Landfill Leachate Nutrient Removal Using Intermittent Aeration

Abstract

The aim of this study was to investigate the biological removal of nitrogen and phosphorus from an intermediate age leachate diluted with domestic wastewater. A sequencing batch reactor (SBR) with alternate aeration was operated under aerobic (Ox) and anoxic (Ax) phases of different durations (Ox 3 or 6 h and Ax 1, 2 or 3 h), for a total cycle period of 24 or 48 h. Crude glycerol from biodiesel production was used as external carbon source to improve denitrification. Leachate mixture of 15 % v/v in municipal wastewater was found to be the optimum concentration at which no adverse effects were observed. Experiments without the use of external carbon source resulted in a low denitrification potential and a strong NO -P release at the non-aeration stage was needed in order to favor a poly-P enriched biomass. In conclusion, an intermittently aerated SBR working at various aerobic/anoxic duration phases was used to treat a mixture of wastewater and semi-mature landfill leachate. Glycerol added as external carbon source was necessary to complete denitrification. Enhanced phosphorus removal was achieved at sufficient anoxic phase duration (2-3 h).

Removal of Nutrients From Anaerobically Digested Swine Wastewater Using an Intermittent Cycle Extended Aeration System

“…However, when the mixing time was too long (i.e., the hydraulic retention time increases), the degradation of organic compounds was efficient, although nutrient depletion caused a reduction in the efficiency of microorganisms. A similar observation was previously reported by Melidis (2014) during landfill leachate treatment. The nitrogen and phosphorus removal efficiencies also decreased when the mixing time was 2 h. The TOC and BOD 5 removal efficiencies in all the three cycles were over 90%, which proves the ability of ICEAS to treat organic compounds.…”

“…The nitrogen and phosphorus removal efficiencies after a cycle time of 8 h significantly decreased compared to those with a cycle time of 6 h. The nitrogen and phosphorus removals mainly occurred in the non-aerated phase ( Gao et al, 2013 ) by the conversion of nitrate (NO 3 − ) into N 2 gas and phosphate (PO 4 3− ) consumption by phosphorus-accumulating bacteria (i.e., for every 1 mg/L of phosphorus consumed, approximately 7.5–10.7 mg/L of COD; Song et al, 2017 ). Thus, the nitrogen and phosphorus removal efficiencies increased when increasing the non-aerated phase time (mixing time; Akin and Ugurlu, 2004 ; Melidis, 2014 ). However, when the mixing time was too long (i.e., the hydraulic retention time increases), the degradation of organic compounds was efficient, although nutrient depletion caused a reduction in the efficiency of microorganisms.…”

Revamping of a Full-Scale Membrane Plant for Landfill Leachate Pretreatment Using Partial Nitritation

“…During storage, in fact, conditions may be created for the fermentation of rapidly biodegradable COD to take place, resulting in the formation of VFA. In addition, the intermittent aeration mode may provide a good environment for the development of PAOs, which release/absorb P-PO 4 3− during the anoxic/aerobic phases, respectively [12,13].…”