Evolution of nitrogen species in landfill leachates under various stabilization states. (November 2017)

• Record Type: Journal Article
• Authors: Zhao, Renzun; Gupta, Abhinav; Novak, John T.; Goldsmith, C. Douglas
• Is Part Of: Waste management. Volume 69(2017)
• Page Start: 225
• Page End: 231
• Publication Date: 2017-11
• Subjects: Landfill leachate -- Organic nitrogen -- Ammonia -- XAD-8 resin -- solid state NMR; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2017.07.041
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: Significant amount of organic nitrogen was found in landfill leachates. Organic nitrogen concentration shows decreasing trend with landfill age. Proteinaceous organic nitrogen in fresh leachates is prone to bio-degradation, while. Recalcitrant organic nitrogen is believed to be heterocyclic nitrogen and other un-identified species. Abstract: In this study, nitrogen species in landfill leachates under various stabilization states were investigated with emphasis on organic nitrogen. Ammonium nitrogen was found to be approximately 1300 mg/L in leachates from younger landfill units (less than 10 years old), and approximately 500 mg/L in leachates from older landfill units (up to 30 years old). The concentration and aerobic biodegradability of organic nitrogen decreased with landfill age. A size distribution study showed that most organic nitrogen in landfill leachates is <1 kDa. The Lowry protein concentration (mg/L-N) was analyzed and showed a strong correlation with the total organic nitrogen (TON, mg/L-N, R 2 = 0.88 and 0.98 for untreated and treated samples, respectively). The slopes of the regression curves of untreated (protein = 0.45TON) and treated (protein = 0.31TON) leachates indicated that the protein is more biodegradable than the other organic nitrogen species in landfill leachates. XAD-8 resin was employed to isolate the hydrophilic fraction of leachate samples, and it was found that the hydrophilic fraction proportion in terms of organic nitrogen decreased with landfill age. Solid-state 15 N nuclear magnetic resonance (NMR) was utilized to identify the nitrogen species. Proteinaceous materials were found to be readily biodegradable, while heterocyclic nitrogen species were found to be resistant to biodegradation.