Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 15, 2001
Publication Date: N/A
Interpretive Summary: Odor mitigation in biosolids is important for the sustenance of a wastewater treatment plant's biosolids land application program. The Blue Plains wastewater treatment plant is currently evaluating its future biosolids program. For the next few years, lime stabilization will be the main method of biosolids stabilization. In the future, however, anaerobic digestion will replace this practice. The plant is intent on maintaining a viable land application program during both these scenarios. Therefore, it is essential to obtain a properly stabilized product that is largely odor-free. To this end, the odors from lime stabilized and digested biosolids were evaluated in this study. In short, digested sludge produced less order than undigested sludge. The former got less affected by long term storage than the latter in terms of mal-odor. Lime stabilization may be good practice to condition sludge and mitigate reduced sulfur and fatty acid odor. However, it generated high level of trimethylamine by breaking amines in polymer and proteins in the sludge. Therefore, the care should be exercised to reduce the anmine odor in the lime stabilization.
The impact of polymer dose and storage were evaluated for lime stabilized biosolids, and the impact of storage was evaluated for dewatered digested biosolids. This paper will present the qualitative odor profiles from lime stabilized and digested biosolids, the odorous compounds released from biosolids, and the in-plant (on-site) conditions that promote odorous biosolids products. Odorous compounds that were quantified included the decaying odors related to organic sulfur compounds or fishy odors related to amine compounds. The polymer dose was varied on one dewatering centrifuge during full-scale dewatering operations to obtain optimized, underdosed and overdosed polymer conditions. The lime dose was also varied to evaluate the impact of lime dose variations on product odor. Trimethyl amines (TMAs) were detected in all the lime-stabilized samples, and in none of the digested samples. This ssuggests that lime might play a role in the breakdown of sludge components polymers. The quantity of TMA increased with time and with an increase in polymer dose, which stresses the importance of maintaining an appropriate polymer dose. Odors can be generated from the storage of biosolids. The biosolids were stored over a one-month period to evaluate the effect of storage time on odors from biosolids with variations in lime and polymer dosage. Over time, the digested samples had fewer odors than the undigested samples.