The case for anaerobic reduction of oxygen requirements in biological phosphorus removal systems

Randall, Clifford W.; Brannan, Kenneth P.; McClintock, Samuel A.; Pattarkine, Vikram M.

doi:10.2175/wer.64.6.11

Cited by 14 publications

(6 citation statements)

References 9 publications

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“…Reduction of organic matter in the anaerobic and anoxic zones established conditions for nitrification in the aerobic zone. In the anaerobic zone, a portion of the COD was stabilized, and denitrification consumed COD in the anoxic zone as reported by Randall et al (1992a). The exact magnitude of anaerobic and anoxic COD removal was not calculated.…”

Section: Discussionmentioning

confidence: 99%

Experience with Biological Nutrient Removal at Low Temperatures

Ydstebø¹,

Bilstad²,

Barnard³

2000

Water Environment Research

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Operating experience for the first enhanced biological phosphorus (EBPR) and biological nutrient removal (BNR) plant in Norway are summarized. The primary objective during the first years of operation was to remove phosphorus at low temperatures both in an EBPR mode and a BNR mode. Enhanced biological phosphorus removal was accomplished at 5°C with 0.6 mg/L total phosphorus in the effluent, and BNR was achieved at 6 to 8°C with an average of 0.25 mg/L phosphorus and 5.3 to 9.6 mg/L nitrogen in the effluent. Solids were separated by gravity settling only. Sufficient solids retention time resulted in biological phosphorus and nitrogen removal at low temperatures with two-thirds of the sludge production compared with chemical phosphorus removal. In the approximate plug-flow biological reactor, a completely stirred tank reactor with seven compartments, a mixed liquor suspended solids concentration of 6000 to 8000 mg/L was maintained because of the excellent settling characteristics of the sludge (diluted sludge volume index ϭ 60 to 80 mL/g). Plug-flow mixing characteristics result in a substrate gradient that promotes growth of rapid-settling bacteria and depresses growth of filamentous bacteria. Organic reduction in the anaerobic and anoxic zones results in a low organic loading rate to the aerobic zones with subsequent favorable conditions for nitrification. Water Environ. Res., 72, 444 (2000).KEYWORDS: biological nutrient removal, enhanced biological phosphorus removal, low-strength wastewater, low temperature, organic loading rate, solids production. Credits. The authors thank the plant operators, Rolf Jensen and Leif Å ge Johansen, at Groos BNR WWTP. They also thank students and staff at Agder College for participation in parts of the study and Barry Rabinowitz and Patrick Coleman of Reid Crowther for valuable guidance with plant operation.

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Section: Discussionmentioning

confidence: 99%

Experience with Biological Nutrient Removal at Low Temperatures

Ydstebø¹,

Bilstad²,

Barnard³

2000

Water Environment Research

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“…Given the quality of our N mass balances ͑again, assuming an f N of 0.1239͒, analytical error of this magnitude seems unlikely. This COD mass balance discrepancy may have been due to the poorly understood and controversial phenomena of "anaerobic stabilization" ͑loss of COD in anaerobic zones; Randall et al 1992; Barker and Dold 1995͒.…”

Section: Effects Upon Oxygen Consumption Sludge Production and Cod mentioning

confidence: 99%

Contrasting the Benefits of Primary Clarification versus Prefermentation in Activated Sludge Biological Nutrient Removal Systems

2006

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The potential benefits prefermentation can provide to biological nutrient removal are measured and compared to the costs of excess oxygen consumption and sludge production incurred by an activated sludge system that utilizes prefermentation, instead of primary clarification. Prefermentation was found to produce superior performance in regards to enhanced biological phosphorus removal. A lower soluble orthophosphorus effluent value ͓3.2 mg/ L for the prefermented activated sludge ͑PAS͒ train versus 4.6 mg/ L for the control train with primary clarification ͑PCAS͔͒ and a higher percent phosphorus ͑% P͒ content of the biomass ͑9.0% for the PAS train versus 7.8% for the PCAS train͒ were both found to be statistically significant ͑P values of 4.26ϫ 10 −5 and 0.0082, respectively͒. In addition statistically significant improvements in denitrification rates and reduced observed yields were observed due to prefermentation. However statistically significant increases in solids inventory and in particular oxygen uptake rates offset these improvements. Waste activated sludge production was slightly higher in the PAS train but was not found to be statistically significant.

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“…The investigation conducted by Randall et al (1992) found that the oxygen requirements of biological phosphorus removal systems may be reduced substantially by processes occurring in the anaerobic reactors. This reduction is in addition to any oxygen credit achieved by denitrification.…”

Section: Organic Removalmentioning

confidence: 99%

A Study of a Nutrient Removal Modified Sequencing Batch Reactor

Yang¹,

McKinney²,

Mikkelson³

et al. 2001

proc water environ fed

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The Modified Sequencing Batch Reactor, MSBR ® system combines the advantages of a flowthrough activated sludge system and sequencing batch reactor technology. A nutrient removal MSBR system adds the features of biological nutrient removal to the activated sludge system. Additionally, thickening of return mixed liquor suspended solids combined with anaerobic mixed liquor flow splitting to the anoxic cells was developed in this study. The improved system achieved high removal efficiency for BOD 5 , COD, total nitrogen, and phosphorus.

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The case for anaerobic reduction of oxygen requirements in biological phosphorus removal systems

Cited by 14 publications

References 9 publications

Experience with Biological Nutrient Removal at Low Temperatures

Experience with Biological Nutrient Removal at Low Temperatures

Contrasting the Benefits of Primary Clarification versus Prefermentation in Activated Sludge Biological Nutrient Removal Systems

A Study of a Nutrient Removal Modified Sequencing Batch Reactor

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