68. During the operating period of a biogas collection system that has a gas pumping device pursuant to the second paragraph of section 32, the flow of biogas must be continuously measured and the results recorded. For the purpose of ensuring compliance with the requirements of section 62, the operator must also monitor or have the following monitored: (1) at least every 3 months:
— the concentration of methane generated by the residual materials;
— the concentration of nitrogen or oxygen and the temperature in each drain and wet well;
(2) at least once a year, the concentration of methane at the surface of the disposal areas of an engineered landfill that receives 100,000 tons or less of residual materials per year; or
(3) at least 3 times a year, in the spring, summer and fall, the concentration of methane at the surface of the disposal areas of an engineered landfill that receives more than 100,000 tons of residual materials per year. The frequency may, however, be reduced to once a year for all or part of a disposal area that has received a final cover if, after a minimum 2-year monitoring period of that area or part of area, none of the measurements has shown that the limit value set out in the second paragraph of section 62 has been exceeded. The reduction applies as long as the annual monitoring shows compliance with the limit value, otherwise the frequency of the measurements is 3 times a year until the situation is remedied for that area or part of area.
Where thermal destruction equipment for biogas is required pursuant to the second paragraph of section 32, the destruction temperature and flow rate of the biogas must be continuously measured and recorded and the destruction efficiency for the organic compounds other than methane must be verified at least once a year.