Reeve, Matt, Reeve

Reeve, Matt

Matt is a licensed professional engineer from Ontario, Canada, where he works for Veolia Water Tech. His work focuses on bridging the gap between research and practical implementation, bringing innovative biological intensification technologies from RD into real-world applications. In addition to MABR, Matt is working on technology combinations of MABR and MBR with continuous flow densification. Matts commitment to continuous learning extends beyond engineering he has maintained a streak of over four years on DuoLingo, though he admits hes not fluent in French.

Titles from this speaker

Description: Defining Best Operating Points of Biomass Densification for MBR and Clarifiers:...

Defining Best Operating Points of Biomass Densification for MBR and Clarifiers: Lessons Learned from Two-year Operation at Full-scale Plants

Abstract

Densified Activated Sludge (DAS) in Continuous Flow with MABR and MBR has been implemented at full-scale wastewater treatment plants for over 2 years. While new indicators such as SVI5, DI% and TTFOF have been revealed to be enhancing process control and helping operators better scrutinize and control process events (Shaw, Donnaz et al, 2024), steady-state operations also showed the existence of a climax for clarifier and ultrafiltration performance in terms of SVI30 and Densification Index. DI is defined as the sum of bio-aggregates > 200 µm in the Total Suspended Solids (gMLSS>200/gMLSS).

At Yorkville Wastewater Treatment Plant (WWTP), the long term operation of MABR DAS with clarifiers demonstrated the ability to operate with half of the hydraulic capacity of the plant (Regmi, Astrand et al, 2024; Roche et al, 2021; Donnaz et al, 2020).

From November 2023, SVI30 reached 72 mL/g at 95%ile and 58 mL/g on average. TSS in the outlet of the clarifier reached 13 mg/L at 95%ile and 5 mg/L on average (Figure 1).

However, when SVI30 reached a threshold below 40 mL/g, TSS in the secondary effluent increased from 5-7 to hit the 13 mgTSS/L mark. This was rapidly compensated by adjusting SVI30 back between 50 and 60 mL/g and by increasing the RAS rate from 45 to 50%.

Total SRT of Yorkville secondary biological system is 11-13 days, aerobic SRT 9-11 days, F/M 0.26 kgCOD/kgMLVSS/d (COD/BOD ratio 1.6).

At Detroit Lakes WWTP, the long term operation of MBR DAS with ultrafiltration provided benefits (Donnaz, Shaw et al, 2023) in terms of membrane resistance (-30%), colloidal fraction (-60% cCOD to -80% cTOC) and membrane cleaning (maintenance and recovery). Improvement of membrane filtration was correlated to rapid drops of SVI, time-to-filter and superfine colloids (sfCOD) in the membrane tank mixed liquor (Donnaz, Shaw et al, 2023). Time-to-filter is a direct test of filterability and membrane performance. Results of these tests show a very close correlation with settleability, meaning that improved settling and higher densification also improve filterability (Shaw, Donnaz et al, 2024). Total SRT of Detroit Lakes secondary biological system is 15-25 days, aerobic SRT 9-10 days, F/M 0.05 kgBOD/kgMLVSS/d.

This was confirmed in line with supporting research demonstrating that MBR mixed liquor quality can be enhanced by using hydrocyclones as gravimetric selectors, whereby MBR performance has been improved due to the removal in overflow of lighter flocs and colloidal fraction from the mixed liquor (Nogushi et al, 2018). External gravimetric selectors help regulate particles and granules size below 1 mm, which is believed to minimize pore blocking (Zhang & Jiang, 2018). Particle size distribution of densified biomass has shown to be 200 to 500 µm in majority, with 1,000 µm maximum (Roche et al, 2021). An external gravimetric selector such as memDENSE technology helps regulate particle and granule sizes above 100 µm and below 1 mm, which is believed to minimize pore blocking fouling observed with full granulation process by remaining below the 1 to 1.2 mm critical value range described by Zhang & Jiang (2018).

As DI% evolved from 30% to 80% in the biological system (Figure 2), the following was observed (Figure 3):
- optimum of TTF around SVI30 of 60 mL/g
- drop of permeability observed for SVI30 >70 mL/g and SVI30 < 40 mL/g
- optimum Permeability observed around DI 50%

DI-SVI correlation enables the prediction and the accurate assessment of DAS mixed liquor performance in secondary biological continuous flow systems (Guo, Donnaz et al 2024). Experimental data show that there is a linear correlation between DI and Particle Size Distribution (PSD) with DAS for all particle fractions.

Figure 4 shows how PSD evolves as DI increases over 50% in the system (aerobic and underflow):
- Fraction >550 µm increases when DI gets over 50% (blue)
- Fraction 200-550 µm is the one which increases the most when DI gets >50% (orange)
- Particles fraction < 100 µm (Σ<50;50-100 µm) decreases significantly as DI augment (yellow and red)
- Fraction 100-200 µm is the third that is decreasing the most after DI increases over 50% (green)
- Correlation between PSD and DI% shows that as DI increases from 40 to 80%, volume % of particles
> 200 µm increases while volume % of particles < 200 decreases

Evolution of DI above 50% in the biological system introduces the presence of big granules (>550 µm), while smaller granules are still abundant (relative vs absolute fractions). Therefore, there is a combined effect of the emergence of bigger granules (teal blue) close to the critical threshold of 1-1.2 mm and pore blocking by fine particles on the membrane permeability (Campo et al 2021). While Campo et al claim that one of the main factors for stable operation is to "verify that granules mean dimensions are far from critical values (1-1.2 mm)", these results imply a noticeable drop of permeability when d90 starts to flirt with 590 µm. It appears that the shear effect of the memDENSE selector's ability to self-regulate the size of the particles below 1 mm functions until DI reaches 60-80%.

Densified Activated Sludge in continuous flow has been coupled with membranes at full-scale with two different separators: secondary settling tank (MABR and clarifier) and ultrafiltration (MBR). In two projects, steady state densification has been implemented to find the best the best operating points.

This paper was presented at WEFTEC 2025, held September 27-October 1, 2025 in Chicago, Illinois.

Presentation time

16:00:00

16:10:00

Session time

15:30:00

17:00:00

SessionDensified Activated Sludge Full Scale Performance and Optimization

Session locationMcCormick Place, Chicago, Illinois, USA

TopicAdvanced Water Treatment and Reuse

Author(s)

Donnaz, Sylvain, Guo, Hui, Shaw, Chris, Astrand, Niclas, Gagnon, Jean, Fyfe, Sheila, Reeve, Matt

Author(s)S. Donnaz1, H. Guo1, C. Shaw1, N. Astrand1, J. Gagnon1, S. Fyfe1, M. Reeve1

Author affiliation(s)Veolia WTS USA Inc.1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2025

DOI10.2175/193864718825159937

Volume / Issue

Content sourceWEFTEC

Word count20

Description: From Seasonal to Year-round Nitrification: Performance Evaluation of North America's...

From Seasonal to Year-round Nitrification: Performance Evaluation of North America's Largest MABR Installation

Abstract

This study evaluated the performance of North America’s largest MABR installation under different operational and seasonal conditions. Total nitrogen (TN) removal improved from 40- 50% when the plant was in a conventional activated sludge configuration to 75-85% after the MABR upgrade. The MABR reduced effluent ammonia during winters and nitrate concentrations during summer to below 10 mg-N/L in both the cases. The nitrification rate in the MABR varied between 0.7-2.2 gNm-2 d -1 with lower nitrification rates observed during reduced airflow operation and winter conditions. The development of thicker biofilms limited ammonia diffusion into the biofilm that resulted in reduced nitrification rate. Increasing the flow of sparging air was able to control the biofilm thickness to improve nitrification. The denitrification rate in the MABR process was between 100-200 gNm-3 d -1 which followed a close trend with nitrification rate. The nitrification rate in the MABR was found to be the rate limiting step for TN removal in the process.

Addition of an MABR to an existing conventional activated sludge process substantially improved TN removal and reduces seasonal spikes in effluent ammonia. The improved TN removal in the plant was due to elevated levels of simultaneous nitrification and denitrification in the hybrid MABR process.

SpeakerLakshminarasimman, Narasimman

Presentation time

15:30:00

15:50:00

Session time

15:30:00

17:00:00

SessionAlternative Approaches to Intensify Secondary Treatment

Session locationRoom S404a - Level 4

TopicIntermediate Level, Municipal Wastewater Treatment Design, Nutrients

Author(s)

Lakshminarasimman, Narasimman

Author(s)N. Lakshminarasimman 1; D. Celmer-Repin 2 ; J. Mank 3; J. Gagnon 4; M. Reeve 5; J. Peeters 6; W.J. Parker 1; N. Lakshminarasimman 1;

Author affiliation(s)Department of Civil and Environmental Engineering, University of Waterloo, ON, Canada 1; Region of Waterloo, ON, Canada 2 ; Ontario Clean Water Agency, ON, Canada. 3; Veolia Water Technologies 4; Veolia Water Technologies 5; Veolia Water Technologies 6; Department of Civil and Environmental Engineering, University of Waterloo, ON, Canada 1; Department of Civil and Environmental Engineering, University of Waterloo, ON, Canada 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159017

Volume / Issue

Content sourceWEFTEC

Word count14

Description: MABR Breathing Insights: Monitoring Biofilm Health in Full-scale System Based on...

MABR Breathing Insights: Monitoring Biofilm Health in Full-scale System Based on Exhaust Gas Measurements

Abstract

Introduction:
With the current needs for balancing process intensification and operational cost, Membrane aerated biofilm reactors (MABR) stand out as an advanced intensification technology. Using gas-permeable membranes, MABR is bubbleless aeration technology where oxygen is effectively delivered to the biofilm grown on the biofilm surface (Houweling & Daigger 2019). Uniquely, MABR's gas-substrate counter diffusional pattern provides the opportunity to obtain 'Breathing Insights' by assessing the oxygen transferred to the biofilm which can be utilized to monitor, diagnose, and control biofilm and process performance. To this end, studies reported that the relationship between Oxygen purity in the exhaust gas and ammonia concentrations can be used to measure the response from the MABR to ammonia loads which indirectly indicates biofilm health or nitrification capacity (Houweling & Daigger 2019; Uri-Carreno et al. 2021). In accordance, a soft sensor named 'MABR fingerprint' was proposed based on the response of the MABR to the diurnal changes in the bulk liquid ammonia concentration (Yang et al., 2022; Cao et al., 2023). In such studies, the fingerprint concept was assessed based on the outcomes from steady state and dynamic simulations. However, validation of such concepts has not been performed in full-scale systems. In addition to the MABR fingerprint, based on exhaust oxygen purity, OTE and oxygen transfer rates (OTR) can be determined (Houweling & Daigger 2019). The obtained OTR can be translated into maximum nitrification rates (Max_NR) of the MABR. Hence, monitoring and comparing the actual daily nitrification rates (NR) with the Max_NR can, also, be used as a simple indication of biofilm nitrification activity. Therefore, in this study, we leverage the data from one of the largest ZeeLung™ MABR installations in North America, to evaluate the feasibility of using MABR fingerprint and NR/Max_NR ratio to monitor and diagnose MABR performance.

Operational information:
The data used in this study is from Hespeler WRRF, Cambridge, Ontario, Canada. The data covers a period of 5 months grouped into 5 phases as described in Table 1. Significantly, biofilm thickness was measured three times during the 5 months which had a clear gradient as biofilm thickness decreases over time. Detailed information on biofilm thickness are provided in (Lakshminarasimman and Parker, 2025).

MABR fingerprint plot:
The fingerprint plot is obtained by plotting the daily data of the Exhaust oxygen Purity (%) vs the bulk/effluent ammonia concentrations. In prior studies where data were obtained from model simulations, high correlation (above 0.9) was obtained between both variables (Cao et al., 2023). Accordingly, the fingerprint slope, referred hereafter as the daily slope, was obtained. Such fingerprints plots were not consistently observed with the actual daily, where correlations ranged between 0.5 and 0.9. Dirunal dynamics yielded two major shapes, presented in Figure 1. The Fingerprint was grouped into three major periods. The first is when the influent ammonia is increasing (the loading period), and two periods when bulk ammonia is decreasing (the recovery period). In addition to the daily slope, each period's slope was determined separately.

Monitoring MABR:
By examining the generated plots over different periods, the shape with exponential decay was observed mainly during the first two phases where relatively low ammonia loading rates were applied in comparison with phases III and IV. This can be referred to mass transfer limitations due to the very thick biofilm thickness (850-1000 micron), such effect was not mitigated when air flow rate increased to 6 Qair/m2/d from 4.5. Such a pattern started to disappear and an inclined line was observed when biofilm thickness started to be reduced in the following phase. This can be leveraged as a useful tool to control scouring and air flow rates to either reduce biofilm or overcome mass transfer limitation by higher air flow rates.

In Figure 2, the obtained slopes from different phases are presented. Clearly lower slopes were obtained at the phases closer to the time biofilm thickness decreased to 450 micron (Phase IV and V). It can be seen that such effect was captured clearly in the loading slope and to much lesser extent in the daily slope. A steeper slope indicates better response from the biofilm to ammonia load, especially when fingerprint plot are closer to those in Figure 1a.

In Figure 3, NR/Max_NR for different phases is plotted. It might not be as representative to biofilm thickness as the finger print plot, but it provides useful information on oxygen utilization by nitrifiers in the system. Phase I and V had low NR/Max_NR, but in the case of Phase I, this was due to the very thick biofilm thickness and low ammonia loads which probably led to higher growth of heterotrophs and other oxygen utilizing organisms. This is in agreement with microbial analysis performed, results not published. On the other hand, low NR/Max_NR at Phase V is mainly due to low ammonia loading rate which is confirmed from the fingerprint plot that shows relatively steep slopes.

Conclusion & significance:
This is the first study to examine, in full-scale with real-life data, off-gas based metrics to monitor MABR biofilm health and performance. This provides simple and easy to understand tools not only to monitor the performance but also to inform decisions.

This paper was presented at WEFTEC 2025, held September 27-October 1, 2025 in Chicago, Illinois.

Presentation time

14:30:00

15:00:00

Session time

13:30:00

15:00:00

SessionFull-Scale MABR Successes in Performance Optimization and N2O Control

Session locationMcCormick Place, Chicago, Illinois, USA

TopicProcess Control and Modeling

Author(s)

AlSayed, Ahmed, Astrand, Niclas, Reeve, Matt, Peeters, Jeff, Donnaz, Sylvain

Author(s)A. AlSayed1, N. Astrand1, M. Reeve1, J. Peeters1, S. Donnaz1

Author affiliation(s)Veolia WTS USA Inc.1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2025

DOI10.2175/193864718825160130

Volume / Issue

Content sourceWEFTEC

Word count15

Description: MABRs Are Neat, But How Do I Design Them? A Practical Design Methodology for Hybrid...

MABRs Are Neat, But How Do I Design Them? A Practical Design Methodology for Hybrid MABR/AS

Abstract

Membrane Aerated Biofilm Reactors (MABR) have been applied at full-scale wastewater treatment plants since 2017 (Underwood et al., 2018) to intensify conventional activated sludge (CAS) to increase flow and/or meet stricter effluent limits. MABRs are typically installed in a pre-anoxic zone and add nitrifying biomass to increase the nitrification capacity (Houweling et al., 2017). The design of MABRs is often done using a combination of process modelling, spreadsheet mass balances, and empirical methods. The objective of this paper is to demonstrate a straightforward design methodology for MABRs that references common design practice for CAS systems.

To achieve reliable nitrification in CAS, process designers typically define a design aerobic solids retention time (aSRTdesign) by applying a safety factor (SF) to a minimum aSRT (aSRTmin) as follows.

aSRTdesign=SF x aSRTmin

Where aSRTmin is commonly defined by kinetic equations presented in Metcalf & Eddy (2014) and can be adjusted to target specific effluent ammonia concentrations across a range of design temperatures, as discussed in Chapter 1 of Houweling and Daigger (2020). Figure 1 shows representative curves for aSRTmin and aSRTdesign with a safety factor of 2 as a function of temperature for an effluent ammonia target of 1 mg/L.

In order to intensify the treatment capacity of nitrifying CAS plants, a media-supported biofilm can be added into the system to enable reliable nitrification at shorter aSRTs than would be typically used. Houweling and Daigger (2020) published a set of design curves relating the fraction of inlet ammonia treated by the biofilm, FNit,B, to aSRT and nitrification safety factor. Figure 2 shows an example of one of these curves at 15°C.

A design methodology is proposed using a combination of the theory used in Figures 1 and 2, where the designer
a) selects a safety factor and design aSRTdesign for a CAS plant to achieve their nitrification goal and,
b) correlates the aSRTdesign and safety factor to a lower aSRT (typically the aSRT available at an overloaded CAS plant, aSRTavailable) plus a fraction of influent ammonia removal by the biofilm.

Application of the design methodology is demonstrated using examples from two real-world MABR designs, with one operating MABR equipped plant and one plant that requires an upgrade using MABR.

Case Study 1
The Hespeler WWTP located in Cambridge, Ontario, Canada is a 9.32 MLD facility that was upgraded with MABR in 2022. The MABR upgrade has achieved year-round nitrification at this facility, which was previously only able to nitrify seasonally (Lakshminarasimman et al., 2023). The design criteria for the Hespeler WWTP was to achieve an effluent of 5 mg/L as ammonia nitrogen at a temperature of 10°C with as low as 4 to 5 day aSRT in the aeration tanks (Natvik et al., 2020).

Figure 3 shows the conventional nitrification curves for the Hespeler case, targeting an effluent ammonia concentration of 5 mgN/L. At 10°C the aSRTmin to achieve 5 mgN/L is 5 days, whereas the aSRTdesign with 1.5 times safety factor is 7.5 days.

Applying the design points to the biofilm safety factor curves by Houweling and Daigger as shown in Figure 4, a 7.5 day aSRT corresponds approximately to a SF of 1.5 when FNit,B = 0. To maintain the nitrification safety factor at 1.5, some removal on the biofilm is required. In this case a 5 day aSRTavailable at SF of 1.5 corresponds to an FNit,B of 0.42, meaning that 42% of the influent ammonia must be removed in the biofilm.

The Hespeler WWTP has 36 ZeeLung™ MABR cassettes by Veolia with 1,920 m2 of surface area each for a total of 69,120 m2. At an average nitrification rate of 1.7 gN/m2/d the MABR will remove 117.5 kgN/d. The influent design ammonia load is 260 kgN/d. Therefore, the MABR will remove 45% of the influent ammonia load, which approximately corresponds to the design points illustrated in Figures 3 and 4.

Case Study 2
A wastewater plant in Texas, USA is approaching design capacity and requires a biological upgrade within a short time frame. The plant has a design temperature of 20°C and is required to meet a monthly effluent ammonia limit of 1.4 mgN/L and can operate at a bulk aSRTavailable of 4.3 days. Figure 5 shows the conventional nitrification curves for the Texas case for a target effluent ammonia of 1.4 mgN/L at 20°C where aSRTmin is 2.8 days and aSRTdesign is 5.5 days with a SF of 2.

Applying a 5.5 day aSRTdesign to the biofilm safety factor curves at 20&Deg;C corresponds to a SF of ~2.25, as shown in Figure 6. In order to maintain a SF of 2.25 at an aSRTavailable of 4.3 days an FNit,B of 0.29 is required.

The influent ammonia load for the Texas WWTP is 1340 kgN/d. To achieve a 29% ammonia removal, 389 kgN/d are required to be removed by the MABR biofilm. Assuming a nitrification rate of 2.6 gN/m2/d, a surface area of ~150,000 m2 is required.

The designs in case studies 1 and 2 use different safety factors, where a less stringent ammonia limit requires a lower safety factor and vice versa. Recommendations for safety factor for ranges of effluent ammonia limits will be presented along with one or more additional case studies.

This paper was presented at WEFTEC 2025, held September 27-October 1, 2025 in Chicago, Illinois.

Presentation time

13:30:00

14:00:00

Session time

13:30:00

15:00:00

SessionExploring the Capability and Flexibility of MABRs

Session locationMcCormick Place, Chicago, Illinois, USA

TopicLiquid Stream Treatment Technology - Secondary & Tertiary Treatment

Author(s)

Reeve, Matt, Houweling, Dwight, Downing, Leon, Redmond, Eric, Cecconi, Francesca

Author(s)M. Reeve1, D. Houweling2, L. Downing3, E. Redmond3, F. Cecconi3

Author affiliation(s)Veolia Water Tech1, Polytechnique Montreal2, Black & Veatch3

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2025

DOI10.2175/193864718825160087

Volume / Issue

Content sourceWEFTEC

Word count17

Description: Process Intensification At The WNWRP: Evaluating MABR With Piloting and Process...

Process Intensification At The WNWRP: Evaluating MABR With Piloting and Process Modelling

Abstract

Background
The Sanitation Districts are evaluating the potential of the MABR process to increase the biological treatment capacity of the Whittier Narrows Water Reclamation Plant (WNWRP). The WNWRP has a design capacity of 15 million gallons per day (MGD) and employs the Modified Ludzack-Ettinger (MLE) process to achieve nitrogen removal (Figure 1). The plant currently treats approximately 9 - 10 MGD of wastewater. National Pollutant Discharge Elimination System (NPDES) permit requirements for nitrogen, activated sludge process general design criteria, and typical activated sludge process operating conditions are shown in Tables 1, 2, and 3, respectively. WNWRP meets the NPDES permit requirements at current flows and loads but may struggle to meet the limits at the design capacity of 15 MGD, particularly with respect to nitrate + nitrite.
For this research project, the Sanitation Districts evaluated MABR using the ZeeLung product manufactured by SUEZ, described in Figures 2 - 5. Potential benefits of the MABR process include: (1) the potential to increase capacity within existing tanks while meeting NPDES limits for nitrogen; (2) the potential to increase capacity without increasing solids loading on the secondary clarifiers; (3) the potential to reduce aeration energy requirements due to efficient transfer of oxygen through gas-transfer media.
Objectives
The MABR process is being evaluated through pilot testing, subsequent development of a calibrated process model in BioWin process simulator, and planning level cost estimation for full-scale implementation. The specific objectives for pilot testing include: (1) evaluating the removal of organics, nitrogen and suspended solids over a range of flowrates representing current and potential future operating conditions; (2) evaluating key MABR performance indicators including oxygen transfer rate (OTR), oxygen transfer efficiency (OTE), and nitrification rate (NR); and (3) collecting information necessary to develop a calibrated process model for plant design and planning level cost estimate.
Methodology Pilot System
Based on preliminary BioWin modeling projections by SUEZ (Figure 6), a pilot system was designed and constructed to simulate WNWRP operation with an MABR zone (Figures 7 and 8, Table 4). The pilot system included an anaerobic selector (3%), MABR zone (31%), aerobic zone (66%), and secondary clarifier. The MABR zone was equipped with a 3 module ZeeLung cassette provided by SUEZ (Figure 9). The resulting media packing density, 2.53 ft2/gallon, is similar to that assumed for the full-scale preliminary modeling projections, 2.73 ft2/gallon. The pilot system was equipped with sensors to continuously monitor ammonia in the MABR zone and O2 in MABR exhaust gas.
MABR Pilot System Operation and Performance Monitoring
The pilot system was operated in multiple phases (Table 5) with the ultimate goal being to maximize flowrate through the system while meeting permit requirements for nitrogen. All five phases of pilot operation are now complete. MABR performance parameters monitored include OTR, OTE, NR. Overall pilot performance was also being monitored by collection of operations and water quality data (Tables 6 and 7). Process Modelling A BioWin model of the WNWRP was created by the Sanitation Districts and calibrated to current plant flows, loading, and performance (Figure 10). The model was extended to 15 MGD to show predicted future performance. After the release of BioWin 6.2 containing an MABR specific element with a 1-D biofilm model, the WNWRP model was updated to include MABR in the anoxic zone of the plant (Figure 11). The MABR element in the BioWin model was calibrated using SUEZ developed calibration parameters (Table 8) and fine-tuned using operating data for OTR and NR collected during the pilot trial.
Results Pilot System
Phase 1 of pilot operation (Table 9) included start-up and biofilm development. OTE and OTR results are shown in Figures 12 and 13. The results indicate that an active biofilm was completely developed in approximately one month as reported in previous studies (Cote et al., 2015; Kunetz et al., 2016).
Phases 2 through 5 simulated various WNWRP operating conditions (~ 3 - 5 MGD/reactor, Tables 10 to 15) with the addition of a fully functioning MABR zone. OTR results are shown in Figure 14 and average results for OTR, OTE, and NR are shown in Table 16, along with results from previous studies for comparison. The potential to reduce aeration energy requirements is illustrated by comparing the OTE achievable by the MABR process to the OTE observed under field conditions for fine bubble diffusers at Sanitation Districts' facilities, which is typically approximately 10 - 20% depending on fouling condition (Wong et al., 2018). Previous studies have demonstrated that the primary factor impacting MABR performance is ammonia load (Cote et al., 2015; Houweling et al., 2017). This has been demonstrated by observing the diurnal response of OTR, NR, or OTE to primary effluent ammonia load variation (Figures 15 to 17). Results of nitrogen analyses conducted during Phases 2, 4A, and 5B are shown in Table 17. Average effluent ammonia and nitrate + nitrite concentrations were below permit requirements.
Modelling The process models of the WNWRP were run at both steady state and dynamic conditions, with steady state operating conditions summarized in Table 18 for both models. The current plant model was extended to run at 15 MGD and showed the plant would be unable to meet the NPDES permit for nitrate + nitrite limits under steady state or dynamic conditions, as shown in Figures 18 and 19 and Table 19. The MABR model showed that the plant can meet the effluent requirements, under both steady state and dynamic conditions, as shown in Figures 20 and 21 and Table 19. The model predicted effluent NOx-N of 8 mg/L was higher than the NOx-N achieved during piloting and refinement of the model will equate the performance between model and pilot. The model response of OTR and NR to ammonia concentration is captured in Figures 22 and 23, showing the model OTR and NR results are close to the results obtained during the pilot study. The improved performance with the MABR model can be attributed to: a) removal of ~28% of the influent ammonia and seeding effect of the biofilm on the bulk MLSS (Houweling et al, 2018); and b) simultaneous nitrification and denitrification in the MABR zone enabling increased denitrification capacity. The modelling results also show that the MABR process will use 15% less energy for aeration than the current plant at its' design capacity of 15 MGD. The pilot study and modelling exercise demonstrate that MABR is a viable technology to upgrade the capacity of the WNWRP while meeting the NPDES permit limits and saving energy. The results will be used as the basis for a planning level cost estimate, which be used in the planning of the potential MABR implementation at WNWRP.

Whittier Narrows Water Reclamation Plant (WNWRP) conducted an 18-month pilot-scale study and full-scale process modeling to evaluate membrane aerated biofilm reactor (MABR) technology for process intensification in the full-scale plant. The results from this study demonstrate some of the key benefits of MABR, including the ability to enhance nitrogen removal capacity, which can help to increase capacity at WNWRP from 10 mgd to 15 mgd while meeting nitrogen discharge limits for reuse water.

SpeakerReeve, Matt

Presentation time

14:15:00

14:25:00

Session time

13:30:00

15:00:00

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

Author(s)

Reeve, Matt

Author(s)Bruce Mansell1; Matt Reeve2; Charles Harris1; Phillip Ackman1; Nikos Melitas1; Jeff Peeters2

Author affiliation(s)Los Angeles County Sanitation Districts, CA1; SUEZ Water Technologies & Solutions, ON, Canada2