The effect of solids residence time on phosphorus adsorption to hydrous ferric oxide floc

Conidi, Daniela; Parker, Wayne

doi:10.1016/j.watres.2015.07.046

Cited by 33 publications

(11 citation statements)

References 18 publications

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“…The model was developed assuming a reversible reaction between the soluble‐phase and adsorbed‐phase P concentrations that contradicted previously reported results in which P desorption from HFO floc was determined to be negligible (Conidi & Parker, ). Hence, application of this model was limited to describing adsorption from the liquid to the solid phase only.…”

Section: Approachmentioning

confidence: 71%

“…The testing conducted in this study employed four continuously operating SBRs (A, B, C, and D) that each had a different SRT and which have been previously described in detail (Conidi & Parker, ). The SBRs were equipped with pH control, aeration, and mechanical mixing and were operated with React (flocculate), Waste, Settle, and Decant phases in each cycle.…”

Section: Approachmentioning

confidence: 99%

“…In the development of these equations, it was assumed that the rate of mass transfer is a function of a mass transfer coefficient ( k ) that accounts for diffusive transfer limitations between the bulk and solid phases. Further, the rate of mass transfer is controlled by the difference between the bulk soluble‐phase P concentration (P) and the soluble P concentration that is in equilibrium with the sorbed concentration ( q ) at the solids surface as described by the Freundlich isotherm (Conidi & Parker, ).…”

Section: Approachmentioning

confidence: 99%

“…However, existing models do not address time‐dependent phenomena active in WRRFs which might impact upon the ability of WRRFs to consistently achieve extremely low effluent P targets. For instance, existing models do not address the impacts of HFO aging, which is influenced by solids residence time (SRT) (Conidi & Parker, ), on the rate of P removal from wastewater (Benisch, deBarbadillo, Barnard, & Neethling, ). Further, current models do not address mass transfer limitations to P removal that may become significant under time‐varying low‐P‐concentration conditions.…”

Section: Introductionmentioning

confidence: 99%

“…There is a clear need for kinetic models that describe uptake of P in continuous‐flow systems and which can be integrated into process simulators that can be employed for process analysis and design. Further, it was hypothesized that the SRT of the HFO floc may impact on mass transfer rates due to changes in floc morphology that could arise from increased crystallization with age (Conidi & Parker, ).…”

Section: Introductionmentioning

confidence: 99%

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Effect of solids residence time on dynamic responses in chemical P removal

Conidi

Parker

Smith

2019

Water Environment Research

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The impact of solids residence time (SRT) on the dynamics of phosphorus (P) removal by hydrous ferric oxide (HFO) floc was characterized through experimental and modeling studies. Three abiotic process conditions were considered in systems operated over a range of SRTs (~3 to 27 days): uptake in sequencing batch reactors (SBRs) under (a) constant and (b) dynamic P loading conditions, and (c) uptake in batch sorption tests with preformed HFO solids. P removal under all conditions was characterized by an initial period of fast removal followed by a period of slower removal until pseudoequilibrium was reached. The initial removal rate increased with increasing P concentrations and was attributed to a larger concentration gradient between soluble-and adsorbed-phase concentrations. A kinetic model was developed and found to describe the dynamic behavior of P adsorption onto HFO floc under all conditions tested. A consistent mass transfer rate coefficient (k) was found to describe mass transfer over a range of SRTs for low initial P concentrations. At elevated SRTs (23-27 days) and elevated influent P concentrations, k values were found to deviate from those estimated at reduced SRTs. Differences in process mixing conditions were reflected in the estimated rate coefficients (k). Integration of the kinetic model with existing equilibrium models in wastewater process simulators will improve the ability to predict P uptake onto HFO floc under dynamic loading conditions in water resource recovery facilities. Models that consider the kinetics of P uptake will be particularly relevant for facilities that are required to achieve ultralow P concentrations. • Practitioner points• This work provides a kinetic model that can be integrated with existing equilibrium models in wastewater process simulators to improve the ability to predict P uptake onto HFO floc under dynamic loading conditions. • This research can be used to assist WRRFs to achieve ultralow effluent P requirements.

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Section: Approachmentioning

confidence: 71%

Section: Approachmentioning

confidence: 99%

Section: Approachmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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