Date of Award

8-2017

Degree Name

MS in Civil and Environmental Engineering

Department

Civil and Environmental Engineering

Advisor

Nirupam Pal

Abstract

This research entails investigation of ammonia, nitrate, and nitrite removal from wastewater using a proprietary blend of bacteria known as BiOWiSHTM. The degradation rates of ammonia, nitrate, and nitrite for Aqua were determined using wastewater at the San Luis Obispo Water Resource Recovery Facility (SLO WRRF). Laboratory and field experiments were conducted to test how Aqua compared with natural bacteria for removal of nitrogen compounds. Preliminary data suggested that Aqua performed nitrate removal best in SLO WRRF wastewater at the secondary clarifier. Aqua could perform anoxic and aerobic denitrification in secondary clarifier wastewater. In mineral media, Aqua removed 6.6 mg NO3-N/L/hr. In partially sterilized wastewater, Aqua removed 2.67 mg NO3-N/L/hr. Field experiments using a batch reactor suggested that Aqua aided in nitrate removal when dosed above 25 ppm in secondary clarifier wastewater. A dose of 25 ppm Aqua resulted in a 0.1 mg NO3-N/L/hr removal rate. A dose of 50 ppm Aqua resulted in a 0.15 mg NO3-N/L/hr. Aqua did not aid in ammonia or nitrate removal in sludgewash at the SLO WRRF likely due to high concentrations of nitrate and ammonia existing in the wastewater were toxic to Aqua. Aqua removed about 5 ppm more nitrate than a competitor bacteria blend in a laboratory setting. Activating Aqua to increase initial cell count before inoculation did not have any effect on removal. Providing partial aeration did not help nitrification rates and inhibited nitrate removal for Aqua. Laboratory experiments showed that Aqua did not remove nitrate in final clarifier wastewater most likely due to a limited carbon source. Aqua can perform nitrification in mineral media. Aerobic activation of Aqua inhibited denitrification. Aqua activated anoxically can perform denitrification. Using a powder with 70% microbial cultures, instead of the 1% found in Aqua, resulted in quicker nitrate removal. Inoculating as a concentrated liquid versus a dry powder did not affect nitrate removal rates. Use of trace mineral media did not affect nitrate removal rates.

Available for download on Wednesday, August 29, 2018

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