title: Organic nitrogen transformations in a 4-stage Bardenpho nitrogen removal plant and bioavailability/biodegradability of effluent DON.
abstract: Nitrogen species, specifically, the fate and occurrence of organic nitrogen (ON) within a 4-stage Bardenpho process bioreactor producing low total nitrogen (TN) effluents were investigated in this study. The results showed release of ON in primary anoxic zone and no ON release in the first aerobic zone of the process. The research included investigation of biodegradability/bioavailability of wastewater-derived effluent dissolved ON (DON). The final-effluent DON utilization was evaluated by two different bioassay protocols in the presence and absence of nitrate. About 28-57% of the effluent DON was bioavailable/biodegradable. Bioavailable (to algae and bacteria) DON (ABDON) and biodegradable (to bacteria) DON (BDON) results did not show significant differences in terms of quantity, but DON utilization rates by ABDON (0.13 day(-1)) protocol were higher than that of the BDON (0.04 day(-1)) protocol in the nitrate-removal samples. As a result, ABDON requires a shorter time to exert the bioavailable fraction due to symbiotic relationship between algae and bacteria. In the nitrate-containing samples, it appears that nitrate competes with labile DON as a nitrogen source to microorganisms in both ABDON and BDON protocols. The first order decay rate of DON in the presence of nitrate was 0.11 day(-1) and 0.02 day(-1) for ABDON and BDON, respectively.
authors.affiliation: Civil, Architectural, and Environmental Engineering, Illinois Institute of Technology, 3201 S. Dearborn Street, Chicago, IL 60616, USA.
authors.forename: Chakkrid
authors.initials: C
authors.lastname: Sattayatewa
authors.forename: Krishna
authors.initials: K
authors.lastname: Pagilla
authors.forename: Paul
authors.initials: P
authors.lastname: Pitt
authors.forename: Kevin
authors.initials: K
authors.lastname: Selock
authors.forename: Theresa
authors.initials: T
authors.lastname: Bruton
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001682:Biological Availability; D019149:Bioreactors / Q000382:microbiology*; D017753:Ecosystem; D004784:Environmental Monitoring; D056890:Eukaryota / Q000254:growth & development / Q000378:metabolism*; D009566:Nitrates / Q000737:chemistry / Q000378:metabolism; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism* / Q000493:pharmacokinetics; D009930:Organic Chemicals / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000378:metabolism
chemical_list: D009566:Nitrates; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D009584:Nitrogen