SUPPORTING THE COMPOST INDUSTRY:
Aerated Static Pile with Biofilter Layer (+ASP/BFL)
Our team had the privilege of participating in a research and development program conducted for the San Joaquin Valley Air Pollution Control District (SQVAPCD). This program was part of the Technology Advancement Program (TAP) and our involvement included conducting the air emission assessment of a positive aerated static pile (+ASP) pilot-scale compost technology employing a biofilter layer (BFL) as a control technology (Photo 1). Compostable material is added to a perforated air introduction system, the compost is covered with a finished compost layer as the control technology, the pile is irrigated, and air is added at a low flow rate. The compost cycle is complete in 22 days without turning the compost pile thus the name aerated 'static' pile. The assessment included intense emission assessment of both the +ASP/BFL pilot scale unit as well as a comparative windrow compost technology considered the 'baseline' comparison for the project. In total, eleven days of the 22 day compost technology were studied generating life-cycle emissions plots (Figure 1), and emission factors and percent control data for the species studied (Table 1).
Since this study, we have conducted many of these studies for various clients in the compost industry, including biosolids composting and food waste composting. Several clients have changed their composting technology and have adopted the +ASP/BFL technology. They are realizing the benefits of changing over to a more sustainable compost technology. In the process of conducting dozens of these studies for clients, our team has gained knowledge working knowledge that facilitates low air emission. In addition, we have had the chance to work with other expert consultants in this field, like Peter Moon with O2 Compost in designing and operating +ASP/BFL processes. Having worked with clients in applying this technology, which can be a bit challenging given site conditions or operating procedures, we can now offer council in 'fine-tuning' this innovative compost technology meeting air District requirements for acceptable emission control. Like with all our technical services, our assessment approach includes using the USEPA or the SCAQMD modified USEPA Emission Isolation Flux chamber technology (Photo 2) to measure emissions from the +ASP/BFL application and generate life-cycle compost emission plots for key study compounds such as total non-methane non-ethane organic compounds (TNMNEOC, SCAQMD Method 25.3) ammonia (SCAQMD Method 207.1), and olfactory odor (ASTM Method E-679).
We would be most happy to assist you in conducting a pilot-study demonstration to determine if this compost technology is right for your site and application, as well as assisting in fine-tuning your operating approach in pursuit of achieving acceptable air emission standards at your site.
Photo 1. +ASP/BFL Pilot Scale Project
Figure 1 . Life-Cycle Plot of VOC Emissions for the +ASP/BFL TAP Pilot-Study.
Table 1. Measured Emission per Ton of Compost Mix and Control Efficiency.
Photo 2. SCAQMD Modified USEPA Flux Chamber Technology for Advective Sources.