of Natural Resources and Environmental Management

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