Dr William P. Barber, Atkins Water, UK
(free)This paper analyses the data from 16 full-scale anaerobic digester plants worldwide and investigates the influence of various parameters on digester and downstream dewatering performance characteristics. The plants varied in size from 35,000 to 900,000 population equivalents with loading rates from 0.5 to 2.7 kg VS/m3 d. Biogas yield varied from 221 l/kg VSfed to 551 l/kg VSfed. The average production rate was 881 l/kg VS destroyed, which is lower than literature values of up to 1000 l/kg VS destroyed. In spite of different operating regimes and conditions, various relationships were discovered between: sludge quality and volatile solids destruction; sludge quality and biogas yield and effluent volatile solids and dewatering. Where correlations existed, these were used to make predictions on operating costs of the digestion and dewatering plant based on sensitivity analysis. The results of the model were used to make recommendations on how to optimise the operation of an anaerobic digestion plant.
KEY WORDS Anaerobic digestion; Biogas; Cost analysis; Dewatering; Renewable Energy; Sludge quality.
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