Thompson, Daniel

Daniel Thompson is a speaker at WEFTEC 2026.

Titles from this speaker

Piloting Primary Filtration: Impacts on Removals, Secondary Loading, and Disinfection

Abstract

The Water Pollution Control Authority (WPCA), City of Bridgeport, Connecticut is in the process of upgrading their West Side Wastewater Treatment Plant (WWTP). The 2020 Wastewater Facilities Plan completed by the WPCA and CDM Smith recommended increasing the WWTP's wet weather peak flow capacity from 340 ML/d (90 mgd) to 757 ML/d (200 mgd). This increase was recommended to enable treatment of wet weather flows that reach the plant and cost-effectively reduce overall untreated CSO volumes upstream in the collection system. Due to the tight footprint of the site, construction of traditional primary settling tanks was not feasible. Advanced dual-use primary filtration technologies were investigated in the Facilities Plan and recommended for full-scale implementation. Primary filtration offers a substantial space savings and due to superior removal efficiency, have an added benefit of reducing the load on the biological treatment system. To evaluate and select a primary technology for the West Side WWTP upgrade, an onsite side-by-side pilot study of two technologies was completed from March to May 2023. CDM Smith and WPCA identified Aqua Aerobic Systems' (AASI) AquaPrime cloth media filtration and Tomorrow Water's (TW) Proteus upflow media filtration as two promising technologies for full-scale implementation. The AquaPrime system consists of pile cloth media filter disks with an inside out flow path, and the Proteus system consists of a layer of expanded cross-shaped polypropylene media. Both vendors provided trailer mounted units for the pilot study, shown in Figure 1 and Figure 2. During the pilot study, screened primary influent flow from the West Side WWTP served as the influent to both pilot units. Various influent and effluent parameters including TSS, BOD, COD, NH3-N, TKN, TP, Turbidity, and UVT were assessed to evaluate the treatment performance of both units. Collimated beam testing and bacteria counts were also completed to determine the suitability of the effluent for ultraviolet (UV) disinfection. Operational parameters, such as backwash frequencies, backwash volumes, backwash settleability, along with fats, oils and grease (FOG) and solids generation were also monitored throughout the study. Both pilot units were tested under a range of hydraulic loads, representative of anticipated full scale operating conditions. The hydraulic loading rates for each pilot unit are presented in Table 1. Additionally, the pilot study captured two significant wet weather events, and at times, additional solids were used to artificially increase solids loading, simulating a 'first flush' condition. TSS and BOD Removal The two piloted primary filtration technologies met expectations for both TSS and BOD removal. During ambient conditions across all flow conditions, AquaPrime averaged 81% TSS removal and Proteus averaged 71% removal. Ambient was defined as incoming screened primary flow without the addition of spiked solids. For BOD removal during ambient conditions, AquaPrime averaged 64% removal and Proteus averaged 53% removal. The influent and effluent data are reported in Table 1 and Table 2 in the following format: Median value (min. value — max. value) [Number of values] Figure 3 and Figure 4 depict the primary influent and pilot effluent conditions in a graphical format. Generally, AquaPrime's TSS removal effectiveness remained constant between the lowest and highest hydraulic loading rates, while Proteus saw a decline in removal from the highest to lowest rates of about 15%, as expected. Hydraulic loading rate had little to no impact on BOD removal effectiveness for both pilot systems. Backwash and Solids Waste Production For both systems, as hydraulic and solids loading rate increased, both the backwash frequency and volumes increased. The study defined an efficiency parameter to measure the impact of backwash volumes on process efficiency. AquaPrime demonstrated consistent efficiency, ranging from 70 to 100%, with most trials between 90 and 100%. Proteus efficiency generally decreased with increased hydraulic loading rates, ranging from 68 to 85%. The backwash from both AquaPrime and Proteus was observed to be much thinner than primary sludge from traditional settling tanks, averaging 1400 mg/L and 700 mg/L during ambient conditions respectively. Disinfection Effectiveness The facilities plan recommended dual-use advanced primary filtration, with primary effluent flows beyond the secondary capacity of the plant (wet weather bypass) receiving UV disinfection prior to discharge. Collimated beam testing for UV disinfection effectiveness revealed that UV could not reliably inactivate enterococci in the primary filter effluent for both AquaPrime and Proteus to the WWTPs permit limits. This was true for both primary effluent, as well as primary effluent that was 'blended' with secondary effluent from the WWTP to match a real-world condition. These enterococci results can be compared to the West Side WWTP's instantaneous and monthly geomean permit limits in Figure 5 and Figure 6. AquaPrime effluent is shown, but Proteus produced comparable results. Subsequent dose testing with hypochlorite disinfection proved successful, meeting all WWTP permit limits within 30 minutes. These results can be seen for AquaPrime in Figure 7. Overall, this hypochlorite disinfection was successful for both AquaPrime and Proteus.

The performance of two primary filtration technologies was evaluated in a side-by-side pilot study in Bridgeport, CT. Aqua-Aerobic Systems' AquaPrime cloth media filtration and Tomorrow Water's Proteus upflow media filtration were evaluated based on various water quality parameters. Both systems achieved high solids and BOD removal over the piloting period. However, UV collimated beam testing revealed complications meeting the WWTP's bacteria limits at reasonable UV doses for both systems.

SpeakerThompson, Daniel

Presentation time

11:30:00

12:00:00

Session time

10:30:00

12:00:00

SessionThree Different Flavors of Improvement for Preliminary/Primary Treatment

Session number522

Session locationRoom 349

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

Author(s)

Thompson, Daniel, McBennett Mappa, Lauren, Kaldate, Amit, Dyson, John

Author(s)D. Thompson1, L. McBennett Mappa2, A. Kaldate3, J.D. Dyson4

Author affiliation(s)1CDM Smith, CT, 2WPCA, City of Bridgeport, CT, 3Tomorrow Water, VA, 4Aqua-Aerobic Systems, Inc., VA

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159601

Volume / Issue

Content sourceWEFTEC

Word count11

Primary Filtration, Don't Forget the First Flush!

Abstract

Background: The Water Pollution Control Authority (WPCA), City of Bridgeport, Connecticut is in the process of upgrading their East Side Wastewater Treatment Plant (WWTP). The East Side WWTP currently has an average daily flow of 20.8 ML/d (5.5 mgd) with a 90.8 ML/d (24 mgd) secondary treatment capacity. The WWTP utilizes traditional primary settling tanks, MLE activated sludge process, and sodium hypochlorite disinfection. WPCA's 2020 Facilities Plan recommended increasing the peak flow capacity from 151 ML/d (40 mgd) to 303 ML/d (80 mgd). This increase was recommended to enable treatment of wet weather flows that reach the plant and cost-effectively reduce overall untreated CSO volumes upstream in the collection system. Due to the tight footprint of the site, construction of conventional primary settling tanks was not feasible. Primary filtration technologies were investigated in the Facilities Plan and recommended for full-scale implementation. Primary filtration offers space savings and due to superior removal efficiency, have an added benefit of reducing the load on the downstream biological treatment system. West Side WWTP Primary Filtration Pilot: A 6-week onsite primary filtration pilot study was completed from March to May 2023 at the WPCA's larger West Side WWTP [1]. Figures 1 and 2 depict the pile cloth media filtration (PMCF) unit used during the pilot study. WWTP primary influent flow served as the influent to the pilot unit. Influent and effluent parameters were assessed to evaluate the performance of the PMCF. The unit was tested under a range of flows and loads, representative of full-scale operating conditions. Through this piloting effort, Aqua Aerobic Systems' (AASI) PCMF was identified as a promising technology for full-scale implementation at both WWTPs. During two wet weather events that occurred during that study period, Total Suspended Solids (TSS) and Biological Oxygen Demand (BOD) concentrations reached a peak of 260 mg/L and 180 mg/L respectively. As design activities progressed from the West Side WWTP to the East Side WWTP, it was initially anticipated that TSS and BOD concentrations at the two WWTPs would be comparable, as both are CSO systems, though with different tributary areas. Operators at the East Side WWTP indicated that the facility could see a sustained first flush of solids during a rain event. They described a significant influx of solids at the start of an event that could last for many hours. CDM Smith and the WPCA decided to complete a wet weather sampling program to define this phenomenon on the East Side WWTP and determine the impact it would have on the design and operation of a primary filter installation. Wet Weather 'First Flush' Profiling: Field sampling activities were completed in October 2025, to better understand when the first flush occurs during an event, and to quantify the spike loading that would occur. It was expected that the first flush would occur prior to peak flow conditions. At peak flow, solids concentrations were expected to be diluted by rainwater in the combined sewer system. An indexing sampler was set up adjacent to the primary influent channel to collect 4 sample increments into an hourly composite sample. Samples were collected from the primary influent channel on October 7, 12, and 29, 2025 during wet weather events. Sampling started prior to the predicted rainfall and ran for 24 hours, and WPCA staff recorded hourly plant flows to correlate to the sample intervals. Table 1 depicts the wet weather events that were captured during this effort. During all 3 events, a sustained 'first flush' condition was observed, where a period of elevated organic and solids loading coincided with elevated plant influent flow. Figures 3 through 8 illustrate the WWTP influent flow during these 3 storms against the influent TSS and BOD concentrations. These events lasted from 3 to 5 hours before solids concentrations diluted from the incoming stormwater. TSS concentrations peaked during all 3 events between 500-600 mg/L. This was a more substantial wet weather response, with higher solids concentrations, than were seen at the West Side WWTP. Of particular note, the results from the October 29th storm showed that the peak WWTP flow during the event (130.2 ML/d, 34.4 mgd) coincided with the peak solids loading (580 mg/L), resulting in a very high solids loading rate of 166,400 lb/d. The solids loading rate during this 'first flush' period during the October 29th storm exceeded the vendor recommendations of 10-12 lbs/ft2/day. This dictated a revision to the design concept. It had been anticipated that providing a filter system with a filter rate of 4.30 gpm/sf to handle the diluted peak flow of the new facility (303 ML/d, 80 mgd) would also have adequate capacity to meet solids loading at any interim flow and load condition. The field sampling proved that this was not true, and the first flush could be so significant that it necessitated the inclusion of additional filter units into the planned primary filter facility. Conclusion: The sampling conducted at the East Side WWTP was an invaluable tool to help the team understand the first flush response of the combined system. The results informed the solids loading rate and drove the decision to add additional filter units to the design. This first flush condition controlled the design sizing, and must be considered in any primary filtration design.

This paper was presented at WEFTEC 2026 in New Orleans, Louisiana.

Presentation time

09:30:00

10:00:00

Session time

8:30:00

10:00:00

SessionAdvanced Primary Treatment Pathways: High-rate Filtration and Sludge Process Integration

Session locationErnest N. Morial Convention Center

TopicFacility Operations and Maintenance, Municipal Wastewater Treatment Design

Author(s)

Thompson, Daniel, Gupta, Vedansh