Use of bioreactor landfill for nitrogen removal to enhance methane production through ex situ simultaneous nitrification-denitrification and in situ denitrification. (August 2017)

• Record Type: Journal Article
• Authors: Sun, Xiaojie; Zhang, Hongxia; Cheng, Zhaowen
• Is Part Of: Waste management. Volume 66(2017)
• Page Start: 97
• Page End: 102
• Publication Date: 2017-08
• Subjects: Bioreactor landfill for nitrogen removal -- Simultaneous nitrification-denitrification -- Methane production -- NO3−-N; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2017.04.020
• Languages: English
• ISSNs: 0956-053X

Abstract

Highlights: Ex situ SND and in situ denitrification bioreactor landfill was conducted. Ex situ SND and in situ denitrification bioreactor landfill improve CH4 production. Ex situ SND and in situ denitrification bioreactor landfill shorten the lag phase time. Ex situ SND and in situ denitrification bioreactor landfill can be a novel approach. Abstract: High concentrations of nitrate-nitrogen (NO3 − -N) derived from ex situ nitrification phase can inhibit methane production during ex situ nitrification and in situ denitrification bioreactor landfill. A combined process comprised of ex situ simultaneous nitrification-denitrification (SND) in an aged refuse bioreactor (ARB) and in situ denitrification in a fresh refuse bioreactor (FRB) was conducted to reduce the negative effect of high concentrations of NO3 − -N. Ex situ SND can be achieved because NO3 − -N concentration can be reduced and the removal rate of ammonium-nitrogen (NH4 + -N) remains largely unchanged when the ventilation rate of ARB-A2 is controlled. The average NO3 − -N concentrations of effluent were 470 mg/L in ex situ nitrification ARB-A1 and 186 mg/L in ex situ SND ARB-A2. The average NH4 + -N removal rates of ARB-A1 and ARB-A2 were 98% and 94%, respectively. Based on the experimental data from week 4 to week 30, it is predicted that NH4 + -N concentration in FRB-F1 of the ex situ nitrification and in situ denitrification process would reach 25 mg/L after 63 weeks, and about 40 weeks for the FRB-F2 of ex situ SND and in situ denitrification process . Ex situ SND and in situ denitrification process can improve the methane production of FRB-F2. The lag phase time of methane production for the FRB-F2 was 11 weeks. This phase was significantly shorter than the 15-week phases of FRB-F1 in ex situ nitrification and in situ denitrification process. A seven-week stabilization phase was required to increase methane content from 5% to 50% for FRB-F2. Methane content in FRB-F1 did not reach 50% but reached the 45% peak after 20 weeks.