This paper presents the preliminary results of a Life Cycle Assessment (LCA) study comparing different wastewater treatment works, operated by Thames Water Utilities Ltd. in the UK. Fifteen works have been studied, representing a range of size and type of treatment works. Five management regimes for centralising sludge treatment and disposal were analyzed in the context of LCA to provide guidance on choosing the best practicable environmental option (BPEO).

Consideration of Global warming potential indicates that the four proposed management regimes with centralisation of sludge for treatment and disposal, as adopted by Thames Water Utilities Ltd., is an environmental improvement upon the current practice. One of these options, that of complete centralisation and composting of sludge prior to disposal, exerts the least environmental impact with respect to Global warming potential. This suggests that the adoption of composting at Crawley is environmentally preferable to increasing the digestion facility at this works.

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