SURVEY OF ODOR EMISSIONS FROM SEVERAL LIME STABILIZATION PROGRAMS IN THE DISTRICT OF COLUMBIA AND MARYLAND

Five lime-stabilization processes for land application of biosolids were surveyed to determine the relationship between different process parameters and odor production from limed-biosolids. The survey includes: one pre-liming facility with two dewatering processes (Plants #1a and #1b) and three post-lime stabilization facilities (Plants #2, #3a, and #3b). This group of lime stabilization facilities portrayed a variety of process variations. Anaerobic production of odors (assessed by TMA and RSC concentrations in headspace samples) of stored biosolids and on the surface of land-applied biosolids (assessed by olfactory analyses) appeared to be closely related to the quality of lime stabilization achieved in the biosolids samples. Lime stabilization requires both ample lime dosage and proper lime incorporation in sludge to sustain high pH levels, inhibit microbial activity, and reduce odor production during storage. Lime dosages that just meet the lime dosage required to reach pH ≥ 12 may produce additional odors with storage time, due to pH decay. Minimal lime dosages appeared to dramatically increase odor production (TMA and RSC concentrations) in biosolids, presumably due to increased microbial activity with storage time. Lower levels of lime incorporation in sludge appeared to increase the odor production of biosolids significantly, presumably due to increased microbial activity. Lower levels of lime incorporation appeared to contribute to increased concentrations in both RSC and TMA concentrations.