GOALI: Effluent Dissolved Organic Nitrogen: Compound Level Assessment of Sources and Sinks

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1511120BronkA substantial portion of the nitrogen released in wastewater effluent from water resource recovery facilities is in the form of dissolved organic nitrogen. Despite the economic and ecological importance of the dissolved organic nitrogen, relatively little is known about how different nutrient removal treatments and disinfection procedures impact the chemical composition. This work is potentially transformative because the first step in dealing with the problem of organic compounds in effluent is to determine what is in it and then the extent that it is a problem in receiving waters. This proposal fits in one of the 14 Grand Challenges in Engineering which were articulated in a National Academy of Engineering report, managing the nitrogen cycle.Past research has shown that a large fraction of effluent dissolved organic nitrogen can be bioavailable to estuarine microbes, and that low molecular weight-N substrates are released from effluent dissolved organic nitrogen during disinfection with germicidal doses of UV and chlorination and when it is exposed to sunlight or elevated salinities in the environment. What is still not known, however, is the amount and type of effluent dissolved organic nitrogen that is produced during different combinations of treatment and disinfection procedures within WRRFs and how these differences will impact how effluent dissolved organic nitrogen responds in the environment. The research proposed seeks to answer these questions. The proposed work will also extend past efforts primarily focused on N to include both C and P. This expanded emphasis is important because of the potential for effluent dissolved organic carbon to contribute to hypoxia/anoxia and effluent dissolved organic phosphorus to eutrotrophication in the environment, particularly in freshwater. The proposed research has three objectives: 1. Chemically characterize the carbon, nitrogen, and phosphorus pools present in the influent and after treatment in four sequencing batch reactors performing four different treatments (nitrification only, nitrogen removal, nitrogen and biological phosphorus removal, and nitrogen and chemical phosphorus removal) during winter and summer using wet chemical and high-resolution analyses. 2. Determine how differences in treatment process configuration impact the concentration and composition of low molecular weight-nitrogen and phosphorus following germicidal UV and chlorination relative to the effluent dissolved organic matter that receives no disinfection using wet chemical and high resolution analyses. 3. Determine how treatment process configuration and disinfection procedure combinations impact the effluent dissolved organic matter produced with respect to biological uptake and any changes in concentrations of low molecular weight carbon, nitrogen and phosphorus after exposure to sunlight and elevated salinities in receiving waters using wet chemical analyses. Perhaps one of the most important aspects of the project is bringing together a team of oceanographers (PIs Bronk and Sipler) with an environmental engineer (PI Bott) to be a valuable means of cross fertilization of knowledge, tools, and approaches between the disciplines and communities of oceanography and engineering.