WANG, JIEFU, WANG

Wang, Jiefu

Jiefu Wang was a speaker at the WEFTEC 2024 conference in New Orleans, LA October 5-9, 2024.

Titles from this speaker

Description: Combination of EBPR, Endogenous Denitrification, Partial...

Combination of EBPR, Endogenous Denitrification, Partial Nitrification/Denitrification and Anammox to Achieve Cost-effective Nutrient Removal

Abstract

To address the problem of eutrophication in the marine environment caused by excessive nutrient release and meet stringent nutrient discharge limits (e.g., TIN < 3 mg/L), a costeffective BNR (biological nutrient removal) technology is needed for equipping coastal wastewater treatment plants (WWTPs) with nutrient removal capacity. This pilot work was aimed to demonstrate how a conventional “A2O + tertiary MBBR” process can be easily modified to collectively achieve EBPR, endogenous denitrification, and Partial nitrification/ denitrification and anammox (PANDA) in one combination under novel system automation control. Nutrient discharge limits (average TIN < 3 mg/L) were met. Large amount of carbon and oxygen can be saved throughout the secondary and tertiary treatment innovation. The volume of aeration tank can be reduced.

Enhanced biological phosphorus removal (EBPR), endogenous denitrification, and Partial nitrification/ denitrification and anammox (PANDA) can be incorporated in an 'A2O + tertiary MBBR' process to achieve cost-effective nutrient removal under system automation control. Nutrient discharge limits (average TIN < 3 mg/L) were met. Large amount of carbon and oxygen can be saved throughout the secondary and tertiary treatment innovation. The volume of aeration tank can be reduced.

SpeakerWANG, JIEFU

Presentation time

09:30:00

10:00:00

Session time

08:30:00

10:00:00

SessionPdNA Whole Plant Considerations

Session locationRoom S504a - Level 5

TopicIntermediate Level, Nutrients

Author(s)

Wang, Jiefu

Author(s)J. Wang 1; Y. Sun 2 ; W. Khunjar 3; Z Wang 1; M. Winkler 4; R.K. Goel 5;

Author affiliation(s)Department of Biological Systems Engineering, Virginia Tech 1; Hazen and Sawyer 2 ; Hazen and Sawyer 3; Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA, USA 1; Department of Civil and Environmental Engineering, University of Washington 4; Department of Civil and Environmental Engineering, University of Utah 5;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159157

Volume / Issue

Content sourceWEFTEC

Word count15

Description: Full-scale Mainstream Deammonification via Partial...

Full-scale Mainstream Deammonification via Partial Nitrification-Denitrification-Anammox

Abstract

Introduction Partial nitrification/denitrification coupled with anaerobic ammonia oxidation (PdNA, PANDA) process has the potential to result in capacity, chemical and energy savings at water resource recovery facilities (WRRFs). In this process, ammonia oxidation is controlled to achieve a specific NO3/NH3 ratio. Partial denitrification driven by supplemental carbon addition (e.g., methanol) is then used to stably generate NO2--N accumulation. Anaerobic ammonia oxidizers can then remove both nitrite and ammonia to achieve effluent NH3 and TN limits. Successful PdNA/PANDA has been documented in pilot and full-scale. This work documents advancement and implementation of PANDA at the Fairfax County Noman M. Cole Pollution Control Plant (NCPCP) to achieve TN limits less than 3 mg/L. Specifically, the work will discuss full-scale results demonstrating effective anoxic ammonia removal via the PANDA mode of operation Materials and methods Full-scale reactor setup. The full-scale MBBR system was commissioned in 2013 and is comprised of six trains, five of which are currently equipped with fixed-film media and ancillary equipment. Each train includes two anoxic denitrification cells (approximately 2.4 MG in total volume) in series followed by a single re-aeration cell (approximately 0.6 MG in volume). The anoxic denitrification cells are equipped with mixers and flat screens for media retention. The re-aeration cells are equipped with medium bubble aeration diffusers and cylindrical screens. All cells are equipped with K1 media, which provide the surface area necessary for attached growth of nitrifying and denitrifying bacteria. Methanol dosing was controlled via feed-back nitrate paced addition. Ammonia and nitrate for the tertiary MBBR PANDA demonstration was provided via process control adjustments to the secondary process, including changes to step-feed configuration, DO and airflow setpoints, load paced equalization and methanol feeding. Results and discussion Full-scale results — Full-scale demonstration testing of PANDA mode commenced in Q3 of 2022 and is ongoing. Results indicated:

*Anoxic ammonia removal between 1 and 2.0 mg/L has been observed since startup and the full-scale facility has been able to maintain weekly effluent ammonia concentration below 0.5 mg/L, monthly effluent TN concentrations of between 2 and 4 mg/L and an average annual effluent TN of 2.9 during the past 12 months of operation (2023).

*Unit methanol use at the facility has decreased by approximately 20% and unit energy demand at the facility has decreased by approximately 5% relative to 2021-2022 plant operations since operating in PANDA mode.

*Full-scale demonstration has confirmed that partial denitrification/anammox is sensitive to the NO3/NH3 ratio in the MBBR influent. Optimal performance (greater than 90% anoxic ammonia removal, COD to Nitrate removed less than 4.0 and influent ammonia above 1.1 mg/L) has been observed at NO3/NH3 ratio of 3.1 to 5.1.

*The FFX NCPCP has historically observed intermittent spikes in secondary effluent ammonia concentration. Potential causes of these spikes may be attributed to load peaking and/or suppressive compounds in the wastewater. A recent ammonia spike resulted in secondary effluent ammonia of 3.6 mgNH3-N/L to the MBBR. The PANDA mode of operation reduced 2.7 mgNH3-N/L to achieve a MBBR effluent ammonia of 0.9 mgNH3-N/L and MBBR effluent TIN of 2.5 mgTIN/L at a NO3/NH3 ratio of 1.5.

*NCPCP operators have easily shifted from PANDA to conventional mode of treatment when necessary to manage outside factors that might interfere with normal operations. Cumulatively, this work is the first to effectively demonstrate full-scale deammonification via PANDA while meeting stringent nutrient limits. Ongoing efforts are focused on optimizing the NO3/NH3 ratio, stabilize phosphorus removal while continuing to reduce energy and methanol associated with nutrient removal at the NCPCP.

This paper was presented at the WEFTEC 2024 conference in New Orleans, LA October 5-9.

SpeakerPace, Gregory

Presentation time

09:30:00

10:00:00

Session time

08:30:00

10:00:00

SessionProgression of PdNA: Development to Full-Scale

Session number504

Session locationRoom 240

TopicFacility Operations and Maintenance, Intermediate Level, Municipal Wastewater Treatment Design, Nutrients, Research and Innovation

Author(s)

Pace, Gregory, Khunjar, Wendell, Sun, Yewei, Wang, Jiefu, Wang, Zhiwu, Chitrakar, Sajana, Rasel, Munshi Md

Author(s)G.J. Pace1, W. Khunjar2, Y. Sun3, J. Wang4, Z. Wang4, S. Chitrakar5, M. Rasel5

Author affiliation(s)1Hazen and Sawyer, 2Hazen & Sawyer, 3Hazen and Sawyer, 4Virginia Tech, 5Noman M Cole Jr Pollution Control Center, 5City of Springfield

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159719

Volume / Issue

Content sourceWEFTEC

Word count7

Description: Mechanistic Understanding of the Kinetic Difference Between the Methanol and...

Mechanistic Understanding of the Kinetic Difference Between the Methanol and Glycerol-driven Partial Denitrification Anammox in Low Nitrogen Polishing Moving Bed Biofilm Reactors

Abstract

Introduction Partial denitrification coupled with anaerobic ammonia oxidation (PdNA) process has been identified as a promising approach to intensify biological nutrient removal systems to increase total nitrogen removal capacity while reducing chemical and energy demand (Campolong, 2019; Le et al., 2019; Zhang et al., 2020). Understanding how operational factors impact PdNA is necessary to extract optimal performance at water resource recovery facilities (WRRFs) regardless of the configuration employed. For example, work performed previously (Campolong, 2019; Le et al., 2019) has shown that PdNA is impacted by multiple factors including the type of carbon utilized e.g., methanol, glycerol, acetate, etc.). This prior work hypothesized that partial denitrification results due to two main mechanisms, i) rate differential between heterotrophic nitrate and nitrite reduction due to different substrate availability and carbon sources, ii) nitrite sink due to anammox activity (Al-Omari et al., 2021). This current study provides insights into understanding how these different mechanisms may dictate partial denitrification in a low nitrogen polishing environment. Data from long term operation (417 days) of two pilot-scale MBBR treatment trains treating secondary effluent from the Noman M. Cole Jr. Pollution Control Plant (NCPCP) was used to develop a mechanistic understanding of methanol versus glycerol driven PdNA performance with a view to informing how to scale PdNA into other WRRFs. This work also provides a framework for informing design practices as related to stimulating stable PdNA. Materials and methods Reactor setup and operation: Two parallel MBBR treatment trains dosed with methanol and glycerol, respectively, were operated on site at NCPCP. In each treatment train, two 14 L working volume anoxic MBBRs filled with K1 media at a volumetric fraction of 45% were connected in series, followed by an 8 L working volume reaeration reactor filled with K1 media at a volumetric fraction of 32% (configuration simulated full-scale MBBR trains at NCPCP). K1 media with established biofilms of heterotrophs and nitrifiers from the full-scale MBBR train were used to seed the pilots. The pilots were operated for 417 days with a focus on demonstrating the ability to achieve effluent nutrient limits while reducing supplemental carbon needs. A description of performance is provided in (Sun, 2022; WANG, 2022). Model development: Kinetic analysis of PdNA was investigated by developing expressions describe denitratation (NO3--N â†’ NO2--N) and denitritation (NO2--N â†’ N2) (Glass and Silverstein, 1998). The specific nitrate uptake rate of denitratation culture (qDenitra.) can be expressed as Equation 1 according to Activated Sludge Model NO. 1 (Henze et al., 2000). Similarly, the specific nitrite uptake rate of denitritation culture (qDenitri.) can also be expressed as Equation 2. Equation 3 shows the specific nitrite uptake rate of anammox (AMX) bacteria (Bi et al., 2015). qAMX/qDenitri., qAMX/qDenitra. and qDenitra/qDenitri. as shown in Equations 4, 5 and 6 were used to compare effects of conditions on specific substrate uptake rates with a view to identifying which process might govern performance. All the kinetic parameters used in the investigation are listed in Table 1. Results and discussion Pilot results: Methanol-driven PdNA achieved an effluent TIN concentration of 2.6 +/- 0.6 mg/L and observed an average of 1.3 mg/L anoxic NH4+-N removal. Glycerol-driven PdNA achieved an effluent TIN concentration of 2.7 +/- 1.0 mg/L and observed an average of 1.3 mg/L anoxic NH4+-N removal. Results confirmed it was possible to achieve nutrient targets while also reducing supplemental carbon by 20 to 30% relative to conventional BNR. Nitrite sink by AMX governed PdNA performance in methanol fed train: Data from pilot operation were overlaid on heat maps plotting specific utilization rate ratios of denitratation, denitritation and AMX (Figures 1, 2 and 3). Results indicated that the in situ anammox substrate utilization rate (qAMX) was likely greater than the denitritation utilization rate (qDenitri) for the entire 372 days of operation period. Additionally, it was observed that anammox substrate utilization and denitratation utilization rates were similar i.e., qAMX/qDenitra ~ 1. Collectively, these results suggest that heterotrophic denitritation was outcompeted by anammox for nitrite in the methanol system. This implies that nitrite sink from anammox governed PdNA performance. Rate differential for heterotrophic denitratation versus denitritation governed PdNA performance in glycerol fed train: In contrast to the methanol train, pilot data from the glyercol train suggested that qAMX was less than qDenitri for the majority of pilot operation. Further, it was observed that qAMX was less than qDenitra while qDenitra. was greater than qDenitri. This data implies that the rate differential for heterotrophic nitrate and nitrite reduction dictated PdN performance in the glycerol train. Significance of Results The approach described in this paper can be used to help improve our understanding of existing PdNA systems to help clarify how different conditions may impact which mechanisms dictate performance.

This study explores using methanol and glycerol as carbon sources in partial denitrification coupled with anammox (PdNA) in tertiary moving bed biofilm reactors (MBBRs). Over 371 days, two MBBR trains were tested. Both achieved effluent total inorganic nitrogen (TIN) below 3 mg/L, with methanol being more cost-effective for nitrogen removal. Anammox (AMX) played a key role in nitrite sink, guiding future full-scale PdNA applications for improved efficiency and cost savings.

SpeakerWang, Jiefu

Presentation time

16:30:00

17:00:00

Session time

15:30:00

17:00:00

SessionEnhancing Nitrogen Removal: Insights Into Carbon Sources and Mechanisms

Session number420

Session locationRoom 340

TopicAdvanced Level, Facility Operations and Maintenance, Municipal Wastewater Treatment Design, Nutrients, Research and Innovation

Author(s)

Wang, Jiefu, Chitrakar, Sajana, McGrath, Michael, Sun, Yewei, Khunjar, Wendell, Pace, Gregory, Wang, Zhiwu

Author(s)J. Wang1, S. Chitrakar2, M.J. McGrath3, Y. Sun4, W. Khunjar5, G.J. Pace6, Z. Wang1

Author affiliation(s)1Virginia Tech, VA, 2Noman M Cole Jr Pollution Control Center, VA, 3Fairfax County Government, VA, 4Hazen and Sawyer, VA, 5Hazen & Sawyer PC, VA, 6Hazen and Sawyer, DC

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159506

Volume / Issue

Content sourceWEFTEC

Word count23

Description: Optimizing Dissolved Organic Nutrient Management: Exploring Carbon-Based Advanced...

Optimizing Dissolved Organic Nutrient Management: Exploring Carbon-Based Advanced Treatment Strategies

Abstract

Introduction As population growth, urbanization, and climate change intensify pressures on water resources, utilities are faced with an increased urgency for advanced water treatment (AWT) solutions and a need to enhance resilience against evolving climatic conditions. Concurrently, wastewater resource recovery facilities (WRRFs) are faced with increasingly stringent nutrient discharge limits that surpass the capabilities of conventional treatment methods. Consequently, utilities are compelled to adopt innovative approaches to address the quality and quantity of water supplies while ensuring regulatory compliance and sustainability. In this work, we highlight case studies of two forward-thinking utilities, distinguished by geographical contexts and unique drivers, yet united by a commitment to advance climate change adaptation strategies, achieve ultra-low nutrient limits, and integrate holistic one water initiatives. Metro Water Recovery (Denver, CO): Upcoming Colorado water quality regulations are set to impose stringent stream standards, notably 2.01 mg/L for total nitrogen (TN) and 0.10 mg/L for total phosphorus (P) on WRRFs, including Metro Water Recovery's Robert W. Hite Treatment Facility (RHWTF) and Northern Treatment Plant (NTP). AWT technologies like carbon-based advanced treatment (CBAT) schemes (e.g., coagulation/flocculation/sedimentation (floc/sed), ozone (O3), biofiltration (BAF), and granular activated carbon (GAC)) may address stringent nutrient limits while also aligning with Direct Potable Reuse (DPR) requirements. A study was initiated to: 1) assess the treatability of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and soluble non-reactive phosphorus (sNRP) using CBAT technologies; and 2) discern the capabilities of CBAT in concurrently achieving nutrient limits and DPR compliance. Evaluation of nutrient removal through tertiary CBAT processes spanned full-scale applications (floc/sed at NTP and BAF/floc/sed at RHWTF's Denver Water Recycling Plant (DWRP)) and pilot-scale (O3 only, BAF only, and O3/BAF at RHWTF), supplemented by bench-scale floc/sed (jar testing) and GAC evaluations (rapid small-scale column tests). Parameters such as O3 dose and empty bed contact times aligned with potable reuse standards. While full-scale floc/sed/filtration at NTP (Figure 1; Figure 2) and DWRP (Figure 3, Figure 4) (~20 mg/L alum) effectively managed particulate P and sNRP removal, it did not meet DOC and DON targets for Direct Potable Reuse (DPR) applications. CBAT testing showed potential for control of DOC and DON, albeit with the need for multiple potentially costly unit processes. The GAC runtime (up to 3,500 Bed Volumes for DOC and DON targets) was notably extended through enhanced upstream treatment. While floc/sed processes achieved comparable DOC and DON removal rates (up to 40% each) at the expense of elevated coagulant doses (80 mg/L Ferric chloride), O3/BAF treatments realized a modest 26% reduction in DON. Future pilot efforts aim to assess the efficacy of a comprehensive CBAT treatment train, inclusive of tertiary denitrifying BAF, to fulfill TN requirements and optimize DPR suitability. AWT Utility (Midwest): A midwest AWT utility has seen significant population growth in recent years and is estimated to double by 2040. Rapid growth and a desire improve the health of the receiving water body have urged the utility to consider alternative water supplies. Subsequently, the utility commissioned a CBAT pilot consisting of O3, two-stage BAF, GAC, and UV advanced oxidation process (UVAOP). The objective of this study was to pilot CBAT technologies to demonstrate the ability of AWT process trains to produce high quality finished water that meets stringent water quality targets. This study utilized a multi-barrier scheme of O3/two-stage BAF (aerobic/anoxic) to meet low TN limits. Filters were operated in several phases (Table 1) until effluent quality targets were met (TOC < 3 mg/L, TN < 2 mg/L, contaminants of emerging concern (CECs)- meet MCLs) and steady-state was achieved. Select operational parameters were varied during each phase and the resulting water quality surrounding the first anoxic BAF (BAF 3) is shown in Figure 8. Table 2 shows the effluent DO, nitrate (NO3-N) concentrations and corresponding % NO3-N removal achieved across each anoxic BAF. Results indicate that when supplemental carbon and upstream feed DO levels were controlled, anoxic BAF 1 established and maintained anoxic conditions and achieved NO3-N removals up to 60% with anoxic BAF 2 acting as a polishing biofilter (%NO3-N removal ~30%). When supplemental carbon and upstream DO quenching chemical doses were reduced, anoxic BAF 1 turned into a sacrificial BAF, consuming excess DO and displaying poor nitrate removals (~15%), while anoxic BAF 2 became the dominant anoxic biofilter (> 60% NO3-N removal). Piloting efforts demonstrate how a modified CBAT train may simultaneously meet low TN targets (< 2 mg/L) and produce high quality product water. Conclusion Case studies at Metro Water Recovery and a midwest AWT utility demonstrate CBAT's potential for improving finished water quality for reuse and meeting ultra-low nutrient discharge requirements. Project findings provide first guidance on how WRRFs can adjust operational setpoints using CBAT process infrastructure to meet DPR or discharge water quality requirements in ecologically sensitive and drought-prone watersheds.

This study explores carbon-based advanced treatment (CBAT) as an alternative to reverse osmosis for removing dissolved organics and nutrients. Case studies at the Franklin Water Reclamation Facility in Tennessee and the Metro Water Recovery Robert W. Hite Treatment Facility in Colorado evaluated CBAT pilots. Using various configurations, the study measured the removal efficiency of dissolved organic carbon, dissolved organic nitrogen, dissolved organic phosphorus, and total inorganic nitrogen.

SpeakerHlad, jeffrey

Presentation time

11:00:00

11:30:00

Session time

10:30:00

12:00:00

SessionAdvancements in Non-RO Treatment for IPR/DPR: Exploring Cutting-Edge Solutions

Session number530

Session locationRoom 235

TopicIntermediate Level, Microconstituents and Contaminants of Emerging Concern (Non-PFAS), Sustainability and Climate Change, Water Reuse and Reclamation

Author(s)

Hlad, jeffrey, Freedman, Daniel, Ram Mohan, Gayathri, Khunjar, Wendell, Scopp, Anna, Peterson, Eric, Rauch-Williams, Tanja, Wang, Jiefu

Author(s)J. hlad1, D. Freedman1, G. Ram Mohan2, W. Khunjar3, A. Scopp4, E. Peterson4, T. Rauch-Williams1, J. Wang5

Author affiliation(s)1Metro Water Recovery, 2Hazen and Sawyer, 3Hazen and Sawyer, VA, 4Hazen and Sawyer, 5Virginia Tech, VA

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159696

Volume / Issue

Content sourceWEFTEC

Word count11

Description: Partial denitrification with glycerol as external carbon in moving bed biofilm...

Partial denitrification with glycerol as external carbon in moving bed biofilm reactors applied for anaerobic ammonia oxidation of low nitrogen concentration secondary effluent

Abstract

Introduction
Partial denitrification (PD) has been considered to be a promising alternative to partial nitrification (PN) for NO2--N generation in view of the challenge in suppressing nitrite oxidizing bacteria (NOB) under the low mainstream temperature and nitrogen level (Zhang et al. 2019). The PD prepares NO2--N for enriching anaerobic ammonium oxidizing bacteria (AnAOB) required for successful annamox (AMX). Glycerol has been regarded as a preferred carbon source for PD which has been reported to achieve PD efficiency as high as 56% to 94% (Baideme 2019, Campolong 2019, Le et al. 2019, Sharp et al. 2017, Zhang et al. 2020). However, all of these studies were performed in high strength wastewater with NO3--N > 10 mg/L and COD/NO3--N ranging from 2.5 to 4.5, which raises the question whether the same PD approach can be applied in low strength tertiary effluent. The moving bed biofilm reactors (MBBRs) have often been used as a tertiary effluent polishing process for biological nitrogen removal (BNR) to meet the permissible total nitrogen (TN), e.g., 3 mg TN/L level, in the plant discharge. Although PdNA/PANDA has been pursued in recent years to reduce carbon and aeration demand in mainstream biological nitrogen removal, the applicability of glycerol as an external carbon source for PdNA/PANDA in tertiary effluent with NO3--N and NO2--N as low as 6.3 Â± 1.6 and 0.07 Â± 0.10 mg N/L in the context of this study has not been explored. Such low substrate concentration makes the enrichment of denitratating culture and AnAOB especially difficult. These being said, the objectives of this study are to: i) verify the feasibility of performing nitrogen removal in the tertiary effluent via the PdNA/PANDA with glycerol as an external carbon source; ii) evaluate the system performance and unravel the mechanism behind it; and iii) make recommendations for full-scale applications of the technique.
Materials and methods Reactor setup. A MBBR treatment train dosed with glycerol were operated on site at Noman M. Cole Jr., Pollution Control Plant (NCPCP) (Figure 1). Briefly, two 14 L working volume anoxic MBBRs filled with K1 media at a volumetric fraction of 45% were connected in sequence and then followed by an 8 L working volume reaeration reactor filled with K1 media at a volumetric fraction of 32% to simulate the full-scale MBBR trains at NCPCP (Figure 1). Realtime feed-forward control. Real-time NO3--N, NO2--N, NH4+-N and DO data of tertiary effluent from Chemscan analyzer and DO probe (Figure 1) were sent to Spyder (python 3.8) in a PC. A programmable pump receiving signals from the PC can precisely dose chemicals to the system.
Activity Testing. In-situ batch tests for denitrification activity were conducted by dosing nitrate sodium at 10 mg NO3--N /L and sCOD at 50mg/L (20% glycerol) after isolating reactors and suspending COD dosing for one hours prior to the test. NO3--N, NO2--N, NH4+-N, and sCOD were evaluated with Hach tubes in 0.45Î¼m-filtered grab samples for a period of 1 to 2.5 hours.
qPCR analysis. Quantitative polymerase chain reaction (qPCR) was performed to quantify the copy numbers of total bacterial 16S ribosomal RNA (rRNA) gene, the 16S rRNA of Candidatus Kuenenia and hzsB gene on a QuantStudio 3 thermocycler (Applied Biosystems, Waltham, MA). Each 20-Î¼L qPCR reaction mixture contained 10 Î¼L of 2Ã— SYBRâ„¢ Green PCR Master Mix with ROX (Life Technologies, Carlsbad, CA), 1 Î¼L each of forward and reverse primers (0.2 Î¼M), 7 Î¼L molecular-grade water (Sigma-Aldrich, St. Louis, MO), and 1 Î¼L DNA template. Model development and calculations of kinetic parameters using Eadieâ€“Hofstee linearization method in denitrification batch tests. In Eq. 1, rNO3- represents nitrate reduction rate, rm1 represents the maximum rate of nitrate reduction, KNO3- and KCOD1 represent the Monod half saturation constants for nitrate and organic matters in the denitratation, respectively. When nitrate is sufficient (SNO3- Â» KNO3-), Eq. 1 can be simplified as Eq. 2, where rm1' is the maximum rate of nitrate reduction when nitrate is sufficient. This hyperbolic function of Monod in Eq. 2 can be converted into a linear form in Eq. 2 using the Eadieâ€“Hofstee linearization method. When we plot rNO3- against rNO3-/ SCOD, the absolute value of the slope is KCOD1 and the intercept is rm1' according to Eq. 3.
Results and discussion PD performance. By adjusting glycerol dosage, NO3--N removal could be easily achieved (Figure 2a) but PD efficiency in the Cell A dramatically fluctuated between 3 and 79% during the 330-day operation (Figure 2b). Given this unstable PD, AMX activity also dramatically fluctuated according to the %TIN removal by AMX in Figure 2b. It is noteworthy that most of the previous studies have reported the opposite results, i.e., glycerol gave stable and good PD performance. We would like to point out that almost all of these previous studies were performed in secondary or tertiary processes where NO3--N concentration was above 10 mg/L (Du et al. 2019, You et al. 2020). PdNA/PANDA in tertiary effluent with NO3--N concentration as low as 6.3 Â± 1.6 mg/L used in this study has rarely been studied. Figures 2 just indicate glycerol might not be a preferred carbon source for PdNA/PANDA in low nitrogen environment.
R-strategist in glycerol-driven denitratation and denitritation. Monod kinetic parameters of denitratation and denitritation can be calculated according to the model developed in Eqs. (1) to (8). The results in Tables 1 and 2 show that ratios of the half-saturation constants (KCOD1 / KCOD2 and KNO3- / KNO2-) and the maximum rates (rm1' /rm2' and rm1'' / rm2'') determined from this study and reported in all the literature we can find are all greater than 1. That being said, the glycerol-driven denitratation has lower COD and nitrogen affinities but higher maximum reaction rates than denitritation process, i.e., R-strategy is taken by glycerol-driven PD. This could potentially explain why glycerol performs better PD at high NO3--N concentrations but otherwise in the low-strength tertiary effluent herein. Thus, it is recommended to perform glycerol-driven PdNA/PANDA in primary or secondary processes with high substrate concentrations.
qPCR results and Carbon savings. The abundance of Anammox 16S rRNA and hzsB measured by qPCR in Figure 3a evidenced the existence of AMX in Cell A but not Cell B in Figure 1. Owing to the existing of these AMX, Î”sCOD / Î”TIN profiles in Figure 3b showed that this glycerol-driven PdNA/PANDA pilot still consumed less COD to removal a unit of TIN than the full-scale MBBR. However, due to the unstable PD efficiency and AMX activity as a result of the R-strategy in glycerol-driven denitratation and denitritation (Figure 2b), glycerol-driven PdNA/PANDA might not be an optimal choice for tertiary effluent polishing.

In this study, a tertiary treatment train (moving bed bioreactor) dosed with glycerol was operated on site to remove nitrogen from secondary effluent. This pilot tertiary treatment phase was operated to test the feasibility of achieving TN limits < 3 mg/L using partial nitrification/denitrification/anammox. The results indicate that it is feasible to achieve glycerol-driven partial denitrification anammox (PdNA) in MBBRs with low nitrogen concentrations in the long term.

SpeakerWANG, JIEFU

Presentation time

09:30:00

09:55:00

Session time

08:30:00

10:00:00

TopicAdvanced Level, Municipal Wastewater Treatment Design, Nutrients, Research and Innovation

Author(s)

WANG, JIEFU

Author(s)J. WANG1; W. Khunjar2; G.J. Pace3; A. Pathak4; M.J. McGrath5; M. Ali4; Y. Sun6; Z.(. Wang1; J. WANG1

Author affiliation(s)Virginia Tech, VA1; Hazen & Sawyer PC, VA2; Manhattan College3; VA4; Fairfax County, VA 5; Hazen and Sawyer, VA6