Summary
In mechanical-biological pretreatment plants (MBP) microbial conversion processes are used to stabilise the waste to be treated. The focal point here is the oxidation of the degradable organic part of the waste to carbon dioxide.
Four process technologies were examined to indicate which emissions can be expected from MBP, and which possibilities exist to reduce emissions. The tests consisted of aerobe and anaerobe processes. volatile organic compounds (VOC) and gases relevant to the climate were particularly examined for emissions balancing.
Results:
- At the exit of the exhaust treatment system, the concentration of clean gas required by law was met.
- Because of biofilter efficiency attained for Non Methane Volatile Organic Compounds, a 50% separation for NMVOC seems realisable under large-scale operational conditions.
- The leading substances of the Microbial VOC are ethanol, acetaldehyde, 2-butanone, acetone and terpenes with emission masses up to 100 g substances per Mg of municipal solid waste (MSW). MVOC show a good degradation rate in biofilters, whereas xenobiotica pass the biofilter because of their high persistence and can become the dominating compounds in clean gas.
- The fermentation of MSW has an advantage for the emissions since a part of the volatile gaseous contaminants are burned and therefore destroyed with the biogas. MBP produce and emit the greenhouse gases carbon dioxide, methane and dinitrogen oxide.
