Acetylene has been found to significantly inhibit biological activity of methanogens and thus might be applicable for reducing the generation and emission of methane from municipal solid waste landfills. However, acetylene is gaseous and so it is considered physically infeasible to directly apply this gas to waste in landfill conditions. In the present study, a novel acetylene release mechanism was tested, using a matrix of acetylene entrapped in high hydrophobic paraffin wax and/or rosin and calcium carbide capsules with a ratio of 1.0 g g^–1 matrix and a diameter of 10 mm to facilitate the gradual release of acetylene. A diffusion mechanism model (Q = x t ^0.5) for the matrix was derived based on the T. Higuchi equation, and the effective diffusion coefficients (D _e) were acquired by linear fitting. Additionally, it was found that D _e remained constant when the rosin content was up to more than 20% g g^–1 matrix.

Thermal utilization of municipal solid waste and commercial wastes has become of increasing importance in European waste management. As waste materials are generally composed of fossil and biogenic materials, a part of the energy generated can be considered as renewable and is thus subsidized in some European countries. Analogously, CO₂ emissions of waste incinerators are only partly accounted for in greenhouse gas inventories. A novel approach for determining these fractions is the so-called balance method. In the present study, the implementation of the balance method on a waste-to-energy plant using oxygen-enriched combustion air was investigated. The findings of the 4-year application indicate on the one hand the general applicability and robustness of the method, and on the other hand the importance of reliable monitoring data. In particular, measured volume flows of the flue gas and the oxygen-enriched combustion air as well as corresponding O₂ and CO₂ contents should regularly be validated. The fraction of renewable (biogenic) energy generated throughout the investigated period amounted to between 27 and 66% for weekly averages, thereby denoting the variation in waste composition over time. The average emission factor of the plant was approximately 45 g CO₂ MJ^–1 energy input or 450 g CO₂ kg^–1 waste incinerated. The maximum error of the final result was about 16% (relative error), which was well above the error (<8%) of the balance method for plants with conventional oxygen supply.

Energy and greenhouse gas balances for a waste incineration plant (Reno–Nord I/S, Aalborg, Denmark) as a function of time over a 45-year period beginning 1960 are presented. The quantity of energy recovered from the waste increased over time due to increasing waste production, increasing lower heating value of the waste and implementation of improved energy recovery technology at the incineration plant. Greenhouse gas (GHG) balances indicated progressively increasing GHG savings during the time period investigated as a result of the increasing energy production. The GHG balances show that the Reno–Nord incineration plant has changed from a net annual GHG emission of 30 kg CO₂-eq person^–1 year^–1 to a net annual GHG saving of 770 kg CO₂-eq person^–1 year^–1 which is equivalent to approximately 8% of the annual emission of GHG from an average Danish person (including emissions from industry and transport). The CO₂ emissions associated with combustion of the fossil carbon contained in the waste accounted for about two-thirds of the GHG turnover when no energy recovery is applied but its contribution reduces to between 10 and 15% when energy recovery is implemented. The reason being that energy recovery is associated with a large CO₂ saving (negative emission).