Approach for a novel control strategy for simultaneous nitrification/denitrification in activated sludge reactors

Fuerhacker, Maria; Bauer, Heidi; Ellinger, Reinhard; Sree, Usha; Schmid, Heidrun; Zibuschka, F.; Puxbaum, Hans

doi:10.1016/s0043-1354(00)00016-6

Cited by 67 publications

(32 citation statements)

References 11 publications

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“…Online monitoring of DO and ORP have been proved to be practical and effective indicators for SND control in nitrogen removal process [26][27][28]. In this study, on-line ORP measurement for SND optimization in the outer channel was also implemented due to its strong correlation with DO and wider range for process control under very low oxygen condition [26].…”

Section: Resultsmentioning

confidence: 99%

“…In this study, on-line ORP measurement for SND optimization in the outer channel was also implemented due to its strong correlation with DO and wider range for process control under very low oxygen condition [26]. Unlike low ORP ranged from À100 mv to À50 mv in non-aerated anoxic zones in A/O process [29,30], ORP value of À50 mv to 50 mv under the aerated-anoxic condition was higher due to the presences of micro-aeration and oxidized nitrogen.…”

Section: Resultsmentioning

confidence: 99%

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Enhanced total nitrogen removal performance in a modified Orbal oxidation ditch system with internal nitrate recycle

Zhou

Han

Guo

2013

Chemical Engineering Journal

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h i g h l i g h t sAn Orbal oxidation ditch with nitrate recycle for enhanced TN removal was developed. The optimal DO for SND was 0.15-0.25 mg/L. The highest TN removal was achieved at internal recycle ratio of 9.4. Nitrogen mass balances confirmed SND coupled with pre-denitrification. Nitrogen removal was closely related to bacterial community composition. a r t i c l e i n f o b s t r a c tA pilot-scale modified Orbal oxidation ditch with internal recycle of the nitrified liquor was developed to significantly enhance total nitrogen (TN) removal through simultaneous nitrification/denitrification (SND) coupled with pre-denitrification under the aerated-anoxic condition. Long-term operational results showed that the highest TN removal efficiency was achieved at very low dissolved oxygen (DO) of 0.15-0.25 mg/L and oxidation-reduction potential (ORP) of 10-40 mv within the outer channel. Appropriate internal recycle ratio played a significant role for increasing nitrates reduction within the outer channel, however, excessively high recycle flow deteriorated nitrogen removal instead because of diluted carbon source. At recycle ratio of 9.4, TN removal efficiency further increased to about 87% at optimal DO and pre-denitrification was responsible for TN removal improvement according to nitrogen mass balances. Molecular biology analysis revealed the correlation between variations in nitrogen removal and changes in bacterial community composition.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Enhanced total nitrogen removal performance in a modified Orbal oxidation ditch system with internal nitrate recycle

Zhou

Han

Guo

2013

Chemical Engineering Journal

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“…The ORP gives a measure of the general condition of the liquid and 230 whether the oxidation or the reduction reactions dominate as a process (Gray, 2004). This is mainly dependent on DO concentrations but the ORP as an indicator of the DO provides much better information about the processes at low DO concentrations and in the anoxic phase (Fuerhacker et al, 2000;Akin and Ugurlu, 2005;Hu et al, 2005). Figure 2 shows typical ORP and pH profiles in the four reactors that were recorded during both 235 experiments.…”

Section: Orp and Ph Monitoringmentioning

confidence: 99%

The effect of anoxia and anaerobia on ciliate community in biological nutrient removal systems using laboratory-scale sequencing batch reactors (SBRs)

Dubber

Gray

2011

Water Research

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Please cite this article as: Dubber, D., Gray, N.F. The effect of anoxia and anaerobia on ciliate community in biological nutrient removal systems using laboratory-scale sequencing batch reactors (SBRs), Water Research (2011Research ( ), doi: 10.1016Research ( /j.watres.2011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractLittle is known about the effect of anaerobic and anoxic stages on the protozoan community in the activated sludge process and how this subsequently affects performance. Using a laboratory-scale BNR system the effect of different periods of anoxia on both the protozoan community and performance efficiency have been 15 examined. Four SBRs were operated at two cycles per day using a range of combined anoxic/anaerobic periods (0, 60, 120 to 200 min). Effluent quality (TOC, BOD, TP, TN, NH 4 -N, NO 3 -N and NO 2 -N), sludge settleability and ciliate community (species diversity and abundance) were analyzed over a periods of up to 24 days of operation. The species richness and total abundance of ciliates were found to decrease with longer 20 anoxic/anaerobic periods. Both, positive and negative significant correlations between the abundance of certain species and the period of anoxia was observed (e.g. Opercularia microdiscum, Epicarchesium granulatum), although other species (i.e. Acineria uncinata, Epistylis sp.) were unaffected by exposure to anoxia. In the laboratory-scale units, the 60 minute anoxic/anaerobic period resulted in good process performance (TOC and BOD 25 removal of 97 to 98% respectively), nitrification (80-90%), denitrification (52%) but poor levels of biological P removal (12%); with the protozoan community moderately affected but still diverse with high abundances. Increasing the length of anoxia to up to 200 min did not enhance denitrification although P removal rates increased to between 22-33%; however, ciliate species richness and total abundance both decreased and sludge 30 settleability became poorer. The study shows that activated sludge ciliate protozoa display a range of tolerances to anoxia that result in altered ciliate communities depending on the length of combined anoxic/anaerobic periods within the treatment process. It is recommended that anoxic/anaerobic periods should be optimized to sustain the protozoan community while achieving maximum performance and nutrient removal. 35

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“…Sequencing batch reactor (SBR) method is a promising technology for leachate treatment (Ding et al 2001;Yalmaz & Ozturk 2001;Neczaj et al 2005;Laitinen et al 2006), because proper control of the aerobic and anoxic cycles of a system is possible with a real-time control process using oxidation-reduction potential (ORP) and/or pH as parameters (Lo et al 1994;Fuerhacker et al 2000;Kim et al 2004). However, insufficient electron donors hampered high efficient nitrogen removal from landfill leachate due to the low C/N ratios, especially for those landfill sites with an old age (Im et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Effect of chloride concentration on nitrogen removal from landfill leachate in sequencing batch reactor after MAP pretreatment

Chen

Qian

et al. 2010

Water Science and Technology

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Leachate generated from landfill is becoming a great environmental challenge to China as it contains high concentration of COD, ammonium and some other substances. Nitrogen removal through the conventional nitrification-denitrification process is hampered by the low C/N ratio especially for the old age landfill sites and the high energy consumption for aeration. In this study, the combination of magnesium ammonium phosphate (MAP) precipitation and Sequencing batch reactor (SBR) was suggested as a new process for the treatment of high strength ammonium, and the effect of high concentration of Cl 2 after MAP precipitation because of the use of MgCl 2 was investigated on SBR performance. The practical upper limit of Cl 2 for nitrification was found to be 12,000 mg/L, above which resulted in significant accumulation of ammonium in SBR system. It is suggested that an ammonium removal of 70% was suitable for the MAP treatment to achieve a balance between increasing the C/N ratio and avoiding detrimental effect from high concentration of Cl 2 in the succeeding SBR system. DGGE analysis indicated that high diversity of Ammonium oxidizing bacteria (AOB) could be maintained at a Cl 2 concentration of 12,000 mg/L.

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Approach for a novel control strategy for simultaneous nitrification/denitrification in activated sludge reactors

Cited by 67 publications

References 11 publications

Enhanced total nitrogen removal performance in a modified Orbal oxidation ditch system with internal nitrate recycle

Enhanced total nitrogen removal performance in a modified Orbal oxidation ditch system with internal nitrate recycle

The effect of anoxia and anaerobia on ciliate community in biological nutrient removal systems using laboratory-scale sequencing batch reactors (SBRs)

Effect of chloride concentration on nitrogen removal from landfill leachate in sequencing batch reactor after MAP pretreatment

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