Grantee Research Project Results
1999 Progress Report: Integrated Approach for the Control of Cryptosporidium parvum Oocysts and Disinfection By-Products in Drinking Water Treated with Ozone and Chloramines
EPA Grant Number: R826830Title: Integrated Approach for the Control of Cryptosporidium parvum Oocysts and Disinfection By-Products in Drinking Water Treated with Ozone and Chloramines
Investigators: Mariñas, Benito J. , Minear, Roger A.
Institution: University of Illinois Urbana-Champaign
EPA Project Officer: Hahn, Intaek
Project Period: September 1, 1998 through August 31, 2002 (Extended to March 31, 2003)
Project Period Covered by this Report: September 1, 1998 through August 31, 1999
Project Amount: $367,427
RFA: Drinking Water (1998) RFA Text | Recipients Lists
Research Category: Water , Drinking Water
Objective:
The overall goal of this project is the development of process design recommendations for the simultaneous control of Cryptosporidium parvum oocysts and disinfection by-products (DBPs) during ozone/chloramines sequential disinfection of natural waters. Because the main objective of the study is to develop an integral control strategy, the scope of work focuses on a limited number of selected DBPs (bromate, formaldehyde, and cyanogen halides) associated with the ozone/chloramines sequential disinfection process.Progress Summary:
Experiments have been performed to investigate the kinetics of C. parvum oocyst inactivation resulting from the sequential application of ozone and monochloramine as primary and secondary disinfectants, respectively. Experiments with single disinfectants resulted in inactivation curves characterized by the presence of an initial lag phase, during which little inactivation occurred followed by pseudo-first order inactivation kinetics. The rate of C. parvum oocyst inactivation with monochloramine was enhanced when this chemical was used as a secondary disinfectant. Ozone pretreatment resulted in the removal of the lag phase during the secondary inactivation with monochloramine. Furthermore, the rate of secondary monochloramine inactivation was faster than that observed for post-lag phase primary disinfection. This synergistic effect was found to be more pronounced at lower temperatures. For example, the rate of secondary inactivation with monochloramine after ozone treatment was five times faster at 20o C, and 22 times faster at 1o C, than the corresponding post-lag phase rate for primary disinfection with monochloramine. This is a very important finding, with great implications toward optimizing the control of both pathogens and DBP in later phases of this study. Regarding DBP formation kinetics, most efforts during this reporting period have been aimed at developing and verifying a model for bromate formation under ozone disinfection conditions. The kinetics of ozone decomposition and bromate formation were investigated by performing experiments with a headspace-free batch reactor. The roles of pH, ozone dosage, bromide concentration, and inorganic carbon content in these reactions have been assessed with synthetic solutions. Computer models for both batch and flow-through reactors have been developed and verified with experimental results. The model is designed to solve rate expressions for N chemical species undergoing elementary reactions. The system of N coupled nonlinear ordinary differential equations with N variables was solved by a semi-implicit extrapolation method selected to address the stiffness problems characteristic of chemical systems involving fast-reacting radicals. This solver algorithm provided an adaptive step size control over the period of integration for achieving desired accuracy with minimal computational effort. Efforts also were aimed at investigating the formation of target DBPs associated with secondary disinfection with monochloramine. Research accomplishments included the establishment of analytical methods for cyanogen halides (ClCN and BrCN). The gas chromatography method developed allowed for the determination of reporting levels of 0.5 µg/L for both cyanogen halides. Preliminary experiments revealed that the presence of bromide greatly enhanced the production of cyanogen bromide, with bromide conversions into BrCN as high as nearly 50 percent. Experiments are currently being performed to assess the various formation pathways for both ClCN and BrCN. The model developed for primary ozonation will be expanded to include both DBP formation and secondary inactivation synergy in the presence of monochloramine in preozonated natural waters.Future Activities:
Research plans for the next reporting period include the performance of additional experiments to assess the role of natural organic matter in the formation of bromate and cyanogen halides. Experiments will be performed with both batch and flow-through reactors. The kinetic information obtained from these experiments will be incorporated into the computer model. Additional experiments will be performed with natural waters to verify the models.Journal Articles on this Report : 2 Displayed | Download in RIS Format
Other project views: | All 23 publications | 8 publications in selected types | All 8 journal articles |
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Driedger AM, Rennecker JL, Marinas BJ. Inactivation of Cryptosporidium parvum oocysts with ozone and monochloramine at low temperature. Water Research 2001;35(1):41-48. |
R826830 (1999) R826830 (2000) R826830 (2001) R826830 (Final) |
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Rennecker JL, Driedger AM, Rubin SA, Marinas BJ. Synergy in sequential inactivation of Cryptosporidium parvum with ozone/free chlorine and ozone/monochloramine. Water Research 2000;34(17):4121-4130. |
R826830 (1999) R826830 (2000) R826830 (2001) R826830 (Final) |
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Supplemental Keywords:
drinking water, Cryptosporidium parvum, chloramination, monochloramine, ozonation, bromate, disinfection by-product., RFA, Scientific Discipline, Water, Environmental Chemistry, Chemistry, Analytical Chemistry, Drinking Water, alternative disinfection methods, cryptosporidium parvum oocysts, public water systems, integrated approach, disinfection byproducts (DPBs), bromate formation, brominated DPBs, treatment, cyanogen halides, microbial risk management, chloramines, DBP risk management, drinking water contaminants, monochloramine, drinking water systemProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.