Phosphorus Release in Aerobic Sludge Digestion

Ju, Lu‐Kwang; Shah, Hemant K.; Porteous, J.D.

doi:10.2175/193864702784900110

Cited by 6 publications

(6 citation statements)

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“…However, if sludge is digested (either aerobically or anaerobically), significant fractions of the nitrogen and phosphorus contained in the sludge are likely to be re‐released back into the liquid phase (e.g., Holloway, Childress, Dennett, & Cath, ; Ju, Shah, & Porteous, ; Martí, Pastor, Bouzas, Ferrer, & Seco, ; Münch & Barr, ; Phillips, Kobylinski, Barnard, & Wallis‐Lage, ). This can be problematic because the liquid portion of the digester effluent (sometimes called the “sidestream” or the “centrate”) is typically returned to the headworks of the mainstream treatment facility, thereby recycling the nitrogen and phosphorus back into the system.…”

Section: Introductionmentioning

confidence: 99%

“…Are the concentrations and fluxes of inorganic nitrogen in the sidestream high enough to interfere with EBPR in the mainstream treatment process? Bishop and Farmer (), Matsuda, Ide, and Fujii (), Tonkovic (), Anderson and Mavinic (), Kim et al (), and Ju et al () have partially addressed these questions in bench‐ or pilot‐scale systems, but to the best of our knowledge, there has not yet been an investigation of nutrient mass fluxes at a full‐scale facility employing aerobic digestion.…”

Section: Introductionmentioning

confidence: 99%

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Mass fluxes of nitrogen and phosphorus through water reclamation facilities: Case study of biological nutrient removal, aerobic sludge digestion, and sidestream recycle

Kassouf

Parra

Mulford

et al. 2019

Water Environment Research

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At water reclamation facilities, recycling of nutrients (nitrogen and phosphorus) from solids‐handling processes to the mainstream treatment process can have detrimental effects on biological nutrient removal systems. In this study, mass fluxes of nitrogen and phosphorus were quantified through the treatment trains at the Northwest Regional Water Reclamation Facility (NWRWRF) and the adjoining Biosolids Management Facility (BMF), which receives sludge from several water reclamation facilities in Hillsborough County, Florida. The driving objectives were to determine (a) whether the return stream from BMF to NWRWRF (i.e., the “sidestream”) represents a significant source of nitrogen and phosphorus to NWRWRF, and (b) whether the sidestream return from BMF is interfering with biological nutrient removal processes at NWRWRF. We determined that nearly half of the overall phosphorus flux into NWRWRF is recycled from the BMF sidestream. This leads to an increased cost of treatment, for example, for alum used in phosphorus removal at NWRWRF. In contrast to phosphorus, the flux of nitrogen from BMF to NWRWRF is small (~3%) compared with the flux of nitrogen entering NWRWRF in raw wastewater. However, nitrogen in the sidestream is mostly in the form of nitrate, which prevents anaerobic conditions from developing in the fermentation basin at NWRWRF, and thereby interferes with the enhanced biological phosphorus removal (EBPR) process. Some measurements suggest that fermentation and release of phosphorus may occur in the return activated sludge line (despite the relatively short residence time in that line), which supports EBPR and may partially compensate for anoxic (denitrifying) conditions in the fermentation basin. Therefore, overall, NWRWRF is able to meet its permit limits for phosphorus through a combination of EBPR and alum addition. Although the fluxes measured here are particular to the treatment systems under consideration, the general trends observed are likely to apply to many similar facilities that employ biological nutrient removal, aerobic digestion, and sidestream recycle, particularly those with regional biosolids management facilities. We recommend that such facilities consider (a) removal or recovery of phosphorus from their sidestreams and (b) returning sidestreams downstream of fermentation basins to avoid inhibition of EBPR processes. Practitioner points Sidestreams from aerobic digestion can represent significant sources of phosphorus to mainstream wastewater treatment. Recycle of nitrate in aerobic digestion sidestreams can interfere with enhanced biological phosphorus removal (EBPR) during mainstream treatment. Fermentation of return activated sludge (RAS) can support EBPR, even under short average hydraulic residence times (minutes).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mass fluxes of nitrogen and phosphorus through water reclamation facilities: Case study of biological nutrient removal, aerobic sludge digestion, and sidestream recycle

Kassouf

Parra

Mulford

et al. 2019

Water Environment Research

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“…As water is treated in the aeration basin, P is removed by microorganisms at rates estimated to equal 40 and 90%, respectively, for a conventional treatment plant and one already incorporating an EBPR process (De‐Bashan and Bashan, 2004; Stark, 2004; Vaccari, 2011). After P removal, solids and microorganisms in the waste‐activated sludge stream are processed during anaerobic digestion to release 60 to 80% of P from sludge into the liquid phase (Ju et al, 2005). The dewatering facility concentrates the digested sludge to 22% solids content, and the sidestream is pumped back to the headworks for further treatment.…”

Section: Methodsmentioning

confidence: 99%

Mass Balance Model for Sustainable Phosphorus Recovery in a US Wastewater Treatment Plant

et al. 2016

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In response to limited phosphorus (P) reserves worldwide, several countries have demonstrated the prospect of recovering significant amounts of P from wastewater treatment plants (WWTPs). This technique uses enhanced biological P removal (EBPR) to concentrate P in sludge followed by chemical precipitation of P as struvite, a usable phosphate mineral. The present study models the feasibility of this enhanced removal and recovery technique in a WWTP in Arizona with design parameters typical of infrastructure in the United States. A mass balance was performed for existing treatment processes and modifications proposed to estimate the quantity of P that could be recovered under current and future flow conditions. Modeling results show that about 71 to 96% of the P being lost potentially could be recovered as struvite. About 491 ± 64 t yr of struvite may be recovered after process modification, which corresponds to $150,000 ± $20,000 yr in P sales to fertilizer industries. The process was projected to be economically feasible, with a payback period of 45 ± 30 yr in the studied WWTP and a much shorter duration of 3 ± 1 yr for WWTPs already using an EBPR process. Furthermore, modeling results suggest that P recovery can improve the quality of biosolids by favorably reducing the P:N ratio. Implementation of this strategy at US WWTPs may increase national security by reducing dependence of limited P resources. Considering all aspects of the recovery process with respect to environmental, economic, and social implications, the examined technique is concluded to represent a cost-attractive and sustainable method for P management in US WWTPs.

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“…The cost of transporting and further treating such large volume of wet sludge is a big part of the whole process expenses. In EBPR process, although P has been accumulated as polyphosphate in microbial cells, there's still a chance that DRP would be released into the liquid phase, if sludge is exposed to an anaerobic condition for a long time (Eikum et al, 1975;Pitman et al, 1991;Ju et al, 2005). Thus, proper sludge thickening and treatment technologies are required to minimize P release and maximize nutrient recovery.…”

Section: Sludge Thickeningmentioning

confidence: 99%

Enhanced Biological Phosphorus Removal for Liquid Dairy Manure

Ogejo

Knowlton

Love³

et al. 2008

2008 Providence, Rhode Island, June 29 - July 2, 2008

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Enhanced biological phosphorus removal (EBPR) has been widely used in municipal wastewater treatment, but no previous studies have examined the application of EBPR to treat dairy manure. This study was conducted to evaluate the (i) performance of pilot-scale EBPR systems treating liquid dairy manure, to balance the ratio of nitrogen to phosphorus in manure to meet crop nutrient requirements, (ii) effects of dissolved oxygen and solids retention time on the efficiency of EBPR, and (iii) I would like to express my appreciation to my advisor, Dr. Jactone Arogo, for his time and guidance throughout this research. I would also like to thank my committee members, Dr. Katharine F. Knowlton and Dr. Amy J. Pruden, for their invaluable comments and assistance in my study. I am very grateful to Dr. Clifford W. Randall and Dr. Chao Shang for their time and patience to answer my questions. I am very appreciative of Hope White, Jody Smiley and Julie Jordan for being so supportive and helpful, when I was using IC, GC and other facilities in their labs. I want to thank Karen Hall for her hard work and continuous support for my sample analysis. Also, I want to thank Monika Corbett and Jo DeBusk for kindly teaching me many laboratory skills. Many thanks go to Lifeng Li for his tremendous support, help and encouragement during my graduate studies. Finally, I would like to extend thanks to Sonja Galley,

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Phosphorus Release in Aerobic Sludge Digestion

Cited by 6 publications

References 0 publications

Mass fluxes of nitrogen and phosphorus through water reclamation facilities: Case study of biological nutrient removal, aerobic sludge digestion, and sidestream recycle

Mass fluxes of nitrogen and phosphorus through water reclamation facilities: Case study of biological nutrient removal, aerobic sludge digestion, and sidestream recycle

Mass Balance Model for Sustainable Phosphorus Recovery in a US Wastewater Treatment Plant

Enhanced Biological Phosphorus Removal for Liquid Dairy Manure

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