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Adaptive Facility Plan Tackles Uncertainty and Cold-Weather Ammonia Removal
A case study on the development and implementation of an adaptive facility plan for the City of Palmer, Alaska will be presented. The first phase of upgrades has been completed and includes conversion from aerobic lagoons to a moving bed bioreactor (MBBR) process for year-round cold-climate nitrification and compliance with ammonia limits. An adaptive facility plan was developed to manage uncertainty in flow projections driven by a controversial highway/bridge project and ranging from 130% to 250% of the current 0.6 mgd average daily flow rate. The adaptive phased facility plan reduced project costs and risk of stranded assets otherwise resulting from designing to unrealized growth conditions, resulting in saving over $30 million versus the original facility plan membrane bioreactor alternative. The MBBR was commissioned in July 2018, and nitrification was quickly established after startup. Results from the ongoing critical winter performance demonstration period (January – March 2019) will be presented. Minimum winter process temperatures are anticipated to be as low as 5°C. Operator insights gained in the transition from lagoons to MBBR technology will also be highlighted.
8:45am - 9:30am
Intensifying Nutrient Removal using Membrane Aerated Biofilm Reactor
Yueyun Tse1, Sandeep Sathyamoorthy1, Samik Bagchi1, Kelly Gordon1, Daniel Coutts2, Dwight Houweling2
1Black and Veatch, United States of America; 2SUEZ Treatment Solutions, Canada;
The Membrane Aerated Biofilm Reactor (MABR) is an innovative technology using counter-diffusional biofilm, wherein the substrate is supplied from the bulk liquid, but the electron acceptor is supplied from the attachment surface. Compared to co-diffusional biofilms, counter-diffusional biofilms can exhibit higher efficiencies of substrate and electron acceptor utilization.
While the concept and principles of an MABR process have been extensively evaluated at lab-scale for over three decades, only a limited number of pilot scale studies have been reported. With the objective to fill key knowledge gaps related to the application of MABRs in ‘real-world’ applications, our research investigates the performance of a pilot-scale MABR‑suspended growth (MABR‑SG) process, operated in a Modified Ludzack Ettinger (MLE) configuration, treating primary effluent at the Hayward Water Pollution Control Facility. The nitrification-denitrification performance under different hydraulic retention time (HRT), solid retention times (SRT) and influent carbon to ammonia-N (C/N) ratios are tested. High throughput 16S-rRNA amplicon sequencing was used to elucidate the microbial community shifts under different conditions.
Results indicate that effluent total inorganic nitrogen (TIN) concentrations of less than 15 mg‑N/L can be achieved at a suspended‑SRT (i.e., SRT calculated only using the mixed liquor inventory, waste sludge flow and effluent TSS) of approximately 4 days in the MABR‑SG process. Furthermore, TIN removal of 40-50% can be achieved even when operating the MABR‑SG process at a suspended‑SRT of less than 2 d. Such an intensified process holds values for those utilities considering cost-effective nutrient upgrades. Results from modeling a comparable suspended growth system suggests that the MABR biofilm accounts for a significant fraction of the nitrification at this low SRT.
Our presentation will provide details on MABR‑SG operation at a range of SRTs, highlighting performance and lessons learned. In addition, a comparison of the microbial communities of the biofilm and suspended growth mixed liquor will be described.