Denitrification with Carbon Addition—Kinetic Considerations

Dold, Peter; Takács, Imre; Mokhayeri, Yalda; Nichols, Adam; Hinojosa, Jeneva; Riffat, Rumana; Bott, Charles; Bailey, Walter; Murthy, Sudhir

doi:10.2175/106143007x221085

Cited by 41 publications

(44 citation statements)

References 11 publications

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“…The use of ethanol with methanol and acetate grown biomass generated SDNRs of 7.2 and 4.7 mg NO 3 -N/g VSS/hr, respectively. The SDNR of ethanol with methanol grown biomass is similar to the SDNR of methanol with methanol grown biomass, suggesting that the methanol grown biomass can use ethanol, nearly as well as methanol, confirming the work by Dold et al (2007) and Nyberg et al (1996). The use of acetate with ethanol grown biomass produced the highest SDNR of 18.9 mg NO 3 -N/g VSS/hr.…”

Section: Ex Situ Specific Denitrification Rate Testssupporting

confidence: 73%

Characterizing denitrification kinetics at cold temperature using various carbon sources in lab-scale sequencing batch reactors

Mokhayeri

Riffat

Takács

et al. 2008

Water Science and Technology

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Wastewater treatment plants in the Chesapeake Bay region are becoming more interested in external carbon sources for denitrification. This is in response to the recent regulations to remediate the Chesapeake Bay, which will limit effluent total nitrogen to near 3 mg/L for plants, thus requiring near complete elimination of inorganic nitrogen species. Since sufficient internal carbon is usually not available for complete denitrification, external carbon is needed to supplement internal sources. Of particular interest is the use of an alternate external carbon source to replace the least expensive source methanol. This study focuses on three commonly available external carbon sources: methanol, ethanol and acetate. The aim of this study was to obtain the specific denitrification rate (SDNR) of the substrates under several conditions. Sequencing batch reactors (SBRs) were set up to first grow biomass to the specified substrate while in situ SDNRs were conducted concurrently. Once the biomass was grown with the corresponding substrate, a series of ex situ SDNRs were performed using various biomass/substrate combinations to evaluate response to substrate combinations at 13 degrees C. Results from this study indicate that the SDNRs for biomass grown on methanol, ethanol and acetate were 9.2 mg NO(3)-N/g VSS/hr, 30.4 mg NO(3)-N/gVSS/hr and 31.7 mg NO(3)-N/g VSS/hr, respectively, suggesting that acetate and ethanol were equally effective external carbon sources followed by much lower SDNR using methanol. Ethanol could be used with methanol biomass with similar rates as that of methanol. Additionally, methanol was rapidly acclimated to ethanol grown biomass suggesting that the two substrates could be interchanged to grow respective populations with a minimum lag period.

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Section: Ex Situ Specific Denitrification Rate Testssupporting

confidence: 73%

Characterizing denitrification kinetics at cold temperature using various carbon sources in lab-scale sequencing batch reactors

Mokhayeri

Riffat

Takács

et al. 2008

Water Science and Technology

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“…All Rights Reserved. 274 heterotrophic bacteria participating in the process (Grabinska-Loniewska et al, 1985;Dold et al, 2008). Methanol is the most widely used external carbon source for denitrification since it is low in cost (Mokhayeri et al 2006).…”

Section: Introductionmentioning

confidence: 99%

“…Past studies indicate that the maximum specific growth rate of methanol-utilizing organisms is low, 1.3/day at 20ºC, and highly temperature dependent (Nichols et al, 2007;Dold et al, 2008). Thus, when temperatures decrease during the winter, it is difficult for wastewater treatment (WWTP) plants adding methanol as the primary source of external carbon to achieve the required effluent total nitrogen limitations noted above without providing substantial reactor capacity.…”

Section: Introductionmentioning

confidence: 99%

Estimating The Kinetics And Stoichiometry Of Heterotrophic Denitrifying Bacteria With Glycerol As An External Carbon Source

Hinojosa¹,

Riffat²,

Fink³

et al. 2008

proc water environ fed

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Wastewater treatment facilities in the Chesapeake Bay watershed are focusing their attention on nitrogen removal to meet future effluent limitations of about 3-4 mg N/L. External carbon is added during denitrification to facilitate the removal of nitrate. This study investigates the kinetics and stoichiometry of glycerol as an external carbon source for denitrification. Biodiesel-based glycerol acclimated mixed liquor was fed glycerol as an external carbon source in lab scale batch experiments to estimate specific denitrification rate (SDNR), maximum specific growth rate, C:N ratio, growth yield and half saturation constants for COD limiting conditions. The average SDNR for acclimated and unacclimated mixed liquor was 1.4 mg NO x -N /gVSS/hr. The maximum specific growth rate was estimated at 3.4 d -1 . Stoichiometric C:N ratio and growth yield were estimated as 4.2 mg COD/mg NO x -N and 0.32 mg biomass COD/mg NO x -N respectively. The half saturation constant was estimated between 5-8 mg COD/L.

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“…The Espoo modelling work also helped optimize plant operation, and an important finding was to not dose carbon to the last anoxic compartment in order to avoid unnecessary carryover of RBCOD to the aerobic reactors. Also, because methylotrophs are very temperature-sensitive (Dold et al 2007), it was concluded that the yearly average nitrogen removal rate target of 70% could be more cost-effectively met by running the plant at 80% nitrogen removal in the summer and 60% nitrogen removal in winter. Finally, models play a critical role at facilities with low discharge limits such as the Western Branch WWTP in Upper Marlboro, Maryland,…”

Section: The Value Of Modellingmentioning

confidence: 99%

Wastewater treatment modelling in practice: a collaborative discussion of the state of the art

Phillips¹,

Sahlstedt

Frank³

et al. 2009

Water Science and Technology

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Three consulting teams conducted independent modelling projects for three different wastewater treatment plants ranging in size from approximately 113,800 m(3)/d (30 mgd) to 530,000 m(3)/d (140 mgd), in different parts of the world (USA and Finland). The plants have different treatment objectives ranging from nitrification and partial denitrification (nitrate plus nitrite <8.7 mg/L) to enhanced nutrient removal (total nitrogen <3 mg/L, total phosphorus <0.3 mg/L). Commonly-used models were applied in the case studies, including ASM3 (using the GPS-X simulator), New General (using GPS-X), Dold (using BioWin), and a variation of the Dold model methanol degradation capabilities (NGmeth within GPS-X). The authors compare and contrast the modelling approaches taken, including calibration and validation approaches, sensitivity analyses, and the application of results to full-scale studies, designs and operations. Despite several differences between the approaches, there are many similarities which are discussed in light of the IWA draft uniform protocol for activated sludge modelling. The authors also discuss current modelling limitations and offer suggestions to improve the state of the art.

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Denitrification with Carbon Addition—Kinetic Considerations

Cited by 41 publications

References 11 publications

Characterizing denitrification kinetics at cold temperature using various carbon sources in lab-scale sequencing batch reactors

Characterizing denitrification kinetics at cold temperature using various carbon sources in lab-scale sequencing batch reactors

Estimating The Kinetics And Stoichiometry Of Heterotrophic Denitrifying Bacteria With Glycerol As An External Carbon Source

Wastewater treatment modelling in practice: a collaborative discussion of the state of the art

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