This work investigated two different approaches to optimize biological sulphate reduction in order to develop a process control strategy to optimize the input of an electron donor and to study how to increase the feasibility of using a cheap carbon source.
Feast/famine regimes, applied to design the control strategy, were shown to induce the accumulation of storage compounds in the sulphate reducing biomass. This study showed that delays in the response time and a high control gain can be considered as the most critical factors affecting a sulphide control strategy in bioreactors. The delays are caused by the induction of different metabolic pathways in the anaerobic sludge, including the accumulation of storage products. On this basis, a mathematical model was developed and validated. This can be used to develop optimal control strategies.
In order to understand the microbial pathways in the anaerobic oxidation of methane coupled to sulphate reduction (AOM-SR), diverse potential electron donors and acceptors were added to in vitro incubations of an AOM-SR enrichment at high pressure. Acetate was formed in the control group, probably resulting from the reduction of CO2. These results support the hypothesis that acetate may serve as an intermediate in the AOM-SR process.
Chapter 1: Introduction
Chapter 2: Automated Biological Sulphate Reduction: A Review on Mathematical Models, Monitoring and Bioprocess Control
Chapter 3: Sulphide Response Analysis for Sulphide Control Using a pS Electrode in Sulphate Reducing Bioreactors
Chapter 4: Bioprocess Control of Sulphate Reduction in an Inverse Fluidized Bed Reactor: Role of Microbial Accumulation and Dynamic Mathematical Modelling
Chapter 5: Effect of Alternative Co-Substrates on the Rate of Anaerobic Oxidation of Methane and Sulphate Reduction
Chapter 6: General Discussion and Recommendations.
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