Modeling and simulation of multi-stage continuous high cell density culture to disposer-based food waste treatment (HEROS) and VFA production for fuels and chemicals

Abstract

HEROS and VFA production system is modeled by modifying standard ASM1 and ADM1. The accuracy of modified model is demonstrated by dynamic simulation and comparing with experimental data. The improvement of current system by MSC-HCDC is tested by simulation. Type B HEROS reactor for 45 households is modeled as two aerobic packed bed and aerobic CSTR and its dynamic states are simulated to demonstrate its distinguished performance. Fully aerated model shows that final BOD ranges from zero to 90 mg/L. The air supply model is modified as oxygen inhibited model to represent more actual system. Oxygen inhibited model exhibits that final BOD ranges from 75 ~ 150 mg/L. When simulated with 50 % amplitude sine input, the final BOD varies from 25 ~ 160 mg/L. The result fits well with experimental data of actual effluent BOD data of HEROS. When $2n^{nd}$ reactor is extended, final BOD becomes 0 ~ 123 mg/L and thoroughly satisfy the effluent BOD regulation, 125.8 mg/L. When MSC-HCDC is applied to the extended model, final BOD slightly drops to 118 mg/L. In 45 households HEORS system, implementation of MSC-HCDC is difficult because it should treat high loading rate of BOD in relatively short HRT with oxygen inhibition. VFA production for biofuel is modeled with modified ADM1 standard model. Methane production is inhibited in the model. In singe stage continuous production, VFA concentration was 9.565 g/L and it is half of experimental data which is conducted with food waste. In single stage batch production, VFA concentration is 8.74 g/L and the result coincide with experimental data of untreated MSW/SS. Modified ADM1 model can be used to model and simulation for untreated MSW biomass. For future research, modified ADM1 model can be utilized to simulate effect of MSC-HCDC in series of reactors.