Featured Projects



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).  READ MORE



Tom Card and CE Schmidt have been conducting odor source assessment project for over 20 years.  The odor emission assessment protocol treats odor similarly to any other study compound where sample collection and analysis is performed with the USEPA flux chamber.  The results are reported in 'odor emission factors' for the source tested.  Two common applications are shown in Photos 1 and 2, landfill odor assessment and compost site assessment, respectively.  Here odor samples are collected in Tedlar bags and shipped off to an odor lab (Odor Science and Technology or St. Croix Sensory) for analysis by one of two analytical methods: ASTM Method E-679 or EN 13725- both quantify olfactory odor as 'dilution to threshed' or DT units (like concentration).  These data are then used to diagnose odor sources on site, for engineering retrofit and odor abatement, or even input to dispersion models.  These odor emission factors are qualified by published test method, and most useful for predicting off-site odor impacts predicted as an 'odor level', typically ambient DT, which is directly comparable to odor measured in ambient air downwind of the site as determined by field measurement by a technique as a Nasal Ranger or an analytical method such as ASTM Method E-679 or EN 13725.  READ MORE