Waste to energy in the UK: policy and institutional issues

A sustainable waste management policy is necessary to manage the growing stream of municipal solid waste in ecologically sustainable ways. Although landfill has been the dominant form of waste management in the UK there is a need to comply with the European Union landfill directive. Waste to energy (WtE) is a viable waste management option to reduce the reliance on landfills and reap the energy benefits of waste. The first waste-fired power plant was built in the UK in 1885 but several barriers have constrained the use of WtE. This paper assesses the policy and institutional context for the development of WtE in the UK. It discusses how public opinion and choice of technology are important factors in achieving a wider acceptance of WtE in the UK. There is a need to devise coordinated policies on sustainable waste management at the regional and local levels. Furthermore, making all WtE technologies eligible for renewable obligation certificates could support the development of the technology and divert waste from landfills. The absence of efficient heat delivery networks is also a barrier to fulfilling the potential for WtE in the UK

The influence of soil and biosolids type, and microbial immobilisation on nitrogen availability in biosolids-amended agricultural soils - implications for fertiliser recommendations

Soil microbial biomass interactions influencing the mineralisation of N in biosolids-amended agricultural soil were investigated under field conditions in two soil types, a silty clay and a sandy silt loam, with contrasting organic matter contents. Soil treatments included: dewatered raw sludge (DRAW); dewatered and thermally dried, mesophilic anaerobically digested biosolids (DMAD and TDMAD, respectively); lime-treated unstabilised sludge cake (LC); and NH4Cl as a mineral salt control for measuring nitrification kinetics. Soil mineral N and microbial biomass N (MBN) concentrations were determined over 90 days following soil amendment. Despite its lower total and mineral N contents, TDMAD had a larger mineralisable pool of N than DMAD, and was an effective rapid release N source. Increased rates of mineralisation and nitrification of biosolids-N were observed in the silty clay soil with larger organic matter content, implying increased microbial turnover of N in this soil type compared with the sandy silt loam, but no significant difference in microbial immobilisation of biosolids- N was observed between the two soil types. Thus, despite initial differences observed in the rates of N mineralisation, the overall extent of N release for the different biosolids tested was similar in both soil types. Therefore, the results suggest that fertiliser guidelines probably do not need to consider the effect of soil type on the release of mineral N for crop uptake from different biosolids products applied to temperate agricultural soils