Short-Term Enhancement and Long-Term Suppression of Denitrification in Estuarine Sediments Receiving Primary- and Secondary-Treated Paper and Pulp Mill Discharge

• Published in: Environmental science & technology Vol. 45; no. 8; pp. 3400 - 3406
• Main Authors: Oakes, Joanne M, Eyre, Bradley D, Ross, Donald J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15-04-2011
• Subjects: Ammonia - analysis; Applied sciences; Biodegradation, Environmental; Biological and physicochemical properties of pollutants. Interaction in the soil; Biomass; Biomass energy; Denitrification; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Processes; Exact sciences and technology; Fresh Water - chemistry; Geologic Sediments - chemistry; Geologic Sediments - microbiology; Industrial Waste - analysis; Microbial Interactions; Natural water pollution; Nitrogen - analysis; Nitrogen - metabolism; Nitrogen Oxides - analysis; Phytoplankton - growth & development; Phytoplankton - metabolism; Plankton; Pollution; Pollution, environment geology; Pulp & paper mills; Seawater - chemistry; Seawaters, estuaries; Sediments; Sludge; Soil and sediments pollution; Waste Disposal, Fluid - methods; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - metabolism; Water treatment and pollution; Wood - metabolism; Wood waste; Australia; Tasmania; Oceania; Short term; Estuaries; Paper mill; Sediments; Long term; Biological purification; Paper industry; Intertidal zone; Industrial waste water; Denitrification; Physicochemical purification; Waste water purification; Waste water discharge
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es103636d

To determine the role of sediment denitrification in removing inputs of primary- (PE) and secondary-treated effluent (SE) from a pulp and paper mill (PPM), organic matter (OM) associated with PE (residual wood fiber) and SE (activated sludge biomass and phytoplankton) was added to estuarine intertidal sediments and denitrification rates were measured over 27 days. Labile sludge biomass and phytoplankton initially stimulated denitrification, including for pre-existing sediment N. After 2.5 d, however, denitrification was suppressed apparently due to microbial competition for N to process the refractory (high C:N) material remaining. Wood fiber suppressed denitrification throughout the experiment due to competition for N to process the refractory OM. Ultimate long-term denitrification suppression by phytoplankton is offset by initial enhanced denitrification rates. Although nutrient release during degradation of sludge biomass and wood fiber may stimulate phytoplankton production, N equivalent to 127% of the expected daily phytoplankton load was denitrified within 24 h, allowing for permanent removal of PPM-derived N. Compared to primary treatment, secondary treatment of PPM effluent has greater potential for N removal.