Performance Enhancement of SBR Applying Real-Time Control

Yu, Ruey-Fang; Liaw, Shu Liang; Cheng, Wen-Yu; Chang, Cheng-Nan

doi:10.1061/(asce)0733-9372(2000)126:10(943)

Cited by 20 publications

(8 citation statements)

References 20 publications

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“…As shown in Figure 2a for run 4, NO 2 ‐ ‐N constituted a rather high fraction (approximately 36%) of the total NO x ‐ ‐N. This observation was consistent with the nitrite shunt reported in low‐dissolved‐oxygen systems ( Gee and Kim, 2004 ; Yoo et al, 1998 ; Yu et al, 2000 ; Zeng et al, 2003 ). The extent of nitrite shunt occurrence was expected to correlate with the ratio of NO 2 ‐ ‐N/NO 3 ‐ ‐N, which would be larger at a higher extent of nitrite shunt (because of the bypassed involvement of NO 3 ‐ ).…”

Section: Discussionsupporting

confidence: 88%

“…Nitrite shunt is known to require lower COD to drive the nitrate‐bypassed denitrification. The COD/NO x ‐ ‐N ratio required for complete denitrification of nitrate was 5.0 to 6.0 (w/w) ( Tam et al, 1992 ), while complete denitrification in a sequencing batch reactor with nitrite shunt occurring was achieved at a much lower ratio of 2.9 ( Yu et al, 2000 ). Therefore, the low‐dissolved‐oxygen SND process may be particularly beneficial for wastewater with low carbon‐to‐nitrogen ratios.…”

Section: Discussionmentioning

confidence: 99%

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Simultaneous Nitrification, Denitrification, and Phosphorus Removal in Single‐Tank Low‐Dissolved‐Oxygen Systems Under Cyclic Aeration

Huang²,

Trivedi³

2007

Water Environment Research

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Simultaneous nitrification and denitrification (SND or SNdN) may occur at low dissolved oxygen concentrations. In this study, bench‐scale (approximately 6 L) bioreactors treating a continuous feed of synthetic wastewater were used to evaluate the effects of solids retention time and low dissolved oxygen concentration, under cyclic aeration, on the removal of organics, nitrogen, and phosphorus. The cyclic aeration was carried out with repeated cycles of 1 hour at a higher dissolved oxygen concentration (HDO) and 30 minutes at a lower (or zero) dissolved oxygen concentration (LDO). Compared with aeration at constant dissolved oxygen concentrations, the cyclic aeration, when operated with proper combinations of HDO and LDO, produced better‐settling sludge and more complete nitrogen and phosphorus removal. For nitrogen removal, the advantage resulted from the more readily available nitrate and nitrite (generated by nitrification during the HDO period) for denitrification (during the LDO period). For phosphorus removal, the advantage of cyclic aeration came from the development of a higher population of polyphosphate‐accumulating organisms, as indicated by the higher phosphorus contents in the sludge solids of the cyclically aerated systems. Nitrite shunt was also observed to occur in the LDO systems. Higher ratios of nitrite to nitrate were found in the systems of lower HDO (and, to less dependency, higher LDO), suggesting that the nitrite shunt took place mainly because of the disrupted nitrification at lower HDO. The study results indicated that the HDO used should be kept reasonably high (approximately 0.8 mg/L) or the HDO period prolonged, to promote adequate nitrification, and the LDO kept low (≤0.2 mg/L), to achieve more complete denitrification and higher phosphorus removal. The above findings in the laboratory systems find strong support from the results obtained in full‐scale plant implementation. Two plant case studies using the cyclic low‐dissolved‐oxygen aeration for creating and maintaining SND are also presented.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Simultaneous Nitrification, Denitrification, and Phosphorus Removal in Single‐Tank Low‐Dissolved‐Oxygen Systems Under Cyclic Aeration

Huang²,

Trivedi³

2007

Water Environment Research

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“…The monitoring of oxidation-reduction potential (ORP), dissolved oxygen (DO), and pH provides economical, flexible, and effective control parameters for the various wastewater treatment processes (Chang et al 2004;Olsson 2012;Zanetti et al 2012) that have been applied successfully to control systems that remove biological nutrients (Fuerhacker et al 2000;Yu et al 2000;Saby et al 2003;Won and Ra 2011;Martin de la Vega et al 2012), infectious organisms (Yu et al 2009a;Lin et al 2012), and advanced oxidation processes (AOPs) (Gernjak et al 2006;Yu et al 2009b;Lucas and Peres 2009;Ortega-Gomez et al 2012). Due to the fact that nZVI has a high reduction potential, using the nZVI process to degrade TCE in aqueous solutions will decrease the ORP values significantly in the reactor.…”

Section: Introductionmentioning

confidence: 99%

Online monitoring of the nanoscale zero-valent iron process for trichloroethylene wastewater treatment

Chi

Cheng

et al. 2014

Int. J. Environ. Sci. Technol.

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In this study, a batch-type, nanoscale, zerovalent iron process was used to treat trichloroethylene wastewater. Variations in oxidation-reduction potential (ORP) and pH in the reactor were monitored online for use in developing the model for process control. After the addition of nanoscale, zero-valent iron, the pH value increased rapidly, from 5.0-6.0 to around 8.5-9.5, whereas the ORP decreased dramatically, from around 300 mV to -700 to -800 mV. The degradation of trichloroethylene reached equilibrium at a reaction time of about 120 min. The use of a dose of 1.5 g/L to treat an influent that had a trichloroethylene concentration of 50 mg/L resulted in a removal efficiency of 94 %. Two models, i.e., a multiple regression model and an artificial neural network (ANN) model, were used to develop the control model to predict the trichloroethylene removal efficiencies. Both the regression model and the ANN model performed precise prediction results for the trichloroethylene removal efficiencies, with correlation coefficients of about 0.87 and 0.98, respectively, resulting in great potential for controlling the trichloroethylene removal.

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“…N removal via nitrite*shunt may yield up to a 25% reduction in aeration and 40% reduction in COD requirements when compared to conventional nitrification* denitrification. Yu et al (2000) indicated that complete removal of nitrate via nitrite*shunt could be achieved at C:N ratios as low as 2.9. This reduction in COD requirements would be particularly advantageous for WWTPs treating wastewater deficient in readily biodegradable COD.…”

Section: Introductionmentioning

confidence: 99%

Process Control Strategies for Simultaneous Nitrogen Removal Systems

Jiménez¹,

Bott²,

Regmi³

et al. 2013

proc water environ fed

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Different aeration control strategies were investigated to promote simultaneous nitrification* denitrification (SND) in laboratory*scale sequencing batch reactors and a continues*flow pilot plant. The aeration strategies evaluated during this study included: 1) Constant low DO control, 2) Ammonia (NH 4 + )*based aeration control and 3) NH 4 + *based aeration control with NOB suppression. Bench*scale results indicated SND can be achieved with either aeration control strategy. However, the results showed that the constant low DO aeration control provided higher SND removals than the NH 4 + *based aeration control at C:N ratios lower than 6. At higher C:N ratios, both strategies provided comparable SND removal. Nitrification rate measurements were conducted which indicated that the NH 4 + *based aeration control strategy resulted in higher AOB and NOB rates compared to the constant low DO strategy. A further improved aeration control strategy with NOB suppression was tested in a continuous flow pilot plant. Results indicated that this type of NH 4 + *based aeration control can result in nitritation*denitritation (or nitrite*shunt) if NOB growth can be suppressed. Bench*scale results as well as full*plant operation data indicated that SND through constant low DO condition seems to be more susceptible for low DO bulking than systems operated under NH 4 + *based aeration control.

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Performance Enhancement of SBR Applying Real-Time Control

Cited by 20 publications

References 20 publications

Simultaneous Nitrification, Denitrification, and Phosphorus Removal in Single‐Tank Low‐Dissolved‐Oxygen Systems Under Cyclic Aeration

Simultaneous Nitrification, Denitrification, and Phosphorus Removal in Single‐Tank Low‐Dissolved‐Oxygen Systems Under Cyclic Aeration

Online monitoring of the nanoscale zero-valent iron process for trichloroethylene wastewater treatment

Process Control Strategies for Simultaneous Nitrogen Removal Systems

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