Aerobic composting captures the heat energy created from treating sewage, food waste and garden waste. This heat would provide the internal heating system for a building through transportable composting vessels called Aergestors, which are claimed to be the only such systems in the world.
With the ability to produce 1.3 times as much heat energy per tonne of food waste than the total of electrical heat plus heat energy from anaerobic digestion, the system could produce 90 per cent of the heat energy for a building. But so far, there has not been enough funding in order to test the system in a commercial setting.
Alpheco Composting managing director Neil Winship said: “Many people seem to think the only useful form of energy is electrical energy and so this seems to be why the Government are so keen on anaerobic digestion. I’m deeply frustrated by the British for not picking up this technology and soon, I’ll cancel the patent on it and offer it to the rest of the world instead.”
Unlike AD, AC uses oxygen so bacteria and funghi can decompose the organic matter. In this way, AC produces just CO2 and water, whereas AD also produces methane, which can be burned but the facility must be scrubbed first to avoid corrosion and it can be explosive. Using oxygen in AC also means that fibrous matter left over from AD is decomposed further so it is a more useful form of fertilizer.
In order to supply buildings with this heat, the transportable Aergestor vessels, which treat the waste, would be fitted to the building’s water boiler or under-floor heating system and filled with waste.
The heat produced is ‘low grade’ at 40-50 degrees centigrade, which is perfect for under-floor heating systems as the heat does not have to travel. With old boiler heater systems it is possible that a heat pump would need to be used to increase this temperature in order to deliver the average house temperature of 16-20 degrees.
Winship added: “We need to undertake a pilot scheme of the system in order to optimize the settings and measure the heat in commercial surroundings but funding is needed for that. I know the theory of the system and the laboratory findings but I need to demonstrate how effective the system is because most local authorities cannot envisage it from articles - they need to see it working.