BIOENERGY
By integrating anaerobic digestion, and biogas conversion, in the design of our facilities, we help our clients open new revenue streams through energy offtakes to local grids or external markets.
Wet anaerobic digestion
Wet Anaerobic Digestion is a biological process that breaks down organic material in the absence of oxygen, in a liquid environment with high water content, typically around 85%. This technology is ideal for processing feedstocks with a low impurity content and small particle size, such as de-packaged food and or food from food processing industries, agricultural by-products, and sewage sludge. This technology is known as a continuous stirred tank reactor process.
The Thoeni TNV digester can operate at a much higher solids percentage than its competitors, allowing for a higher gas yield per tonne of input material. The digester utilizes slow rotating agitators for minimal energy consumption and maximum agitation of the digestate.
Image credit: Thoeni
Dry anaerobic digestion
Dry Anaerobic Digestion is a biological process that breaks down organic materials with low moisture content, typically between 70-80%, making it ideal for solid and semi-solid feedstocks with high structure and impurity levels. The technology can handle particle sizing of up to 80mm, making it very suitable for feedstocks such as Food and Garden organics – or FOGO, industrial waste and yard trimmings. This system is known as a Plug-flow process.
Due to the high solids design of the system, impurities are retained in suspension, allowing even the most contaminated organic feedstock to be eligible for digestion. This technology is the best choice for kerbside collected streams, where cleanliness is impossible to guarantee.
Image credit: Thoeni
Outputs
Electricity
To power the Organics Recycling facility and its processes behind the meter, and or, export (surplus) energy to the grid.
Heat
Captured from the generator’s exhaust and cooling systems to maintain digester temperature and export (surplus) heat.
Biomethane
Upgrade biogas into biomethane for injection into natural gas grids or use as vehicle fuel.
By further de-watering digestate mechanically, additional end products are created by separating the digestate into a solid and liquid fraction.
Solid Fraction
Can be composted, used as soil amendment, or turned into pellets for fertiliser.
Liquid Fraction
Can be applied as a liquid fertiliser or further refined.