Beter (dan) vergisten

2011

The digestion of organic waste and residues has increased in importance during the last ten years in Germany. New plants have been built mainly for the treatment of agriculture residues (e.g. liquid manure) and municipal solid waste (primarily separately collected organic waste). The potential of biogas generation with 8,7 bill. m 3 /a, which is provided by the accumulating amount of organic waste, is presently hardly utilised at all. Looking ahead, the more efficient use of this great bio-mass resource is an important aim. Many digestion plants do not operate at full capacity, others are overloaded. That fact is due to an improper and uncertain data base during the planning phase. If the conditions have changed in a few years, the plants will not be in the position to operate in an optimal way any longer. Additionally a lot of organic waste accrues only in certain regions during a certain season. The integration of this kind of waste in central, stationary plant concepts seems to b...

2016

2019

The introduction of Feed-in tariffs in the German Renewable Energy Act (EEG) fuelled the growth of anaerobic digestion (AD) industry making Germany the country with highest number of operational AD plants. However, the rapid expansion of AD industry resulted in some unwanted side-effects such as food vs fuel debate, increased prices for electricity and the temporal mismatch between supply and demand of electricity grid. Subsequent amendments in EEG has tried to address some of these issues by reduction in Feed-in tariffs, introduction of a cap on cereal based feedstocks and providing premium for energy production in accordance with market demand. Furthermore, the Feed-in tariffs which were introduced for 20 years are soon going to expire. The changes in legal and political discourse is soon going to introduce some new challanges to the AD industry. This paper has discussed some of these challanges and their potential solutions.

Processes

Anaerobic digestion allows for the proper management of agro-waste, including manure. Currently, more than 18,000 anaerobic digestion plants are under operation in EU, 80% of which are employed in the rural context. Tariff schemes for power generation from biogas produced during anaerobic digestion of agricultural feedstocks in Germany, Italy and Austria are coming to an end and new approaches are needed to exploit the existing infrastructures. Digesters in the rural context can be implemented and modified to be transformed into sustainable multi-feedstock and multi-purpose biorefineries for the production of energy, nutrients, proteins, bio-chemicals such as carboxylic acids, polyesters and proteins. This paper describes how the transition of agricultural anaerobic digesters into multi-products biorefineries can be achieved and what are the potential benefits originating from the application of a pilot scale platform able to treat cow manure and other crop residues while producing ...

Anaerobic Digesters: Perspectives and Challenges

Manure treatment technologies are becoming important tools for the application of regulations concerning water and soil protection, greenhouse gasses emission mitigation, fertilizer resources recovery and renewable energy production. The technological strategy to be applied, as a combination of processes to fulfil a given objectives, depends on many factors, mainly related to local or regional conditions. As a result of the study described, 19,196 treatment units were identified, processing 7.8% of the livestock manure production in the EU, equal to 108 million tonnes/year, containing 556,000 tonnes of nitrogen and 139,000 tonnes of phosphorus. Products obtained from processing were classified in 11 groups, with three types of manure processing products being marketed at considerable volume, namely "separation solids", "manure compost" and "dried manure and pellets". Processing products standards must be developed as a way to support the development of the market infrastructure. Anaerobic digestion was identified as a focal sustainable technology to combine with further processes, because of its contribution to mineralization and better recycling of nutrients, but also due to renewable energy production and greenhouse gases mitigation.

EDIS

Livestock wastes can be important sources of nutrients for crops, but manure must be managed properly to prevent loss of nutrients to the environment in air or ground and/or surface water. Stabilization of manure is important prior to successfully recycling the organic material back to arable lands. Methods for stabilizing livestock wastes include composting, aerobic digestion, anaerobic digestion, lime stabilization, and heat drying. The stabilization process reduces the organic matter and water contents, unpleasant odors, concentrations of pathogenic microorganisms, and weed seeds. Anaerobic digestion (AD), which is the topic of this fact sheet, also results in the production of renewable energy in the form of methane-rich biogas. This 10-page fact sheet informs farmers and Extension agents about types of anaerobic digester systems used in the United States with various manure-handling systems. It points out digester systems currently being used in Florida and the benefits of mana...

This report is dealing with the characterization of processes and technologies applicable to manure treatment. Some possible objectives of treatment systems have been identified, depending of the local constrains. The main driving force for adopting a manure processing plant is considered to be the Nitrates Directive (91/676/EEC) implementation, and the consequent nutrients management requirements, followed by the incentives for renewable energy production (biogas). In this report, 45 unitary processes have been identified and explained. Some of these processes can be found working alone if these are enough for solving the problem that motivated its adoption. Others must be combined for fitting a given objective. Usual combinations have been identified at every unitary process description section and a synthesis of these main combinations is presented. Anaerobic digestion is found to be a key process in strategies dealing with nutrients recovery.