Feasibility of Using High-Rate, On-Line, Fixed-Film Fermenters for SCVFA Generation in a BNR Process Train

Abstract

Two pilot-scale, 3 stage Bardenpho systems were operated to assess the usefulness of high-rate, on-line, fixed-film fermenters in process performance evaluation. One process train had a high-rate, on-line, fixed-film fermenter, while the other served as a control, without fermenter media. In the fixed-film fermenters, using commercially available Ringlace® media, 1.9 to 9 mg l−1 of additional short chain volatile fatty acids were produced. The data indicated that between 5.3 - 7.8 mg l−1 of short chain volatile fatty acids, as acetic acid, was required for removal of 1 mg l−1 of total phosphorus. In this investigation, the potential of using high rate fermenters in biological nutrient removal process performance was clearly established, but their full potential was tempered due to the unexpectedly high concentration (about 26 mg l−1) of short chain volatile fatty acids, already present in the raw domestic wastewater feed. In evaluating the role of the high-rate fermenters, external phosphorus addition to the wastewater may be required to determine the total phosphorus removal capacity of the treatment system.