ENHANCING EXISTING DIGESTER CAPACITY WITH PRE-TREATED FOOD WASTE

Transcription

1 ENHANCING EXISTING DIGESTER CAPACITY WITH PRE-TREATED FOOD WASTE

2 FOOD WASTE PROCESSING Agrivert is the market leader in the design and build of food waste pre-treatment plants. Where organics facilities have spare AD capacity, food waste can enhance energy yield and revenues whilst providing a local service to the community. The biggest hurdle to making this connection happen is the pre-treatment of such food waste as this material is often variable and mostly packaged. Agrivert have a proven and robust solution to solve this challenge. Differentiation through design The Agrivert design is drawn from our extensive on-the-ground experience of operating our own food waste AD facilities. Having designed, built and then operated our AD plants over the last 7 years, we have developed a robust and successful system that allows trouble-free pre-treatment and onward successful digestion. The core principles are: Minimised waiting time for delivery trucks A clean reception building Efficient odour control Maximised contaminant removal Maximised substrate dry solids Homogenous feedstock at maximum calorific value.

3 To/from Anaerobic Digestion Onward digestate recycling f t y t u y w Thin liquids Thick liquids Food waste soup Digestate

4 Access via automated speed door Reliable and fast-acting doors allow vehicle access into the building whilst minimising odour release and any loss of biosecurity. Recessed food waste reception bunker With enough capacity for the largest vehicles as well as any vehicle tipping system, the bunker allows below ground storage for cleanliness and minimised re-handling. Liquid off-loading Liquid wastes can be delivered simultaneously into separate tanks without impeding food waste deliveries. Delivery conveyors Large diameter screw conveyors move the food waste cleanly and continuously from the reception bunker into the depackaging mill. Depackaging mill Robust hammermills depackage the food waste reliably and effectively whilst simultaneously sizing it to the required particle size and diluting it to a pumpable state known as substrate or soup. Contamination The majority of contamination received within food waste is typically primary and secondary packaging. This is removed from the hammermill by sealed screw conveyor. High pressure screw presses High pressure screw presses remove liquids from the separated packaging fraction to produce a high calorific value RDF (Resource Derived Fuel).

5 Waste liquids Waste liquids are delivered into one of two tanks to allow segregation of differing characteristics. These liquids provide the dilution effect in the hammermill whilst also adding calorific value. Soup Depackaged soup is discharged into a large concrete mixing tank to provide buffer storage, homogenisation and de-gritting. This tank also facilitates a hydrolysis function to prepare the food waste for digestion. Anaerobic Digestion The soup is pumped from the mixing tanks to the digesters for energy recovery via anaerobic digestion. Pasteurisation Pasteurisers are used to sanitise the digestate prior to onward recycling. This process utilises heat from the CHP engines or a biogas boiler to batch pasteurise the digestate. Digestate Screening Extremely durable, high capacity screens filter and refine the pasteurised Digestate to remove any remaining plastic particles. Digestate Recycling The Digestate is now ready for dewatering into a cake or recycling to agriculture as a whole liquid. Odour Control The complete Reception Building is kept under negative pressure with frequent air changes treated via the Odour Control System.

6 Agrivert Ltd The Stables, Radford Chipping Norton Oxfordshire OX7 4EB United Kingdom t: +44(0)