Modelling oxygen transfer using dynamic alpha factors

Jiang, Lu-Man; Garrido-Baserba, Manel; Nolasco, Daniel; Al‐Omari, Ahmed; DeClippeleir, Haydee; Murthy, Sudhir; Rosso, Diego

doi:10.1016/j.watres.2017.07.032

Cited by 38 publications

(20 citation statements)

References 32 publications

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“…The organics that otherwise would be oxidized by costly aeration are now being redirected to the anaerobic digester, benefiting the plant's energy balance. The organic‐rich primary sludge diversion to the anaerobic digester had twofold benefits: increasing the amount of primary sludge to energy recovery processes (anaerobic digester), which can yield 30%–50% more methane than secondary sludge (Appels, Baeyens, Degrève, & Dewil, 2008; Gori et al., 2011; Takacs and Vanrolleghem, 2006; Zhou, Zhang, Le, Puah, & Ng, 2013), and also increasing the aeration efficiency during the secondary treatment, improving the oxygen mass transfer indicator (α) due to the lower organics concentrations (Jiang et al., 2017).…”

Section: Resultsmentioning

confidence: 99%

“…Aeration is an essential operation in water resource recovery facilities (WRRFs) and is the main contributor to plant power demand, dominating the process energy requirements with the exclusion of site‐specific pumping (Garrido‐Baserba et al., 2017; Rosso & Shaw, 2015; Rosso & Stenstrom, 2006; WEF, 2009). The oxygen transfer efficiency decreases from its clean water value (SOTE, %) to process conditions (αSOTE, %) because of the loading conditions, among other co‐related factors (i.e., surfactants and process characteristics), and this decrease is quantified through the alpha‐factor (ASCE, 2007; Jiang et al., 2017; Metcalf & Eddy, 2014; Stenstrom & Gilbert, 1981; Manual, US EPA, 1989). Any effort to divert load from the secondary treatment would result in the beneficial reduction of plant energy usage (Gori et al., 2013; Rahman et al., 2017).…”

Section: Introductionmentioning

confidence: 99%

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Oxygen transfer and plant‐wide energy assessment of primary screening in WRRFs

Pasini

Garrido-Baserba

Ahmed

et al. 2020

Water Environment Research

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Primary screening is gaining interest as a method to achieve removal performances comparable to primary clarification while reducing the footprint and increasing operational elasticity. Aeration efficiency indicators in a pilot sequential batch reactor (SBR) and a full scale water resource recovery facility (WRRF) were investigated after the implementation of rotating belt filters/screens (RBF). To compare the impact between screened (350 μm) and nonscreened primary influent, two identical treatment lines were monitored using off‐gas and respirometric measurements. The study provides the first result on improved oxygen transfer efficiency due to primary screening. Consistent aeration efficiency improvements of 27% and 20% between screened and nonscreened were obtained at pilot and full scale, respectively. Changes in aeration efficiency and carbon redirection were integrated into a set of models to investigate the primary screening impact on the WRRF energy balance. While the plant‐wide assessment for different scenarios improved the energy balance up to 15%, a detailed comparative analysis between various treatment schemes gained insight into the advantages and limitations of the energetic sustainability of primary screening. Practitioner points Aeration efficiency improved 27% at pilot scale Aeration efficiency improved 20% at full scale. Use of primary screening can improve the energy balance up to 15 Assessment of advantages and limitations of primary screening.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Oxygen transfer and plant‐wide energy assessment of primary screening in WRRFs

Pasini

Garrido-Baserba

Ahmed

et al. 2020

Water Environment Research

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“…The current practice of using a single value must be changed to the practice of using a dynamic a-factor; a dynamic model should be used to describe aeration energy demand, both in 24-hour periods with load variations and a-factor changes, and over months or years as diffusers become more fouled and aged. However, this approach (Jiang, Garrido-Baserba et al, 2017) should soon be validated with commercial simulators.…”

Section: Bridging the Gap Between Field Measurements And Oxygen Transmentioning

confidence: 99%

A Critical Review of the Factors Affecting Modeling Oxygen Transfer by Fine‐Pore Diffusers in Activated Sludge

Baquero-Rodríguez

Lara-Borrero

Nolasco

et al. 2018

Water Environment Research

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In this review, the factors affecting the transfer of oxygen in activated sludge processes using fine-pore diffusers for water resource recovery are critically discussed. In water resource recovery facilities, the energy required for aeration constitutes 50% to 80% of the total energy consumed by the plant. This critical review highlights the use of fine-pore diffuser aeration and emphasizes the significance of accounting for the following factors: diffuser aging and fouling, diffuser layout, diffuser type, selector benefits, local environmental conditions (temperature and atmospheric pressure), influent wastewater variability, dissolved oxygen control systems, and airflow rates. In our review, we were unable to find mathematical models that could be used to develop dynamic α-factor predictions and diffuser fouling predictions. Although the development of a model that considers all the factors that affect oxygen transfer efficiency (OTE) in activated sludge systems would be extremely valuable, the creation of such a model is outside the scope of this review.

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“…Many factors affect the OTE of aeration systems, such as the airflow rate [9,10], diffuser density [11,12], contaminant concentration [13][14][15], and sludge characteristics [16,17]. However, the influence of these factors is not the same [8].…”

Section: Introductionmentioning

confidence: 99%

The Changing and Distribution Laws of Oxygen Transfer Efficiency in the Full-Scale IFAS Process

Liu

Huang³

et al. 2021

Water

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The integrated fixed-film activated sludge (IFAS) process has been widely used in the upgrading of wastewater treatment plants (WWTPs). The oxygen transfer efficiency (αOTE) is of great significance to the design and operation of the IFAS process. The carrier filling ratio (CFR) and aeration type are two critical factors affecting αOTE and standard oxygen transfer efficiency (αSOTE). However, the distribution and changing laws of αOTE and αSOTE in the full-scale IFAS process areunclear. To optimize the operation of a WWTP and to improve the αOTE of the aeration systems, several off-gas tests were conducted under different aeration types and different CFRs. The results show that for the aerobic tank investigated (the ratio of length and width was 8:1), the αOTE and the αSOTE of the middle of the aeration systems were higher than those of the other two sides. However, the reason for the low αOTE at the beginning and the end of the tank may be different. Coarse-bubble aeration systems had a lower αOTE and almost the same oxygenation capacity (αSOTE) as the fine-bubble aeration systems under constant CFR (43%). The average αSOTE (18.7–28.9%) of the hybrid aeration systems increased with increasing CFR (7.7–57.7%), and different locations exhibited different degrees of change. The results reveal the distribution and changing law of the αOTE of aeration systems in the IFAS process, and attention should be paid to the improvement of the OTE of the plug-flow IFAS process.

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Modelling oxygen transfer using dynamic alpha factors

Cited by 38 publications

References 32 publications

Oxygen transfer and plant‐wide energy assessment of primary screening in WRRFs

Oxygen transfer and plant‐wide energy assessment of primary screening in WRRFs

A Critical Review of the Factors Affecting Modeling Oxygen Transfer by Fine‐Pore Diffusers in Activated Sludge

The Changing and Distribution Laws of Oxygen Transfer Efficiency in the Full-Scale IFAS Process

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