Degradation Characteristics of Influent Solids and the Effect on Industrial Activated Sludge Design

摘要

Understanding and correctly accounting for influent volatile suspended solids (VSS) degradationis important for representative modeling and successful design of industrial wastewater treatmentplants (WWTPs). The key factors for evaluating the degradation characteristics of influent VSSare the first-order rate coefficient of biodegradable VSS (bVSS) reduction (K_P) and thedegradable fraction of the influent VSS (f_x). From these values the non-biodegradable VSS(nbVSS) concentration can be determined as well as the remaining bVSS at a given sludge age(Θ_C). The objective of this study was to develop the Kp and fx values for a variety of industrialwastewaters using a bench*scale test and associated model.The results of the bench*scale testing exhibited a wide range of degradation characteristicsindicating the importance of generating wastewater*specific parameters for industrial WWTPdesign. The Kp values were observed to range from 0.023 day~(-1) (Landfill Leachate A) to0.095 day~(-1) (Municipal wastewater). The f_x values were observed to range from 0.65 (LandfillLeachate A) to 0.97 (Municipal wastewater). Using the K_P and f_x values, the influent VSScontribution to mixed liquor volatile suspended solids (MLVSS) in a hypothetical WWTP wasmodeled. The results indicated influent VSS fractions of MLVSS in the range of 29 percent formunicipal to 63 percent for landfill leachate.This research identifies a simple method for establishing the key values for influent VSSdegradation behavior. In addition, the resulting data set provides a comparison of VSSdegradation kinetics as well as a resource for other wastewater professionals.