Water Resources Research Act Program

Details for Project ID 2016ND317B

UV Light Effect on Bioavailability of Dissolved Organic Nitrogen in a Trickling Filter Process

Institute: North Dakota
Year Established: 2016 Start Date: 2016-03-01 End Date: 2017-02-28
Total Federal Funds: $6,000 Total Non-Federal Funds: $12,000

Principal Investigators: Halis Simsek

Abstract: Dissolved organic nitrogen (DON) in treated wastewater has a complex structure and is not readily available in aquatic systems. DON degradation converts a portion of high molecular weight organic compounds to low molecular weight organic compounds that are bioavailable to marine organisms. Degraded low molecular compounds could be ammonium, amino acids, humic substances, and urea and these substances could be bioavailable to algae and/or bacteria in longer residence time. A portion of DON that is degradable by bacteria is called biodegradable DON (BDON) while DON portion that is bioavailable to both bacteria and algae is called algal-bacterial DON (ABDON). BDON and ABDON contribute to reduction of quality of surface waters. Photodegradable DON (PDON) is a portion of DON that is decomposable by sunlight or artificial light to lower molecular weight organic compounds or inorganic nitrogen, which causes undesirable conditions in aquatic ecosystems. DON biodegradable by bacteria and bioavailable to algal or algal + bacteria following light exposure is defined as photobiodegradable DON (PBDON) and photobioavailable DON (PABDON), respectively. UV light exposure converts high molecular weight DON to low molecular weight compounds. The main scope of this research is to determine the impact of UV light exposure on DON prior to using algal and/or bacterial inoculum for wastewater samples collected from a trickling filter WWTP. The specific objectives are: 1) To examine the effect of UV light exposure time on photochemical degradation of DON, BDON, and ABDON; and 2) To determine ABDON in algae + bacteria inoculated biological reactor that contains moving bed bioreactor media, and PDON, PBDON, and PABDON in UV light applied biological reactor effluent.