Development of a composting system with vacuum-type aeration, 3: Field scale test of a composting system with vacuum-type aeration

Pilot tests on a full-scale compost plant that uses vacuum-type aeration, allowing compost to be turned with a linear crane and ammonia to be removed by mean of chemical scrubbers were conducted to evaluate the collection of ammonia discharge from the composting process. When 300mm-diameter inlets of a vacuum-type aeration system, filled with wood chips, were laid 1.5m apart from one another at the compost bottom, the inlets resisted clogging due to water condensate or sediment, therefore accelerating the digestion of organic matter and the evaporation of raw materials. In addition, ammonia discharge from the compost surface was reduced compared with that of a positive-pressure aeration system; in the vacuum-type system 9.4% of the initial total nitrogen and approximately 90% of the ammonia discharge was removed by the scrubbers while the other 10% was contained in the water condensate or the drainage, which sum was equal to the ammonia discharge in the positive-pressure aeration system.