Abstract of the project

Anaerobic digestion is considered to be an efficient, sustainable and technically feasible way to produce energy from organic wastes. The anaerobic digestion is a highly coupled and complicated non-linear microbiological process, involving combined action and influence of multiple microorganisms. It is important to improve its optimization and control performance and the overall energy conversion efficiency. The two-stage anaerobic digestion concept consists in a hydrogenic process followed by methanogenic process in two separated bioreactors, with simultaneous production of hydrogen and methane.

In this project our attention will be focused on the two-stage anaerobic digestion of agricultural wastes abundantly found in Bulgaria. For increasing the overall energy production for two-stage anaerobic digestion in continuously stirred bioreactors optimization via two different ways will be performed:

1. Experimental optimization of common process parameters.

Only a few articles are known concerning optimization of process parameters of two-stage anaerobic digestion of agricultural wastes. This project will study the influence of common process parameters (temperature, pH, retention time and organic loading rate) for both bioreactors (hydrogen producing and methane producing) in view of optimizing the overall energy production.

2. Optimization of the processes in both bioreactors using mathematical models and automatic control theory.

The existing bioreactor control methods are not sufficiently robust and efficient. This project introduce novel algorithms for control which is resistant to external disturbances and perturbations of system parameters. This models and controllers will optimize hydrogen and methane production and improves the overall economic performance of the system.

We will work on creating stable microbial consortia, generating hydrogen and methane to accomplish enhanced yield of both energy carriers.

The successful implementation of the project will effectively solve the problems addressing the shortcomings of insufficient degradation of organic waste and pollution, single gas-producing species and unstable production, provide an effective path for overcoming energy shortage and green sustainable development that will better serve China's rapid economic development, as well as Bulgarian industrial modernization.