Biogas productivity model Hashimoto’s model By Jin Mi Triolo

Hashimoto’s kinetic model γ = volumetric CH 4 production rate, m 3 CH 4 m -3 reactor volume per day, B 0 =ultimate CH 4 yield, m 3 CH 4 kg -1 (VS), S 0 = influent VS concentration Kg(VS)/m 3 (feed), feed is biomass μ m = maximum specific growth rate/day, days -1, μm = 0.013T – HTR = hydraulic retention times/ day, K=kinetic parameter, dimensionless (K= exp (0.051*S 0 ))

Hashimoto’s kinetic model CH 4 productivity is a function of ultimate CH 4 yield (B 0 ) influent substrate concentration(volatile solids, VS) retention time (HTR) kinetic parameters K μ m K = exp (0.051*VS) μ m = 0.013T – T = temperature K = exp (0.051*VS) μ m = 0.013T – T = temperature For assessing biogas yield by Hashimoto’s model B 0, VS, Operation time(HRT), operation temperature(T) Required ! For assessing biogas yield by Hashimoto’s model B 0, VS, Operation time(HRT), operation temperature(T) Required !

Hashimoto’s two kinetic parameters K = exp (0.051* S 0 )) When VS increases, K increases exponentially. Inhibition strength simply estimated only using VS concentration, but highly predictible. μm = 0.013T – T = temperature Following Hashimoto, μm = temperature dependent μm increase linearly, as T increases But only in (20°C < T <60°C) μm is not applicable for the T lower than 20°C. Requirement of building new kinetic algorithm for lower temperatures.

Example of hashimoto’s curve Batch experiment Predicted by Hashimoto’s model

Exercise Pig fattening manure 5 pigs BMP :350 L/kg VS Hydraulic retention time 30 d Operation temperature 25 °C Calculate how much slurry they excrete per day? Calculate volumetric biogas yield at 25 °C? Cattle manure 2 cows Calculate how much slurry they excrete per day BMP :195 L/kg VS Hydraulic retention time 30 d Operation temperature 25 °C Calculate how much slurry they excrete per day? Calculate volumetric biogas yield at 25 °C?