Specialty micro-perforated covers can be installed on ASP piles to contain volatile organic compounds (VOC’s) and to mitigate odors.  Such covered aerated static pile (C-ASP) are frequently able to meet the more stringent EPA emissions requirements and may be classified as in-vessel systems. C-ASP compost piles are generally not turned at all, or infrequently, and therefore it is critical to combine a good initial blend of raw materials to maintain porosity during the composting cycle, and an AirFloor forced aeration system capable of delivering the necessary oxygen to the microbes.