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Meta-analysis of mass balances examining chemical fate during wastewater treatment.

Heidler J, Halden RU - Environ. Sci. Technol. (2008)

Bottom Line: Occurrence data for organic wastewater compounds detected in digested sludge followed a simple nonlinear model that required only K(OW) or K(OC) as the input and yielded a correlation coefficient of 0.9 in both instances.The model predicted persistence in biosolids for the majority (> 50%) of the input load of organic wastewater compounds featuring a log10 K(OW) value of greater than 5.2 (log10 K(OC) > 4.4).In contrast, hydrophobicity had no or only limited value for estimating, respectively, phi and the overall persistence of a chemical during conventional wastewater treatment.

View Article: PubMed Central - PubMed

Affiliation: Johns Hopkins University Center for Water and Health, Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.

ABSTRACT
Mass balances are an instructive means for investigating the fate of chemicals during wastewater treatment. In addition to the aqueous-phase removal efficiency (phi), they can inform on chemical partitioning, transformation, and persistence, as well as on the chemical loading to streams and soils receiving, respectively, treated effluent and digested sewage sludge (biosolids). Release rates computed on a per-capita basis can serve to extrapolate findings to a larger scale. This review examines over a dozen mass balances conducted for various organic wastewater contaminants, including prescription drugs, estrogens, fragrances, antimicrobials, and surfactants of differing sorption potential (hydrophobicity), here expressed as the 1-octanol-water partition coefficient (K(OW)) and the organic carbon normalized sorption coefficient (K(OC)). Major challengesto mass balances are the collection of representative samples and accurate quantification of chemicals in sludge. A meta-analysis of peer-reviewed data identified sorption potential as the principal determinant governing chemical persistence in biosolids. Occurrence data for organic wastewater compounds detected in digested sludge followed a simple nonlinear model that required only K(OW) or K(OC) as the input and yielded a correlation coefficient of 0.9 in both instances. The model predicted persistence in biosolids for the majority (> 50%) of the input load of organic wastewater compounds featuring a log10 K(OW) value of greater than 5.2 (log10 K(OC) > 4.4). In contrast, hydrophobicity had no or only limited value for estimating, respectively, phi and the overall persistence of a chemical during conventional wastewater treatment.

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Related in: MedlinePlus

Analysis of mass balances conducted for various organic wastewater compounds (OWCs). The fraction of the mass loading that persisted in digested sludge (⧫) is plotted against the logarithmically transformed 1-octanol−water partition coefficient (log10KOW; panel A) and the organic carbon normalized sorption coefficient (log10KOC; panel B); empirical data were fit to a nonlinear model (S-shaped curve; see text and Supporting Information for details). Panels C shows the relationship between KOW and the OWC’s overall persistence, here defined as the chemical mass contained in both sludge and effluent after treatment divided by the initial loading. Panel D shows the aqueous removal efficiency of various OWCs as a function of their respective KOW values. Data points are annotated with numbers that link the OWCs to original references listed in Table 3.
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fig3: Analysis of mass balances conducted for various organic wastewater compounds (OWCs). The fraction of the mass loading that persisted in digested sludge (⧫) is plotted against the logarithmically transformed 1-octanol−water partition coefficient (log10KOW; panel A) and the organic carbon normalized sorption coefficient (log10KOC; panel B); empirical data were fit to a nonlinear model (S-shaped curve; see text and Supporting Information for details). Panels C shows the relationship between KOW and the OWC’s overall persistence, here defined as the chemical mass contained in both sludge and effluent after treatment divided by the initial loading. Panel D shows the aqueous removal efficiency of various OWCs as a function of their respective KOW values. Data points are annotated with numbers that link the OWCs to original references listed in Table 3.

Mentions: An analysis of mass flow into and out of the WWTPs yields important information on the ultimate fate of OWCs during treatment. Mass flow is determined by taking into account analyte concentrations in influent, effluent, and sludge as well as volumetric flow rates (Supporting Information). Loss of chemicals due to volatilization ideally also should be assessed, at least for volatile compounds. The mass fractions of chemical loading (Table 3) reported to be present in effluent and sludge either were taken from the literature (10–13,15,16,20) or calculated based on published data (9,14,17–19,21).


Meta-analysis of mass balances examining chemical fate during wastewater treatment.

Heidler J, Halden RU - Environ. Sci. Technol. (2008)

Analysis of mass balances conducted for various organic wastewater compounds (OWCs). The fraction of the mass loading that persisted in digested sludge (⧫) is plotted against the logarithmically transformed 1-octanol−water partition coefficient (log10KOW; panel A) and the organic carbon normalized sorption coefficient (log10KOC; panel B); empirical data were fit to a nonlinear model (S-shaped curve; see text and Supporting Information for details). Panels C shows the relationship between KOW and the OWC’s overall persistence, here defined as the chemical mass contained in both sludge and effluent after treatment divided by the initial loading. Panel D shows the aqueous removal efficiency of various OWCs as a function of their respective KOW values. Data points are annotated with numbers that link the OWCs to original references listed in Table 3.
© Copyright Policy - open-access - ccc-price
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2665886&req=5

fig3: Analysis of mass balances conducted for various organic wastewater compounds (OWCs). The fraction of the mass loading that persisted in digested sludge (⧫) is plotted against the logarithmically transformed 1-octanol−water partition coefficient (log10KOW; panel A) and the organic carbon normalized sorption coefficient (log10KOC; panel B); empirical data were fit to a nonlinear model (S-shaped curve; see text and Supporting Information for details). Panels C shows the relationship between KOW and the OWC’s overall persistence, here defined as the chemical mass contained in both sludge and effluent after treatment divided by the initial loading. Panel D shows the aqueous removal efficiency of various OWCs as a function of their respective KOW values. Data points are annotated with numbers that link the OWCs to original references listed in Table 3.
Mentions: An analysis of mass flow into and out of the WWTPs yields important information on the ultimate fate of OWCs during treatment. Mass flow is determined by taking into account analyte concentrations in influent, effluent, and sludge as well as volumetric flow rates (Supporting Information). Loss of chemicals due to volatilization ideally also should be assessed, at least for volatile compounds. The mass fractions of chemical loading (Table 3) reported to be present in effluent and sludge either were taken from the literature (10–13,15,16,20) or calculated based on published data (9,14,17–19,21).

Bottom Line: Occurrence data for organic wastewater compounds detected in digested sludge followed a simple nonlinear model that required only K(OW) or K(OC) as the input and yielded a correlation coefficient of 0.9 in both instances.The model predicted persistence in biosolids for the majority (> 50%) of the input load of organic wastewater compounds featuring a log10 K(OW) value of greater than 5.2 (log10 K(OC) > 4.4).In contrast, hydrophobicity had no or only limited value for estimating, respectively, phi and the overall persistence of a chemical during conventional wastewater treatment.

View Article: PubMed Central - PubMed

Affiliation: Johns Hopkins University Center for Water and Health, Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.

ABSTRACT
Mass balances are an instructive means for investigating the fate of chemicals during wastewater treatment. In addition to the aqueous-phase removal efficiency (phi), they can inform on chemical partitioning, transformation, and persistence, as well as on the chemical loading to streams and soils receiving, respectively, treated effluent and digested sewage sludge (biosolids). Release rates computed on a per-capita basis can serve to extrapolate findings to a larger scale. This review examines over a dozen mass balances conducted for various organic wastewater contaminants, including prescription drugs, estrogens, fragrances, antimicrobials, and surfactants of differing sorption potential (hydrophobicity), here expressed as the 1-octanol-water partition coefficient (K(OW)) and the organic carbon normalized sorption coefficient (K(OC)). Major challengesto mass balances are the collection of representative samples and accurate quantification of chemicals in sludge. A meta-analysis of peer-reviewed data identified sorption potential as the principal determinant governing chemical persistence in biosolids. Occurrence data for organic wastewater compounds detected in digested sludge followed a simple nonlinear model that required only K(OW) or K(OC) as the input and yielded a correlation coefficient of 0.9 in both instances. The model predicted persistence in biosolids for the majority (> 50%) of the input load of organic wastewater compounds featuring a log10 K(OW) value of greater than 5.2 (log10 K(OC) > 4.4). In contrast, hydrophobicity had no or only limited value for estimating, respectively, phi and the overall persistence of a chemical during conventional wastewater treatment.

Show MeSH
Related in: MedlinePlus