Optimization and Control of Nitrogen Removal Activated Sludge Processes: A Review of Recent Developments

Yuan, Zhiguo; Keller, Jürg; Lant, Paul

doi:10.1007/978-94-017-0932-3_6

Cited by 16 publications

(14 citation statements)

References 106 publications

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“…In single-sludge suspended-growth systems, the sludge passes through all the existing conditions in the plant, thus at any point in the system only a fraction of the biomass is active (Yuan et al, 2001). In addition, autotrophic nitrifying organisms grow very slowly and thus require a long solids retention time, which biofilm processes provide; conversely, the solids retention time of suspended-growth processes is often inadequate, resulting in washout of nitrifying organisms.…”

Section: Introductionmentioning

confidence: 98%

A pilot-plant study of a moving-bed biofilm reactor system using PVA gel as a biocarrier for removals of organic carbon and nitrogen

Burica

Stražar

et al. 2007

Water Science and Technology

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A pilot-plant study was conducted to evaluate the performance of a moving-bed biofilm reactor process using PVA-gel beads as a biocarrier. Real primary-settled wastewater was fed to the pre-denitrification system and removals of nitrogenous and organic contaminants were evaluated over a 1-year period. The results demonstrated that at a total nitrogen (TN) loading of 18 mg/L.h, a TN removal efficiency in keeping with and even exceeding the theoretical maximum efficiency based on the level of internal recycle, was possible and a nitrification rate of 15 mg/L.h was sustained with a HRT of only 2.5 h at 15 degrees C. Furthermore, soluble COD and BOD5 in the effluent of the pilot plant were reduced to levels well below most regulatory discharge limits. In addition, the possibility of using this biocarrier in a system, including the elimination of waste organic sludge, was discussed.

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Section: Introductionmentioning

confidence: 98%

A pilot-plant study of a moving-bed biofilm reactor system using PVA gel as a biocarrier for removals of organic carbon and nitrogen

Burica

Stražar

et al. 2007

Water Science and Technology

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“…However, a complete evaluation of denitrification systems and a comparison of the effects of different carbon sources and operational strategies on their overall performance are largely missing, and this impedes the optimal use of external carbon sources (38).…”

mentioning

confidence: 99%

Use of Stable-Isotope Probing, Full-Cycle rRNA Analysis, and Fluorescence In Situ Hybridization-Microautoradiography To Study a Methanol-Fed Denitrifying Microbial Community

Ginige

Hugenholtz

Daims

et al. 2004

Appl Environ Microbiol

216

153

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A denitrifying microbial consortium was enriched in an anoxically operated, methanol-fed sequencing batch reactor (SBR) fed with a mineral salts medium containing methanol as the sole carbon source and nitrate as the electron acceptor. The SBR was inoculated with sludge from a biological nutrient removal activated sludge plant exhibiting good denitrification. The SBR denitrification rate improved from less than 0.02 mg of NO 3 ؊ -N mg of mixed-liquor volatile suspended solids (MLVSS)؊1 h ؊1 to a steady-state value of 0.06 mg of NO 3 ؊ -N mg of MLVSS ؊1 h ؊1 over a 7-month operational period. At this time, the enriched microbial community was subjected to stable-isotope probing (SIP) with 14 C]methanol uptake in the enriched biomass. The well-known denitrification lag period in the methanol-fed SBR was shown to coincide with a lag phase in growth of the DEN67-targeted denitrifying population. We conclude that Methylophilales bacteria are the dominant denitrifiers in our SBR system and likely are important denitrifiers in full-scale methanol-fed denitrifying sludges.

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“…There is considerable uncertainty associated with the denitrification potential of aerobically grown methylotrophic bacteria and their effect on full-scale plant design/operation. Yuan, Keller, and Lant (2003) suggested that a complete evaluation of different carbon sources for denitrification and operational strategies for their overall performance is largely missing. Gujer and Irene (1999) suggested that strict anoxic methylotrophs may have somewhat different kinetic capability compared to facultatively-grown methanol-utilizing bacteria.…”

Section: Research Project Overview and Hypothesismentioning

confidence: 99%

The Benefit of Aerobic Methanol Uptake on Denitrification Capacity

Parsons¹,

Bott²,

Oerther³

et al. 2007

proc water environ fed

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The Blue Plains Advanced Wastewater Treatment Plant (AWTP) in Washington, DC has a high rate activated sludge system followed by a suspended growth nitrification-denitrification system. Methanol is used for post-denitrification, because it is the least expensive synthetic compound available that does not leave residual biochemical oxygen demand (BOD) in the process effluent. The process achieves low total nitrogen values in summer, while during winter, the process is more difficult to operate due to increased flows and low temperature. These data suggest kinetic limitations of methylotrophic bacteria. The objective of this project was to evaluate methods for possibly overcoming limitations of methanol addition for full-scale facilities that have limited available cold-weather anoxic solids retention time (SRT). It was hypothesized that methanol addition under aerobic conditions (bleeding a small amount of methanol into the aerobic zone of a BNR process) could alleviate anoxic SRT limitations in a full-scale plant by increasing the active methylotrophic biomass content in the process. There is considerable uncertainty associated with the denitrification potential of aerobically grown methylophic bacteria and its effect on full-scale plant design/operation. Two sequencing batch reactors (SBRs) were operated at the Blue Plains AWTP to address these questions and to assess methylotroph kinetics. This reactor set-up was used to simulate, as closely as possible, the Blue Plains AWTP nitrification/denitrification system, with aerobic and post-anoxic reaction periods (nitrification was not attempted in the SBRs since the focus of this study was denitrification). For both reactors A and B, methanol was added at the beginning of the anoxic period. For reactor B only, methanol was added at the beginning of the aerobic period. SBR data suggested that aerobicallygrown methylotrophs have similar anoxic denitrification potential as strict anoxically-grown methanol utilizing bacteria. These preliminary results indicate that aerobically-grown methylotrophs have the potential to denitrify with kinetics similar to that grown anoxically and that a bleed of methanol into the aerobic zone of a BNR process could alleviate anoxic capacity limitations, albeit with increased methanol demand.

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Optimization and Control of Nitrogen Removal Activated Sludge Processes: A Review of Recent Developments

Cited by 16 publications

References 106 publications

A pilot-plant study of a moving-bed biofilm reactor system using PVA gel as a biocarrier for removals of organic carbon and nitrogen

A pilot-plant study of a moving-bed biofilm reactor system using PVA gel as a biocarrier for removals of organic carbon and nitrogen

Use of Stable-Isotope Probing, Full-Cycle rRNA Analysis, and Fluorescence In Situ Hybridization-Microautoradiography To Study a Methanol-Fed Denitrifying Microbial Community

The Benefit of Aerobic Methanol Uptake on Denitrification Capacity

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