An analysis of the Langage Farm

The anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is a growing technology within the UK and understanding the process efficiency of AD facilities is increasingly important in order to develop the industry further. The study analysed one facility; Langage Farm AD plant is a medium scale plant operating a wet mesophilic digestion system. The study used the mass balance approach and examined all aspects of the plant. The most critical aspect characterised the materials entering, transferred within and exiting the process in order to understand biogasification potentials, degrees of stability of the materials and material composition. This characterisation was used to understand and model the process flow of Langage Farm AD facility and the results highlighted areas for improvement however overall the plant parameters were all above recommended and literature values. The plants Organic Loading Rate (OLR) of 2.33 kg VS m-3day-1 was between recommended values; the well balanced OLR and the longer than average Hydraulic Retention Time (HRT) of 65.64 days enabled a higher rate of degradation of the inputted material as shown by the Volatile Solids Reduction (VSR) of 82.99% which was well above the 38% recommended value by Schafer et el. (2002). Overall the study facility was a well-balanced process which fully utilises the incoming waste to produce a high volume of biogas and a high quality digestate