Study Guide Answer Key

Here are the answers to the Dec. 31, 2020 edition of TPO's Exam Study Guide: In fixed film processes, what must be reduced before nitrification can occur?The answer to the question is A, organic loading rate. Higher organic loading rates favor the growth of heterotrophic bacteria over nitrifying bacteria. In most fixed film systems, the higher OLRs cause rapid growth of heterotrophic bacteria, forcing the weaker nitrifiers to go deeper into the biomass. This process slows their growth rates. By reducing the OLR, the heterotrophic bacteria will slow, preventing the nitrifiers from being overtaken. Operating the system in a series mode where the OLR