Aikan process: General Step by step

• The waste is received and its quality is controlled visually.
• Waste bags are opened. A mixer operated by a tractor is used to break up the waste. The slowly rotating blades open the bags and break up organic compounds into smaller particles, simultaneously ensuring that incorrectly sorted waste such as metal, glass, nappies and plastic do not affect the process. Waste bags are opened gently without shredding them to smaller pieces or breaking glass etc.
• Depending on the amount of impurities the waste is either sorted on a drum screen (80 mm) or mixed directly with wood structure materials. The sorted waste is then shredded in to a smaller fraction, and the structural material that allows for the aeration and drainage of the waste mass is added.
• The waste mass (raw material) is then mixed thoroughly in the mixer and then transferred to a process module via a conveyor belt mounted on the back of the mixer.
• The mixture of waste and structural material is loaded into fully closed process modules in which the entire active AD and compost process takes place.
• When the process module is full, it is closed with an air-tight door.
• Anaerobically digested liquid material from the biogas reactor tank is added through a system of pipes.
• To achieve the fastest possible process time the liquid, which is formed during the process, is collected, reheated and re-circulated in the process module.
• Biogas is continuously produced in a separate reactor tank. Biogas is combusted in a gas turbine, which produces electricity and heat. The biogas can also be refined for fuel. The digestion process runs from two to four weeks - depending of the gas potential of the concrete waste type.
• After the satisfactory conversion of the waste, the waste mass is drained of percolate and the composting process begins.
• During the composting process, the entire waste mass is heated to a minimum of 70ºC for at least 1 hour, thus eliminating disease-causing organisms. The compost can then be used for agricultural purposes without hygienic restrictions.
• After the active process, the door is opened and the compost is either sorted directly after emptying the module - or matured for a period - depending on the field of use. Sorting covers taking out plastic by a windscreen, metals with a magnetic separator and structure for recycling in the process. Screening takes place on a 10 - 15 mm sieve size.

Please note that:

• The process is continuously being optimized in order to achieve the greatest possible gas yield and the best compost products.
• Fluid treatment is easily done by adding two storage tanks to the system. One tank is for incoming fluids a second tank is used to storing of excess de-gasified leachate. Pre-treatment (sanitization) of fluids will be done in process tanks, in which heating to 70 °C for at least one hour is carried out.