Al-Omari, Ahmed

Ahmed Al-Omari is a senior process engineer at Brown and Caldwell based in Dallas/Fort Worth, Texas. He serves as a national wastewater leader for...

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About Al-Omari, Ahmed

Ahmed Al-Omari is a senior process engineer at Brown and Caldwell based in Dallas/Fort Worth, Texas. He serves as a national wastewater leader for biological and chemical treatment. He is focused on technology development and evaluation for nutrient removal, process intensification, resource reovery, and biosolids handling. Ahmed has expertise in bench scale, pilot scale and full schale testing, process design, process modeling and wastewater operations. He currently hold a masters degree in enviromental engineering, a professional licensed engineer, Class IV wastewater operator license, and more than 19 years of experience in the field.

Al-Omari, Ahmed

Titles from this speaker

Application of Vacuum Extraction to Anaerobic Digestion for Process Intensification and Resource Recovery

Abstract

The IntensiCarbTM process utilizes the decoupling of SRT and HRT, like recuperative thickening, to increase process capacity while simultaneously reducing the influence of toxic metabolic by products through extraction (ex. ammonia-N) and recover additional methane. This paper summarizes 3 years of research evaluating the efficacy of the process utilizing a side-by-side comparison of conventional mesophilic digestion with varying intensification factors (2x, 3x, 4x, 5x) in bench-scale trials conducted at Western University in London, Ontario digesting blend of primary and secondary sludge collected from the Greenway Wastewater Treatment Plant. Figure 1 provides a process flow diagram of the IntensiCarbTM process simulated in these tests. Figure 2, plots change in volatile solids reduction (VSr) in relation to hydraulic and solids retention times of IntensiCarb to explore its impact on the rate and extent of digestion. Based on this data it can be seen that the primary mechanism of process enhancement is the rate of digestion, rather than extent, being able to operate a higher loading rate, low HRT, with out significant increase in overall destruction at extended SRT. While some instability was observed in the higher loading rates it was transient during transition periods. With the move toward resource recovery, the energy yield of the digestion process is as critical as maximizing methane production per unit volume has potential long-term operating cost benefits as well as sustainability impacts. Figure 3, plots the impact of digester hydraulic retention time on the methane yield of the digester (m3-CH4/m3digester/d). Figure 3, clearly illustrates that with the IntensiCarbTM process the methane yield on an equivalent digester volume basis is more than 4.5 times higher than the conventional digester at 20 days SRT; 1.28 m3-CH4/m3digester/d verses 0.28 m3-CH4/m3digester/d, respectively. Furthermore, conventional mesophilic digestion typically does not operate, at scale, under 15 days of retention time. This is because below this level significant risk to process stability has been historically observed. The accumulation of ammonia has a self-limiting effect on anaerobic digestion. To date, no technology has effectively managed ammonia-N in-situ, resulting in risks for process instability and or significant population shifts, as reported by Mah et al. (2017) for THP. This is significant in that the control of ammonia in the digester could support high loadings without the negative impacts of toxicity and reduce return stream impacts, often a concern with high rate anaerobic digestion processes. The data shows (Figure 4) that as the digester load increased with IntensiCarbTM, the overall total ammonia-N levels remained around 800 mg-N/L or less, while a more conventional system would be expected to be operating at 2,100 to >5,000 mg-N/L. This observation alleviates one of the primary limits to anaerobic digestion. High loadings and high ammonia concentrations have been attributed to shifts in digester populations, as outlined by Mah et al (2017) when evaluating thermal hydrolysis. With similarly high loads but significantly reduced ammonia-N levels, the population profile of several of the test digesters were evaluated and compared to the control. The relative abundance of bacteria and archaea (methanogens) depicted in Figure 6 indicates that the relative abundance of archaea increases with intensification factor, approximately 40% (Figure 5). Looking at the specific methanogenic population present, there is a shift that occurs between the conventional (Control) digester relative to the intensified digesters. As the intensification level increases the methanogenic population shifts from one dominated by the low-growth rate Methanosaeta to one dominated by high-growth rate Methanosarcina (Figure 6). Some have suggested that digesters dominated by Methanosarcina have a higher overall capacity and stability due to their significantly higher maximum specific growth rate. The opposite was reported for thermal hydrolysis based digestion (Mah et al (2017)). Vacuum enhanced anaerobic digestion represents a novel process for the intensification of anaerobic sludge stabilization. Potentially offering unique opportunities for resource recover, ammonia-N and dissolved methane, as well as providing a mechanism to alleviate the current limitations associated with anaerobic digestion, metabolic byproduct toxicity.

The IntensiCarbTM, process is a vacuum enhanced anaerobic digestion process, that separates solids and hydraulic residence time. Resulting in increased process capacity by six times and in-situ removal of ammonia from the digestion process, exceeding the capacity of all commercially available sludge digestion processes on the market today. The process appears to select for increased methanogenic robustness and ammonia tolerance as well as create new opportunities for resource recovery.

SpeakerMuller, Christopher

Presentation time

16:00:00

16:20:00

Session time

15:30:00

17:00:00

SessionAdvances in Anaerobic Digestion

Session number219

Session locationRoom 344

TopicBiosolids and Residuals, Intermediate Level, Research and Innovation

Author(s)

Muller, Christopher, Khadir, Ali, Abdelrahman, Amr, Al-Omari, Ahmed, Jang, Eunkyung, Bell, Katherine, Norton, John, Sheculski, Chris, Santoro, Domenico, Nakhla, George

Author(s)C. Muller1, A. Khadir3, A. Abdelrahman3, A.A. Al-Omari1, E. Jang2, K. Bell1, J. Norton4, C. Sheculski2, D. Santoro2, G.F. Nakhla3

Author affiliation(s)1Brown and Caldwell, 2USP Technologies, 3Western University, 4Great Lakes Water Authority

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159715

Volume / Issue

Content sourceWEFTEC

Word count14

Description: Arrested Anaerobic Digestion and Recovery of Value-added Products Through...

Arrested Anaerobic Digestion and Recovery of Value-added Products Through Vacuum-intensified Alkaline Fermentation

Abstract

In this proof of concept experimental work, it was demonstrated that vacuum-driven fermentation can enable efficient resource recovery from municipal sludge and provide means to arrest anaerobic treatment to maximize extraction of added value products such as ammonia and volatile fatty acids (VFA). The concept relies on applying low vacuum to strip ammonium from fermented sludge, allowing the recovery of ammonium sulfate by chemisorption. Moreover, volatile fatty acids and soluble phosphorus, highly concentrated in the fermentate, can be separated using a pre-conditioning step based on iron flocculation and hydrogen peroxide (to precipitate phosphates) followed by mechanical filtration. This way, nutrient-free soluble carbon and volatile fatty acids can be recovered in the filtrate, while nutrient-rich solids can be further processed by anaerobic digestion or directly used as soil amendment and fertilizers. In this project, a feasibility study, centered on laboratory tests and model-based analysis, to determine the viability of this new process to accelerate the realization of circular economy in the wastewater industry. The study was designed to confirm the impact of pH on the ability to improve VFA production from fermentation and improve the selective separation of ammonia through stripping compared to conventional fermentation or vacuum assisted fermentation without pH adjustment. It also confirmed whether the value-added products recovered by vacuum technologies can maintain high yields and sufficient purity for circular applications (i.e., supplemental carbon for biological nutrient removal, fertilizers for agriculture, carbon-based precursors to bioplastics, etc.). The study demonstrated the improvement of ammonia recovery by more than double compared to vacuum at neutral pH. In addition, VFA yield was improved by 84% compared to the control. Operating in alkaline conditions ceased the methanogenesis process resulting in accumulation of VFA. On the other hand, the elevated pH reduced the undissociated acids concentrations, which may have resulted in improved hydrolysis and fermentation rates.

SpeakerAl-Omari, Ahmed

Presentation time

14:00:00

14:20:00

Session time

13:30:00

15:00:00

SessionAdvances in Anaerobic Digestion and Sidestream Treatment

Session locationRoom S404a - Level 4

TopicIntermediate Level

Author(s)

Al-Omari, Ahmed

Author(s)A. Al-Omari 1; Kirim 2 ; X. Bai 3; J. J. Walton 4; C. Muller 5; K. Bell 6; D. Santoro 7; G. Nakhla 8; A. Al-Omari 1;

Author affiliation(s)Brown and Caldwell 1; 5; 6; 7; 8;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825158984

Volume / Issue

Content sourceWEFTEC

Word count13

Beyond Energy Savings: A Deep Dive into Carbon Efficiency of Low DO BNR

Abstract

The Seneca Water Resource Recovery Facility (WRRF) uses a 5-stage Bardenpho process for nutrient removal, meeting strict regulations (< 0.2 mgN/L, Total Inorganic Nitrogen (TIN) < 2.0 mgN/L, and orthophosphate < 0.2 mgP/L. This success was attributed to simultaneous nitrification-denitrification (SND) and post-anoxic denitrification, facilitated by ABAC's regulation of dissolved oxygen (DO) levels. The test train achieved significant aeration savings and utilized internally stored carbon for post-denitrification under low DO conditions, eliminating the need for supplemental carbon. Analysis revealed that glycogen, more than polyhydroxyalkanoates (PHA), likely played a major role in this, aligning with the high abundance of glycogen-accumulating organisms (GAO), particularly Competibacter, and Tetrasphaera, the dominant phosphate-accumulating organism (PAO) observed. This system's efficiency suggests an innovative approach to carbon management for enhanced nutrient removal in wastewater treatment.

DO was maintained at ~0.3 mg/L, lower than the usual ~1.5 mg/L. Low DO operation resulted in average effluent ammonia <0.2 mgN/L, <TIN of 1.5 mgN/L, and orthophosphate <0.2 mgP/L, without supplemental chemicals. High P uptake occurred even under low DO conditions, with enhanced nitrogen removal attributed to SND and post-anoxic denitrification. Moreover, specific denitrification rate tests showed higher rates at low DO, indicating efficient utilization of internally stored carbon.

SpeakerRegmi, Pusker

Presentation time

09:30:00

09:50:00

Session time

08:30:00

10:00:00

SessionLow Carbon BNR Fundamentals and Controls

Session locationRoom S502 - Level 5

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

Author(s)

Regmi, Pusker

Author(s)P. Regmi 1; M. Johnson 2 ; C. Nguyen 3; A. Al-Omari 4; G. Wells 5; B. Yeakle 6; P. Regmi 1;

Author affiliation(s)Brown and Caldwell 1; WSSC Water 2 ; WSSC Water 3; Brown and Caldwell 4; Northwestern University 5; WSSC Water 6; Brown and Caldwell 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159064

Volume / Issue

Content sourceWEFTEC

Word count14

Description: Fermentation Intensification with Vacuum-Assisted Technology: An Evaluation of...

Fermentation Intensification with Vacuum-Assisted Technology: An Evaluation of Full-Scale EBPR Alternatives Using a Calibrated Process Model Analysis

Abstract

IntensiCarb® is a vacuum-based intensification technology that provides process benefits in fermentation or anaerobic digestion. Applying this technology to fermentation allows for half the process volume to achieve improved yield of volatile fatty acids (VFA) for beneficial use. Generating VFA from fermentation provides a benefit to facilities that need supplemental carbon for nutrient removal targets in the liquid treatment process. VFA can be used by facilities to improve enhanced biological phosphorus removal (EBPR) performance, lowering effluent total phosphorus (TP) concentrations. An analysis was completed to evaluate the process performance and life-cycle costs of IntensiCarb® relative to chemical addition and conventional fermentation alternatives for TP removal. Experimental results on vacuum-assisted process intensification were used in the process performance analysis and GHG emissions were estimated to compare alternatives. The evaluation suggests IntensiCarb® is competitive with other alternatives to lower effluent TP with EBPR. FeCl3 chemical addition had the lowest life-cycle cost overall

IntensiCarbÂ® is a vacuum-based intensification technology that provides process benefits in fermentation or anaerobic digestion. An analysis was completed to evaluate the performance and life-cycle costs of IntensiCarbÂ® relative to chemical addition and conventional fermentation alternatives for the purposes of phosphorus removal. This paper describes bench-scale experimental results, presents model performance predictions, and compares life-cycle costs and greenhouse gas emission estimates.

SpeakerArmenta, Maxwell

Presentation time

16:10:00

16:30:00

Session time

15:30:00

17:00:00

SessionExtracting Carbon for Nutrient Removal

Session locationRoom S403a - Level 4

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

Author(s)

Armenta, Maxwell

Author(s)M. Armenta 1; F. Kakar 2 ; A. Al-Omari 3; C. Muller 4; K. Bell 5; G. Nakhla 6; D. Santoro 7; J. Boone 7; M. Armenta 1; R. Coleman 8;

Author affiliation(s)Brown and Caldwell 1; Brown and Caldwell 2 ; Brown and Caldwell 3; Brown and Caldwell 4; Brown and Caldwell 5; University of Western Ontario, London, ON 6; USP Technologies 7; PRAB, Kalamazoo, MI 7; Brown and Caldwell 1; Environmental Operating Solutions, Inc. 8;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159027

Volume / Issue

Content sourceWEFTEC

Word count18

Description: Innovation Portfolio Management for Retrofitting Advanced Biotechnologies for...

Innovation Portfolio Management for Retrofitting Advanced Biotechnologies for Anaerobic Digestion Process at Lulu Island Wastewater Treatment Plant

Abstract

Metro Vancouver recently commissioned the Pilot Digestion Optimization Facility (PDOF) at its Lulu Island Wastewater Treatment Plant (LI WWTP) to facilitate the evaluation of different digestion optimization technologies without risk to full-scale plant operation. This study summarizes the integrated approach adopted at the pilot-scale preliminary design stage for two of these technologies. The first technology aims to increase biogas production rates by testing the Direct Interspecies Electron Transfer (DIET) process using electroconductive materials. The second technology utilizes a biological hydrogen methanation (BHM) process to convert the carbon dioxide portion of biogas into renewable natural gas (RNG) using hydrogen. Cost-effective pilot-scale conceptual designs are developed for testing the in-situ and ex-situ configurations of these technologies in order to reach a go/no-go decision quickly, while still producing replicable results for further scale-up. To guide the decision-making process for selecting these technologies for pilot testing, GHG emission reduction calculations and an energy balance model are used to evaluate the environmental impacts of implementing these technologies at full-scale. A Sumo model is used to evaluate the effects of implementing these technologies on process intensification.

Metro Vancouver, in collaboration with its partners, is developing innovative technologies that reduce greenhouse gas emissions and intensify existing digestion processes. Metro Vancouver will first assess the effectiveness and scalability of these technologies at the Lulu Island Pilot Digestion Optimization Facility. Metro Vancouver intends to incorporate these technologies into one of its treatment facilities if the technologies prove successful at pilot-scale.

SpeakerChegounian, Parisa

Presentation time

15:30:00

15:50:00

Session time

15:30:00

17:00:00

SessionImproving Biosolids Treatment Efficiency

Session locationRoom S403b - Level 4

TopicEnergy Production, Conservation, and Management, Intermediate Level, Research and Innovation

Author(s)

Kakar, Farokh Laqa

Author(s)F. Kakar 1; C. Muller 2 ; T. Barber 3; F. Kakar 1; P. Chegounian 4; L. Zaremba 4; T. Gregonia 4; P. Kadota 4; S. Sorensen 4; A. Al-Omari 5;

Author affiliation(s)Brown and Caldwell 1; Brown and Caldwell 2 ; Brown and Caldwell 3; Brown and Caldwell 1; Liquid Waste Services Department, Metro Vancouver, Burnaby, BC, Canada 4; Liquid Waste Services Department, Metro Vancouver, Burnaby, BC, Canada 4; Liquid Waste Services Department, Metro Vancouver, Burnaby, BC, Canada 4; Liquid Waste Services Department, Metro Vancouver, Burnaby, BC, Canada 4; Liquid Waste Services Department 4; Brown and Caldwell 5;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159034

Volume / Issue

Content sourceWEFTEC

Word count18

Description: Intensifying Anaerobic Digestion with a Side-Stream Vacuum-Based Biosolids Treatment...

Intensifying Anaerobic Digestion with a Side-Stream Vacuum-Based Biosolids Treatment Technology: Process Validation Exceeding Expectations

Abstract

This study evaluates the application of a novel ex-situ vacuum-enhanced anaerobic digestion technology, referred to as IntensiCarbTM (IC), for process intensification through decoupling SRT from HRT, and ammonia recovery. Findings revealed that the IC sustain almost the same methane yield and COD destruction efficiency as the control at three times the organic loading rate (OLR). Furthermore, the ammonia concentration in IC- digester operating at 3 times higher organic loading was pretty much the same as the control, demonstrating the effectiveness of IC-technology in elutriating a large fraction of ammonia from IC-digester into the condensate. This leads to stable digester operation as well as a potential to generate revenue. The combination of high organic loading and low ammonia concentrations resulted in the prevalence of the higher growth rate Methanosarcinaceae in the IC-digester compared to the low growth rate Methanoseata predominance in the control.

A novel ex-situ vacuum-enhanced anaerobic digestion technology was evaluated for process intensification in anaerobic digesters. This technology, referred to as IntensiCarbTM (IC), could increase the OLR and volumetric loading by 3 times while maintaining stable methane yields and COD destruction. Ammonia recovery, reduced digester size, as well as reduced nitrogen loadings in sidestreams, are the major advantage of IC-technology.

SpeakerKhadir, Ali

Presentation time

13:30:00

13:50:00

Session time

13:30:00

15:00:00

SessionAdvances in Anaerobic Digestion and Sidestream Treatment

Session locationRoom S404a - Level 4

TopicIntermediate Level

Author(s)

Khadir, Ali

Author(s)A. Khadir 1; F. Omoye 2 ; E. Jang 3; D. Santoro 4; J. Walton 4; C. Muller 5; A. Al-Omari 6; K. Bell 7; G. Nakhla 8;

Author affiliation(s)Western University, Canada 1; Western University, Canada 2 ; USP Technologies, Canada 3; USP Technologies, Canada 4; USP Technologies, Canada 4; Brown and Caldwell, USA 5; Brown and Caldwell, USA 6; Brown and Caldwell 7; Western University, Canada 8;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825158983

Volume / Issue

Content sourceWEFTEC

Word count15

Description: Intensifying Anaerobic Sludge Fermentation Using The Novel...

Intensifying Anaerobic Sludge Fermentation Using The Novel IntensiCarbâ„¢ Technology: Municipal Application and Model Evaluation

Abstract

Abstract
The paper presents the development of a novel technology and a model to simulate the IntensiCarbâ„¢ (IC) process, a patent-pending technology co-developed by USP Technologies and Brown and Caldwell which approaches process intensification through a nearly perfect and extremely efficient solid-liquid separation process enabled by vacuum evaporation at temperatures (20-60 oC) that are compatible with anaerobic biological processes. SumoTM was used to create a new process unit to simulate the physical and biological reactions occurring within the IC process. The model was used to simulate the operation of IC as a sludge fermenter (ICF) and compared against completely mixed fermenter (CMF) to generate volatile fatty acids from a mixture of primary and biological waste activated sludges. The hydrolysis kinetic parameters were modified to reflect the observed improvement in particulate substrate solubilization on mass basis of approximately 16%. The increase in hydrolysis rate could be related to changes in sludge physical characteristics such as viscosity and particle size distribution impacted by the nature of vacuum operation. To address this improvement, the authors used the Contois model and adjusted (Khyd), which is the half saturation constant of the biodegradable particulate COD (xbCOD) that is defined as the ratio of xbCOD to the active biomass (xbCOD/Xbio). Introduction Sludge fermentation is widely accepted to be the key design consideration for sustaining enhanced biological phosphorus removal at wastewater treatment plants by converting particulate substrate to readily biodegradable (hydrolysis), and consequently to VFA (fermentation) (Bernard, 2014). Fermenter design can be either integrated within the mainstream process configuration or conducted in dedicated reactors/separators. The major design elements for dedicated fermentation process include the ability to decouple the main process from the fermentation process, ability to control the solids retention time (SRT) in the fermenter, the ability to decouple SRT from hydraulic retention time (HRT), and the ability to extract VFA to feed the mainstream biological process. Decoupling of SRT and HRT is typically done through gravity-based separation, which suffers from poor effluent quality, difficulty to control SRT and the need for multiple process units. Vacuum evaporation is an established technology for biosolids dewatering (Gnida 2020), which provides a means to decouple the solids phase from the liquid and gas phases. This quality results in a number of benefits that set this technology apart from other conventional technologies. These include process intensification, pH controlled targeted extraction of value-added products such as volatile fatty acids (VFA) (Sonnleitner et al., 2012), effective sludge thickening in the same process unit, and odor containment and control. This paper discusses the application and modeling of the (IC) technology to intensify the fermentation process of municipal sludge based on a proof-of-concept study.
Materials and Methods
The study utilized a pilot scale setup of the ICF and a conventional CMF (Okoye et al., in preparation). The reactors were fed daily a 50:50 by volume mixture of primary and biological WAS from a nearby full-scale treatment plant. The fermenters were temperature controlled and were operated at 60 oC (Figure 1). For the ICF, sludge was wasted daily to maintain the respective HRTs (1.50-2.25 days), while SRT was fixed at 3.0 days. To determine the degree of process intensification, an Intensification Factor (IF) was calculated using the following equation: IF = SRT/HRT. This translates to IF of 1.0, 1.3, and 2.0 for the CMF, ICF at HRT of 2.25 days, and ICF at HRT of 1.5 days, respectively. A vacuum anaerobic digester model unit was created in Sumo21 (Dynamita, France). Principal components of the process include variable volume anaerobic digester, water extraction through the headspace, gas/liquid transfer model for stripping of ammonia, VFA, and other gases. Heating power is calculated using the targeted evaporation rate. The gas phase is considered saturated in terms of water vapor. The headspace pressure is determined using the water equilibrium curve of pressure and gas/liquid temperature (Sharp, 2001).
Results and Conclusions
Table 1 summarizes the operational conditions for each pilot reactor and the overall fermentation performance, after 10 days of operation, measured as % particulate COD solubilization [or % hydrolysis], % acidification to identify how much VFA was produced compared to soluble COD produced, and VFA yield compared to influent COD. The COD mass balances around the fermenter suggested some minor loss of COD with highest gap associated with the ICF, IF=2.0 reactor. This loss could be related to partial digestion at the elevated temperatures. Hydrolysis of particulate substrate was directly calculated from the mass loading reduction in xCOD between the feed and the wasted sludge. It was observed that approximately 16% improvement in %hydrolysis was achieved in the ICF, IF=2.0 over the CMF and ICF, IF=1.3. In addition, the VFA yield has significantly improved by approximately 60% for the ICF, IF=2.0. This improvement was only attainable in the model by adjusting the hydrolysis rate kinetics specifically to each reactor [Table 2]. Our team has chosen to adjust the Khyd parameter to address the changes observed in the overall hydrolysis performance in the ICF, IF=2.0. The rationale used here was that the affinity to the substrate may have increased due to physical changes induced by intense boiling under vacuum evaporation. One hypothesis, yet to be proven, is that the particle size distribution was altered and resulted in an increased surface area and accessibility by biomass. The change in hydrolysis rate with respect to the xbCOD at the modified Khyd is depicted in Figure 2. The fermentation rate was adjusted to achieve a good match with the observed data [Table 2]. Figure 3 shows the model output against observed VFA concentrations for all reactors. Figure 4 shows the model output against observed data for the ICF, IF=2.0.
This experimental study and model exercise showed that intensified fermentation using the vacuum-based IntensiCarbâ„¢ technology could simultaneously enhance hydrolysis and fermentation and thus enhance resource recovery as well as considerably reduce fermenter size compared to CMF fermenters. The outcomes of this study clearly showed the tremendous potential of the vacuum-driven fermentation to reduce cost and enhance performance of the widely used anaerobic wastewater biosolids fermentation. The paper will include results (not shown) for a parallel study conducted at 45 oC using the same IF range.

SpeakerAl-Omari, Ahmed

Presentation time

11:30:00

11:55:00

Session time

10:30:00

12:00:00

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

Author(s)

Al-Omari, Ahmed

Author(s)Ahmed Al-Omari1; Ferenc Hazi2; Frances Okoye3; Gholamreza Bahreini4; Domenico Santoro5; Kati Bell1; Jose Jimenez1; Eunkyung Jang5; George Nakhla4; John Walton5; Imre Takacs2; Elsayed Elbeshbishy3; Chris Muller1

Author affiliation(s)Brown Caldwell1; Dynamita, France2; Department of Civil Engineering, Ryerson University3; Department of Civil and Environmental Engineering, Western University4; USP Technologies, R&D Department, Ontario5

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2022

DOI10.2175/193864718825158573

Volume / Issue

Content sourceWEFTEC

Word count15

Description: Model-based Investigation of the Fate and Transport of Internal and External Carbon...

Model-based Investigation of the Fate and Transport of Internal and External Carbon Sources to Drive Partial deNitrification (PdN)-based Nitrogen Removal Processes

Abstract

This paper was presented at WEFTEC 2023 in Chicago, IL.

SpeakerAl-Omari, Ahmed

Presentation time

11:30:00

11:45:00

Session time

10:30:00

12:00:00

SessionPushing the Boundaries of Our Biological Models

Session locationRoom S404a - Level 4

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

Author(s)

Al-Omari, Ahmed

Author(s)A. Al-Omari 1; P. Regmi 2 ; T. Wadhawan 3; M.L. Bachmann 4; K. Bauhs 5; J.A. Jimenez 7; I. Takacs 8; CB Bott 4; A. Al-Omari 1;

Author affiliation(s)Brown and Caldwell 1; HRSD 2 ; Dynamita 3; HRSD 4; Dynamita 5; Dynamita 7; Dynamita 8; Dynamita 4; Brown and Caldwell 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159193

Volume / Issue

Content sourceWEFTEC

Word count22

Description: Partial Denitrification Model Development in the Context of Shortcut Nitrogen...

Partial Denitrification Model Development in the Context of Shortcut Nitrogen Removal Processes

Abstract

As part of the industry’s direction towards nitrogen removal intensification in wastewater treatment, partial denitrification (PdN) is a promising and a more reliable alternative to partial nitrification (or nitritation) in mainstream deammonification processes, where heterotrophs (OHO) produce nitrite required for anaerobic ammonia oxidizers (AnAOB) for efficient nitrogen removal [4]. The process is called PdNA (i.e. PdN+AnAOB). It is estimated that 50% reduction in air requirement and 80% reduction in carbon addition can be achieved compared to conventional nitrification/denitrification. In this study, the biological denitrification reactions in Sumo 2 were modified to allow for partial denitrification (or denitratation) when volatile fatty acids are used as a carbon source. The model was calibrated using batch anoxic bioassays spiked with acetate and data from PdNA suspended growth pilot data. The validation runs had fairly constant nitrate uptake rates. Hence, the future work for developing and validating the model will entail calibrating the model using various carbon sources and at various nitrate specific uptake rates.

SpeakerAl-Omari, Ahmed

Presentation time

14:50:00

15:10:00

Session time

13:30:00

15:30:00

SessionThe Next Generation Mainstream Deammonification

Session number202

TopicNutrients, Research and Innovation

Author(s)

A. Al-OmariT. WadhawanI. TakacsS. KlausT. LeJ. JimenezS. Murthy

Author(s)A. Al-Omari1; T. Wadhawan2; I. Takacs2; S. Klaus4; T. Le5; J. Jimenez1; S. Murthy6;

Author affiliation(s)Brown and Caldwell, VA1; Dynamita, ON2; DC Water and Sewer Authority3; HRSD, VA4; NEWhub Corp5

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2020

DOI10.2175/193864718825157416

Volume / Issue

Content sourceWEFTEC

Word count13

Description: Partial Denitrification Model Extension for Mainstream Shortcut Nitrogen Removal:...

Partial Denitrification Model Extension for Mainstream Shortcut Nitrogen Removal: Model Evaluation

Abstract

As the development of mainstream partial denitrification and anammox (PdNA) process continues to evolve, and more applications are showing tangible benefits even at full-scale application [Klaus 2020], the modelling of such technology is becoming critical for its implementation at more broad scope. PdNA relies on controlling heterotrophic denitrification to produce nitrite needed by anaerobic ammonia oxidizers (AnAOB) and thus the avoidance of nitrite reduction [De Clippeleir, 2018]. While the PdN selection is still in the realm of research, few hypotheses supported by observations from bench, pilot and fullscale testing were formulated [Tri et al., 2019b; Campolong 2019, Al-Omari et al. 2020]. During WEFTEC 2020, we introduced the early development of the PdN extension to the ASM-based model Sumo2 to account for a mechanism associated with using acetate as carbon source and selecting PdN route based on nitrate concentration. The model was calibrated using data generated from a pilot testing with acetate. In this paper, the extended PdN model is evaluated via simulating implementation in post polishing MBBR. The process was operated using glycerol and methanol as supplemental carbon sources. Overall, the model predicted the performance of these processes when glycerol was used. When methanol is used, the model was underpredicting the nitrite accumulation by methylotrophs. The model parameters such as nitrite half saturation constant were significantly increased to allow nitrite to accumulate and match the measured profiles.

The combined reactions of partial denitrification and anammox (PdNA) have the potential to provide significant operational and capacity improvements for those wastewater treatment plants who are seeking efficient nutrient removal. This paper follows the development of a process model in Sumo to incorporate the latest understanding of the PdN selection mechanisms based on leading edge research conducted at two major utilities in the USA. The model was evaluated by simulating various pilot and fullscale process implementations of PdNA.

SpeakerAl-Omari, Ahmed

Presentation time

16:00:00

16:10:00

Session time

16:00:00

17:30:00

SessionPDNA Applied Research

Session number116

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

Author(s)

Ahmed Al-Omari

Author(s)A.A. Al-Omari1; T. Wadhawan2; V. Srinivasan1; S. Klaus3; J. Jimenez1; S. Murthy4; B. Wett4; S.M. Fevig5; C. deBarbadillo6; C.B. Bott3; H. De Clippeleir7;

Author affiliation(s)Brown and Caldwell, Alexandria VA and Maitland, FL1Dynamita North America, CA2Hampton Roads Sanitation District, Virginia Beach, VA3NEWhub Corp., Herndon, VA4The Water Research Foundation, Alexandria, VA 5District of Columbia Water and Sewer Authority, DC 7

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2021

DOI10.2175/193864718825158010

Volume / Issue

Content sourceWEFTEC

Word count12

Base text size -

Al-Omari, Ahmed

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