The Step Bio-P Process at Lethbridge — Over One Full Year of Operation

Crawford, George; Black, Steve; Elliott, Matthew; Filipe, Carlos D. M.; Stafford, Dalton R.

doi:10.2175/193864700784544587

Cited by 4 publications

(4 citation statements)

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“…Optimal utilization of carbon sources is the main focus of step-feed technology, which optimizes carbon source distribution in the wastewater treatment process to rationally distribute limited carbon sources to denitrification and phosphorous removal reactors. Maximum utilization of carbon sources is achieved because invalid carbon oxidation in the aerobic zone is avoided 3–5 . Step-feed technology was first utilized in the 1990s and has since been implemented in China and other countries 6 .…”

Section: Introductionmentioning

confidence: 99%

Operation mode of a step-feed anoxic/oxic process with distribution of carbon source from anaerobic zone on nutrient removal and microbial properties

Yi-jun

Yang

et al. 2019

Sci Rep

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This study investigated the operation mode of a step-feed anoxic/oxic (A/O) process with distribution of the carbon source from the anaerobic zone in terms of the treatment effects on sewage with low carbon and high nitrogen and phosphorus. After seven phases of operation, an optimal flow distribution ratio of 75%:25% was obtained from the anaerobic zone, and the concentrations of chemical oxygen demand, ammonia nitrogen, total nitrogen, and total phosphorous in the effluent were 20.8, 0.64, 14.2, and 0.89 mg/L, respectively. The presence of an internal reflux system in the deaeration zone improved the treatment. 16S rRNA high-throughput sequencing revealed that the microbial communities in aerobic zone I(O1) of the first-step A/O sludge were different from those in aerobic zone I (O2) of the second-step A/O sludge, whereas microbial communities of the seed sludge were similar to those in O2 of the second-step A/O sludge. The richness and diversity of microbial communities in O1 of the first-step A/O sludge samples were higher than those in O2 of the second-step A/O and seed sludge. At the optimal flow distribution ratio, the microbial abundance and treatment removal efficiency were the highest.

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Section: Introductionmentioning

confidence: 99%

Operation mode of a step-feed anoxic/oxic process with distribution of carbon source from anaerobic zone on nutrient removal and microbial properties

Yi-jun

Yang

et al. 2019

Sci Rep

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“…The operating results showed the average mixed liquid suspended solids (MLSS) and treatment ability was higher than conventional BNR process. The average effluent ammonia and nitrate concentration was lower than 0.5 and 5 mg/L, respectively, in the whole year of 1999 [8].…”

Section: Introductionmentioning

confidence: 90%

“…In addition the solids retention time (SRT) can increase because of suspended solids gradient along the reactors [7]. As a consequence of these features the process has been found to offer relevant advantages for both new and existing plants [8,9].…”

Section: Introductionmentioning

confidence: 99%

Effect of influent flow rate distribution on the performance of step-feed biological nitrogen removal process

Zhu

Peng

Wang

et al. 2007

Chemical Engineering Journal

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The step-feed anoxic/oxic biological nitrogen removal process has been proposed as an attractive alternative for the conventional biological nitrogen removal process for the purpose of enhanced nitrogen removal. For step-feed process, the biological nitrogen removal efficiency is a function of influent flow distribution. In this study, the effects of influent flow rate distribution on the performance of nitrogen removal process were investigated. The effects of influent flow rate distribution on COD, ammonia, total nitrogen removal efficiency, nitrification rate and sludge volume index value were also studied. According to the performance characteristic of the step-feed process, the concept of influent flow rate distribution ratio was firstly introduced. The maximum influent flow distribution ratios (λ max ) under the condition of different influent C/N ratios were determined, respectively, by trial and error method. The experimental results showed that high total nitrogen removal efficiency, higher than 95%, could be achieved under certain influent flow rate distribution ratio without internal nitrate cycle or addition of external carbon source. It was obvious that nitrification rate of each stage under different influent flow distributions decreased along with the decreasing of sludge loading and volume loading in each stage, and the degree of reduction rise gradually with the increasing of influent flow distribution ratio. The sludge volume index value would also increase along with the increase of influent flow distribution ratio.

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“…Performance of the step feed basin was compared with that of an existing plug flow aeration basin of identical size. A significant volume of literature has been devoted to step feed and its applications in recent years, including work by Fillos et al (2000), Carrio et al (2000), and Crawford et al (2000). However, much of this recent work is based on "standalone" step feed systems.…”

Section: Methodsmentioning

confidence: 99%

Side-by-Side Comparison of Step Feed and Plug Flow Activated Sludge Process Performance at the Rock Creek Advanced Wastewater Treatment Facility

Wable¹,

Spani²

2002

proc water environ fed

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Driven by continuing rapid growth, potential site space constraints, and pressures to reduce cost, Clean Water Services (formerly Unified Sewerage Agency of Washington County, Oregon) decided to evaluate the performance of the step feed activated sludge process on a demonstration basis at its Rock Creek Advanced Wastewater Treatment Facility. Construction and startup of a new 1.7 million gallon three-pass step feed demonstration aeration basin was completed in June 2001. Performance of the step feed basin was compared with that of an existing plug flow aeration basin of identical size.Testing was conducted in two modes. Mode 1 involved demonstration of comparable SRT and performance with higher loadings to step feed, while Mode 2 involved higher step feed SRT and comparable performance under similar loading conditions.Testing results demonstrate that the step feed process may be flexibly used to either achieve higher capacity (flow) at comparable sludge ages, or to achieve a higher level of treatment (higher sludge age) at comparable flows, while maintaining comparable solids loading rates to the secondary clarifiers. The results also show that the step feed system achieved a better and more reliable effluent quality as measured in this case by lower effluent ammonia-N concentrations. Results of this testing support the recommendation for future plant-wide conversion from plug flow to step feed at the Rock Creek facility.

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The Step Bio-P Process at Lethbridge — Over One Full Year of Operation

Cited by 4 publications

References 0 publications

Operation mode of a step-feed anoxic/oxic process with distribution of carbon source from anaerobic zone on nutrient removal and microbial properties

Operation mode of a step-feed anoxic/oxic process with distribution of carbon source from anaerobic zone on nutrient removal and microbial properties

Effect of influent flow rate distribution on the performance of step-feed biological nitrogen removal process

Side-by-Side Comparison of Step Feed and Plug Flow Activated Sludge Process Performance at the Rock Creek Advanced Wastewater Treatment Facility

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