Theses and Dissertations at Montana State University (MSU)
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/732
Browse
2 results
Search Results
Item Evaluation of mixed-oxidants against sodium hypochlorite for the disinfection and removal of biofilms from distribution systems(Montana State University - Bozeman, College of Engineering, 1997) Crayton, Cynthia Lynn; Chairperson, Graduate Committee: Anne CamperProblem Statement: As drinking water regulations are applied to smaller utilities, an area of emerging concern for the water industry is the installation of disinfection systems to meet the newly imposed standards. Since traditional disinfection technologies are usually beyond the safety, economic, and/or site restraint considerations for small systems, an alternative is required. The mixed-oxidants disinfection system (MIOX) appears to provide a reasonable alternative for small distribution systems as a safe, reliable, and cost effective technology that is easy to operate and is readily compatible with other treatment systems. The goal of this five-phase study was to evaluate the potential of the MIOX disinfectant (produced on-site using feedstocks of ordinary salt, water, and twelve volt electricity) against free chlorine for biocidal efficacy, biofilm/biofouling removal, biofilm regrowth potential, relative corrosion potential, and cost effectiveness. Although mixed-oxidants have been proven effective in potable water disinfection, biofilm removal is a new application for this alternative disinfection technology.Item Ammonia oxidation by a nitrifying community containing novel ammonia oxidizing archaea(Montana State University - Bozeman, College of Engineering, 2014) Olson, Andrew Jared; Chairperson, Graduate Committee: Anne CamperThe disinfection properties of chlorine have long been known. These properties have been leveraged in the disinfection of drinking water. However, in the presence of organic matter, chlorine can form potentially carcinogenic disinfection by-products (DBPs). As a result, the U.S. Environmental Protection Agency promulgated the Stage I and Stage II Disinfectants/Disinfection By-Products Rules, limiting the amount of DBPs that can be present in a distribution system. An economical solution for many drinking water utilities to meet these new regulations was to use to chloramine as a secondary disinfectant. However, chloramines are not without their own disadvantages: free ammonia is added during chloramine formation and released by chloramine decay. This free ammonia can then be used as an energy source by indigenous microoganisms during nitrification. Nitrification can have deleterious effects on drinking water such as decreased disinfectant residual, pH, dissolved oxygen, and alkalinity, as well as an increase in nitrite, nitrate, and heterotrophic bacteria. This study uses effluent from a nitrifying reactor simulating premise plumbing to quickly establish a nitrifying community in glass bead packed bed reactors. Importantly, ammonia oxidizing archaea have been identified in both systems while no known ammonia oxidizing bacteria have been found. Once this nitrifying community was established, the reactors were used as batch reactors with effluent recycle to measure ammonia oxidation during a two hour batch phase. A least squares regression analysis was performed to generate the kinetic constants v max and K m for the nitrifying community in the packed bed reactors. v max was calculated to be 2.23 hr -1. K m was calculated to be 2.35 mg L -1. This work will aid in the effort to characterize the nitrifying population in a premise plumbing system and mitigate nitrification in drinking water.