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Formation of Trihalomethanes during Chlorination at South Cross Bayou Advanced Water Reclamation Facility, Pinellas County, Florida.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Formation of Trihalomethanes during Chlorination at South Cross Bayou Advanced Water Reclamation Facility, Pinellas County, Florida./
作者:	Grabo, Ian.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2022,
面頁冊數:	50 p.
附註:	Source: Masters Abstracts International, Volume: 83-10.
Contained By:	Masters Abstracts International83-10.
標題:	Environmental engineering. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29061745
ISBN:	9798426809291

Formation of Trihalomethanes during Chlorination at South Cross Bayou Advanced Water Reclamation Facility, Pinellas County, Florida.
Grabo, Ian.

Formation of Trihalomethanes during Chlorination at South Cross Bayou Advanced Water Reclamation Facility, Pinellas County, Florida. - Ann Arbor : ProQuest Dissertations & Theses, 2022 - 50 p.

Source: Masters Abstracts International, Volume: 83-10.

Thesis (M.S.E.V.)--University of South Florida, 2022.

This item must not be sold to any third party vendors.

South Cross Bayou Advanced Water Reclamation Facility (SCB) in Pinellas County, Florida, recently had a spike in effluent concentrations of bromodichloromethane (BDCM) and dibromochloromethane (DBCM) above the regulated limits, due to relying fully on chlorination instead of a combination of chlorination and ultraviolet light. The objective of this study was to determine the operating parameters most strongly affecting the formation of THMs. This was completed by analysis of long-term data sets obtained from SCB by multiple linear regression to create models describing THM formation. In addition, sampling of the chlorine contact chamber (CCC) was done to determine the effects of increasing methanol dosage. It was found that THM formation is strongly influenced by previous conditions in the CCC for up to 24hrs, not just by instantaneous present operating conditions. Chloroform and BDCM showed opposing formation patterns to DBCM and bromoform, with increases in chloroform and BDCM concentrations correlated with decreases in DBCM and bromoform concentrations. The most influential operating parameters were determined to be the chlorine contact chambers (CCC) influent total organic carbon (TOC) concentration, bromide (Br-) concentration, and temperature, with residence time and chlorine dose having a moderate influence over formation of the THMs. THMs at SCB exhibited signs of having sequential formation. Sequential formation of THMs starts with chloroform being formed first then chloroform progresses to BDCM and then BDCM progresses to DBCM and finally DBCM progresses to bromoform. An indicator of this pattern is the temperature having a negative correlation with on chloroforms formation instead of positive; it is hypothesized this is due to the reaction rates for the formation of the other THMs from chloroform outcompete chloroform formation. In addition, the chloroform concentration stays consistent throughout the CCC, while the other THMs are steadily increasing. This indicates that something is stopping the increase in chloroform concentration, most likely this is a result of chloroform decaying or forming other THMs. Methanol concentration was shown to have a high impact on the speciation of the THMs in a short-term sampling experiment of the CCC, with higher dosing of methanol resulting in higher bromoform concentrations. However, due to the lack of other operating parameters for the short-term test and previous research to support this finding makes this finding questionable. The results from this study can be used to manipulate the possible production of THMs by altering TOC concentration or temperature. Methanol doses can be lowered to shift the speciation from higher concentrations of chloroform to higher concentrations of bromoform based on findings from the long-term data analysis. Shifting the speciation from chloroform dominated to bromoform dominated would be ideal due to DBCM having a higher effluent standard than BDCM. However, methanol doses can only be manipulated so far since too low of a dose will result in less nitrogen removal and dosing too high of a dose can result in too many THMs being formed. However, during experimentation, the increase in methanol did not show an increase in the total amount of THMs formed. Shade balls are already installed at SCB to help lower the temperature of the water in the CCC, which will theoretically have the effect of lowering the concentration of THMs by reducing reaction rates.

ISBN: 9798426809291Subjects--Topical Terms:

548583
Environmental engineering.
Subjects--Index Terms:

Bromoform

Formation of Trihalomethanes during Chlorination at South Cross Bayou Advanced Water Reclamation Facility, Pinellas County, Florida.
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520 $a South Cross Bayou Advanced Water Reclamation Facility (SCB) in Pinellas County, Florida, recently had a spike in effluent concentrations of bromodichloromethane (BDCM) and dibromochloromethane (DBCM) above the regulated limits, due to relying fully on chlorination instead of a combination of chlorination and ultraviolet light. The objective of this study was to determine the operating parameters most strongly affecting the formation of THMs. This was completed by analysis of long-term data sets obtained from SCB by multiple linear regression to create models describing THM formation. In addition, sampling of the chlorine contact chamber (CCC) was done to determine the effects of increasing methanol dosage. It was found that THM formation is strongly influenced by previous conditions in the CCC for up to 24hrs, not just by instantaneous present operating conditions. Chloroform and BDCM showed opposing formation patterns to DBCM and bromoform, with increases in chloroform and BDCM concentrations correlated with decreases in DBCM and bromoform concentrations. The most influential operating parameters were determined to be the chlorine contact chambers (CCC) influent total organic carbon (TOC) concentration, bromide (Br-) concentration, and temperature, with residence time and chlorine dose having a moderate influence over formation of the THMs. THMs at SCB exhibited signs of having sequential formation. Sequential formation of THMs starts with chloroform being formed first then chloroform progresses to BDCM and then BDCM progresses to DBCM and finally DBCM progresses to bromoform. An indicator of this pattern is the temperature having a negative correlation with on chloroforms formation instead of positive; it is hypothesized this is due to the reaction rates for the formation of the other THMs from chloroform outcompete chloroform formation. In addition, the chloroform concentration stays consistent throughout the CCC, while the other THMs are steadily increasing. This indicates that something is stopping the increase in chloroform concentration, most likely this is a result of chloroform decaying or forming other THMs. Methanol concentration was shown to have a high impact on the speciation of the THMs in a short-term sampling experiment of the CCC, with higher dosing of methanol resulting in higher bromoform concentrations. However, due to the lack of other operating parameters for the short-term test and previous research to support this finding makes this finding questionable. The results from this study can be used to manipulate the possible production of THMs by altering TOC concentration or temperature. Methanol doses can be lowered to shift the speciation from higher concentrations of chloroform to higher concentrations of bromoform based on findings from the long-term data analysis. Shifting the speciation from chloroform dominated to bromoform dominated would be ideal due to DBCM having a higher effluent standard than BDCM. However, methanol doses can only be manipulated so far since too low of a dose will result in less nitrogen removal and dosing too high of a dose can result in too many THMs being formed. However, during experimentation, the increase in methanol did not show an increase in the total amount of THMs formed. Shade balls are already installed at SCB to help lower the temperature of the water in the CCC, which will theoretically have the effect of lowering the concentration of THMs by reducing reaction rates.
590 $a School code: 0206.
650 4 $a Environmental engineering. $3 548583
650 4 $a Water resources management. $3 794747
653 $a Bromoform
653 $a Chlorine contact chamber
653 $a Chloroform
653 $a Disinfection byproducts
653 $a Wastewater treatment
690 $a 0775
690 $a 0595
710 2 $a University of South Florida. $b Engineering. $3 1680322
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