Fifteen Years of Offgas Transfer Efficiency Measurements on Fine‐Pore Aerators: Key Role of Sludge Age and Normalized Air Flux

Rosso, Diego; Iranpour, R.; Mk, Stenstrom

doi:10.2175/106143005x41843

Cited by 72 publications

(34 citation statements)

References 14 publications

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“…Thus, the aeration efficiency, which depends on the oxygen transfer efficiency (OTE) in the aerated reactors, directly affects the cost of the wastewater treatment process. The main factors that affect OTE in wastewater treatment are reactor design (i.e., depth and shape), characteristics of the wastewater (i.e., suspended solids, temperature, and viscosity), aeration system (i.e., distribution of aeration system and type of diffusers), and ambient conditions (i.e., altitude and temperature) [9][10][11][12]. Suspended carrier elements can also affect OTE during the MBBR process.…”

Section: Introductionmentioning

confidence: 99%

Effects of carrier-attached biofilm on oxygen transfer efficiency in a moving bed biofilm reactor

Wei

Yin

et al. 2015

Front. Environ. Sci. Eng.

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Three laboratory-scale moving bed biofilm reactors (MBBR) with different carrier filling ratios ranging from 40% to 60% were used to study the effects of carrier-attached biofilm on oxygen transfer efficiency. In this study, we evaluated the performance of three MBBRs in degrading chemical oxygen demand and ammonia. The three reactors removed more than 95% of NH þ 4 -N at an air flow-rate of 60 L$h -1 . The standard oxygen transfer efficiency (αSOTE) of the three reactors was also investigated at air flow-rates ranging from 60 to 100 L$h -1 . These results were compared to αSOTE of wastewater with a clean carrier (no biofilm attached). Results showed that under these process conditions, αSOTE decreased by approximately 70% as compared to αSOTE of wastewater at a different carrier-filling ratio. This indicated that the biofilm attached to the carrier had a negative effect on αSOTE. Mechanism analysis showed that the main inhibiting effects were related to biofilm flocculants and soluble microbial product (SMP). Biofilm flocs could decrease αSOTE by about 20%, and SMP could decrease αSOTE by 30%-50%.

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Section: Introductionmentioning

confidence: 99%

Effects of carrier-attached biofilm on oxygen transfer efficiency in a moving bed biofilm reactor

Wei

Yin

et al. 2015

Front. Environ. Sci. Eng.

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“…In aeration systems the oxygen transfer efficiency is a function of the air flow rate and both keep a direct relationship (Gillot, Capela-Marsal, Roustan, & Héduit, 2005;Jenkins, 2013;Liu, Li, & Zhang, 2011;Mueller et al, 2002;D Rosso et al, 2005). High water flow regimens, associated with high air flow rates, has as consequence the increase in internal bubble recirculation of gas and high surface renewal rates (interface gas -liquid) (D. Rosso, Huo, & Stenstrom, 2006).…”

Section: Measurement Oxygen Transfer In Clean Watermentioning

confidence: 99%

“…Factors to be considered when studying oxygen transfer in fine-pore aeration systems covers a wide range: diffuser-related issues (Groves, Daigger, Simpkin, Redmon & Ewing, 1992;Mueller, Boyle & Popel, 2002;Diego Rosso & Shaw, 2015), aerobic reactor characteristics (Eckenfelder, 1959;Mueller et al, 2002;Pittoors, Guo & Van Hulle, 2014;Schierholz, Gulliver, Wilhelms & Henneman, 2006) and operating conditions (Henkel, 2010;D Rosso, Iranpour & Stenstrom, 2005).…”

Section: Introductionmentioning

confidence: 99%

The Influence of Optic and Polarographic Dissolved Oxygen Sensors Estimating the Volumetric Oxygen Mass Transfer Coefficient (KLa)

Baquero-Rodríguez¹,

Lara-Borrero²

2016

MAS

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Aeration is usually the most energy intensive part of the wastewater treatment process. Optimizing the aeration system is essential for reducing energy costs. Field tests oriented to estimate parameters related to oxygen transfer are a common approach to compare aeration systems. The aim of this research is to assess the effect of dissolved oxygen probe lag on oxygen transfer parameter estimation. Experimental procedures regarding to process automation and control were applied to quantify dissolved oxygen probe lag. We have measured oxygen transfer in clean water, under a wide range of conditions (airflow rate, diffuser characteristics and diffuser density), with optic and polarographic sensors for dissolved oxygen measurement. The oxygen transfer was measured as per ASCE Standard procedures. Nonparametric statistical tests were used to compare the estimated volumetric mass transfer coefficient K L a with different sensors. According to the results, there is not significant influence of the probe lag (also known as time constant) or probe characteristics on the parameters used to assess oxygen transfer efficiency. This fact has great relevance in common practice of aerobic process for wastewater treatment because dissolved oxygen monitoring is used as an input for decision making related to the energy optimization in the aeration system. Findings from these tests contradict previous studies which claim that lag time in polarographic sensors for the dissolved oxygen measurement can bias estimate K L a.

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“…The third model (AM3) is inspired by Rosso et al (2005) and assumes a constant standard oxygen transfer efficiency (SOTE), but time-variant a correction factor aSOTE =/l log^ -B where aSOTE is the field oxygen transfer efficiency (-), .4 and B are model parameters (-), and ^ is a lumped variable proportional to sludge age and inversely proportional to airflow rate.…”

Section: Description Of the Wwtp And The Used Models And Datamentioning

confidence: 99%

Impact of influent data frequency and model structure on the quality of WWTP model calibration and uncertainty

Plano¹,

Benedetti²,

Weijers³

et al. 2012

Water Science and Technology

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Application of activated sludge models (ASMs) to full-scale wastewater treatment plants (WWTPs) is still hampered by the problem of model calibration of these over-parameterised models. This either requires expert knowledge or global methods that explore a large parameter space. However, a better balance in structure between the submodels (ASM, hydraulic, aeration, etc.) and improved quality of influent data result in much smaller calibration efforts. In this contribution, a methodology is proposed that links data frequency and model structure to calibration quality and output uncertainty. It is composed of defining the model structure, the input data, an automated calibration, confidence interval computation and uncertainty propagation to the model output. Apart from the last step, the methodology is applied to an existing WWTP using three models differing only in the aeration submodel. A sensitivity analysis was performed on all models, allowing the ranking of the most important parameters to select in the subsequent calibration step. The aeration submodel proved very important to get good NH(4) predictions. Finally, the impact of data frequency was explored. Lowering the frequency resulted in larger deviations of parameter estimates from their default values and larger confidence intervals. Autocorrelation due to high frequency calibration data has an opposite effect on the confidence intervals. The proposed methodology opens doors to facilitate and improve calibration efforts and to design measurement campaigns.

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Fifteen Years of Offgas Transfer Efficiency Measurements on Fine‐Pore Aerators: Key Role of Sludge Age and Normalized Air Flux

Cited by 72 publications

References 14 publications

Effects of carrier-attached biofilm on oxygen transfer efficiency in a moving bed biofilm reactor

Effects of carrier-attached biofilm on oxygen transfer efficiency in a moving bed biofilm reactor

The Influence of Optic and Polarographic Dissolved Oxygen Sensors Estimating the Volumetric Oxygen Mass Transfer Coefficient (KLa)

Impact of influent data frequency and model structure on the quality of WWTP model calibration and uncertainty

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