TITLE:
Influence of Stand-Alone Vertical Gas Vents on Aeration and Denitrification of Organic Municipal Waste Assessed by Two-Dimensional (2D) Lysimeters
AUTHORS:
Tadis Dillon, Takayuki Shimaoka, Teppei Komiya
KEYWORDS:
Organic Waste, Waste Stabilization, Passive Aeration, 2D Lysimeter, COMSOL Multiphysics, In-Situ Aeration
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.11 No.12,
December
29,
2023
ABSTRACT: Landfilled
organic waste, in the presence of oxygen, can undergo aerobic decomposition facilitated
by heterotrophic microorganisms. Aerobic degradation of solid waste can quickly
consume available oxygen thus curtailing further degradation. The aim of this
study was the investigation of a low-cost method of replenishing oxygen
consumed in landfilled waste. Three 2D lysimeters were established to
investigate the effectiveness of stand-alone, vertical ventilation pipes
inserted into waste masses. Two different configurations of ventilation were
tested with the third lysimeter acting as an unventilated control. Lysimeters
were left uninsulated and observed over the course of 6 months with regular
collection of gas and leachate samples. Lysimeters were then simulated for
Oxygen (O2) and Nitrous oxide (N2O) to analyze the
denitrification contributions of each. The experiment revealed that a single
ventilation pipe can increase the mean oxygen level of a 1.7 m × 1.0 m area by up to
13.5%. It also identified that while increasing the density of ventilation
pipes led to increased O2 levels, this increase was not significant
at the 0.05 probability level. A single vent averaged 13.67% O2 while inclusion of an additional vent in the same area only increased the
average to 14.59%, a 6.7% increase. Simulation helped to verify that lower ventilation
pipe placement density may be more efficient as in addition to the effect on
oxygenation, denitrification efficiency may increase. Simulations of N2O
production estimated between 8% - 20% more N2O
being generated with lower venting density configurations.