Organic waste, such as manure or animal slurry, food wastes from domestic, commercial and industrial sources, and sewage sludge, is a resource for energy and nutrients. Biogas plants (anaerobic digesters) produce a methane rich gas and a digestate which is typically considered a waste or ends up as being used a soil improver.
In a biogas plant, the energy from carbohydrates is converted to a gas mixture of methane and carbon dioxide. Biogas can be used to produce electricity and heat, or it can be further purified and used as a natural gas substitute or vehicle fuel.
The nitrogen in the digestate is easily lost as volatile ammonia. Therefore, digestate does not give a balanced and effective nutrient mix to plants when applied as a fertilizer. The nutrient value of the digestate can be significantly improved by treating it with nitrate and nitrite. The nitrogen content can easily be doubled, resulting in a digestate with a value as a balanced fertilizer.
For operators of biogas plants, securing an outlet for digestate is important to avoid disposal, potentially avoid gate fees, and maximize the output of the biogas plant. N2’s technology enables the operators of biogas plants to produce high quality nitrogen fertilizer from digestate and energy produced locally, enhancing overall value creation of the biogas plant.