The Effect of High Temperatures on BNR Process Performance

The City of St. Petersburg (Florida) Southwest Water Reclamation Facility achieves significant levels of nitrogen (N) and biological phosphorus (P) removal. N removal is via SND from operating the aerated zones at low DO. Despite the low DO operation, very good biological P removal performance is achieved. P removal is sustained at mixed liquor summer temperatures reaching 30°C. Full-scale performance data and detailed bench-scale testing were conducted to assess the N and P removal at low DO. Full-scale results showed that the plant achieves effluent total inorganic nitrogen (TIN) and total phosphorus (TP) concentrations of approximately 2.0 mgN/L and 0.5 mgP/L, respectively, at an average influent C: N ratio of 7:1. Specific nitrification rate (SNR) and specific denitrification rate (SDR) testing indicated that the population of nitrite oxidizing bacteria (NOB) is repressed significantly due to the low DO operation and that nitrite-shunt occurs at the plant. Phosphorus release and uptake (PRU) tests indicated that the low DO operation did not hinder the uptake of phosphate and biological P removal was achieved at the low DO conditions.

Section: Special Sampling and Concentration Profiling Resultsmentioning

confidence: 99%

Mainstream Nitrite-Shunt with Biological Phosphorus Removal at the City of St. Petersburg Southwest WRF

Jiménez¹,

Wise²,

Burger³

et al. 2014

“…The temperatures are typically above 80 o F (27 o C) in winter and have reached 107 o F (42 o C) during a summer heat wave. Despite the fact that this temperature is at the very end of acceptable temperatures for nitrification, as detailed in a review paper by Rabinowitz et al (2004), no detrimental impacts on the nitrification were observed.…”

Section: Temperature Concerns and Heat Balancementioning

confidence: 81%

Start-up and Operation of a Leachate MBR Plant

Patoczka¹,

Williams²

2011

The Pollution Control Financing Authority of Warren County (PCFAWC or Authority), New Jersey, operates a solid waste landfill. Leachate collected in the landfill cell underdrain system drains to a lined basin, from which it had historically been pumped via an adjoining wastewater collection system to a 1,890 m 3 /d (0.5 mgd) regional Publicly Owned Treatment Plant (POTW). Significant increases in leachate flow volumes and ammonia loads required the PCFAWC to evaluate alternative leachate disposal options. Pretreatment of the leachate in a Membrane Bioreactor process (MBR) was ultimately selected after the evaluation of alternatives and the completion of pilot tests. The MBR plant has been successfully operating for two years, meeting its design requirements. Initial problems with the MBR reactor foaming and elevated effluent color were overcome. The plant achieves full nitrification and significant denitrification while requiring minimal cleaning of the ultrafiltration (UF) membranes. Elevated process temperatures experienced are demonstrated to be a result of the high energy mechanical equipment (high pressure pumps) and heat of the biological reactions.

“…It is not clear whether increased DO caused improved phosphorus uptake, but the authors speculate higher DO increased phosphorus uptake kinetics and thereby improved effluent quality. Rabinowitz et al, 2004 showed that temperature could have a major impact on phosphorus removal, and specifically that EBPR deteriorates at temperatures over 30 degC. Aeration basin mixed liquor temperatures in July reached 30 degC at the time of the upset, but also stayed up while the process recovered.…”

Section: July 2003 Operational Upsetmentioning

confidence: 99%

Teaming Up to Meet Startup Goals at Las Vegas' BNR Facility

Hughes¹,

Oswalt²,

Chapman³

et al. 2004

Using a startup team that was responsible for operational decisions and intensive data collection were the two major success factors during the smooth startup of Las Vegas' 30 mgd BNR plant. The startup team continued to function after initial startup to optimize operations and improve performance.Much of the credit for success is due to the City of Las Vegas' vision. This startup process followed the plant's business plan and let employees get involved in decision making. The payoff was team buy-in for the project, and processes came online with only minor problems. Overall the project has been a huge success, creating a sense of pride for all members involved. Las Vegas also officially recognized startup team members for their contributions.The startup team itself was comprised of plant employees from the operations, maintenance, laboratory, management and electrical groups. The plant designer and operations specialists also helped the start up team with training and phone consultation prior to start up. The team met weekly to discuss problems and to review progress and process performance data. During this time, the team determined process adjustments. Once the process met permit requirements, the team's focus shifted to optimizing plant performance.Process changes focused on sludge age set point and control, DO control, RAS and internal recycle flow rates, the use of ferric chloride for odor control and effluent phosphorus trimming and other process related targets. Phosphorus, ammonia and nitrate profiles demonstrated process startup and provided feedback for optimization. These data profiles are useful to show when phosphorus release and uptake is taking place, whether there was a lack of nitrate to assure anoxic conditions, if secondary phosphorus release is occurring in the aeration basin/secondary clarifier, any failure of the internal mixed liquor pump and the importance of the influent BOD/P ratio.