Guide to Bioaugmentation for Systems Experiencing Chemical Inhibition using an Operating Envelope

Improved treatment and enhanced biogas production is contingent on the activity and overall health of the biomass. Chemical inhibition and toxicity in wastewater treatment plants has notoriously been difficult to diagnose much less prevent. This paper applies the operating envelope developed by Torrens and Salerno (1996) to inhibition in a treatment plant and thereby provides guidelines for monitoring and controlling the system when chemical inhibition is present. The operating envelope can be used to determine the optimum MLVSS required to treat an inhibited system, but many times increasing the MLVSS alone is not enough. Bioaugmentation can be used to alter the effective biological kinetics both by increasing degradation of the chemical components and increasing the number of active bacteria in the system. Field trials shows that bioaugmentation improved the kinetics in an inhibited sytem increasing the K value from an inhibited 2.1 and increased the K level above normal operating values of 12.2. Bioaugmentation will also secondarily increase the %MLVSS in a system improving the operating envelope. Operator guidelines are established using a bioaugmentaiton-modified kinetic line to determine when to increase the MLVSS and at what point to begin wasting. In practice, spiked DOUR compared to ATP generation and MLVSS values can be used in the field to determine where the system is in the envelope and thereby what response is required.