The purpose of the study was to characterize natural ventilation in full-scale gravity collection system components while measuring other parameters related to ventilation. Experiments were completed at four different locations in the wastewater collection systems of Los Angeles County Sanitation Districts, Los Angeles, California, and the King County Wastewater Treatment District, Seattle, Washington. The subject components were concrete gravity pipes ranging in diameter from 0.8 to 2.4 m (33 to 96 in.). Air velocity was measured in each pipe using a carbon-monoxide pulse tracer method. Air velocity was measured entering or exiting the components at vents using a standpipe and hotwire anemometer arrangement. Ambient wind speed, temperature, and relative humidity; headspace temperature and relative humidity; and wastewater flow and temperature were measured. The field experiments resulted in a large database of measured ventilation and related parameters characterizing ventilation in full-scale gravity sewers. Measured ventilation rates ranged from 23 to 840 L/s. The experimental data was used to evaluate existing ventilation models. Three models that were based upon empirical extrapolation, computational fluid dynamics, and thermodynamics, respectively, were evaluated based on predictive accuracy compared to the measured data. Strengths and weaknesses in each model were found and these observations were used to propose a concept for an improved ventilation model. Water Environ. Res., 83, 265 (2011).
Odor emissions data were collected during a Biosolids Fecal Coliform Regrowth Study in order to gain insight into odor emissions from anaerobically digested biosolids stored on site and during land application. Sampling and concentration analyses were completed for the following: odor (in terms of dilutions to threshold), ammonia, speciated sulfur compounds, volatile organic compounds, speciated amine compounds, and volatile organic acids. The effects of liming centrifuge dewatered biosolids were assessed, and comparison was made of belt filter pressdewatered versus centrifuge-dewatered biosolids.
KEYWORDS
Biosolids, Land application, Odor• Real time field evaluation of hydrogen sulfide (H2S), ammonia, and amine odors• Odor panel analysis of bag samples following ASTM method E679-04• Gas chromatograph/flame photometric detection (GC/FPD) following ASTM method D5504-01 for 20 typical reduced-sulfur-compounds• Mass spectroscopy analysis of bag samples using modified EPA Method TO-15
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