Determinação da vazão ideal de captação (m3/h) de gás metano em drenos horizontais de um aterro sanitário da Região Metropolitana de Fortaleza-CE.

Abstract

This research aimed to determine the optimal methane uptake conditions (m3/h) in three horizontal drains of the Sanitary Landfill from Caucaia-CE, from adjustments and tests on suction pressure, flow and gases quality. In the PH335 drain, the highest concentration of methane (63.6%) occurred with 25% valve aperture, i.e. working at -1.5 mb of pressure and capturing 41.0 m3/h. Above 25%, methane concentration decreases and more contaminants (oxygen, nitrogen and other gases) enter the drain, damaging the quality of the recovery system. In the PH361 drain, the highest methane concentration (61.4%) occurred with the valve opened at 75 and 100%, i.e., under -5.9 and -7.1 mb of pressure, capturing 86.1 and 92.2 m3/h, respectively. Unlike the previous drain, the progressive valve opening does not carry contaminants. In the PH363 drain, the highest methane concentration (55.3%) occurred with the valve open at 75%, that is, at -8.2 mb of pressure and capturing 52.2 m3/h. In the PH363 drain, the highest methane concentration (55.3%) occurred with the valve opened at 75%, i.e., at -8.2 mb of pressure and capturing 52.2 m3/h. In this drain the larger the opening, the greater the input of contaminants. The results show that: (1) each drain has unique characteristics, requiring specific vacuum control, (2) the quality of the gases captured depends on the location of the drain, (3) observed variations can mean changes in field conditions, actual composition of residues, moisture contents, compaction level and temperature, among other parameters.