Perspectives on using pulse electric field to enhance biogas yield in anaerobic digestion

The usage of pulsed electric field for conditioning substrates can significantly enhance biogas yield in commercial biogas plants. Although the primary effect of the electric field is cracking cell structures for better availability of nutrition, other effects like shockwave, electrophoresis or influence on the metabolic condition of cells can play a role. The aim of this review is the presentation of possible effects and a judgement in terms of economic factors like biogas yield and hydraulic retention time.

The technology was developed for treatment of food in the 50ties of least century and adapted for the treatment of waste water (OpenCeL, Atlante, CA; Innovum, H?chst, Austria). Lab scale studies but also experiments in production plants showed a significant enhancement of biogas yield for electrically treated substrate like manure or maize silage. Due to the very complex biogas process, a high variability of the gas yield makes any prediction of the economic effect of electrical treatment dazzling.

In order to optimize for the action of the electric field on the biogas process comprehensive studies on pilot plants but also on small lab reactors are conducted. Besides monitoring of biochemical quantities, the microbial community is investigated as well. This gives deeper understanding of the direct action of the electric but gives also an opportunity of quantitative judgement of side effect.