ODOR PRODUCTION IN BIOSOLIDS: MECHANISMS AND OPTIMAL CONTROL STRATEGIES

Odors produced from biosolids are a major impediment to beneficial reuse of wastewater residuals in many treatment plant operations. As a source of public complaints, they also erode support for land application practices. In this study, the effects of sulfur-containing amino acids (cysteine and methionine) and simulated upset conditions (NaCl) on odor production from digested biosolids were investigated by anaerobic incubation of biosolids samples. Headspace samples were analyzed by solid phase micro-extraction (SPME) and GC-MS. Additions of sulfur-containing amino acids (25 mM each) led to significant sulfurous odor production from biosolids, mostly as dimethyl sulfide (DMS) and methanethiol (MT). Addition of 500 mM NaCl inhibited gas production, but acclimation was aided by the added amino acids. The NaCl exacerbated odorant production, shortening the onset time, and increasing the concentrations of both DMS and MT. The results showed that odor production is associated with anaerobic system imbalance such as increased salinity.