The most common energy application for biogas is on-site power generation using gas engine units. The introduction of a bottoming cycle based on Scroll expander Organic Rankine Cycle (ORC) technology within a biogas plant is of high interest since the excess heat produced by biogas engines can be used to produce additional power. This paper describes the retrofit of a plant consisting of a dige...

Biogas production rate is an important criterion for the entire biogas production process. In the present study the biogas production rate was evaluated using more than 30 process variables measured at an agricultural biogas plant in Germany during two months. The measured variables include the chemical measurements (such as pH, dried matter, amount of organic acids), energy supply specificatio...

Biogas plants are the most complex systems and are heavily studied in the field of renewable energy. A biogas system is mainly influenced by biological and technical parameters that strongly interact with each other. One recommended practice when operating a biogas plant is the recirculation of the substrate from the second fermenter into the first fermenter, which extends the recirculation amo...

Lignocelluloses are often a major or sometimes the sole components of different waste streams from various industries, forestry, agriculture and municipalities. Hydrolysis of these materials is the first step for either digestion to biogas (methane) or fermentation to ethanol. However, enzymatic hydrolysis of lignocelluloses with no pre-treatment is usually not so effective because of high stab...

Biogas production represents a fascinating process for the recovery of nutrients and renewable energy from various organic waste streams. The process is of interest for the production of value-added chemicals by mixed cultures and can also be applied in combined bioenergy production systems. Strategies and opportunities for optimization of biogas quality and quantity are presented.