Following the Kyoto protocol with respect to reducing emissions of greenhouse gases emissions, and EU energy policy and sustainability in waste management, there has been an increased interest in the reduction of emissions from waste disposal operations. From the point of view of nitrous oxide (N2O) emissions, waste incineration and waste co-combustion are very acceptable methods for waste disposal. In order to achieve very low N2O emissions from waste incineration, particularly for waste with higher nitrogen content (e.g. sewage sludge), two factors are important: temperature of incineration over 900°C and avoiding the selective non-catalytic reduction (SNCR) de-NOX method based on urea or ammonia treatments. The more modern selective catalytic reduction (SCR) systems for de-NOX give rise to negligible sources of N2O.