EXAMINATION OF MECHANISMS FOR ODOR COMPOUND GENERATION DURING LIME STABILIZATION

Lime stabilized biosolids produced from a wastewater treatment plant can often emit odors, especially ‘fishy’ and ‘decaying’ odors. These odors can generate public opposition to biosolids land application programs, although it is an environmentally friendly recycling of organic material that is beneficial to agricultural industry. Therefore, it is critical to examine the controlling factors involved in odor production during the lime stabilization process. Results from preliminary experiments examining added polymer and protein material to de-watered limed biosolids show increased TMA production with further increases with 1 hour and 4 hour storage times prior to liming. Further experiments with water/silica slurry reaction media reveal that enzymaticallyfacilitated degradation of polymer and protein is the over-riding factor in TMA and DMDS production. It is hypothesized that macromolecules like polymer and proteins in biosolids are first broken down enzymatically, following which, the addition of lime causes TMA and DMDS to be released.