Pimentel, Anthony

Anthony Pimentel is a speaker at WEFTEC 2026.

Titles from this speaker

Description: Comparative Performance and Economic Analysis of Full-Scale UV LP and LED...

Comparative Performance and Economic Analysis of Full-Scale UV LP and LED Disinfection Systems

Abstract

Introduction: UV disinfection systems have gained popularity in water and wastewater disinfection applications as they can inactivate microorganisms while avoiding any risk of a high chemical disinfectant demand or disinfection byproducts. UV light emitting diodes (LEDs) are an emerging disinfection technology which offer numerous advantages compared to conventional UV systems including instantaneous start/stop, selectable wavelength, and are mercury-free. As UV LEDs have increased in availability for water treatment over the last few years, a comparative analysis on the potential advantages UV LEDs can provide for surrounding infrastructure is needed to evaluate the viability of full-scale integration. Water Research Foundation 5173: Feasibility of Full-Scale Implementation of UV LED Disinfection aims to perform a quantitative assessment of the feasibility of full-scale UV LED water disinfection reactors for water and wastewater treatment applications. WRF 5173 consists of several tasks including regulatory engagement, interlaboratory bench-scale testing, full-scale sampling and monitoring, and an economic and performance analysis between UV LPHO and LED systems. Black & Veatch has conducted an independent economic and performance analysis of the full-scale UV low pressure high output (LPHO) and LED disinfection systems consisting of one drinking water and one wastewater disinfection UV side-by-side comparison performing at flow rates greater than 1 mgd. A summary of the equipment design criteria for each system is shown in Table 1. The paper will also provide an overview of the advancement of full-scale UV LED treatment technologies, a review of current UV LED technology and disinfection efficacy, and will provide a contemporary, unbiased comparative analysis of full-scale UV LPHO and LED disinfection systems in operation at the full-scale for which results indicate a significant difference in total life cycle cost between UV LPHO and LED systems at equivalent performance levels. Materials and Methods: The comparative economic and performance analysis of the full-scale UV LPHO and LED systems was conducted by Black & Veatch based on data collected through the interlaboratory bench-scale testing and full-scale sampling and monitoring. The study evaluated water and wastewater systems with closed vessel UV systems and data collection included performance data including online monitoring of flow, UV transmittance, power level, and measured UV intensity. Sampling from each system includes benchtop measurement of UV transmittance, wavelength scans in the applicable UV LED spectra, influent and effluent microbe counts (fecal coliforms or Legionella), and other applicable water quality parameters. Design and operation of each system was configured in accordance with applicable UV regulatory guidance (REF1 and REF2). Estimated equipment capital cost information from each installation was used to compare the two applications in a side by side comparison. In addition, data provided from operations experience of the UV LPHO and LED systems over the last two years and component replacement costs from each UV system manufacturer was provided to inform the life-cycle cost model which has been used for more than 100 conventional UV disinfection systems over the past two decades. Results and Discussion: Both UV LPHO and LED systems were able to maintain the target UV dose and inactivate fecal coliforms and Legionella effectively to each application's effluent microbe limits per the design intent. Evaluation of the online measured UV intensity and effluent microbe counts provided an indication of reactor sleeve fouling which impacts overall life cycle cost. In addition to the rate of fouling, UV LED testing data indicates that the LED output is reduced at significantly shorter time periods compared to LPHO lamps, which results in a higher LED replacement rate and cost. The operations experience including power draw in operation at the max design and average operating conditions for each UV LPHO and LED system was evaluated to inform overall power consumption and energy cost. For UV LED systems, LED replacement cost due to the shorter component lifetime and its higher component cost is a main driver impacting overall ownership and life cycle cost. When compared to LPHO systems, the electrical energy cost from average operating conditions is significantly higher for UV LED systems. These conclusions, based on actual site-specific data from two applications of full-scale UV LPHO and LED systems in operation, depict a different landscape in UV system technologies than shown in recent trade shows or marketing and identify several key areas where UV LED system equipment will need to improve upon to be cost competitive with UV LPHO systems in water and wastewater applications. These conclusions do not capture all drivers for UV LED system implementation, including mercury risk assessment and mercury supply which are growing concerns for many regions and utilities. Conclusions 1.This study provides the first contemporary and unbiased analysis of UV LPHO and LED disinfection systems installed at full-scale. 2.Equivalent disinfection performance (UV dose and microbe inactivation) can be achieved by both UV LPHO and LED systems with current technology. 3.UV LED systems currently have a significantly higher overall operating cost due to higher electrical demand and component replacement frequency/cost.

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

Presentation time

14:30:00

14:45:00

Session time

13:30:00

15:00:00

SessionUV Disinfection - Advances & Insights

Session locationErnest N. Morial Convention Center

TopicDisinfection and Public Health, Municipal Wastewater Treatment Design

Author(s)

Pimentel, Anthony, Hunter, Gary, Townsend, Bryan

Author(s)A. Pimentel1, G. Hunter1, B. Townsend1

Author affiliation(s)Black & Veatch, 1Black & Veatch, 1Black & Veatch, 1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2026

DOI10.2175/193864718825160387

Volume / Issue

Content sourceWEFTEC

Word count14

Description: Investigation of N-Nitrosodimethylamine UV Sensitivity in Reclaimed Water Reverse...

Investigation of N-Nitrosodimethylamine UV Sensitivity in Reclaimed Water Reverse Osmosis Permeate

Abstract

Introduction As a part of the Pure Water Southern California program, the Metropolitan Water Districts of Southern California (Metropolitan) is planning to implement a full-scale potable reuse facility, including one of the world's largest UV advanced oxidation process (AOP) systems. UV-AOP systems can achieve 6 log pathogen removal in addition to the degradation of organic chemicals that pass through upstream treatment, including N-Nitrosodimethylamine (NDMA) and 1,4-dioxane. These two chemicals are degraded by the combination of UV photolysis and hydroxyl radical oxidation, but degradation mechanisms are often difficult to monitor in real-time and require significant analytical investment to understand in a specific system. UV-AOP challenge tests were conducted at Metropolitan's demonstration facility to compare UV/Cl2 and UV/H2O2-AOP treatment with a potential influent water quality for the future full-scale system. While challenge testing demonstrated removal of NDMA and 1,4-dioxane, reproducibility and scalability of using demonstration system data to develop process design values requires careful consideration, due to variations in UV dose algorithms, observed NDMA UV sensitivity, fluctuations in UV transmittance (UVT), and water quality. This study presents a thorough investigation into quantifying and assessing variability in NDMA UV dose-response, or sensitivity, across various applicable water qualities. NDMA degradation by UV photolysis can be impacted by chloramines or other photolysis and oxidation pathways within the system, and UV dose required to degrade NDMA has been reported to vary among different water qualities and projects (REF1). This variability may result from the difference in influent water quality, the presence of chloramines, or inaccurate UV dose characterization (Figure 1). NDMA UV sensitivity is a critical parameter for UV-AOP system design and operations, as NDMA is commonly detected in municipal wastewater effluent and serves as a key indicator compound for monitoring UV-AOP system performance. Materials and methods NDMA was introduced into the UV-AOP influent water and exposed to sets of UV doses ranging from 1,000 to 3,000 mJ/cm2 at various conditions including UVTs of between 95 to 99% at the demonstration facility. Samples were collected from the UV feed and UV effluent to determine the NDMA log removal in order to develop a correlation between NDMA reduction equivalent dose, ballast power setting and UVT. Bench-scale UV collimated beam testing was conducted using UV feed water collected from the demonstration facility, following established guidance for UV dose-response testing (REF2). Results and discussion Results shown in Figure 2 demonstrate the measured NDMA log removal value (LRV) as a function of relative lamp output and average UVT. These results indicate a linear response in NDMA LRV from between 1.2 to 2.7 log at various UVTs within the design range of most UV-AOP systems in RO-based potable reuse treatment trains. Figure 3 provides the linear correlations between NDMA LRV, system UVTs, and the ballast power level. This study successfully demonstrated an NDMA removal performance model based on relative lamp output, ballast power level, and UVT across a range of RO permeate water qualities at the demonstration facility. However, as pilot/demonstration UV reactors are significantly smaller and different from large full-scale systems, UV-AOP performance data is often difficult to scale up to future full-scale systems due to reactor dose delivery and lack of scalable testing data. As such, this study also employed a bench-scale UV collimated beam system to verify the NDMA UV sensitivity and identify any trends between water qualities or experimental conditions. Figure 4 shows NDMA LRV results from the bench-scale UV system at various UVTs. The results suggested that NDMA UV dose-response curve was not significantly impacted by water matrices and UVT. Figure 5 demonstrates that when chloramine is present, the changing of UVTs during UV exposure did not significantly affect NDMA UV sensitivity when different UVT values were incorporated into the UV dose calculation. Other impacts such as pH and TOC may also impact NDMA UV sensitivity and warrant further investigation in future. The results of this study suggest that the NDMA UV sensitivity in ROP permeate from the demonstration facility ranged from 700 to 750 mJ/cm2 for one log removal. These findings have significant implications for full-scale UV-AOP system design, as recent UV-AOP systems in California have been designed using assumed NDMA UV sensitivity values of 850 to 1,040 mJ/cm2. Once these results are further confirmed and validated, utilities could potentially optimize the UV-AOP system by up to 30% in terms of required UV dose, resulting in substantial reductions in both capital and operating costs. Conclusions NDMA was successfully removed by the UV-AOP system and performance models can accurately predict NDMA removal across various operating conditions observed in RO permeate. UV collimated beam systems can provide useful information for UV-AOP testing and future full-scale design. Although historical data has varied, NDMA UV sensitivity was not impacted by water matrices and UV transmittance in this testing. Additional NDMA UV sensitivity testing may be beneficial to ensure treatment compliance across project lifespan and a wider range of water qualities.

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

Presentation time

15:30:00

15:45:00

Session time

15:30:00

17:00:00

SessionShining a Light on Microconstituents: UV and AOP Solutions

Session locationErnest N. Morial Convention Center

TopicAdvanced Level, Disinfection and Public Health, Microconstituents and Contaminants of Emerging Concern (Non-PFAS), Municipal Wastewater Treatment Design

Author(s)

Jia, Ai, Pimentel, Anthony, Patton, Samuel, Zapata, Jonathan, Maceiko, Shannon, Tanuwidjaja, Dian

Author(s)A. Jia1, A. Pimentel2, S. Patton1, J. Zapata1, S. Maceiko1, D. Tanuwidjaja1

Author affiliation(s)Metropolitan Water District of Southern California, 1Black & Veatch, 2Metropolitan Water District of Southern California, 1Metropolitan Water District of Southern California, 1Metropolitan Water District of Southern California, 1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2026

DOI10.2175/193864718825160399

Volume / Issue

Content sourceWEFTEC

Word count12

Machine Learning In The Dark: Disinfection With <55% UV Transmittance

Abstract

Introduction: UV disinfection systems have gained popularity in wastewater disinfection applications as they can inactivate microorganisms while avoiding the injection of a chemical and any risk of a high disinfectant demand or disinfection byproducts. UV disinfection process design must account for UV Transmittance (UVT) which is a critical parameter that characterizes the ability of UV photons to pass through water and reach a microbiological target. Monitoring of UVT is achieved by online or benchtop readings, but online data can be skewed by sensor drifting or water quality impacts. Black & Veatch worked with two wastewater facilities where UVTs <55% were observed and employed machine learning to analyze correlations between measured UVT and various water quality parameters including carbonaceous biological oxygen demand (CBOD) and total organic carbon (TOC). UVT prediction allows for historical data to be verified whether the sensor was reading correctly or for optimization of UV system operation. Materials and methods: This study collected UVT and additional water quality data from each respective treatment facility secondary effluent at various sample collections intervals over the last 5 years. UVT was collected with online and benchtop instruments while other water quality data were collected via analytical methods accepted by 40 CFR criteria. Data cleaning and analysis was performed in R using various open-source packages and algorithms. Results and discussion: Review of Industry Guidance. Although there is no EPA requirement of a minimum design UVT for wastewater disinfection, guidelines have been followed in various states. The 2012 NWRI Guidelines set minimum allowable UVTs for wastewater applications based on the type of upstream treatment with a 55% minimum for applications with media filtration (REF2). In addition, 10 States standards recommends UV disinfection in wastewater be limited to effluent UVTs greater than 65% (REF3). However, UV disinfection has been implemented in states across the US with UVTs of 55% or lower, where various benchtop and full-scale data supports viable inactivation of microbes relevant to each projects operating permit. This study considered two facilities which are known to produce lower UVTs than conventional nitrifying treatment, Pure Oxygen Activated Sludge and Trickling Filter, from projects in Michigan and California, respectively. Machine Learning Techniques. Machine learning consists of algorithms and statistical models to analyze and draw inferences from patterns in data and can be utilized for various applications relevant to water treatment. This study reviews industry accepted techniques for employing machine learning for numerical predictions models based on multivariate regression and provides an in-depth review of the two algorithms employed in this work, Random Forests (RF) and Support Vector Regression (SVR). Case Study 1. A pure oxygen activated sludge treatment facility in Michigan undergoing a disinfection system evaluation was analyzed to consider UV disinfection to replace previous disinfection systems using sodium hypochlorite and ozone. Black & Veatch implemented an online UVT probe for a period of 12 months where the plant experienced various low UVT trends (<50%) that were impacted by ferric chloride addition, expected industrial source discharges, and sensor drifting. RF and SVR machine learning algorithms were employed to predict UVT based on CBOD, Solids and Temperature. Model results were successful in predicting UVT with an R mean squared value (RMSE) of 0.84 and 0.83, respectively (Figures 2 and 3). To mitigate the impact of excessive drifting of the online UVT probe, the model was further refined to predict periods where the UVT probe may have drifted out of calibration. Outcomes of these predictions could help promote instrument calibration or ensure historical data is accurate and whether or not it should be included in further analysis for process design of a UV disinfection system. Case Study 2. A regional wastewater facility in California undergoing a plant upgrade to employ UV disinfection for Title 22 non-potable reuse was also evaluated. As a part of process design and commissioning of the new Title 22 UV disinfection system, Black & Veatch analyzed 2+ years of water quality data where UVTs less than 50% were observed, which has been documented for trickling filter secondary effluent (REF4). Upstream trickling filter backwashing events were thought to have especially produced organic loads which impacted the UVT sensor and may have altered data collection after the system upset had already passed. TOC and TSS data were used to train the RF and SVR models to predict UVT across the monitoring period, with the SVR achieving a higher success in prediction with an RSME of 0.86 (Figures 5 and 6). Conclusions: 1.Applications where UVT is <55% can be managed contrary to some guidance and provide effective disinfection. 2.Machine Learning can verify analyzer trends to identify correct/incorrect historical data and ensure appropriate process design. 3.Machine Learning can be integrated with control approaches to accelerate response of UV disinfection systems based on anticipated water quality. 4.Multivariate water quality constituent regression could be paired with UV validation equations to predict performance and improve understanding of disinfection operations.

UV disinfection systems rely on the real-time monitoring of UV Transmittance to appropriately inactivate microorganisms and protect public and environmental health. This study demonstrated the use of machine learning to predict UV Transmittance in applications where potential analyzer error or disadvantageous water quality impacts the ease of operations or system cost, further validating process design assumptions and improving UV system control and operations.

SpeakerPimentel, Anthony

Presentation time

10:30:00

11:00:00

Session time

10:30:00

12:00:00

SessionWhat's New in UV?

Session number518

Session locationRoom 238

TopicDisinfection and Public Health, Intelligent Water, Intermediate Level

Author(s)

Pimentel, Anthony, Hunter, Gary, Torkzadeh, Hamed

Author(s)A. Pimentel1, G.L. Hunter2, H. Torkzadeh3

Author affiliation(s)1Black & Veatch, CA, 2Black & Veatch, SC, 3Black & Veatch, GA

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159549

Volume / Issue

Content sourceWEFTEC

Word count11

Resilience, Sustainability, and Risk of Intermittent UV LP And LED Systems

Abstract

UV LP and LED systems were compared in their engineering viability for an intermittent flow, 1 MGD average flow UV wastewater system at 65% UVT regarding resilience, sustainability, and risk. Resiliency to system cycling, sustainability via a life-cycle cost comparison, and risk of maintaining system performance guarantees were evaluated for LP, current LED, and future LED systems. Overall, this assessment demonstrated the feasibility and future optimization of these systems in wastewater disinfection. As UV LEDs continue to develop and enter the wastewater market, full-scale UV LED systems could help wastewater treatment systems reduce energy cost, labor requirements, and monetary risk. Advancement of UV LP and LED systems in treating intermittent flows with minimal energy requirements will help the wastewater industry meet climate change and sustainability initiatives.

UV LP and LED systems were compared in their engineering viability for an intermittent flow, 1 MGD UV wastewater system at 65% UVT regarding resilience, sustainability, and risk. Resiliency to system cycling, sustainability in a life-cycle cost comparison, and risk of maintaining system performance guarantees were evaluated for LP, current LED, and future LED systems. Overall, this assessment will demonstrate the feasibility and future optimization of these systems in wastewater disinfection.

SpeakerPimentel, Anthony

Presentation time

09:00:00

09:30:00

Session time

08:30:00

10:00:00

SessionUV Disinfection: Where are we? Where are we going?

Session locationRoom S404c - Level 4

TopicDisinfection and Public Health, Intermediate Level, Municipal Wastewater Treatment Design, Research and Innovation

Author(s)

Pimentel, Anthony

Author(s)A. Pimentel 1; G. Hunter 2 ; A. Pimentel 1; H. Mettlan 3; R. Osborne 4; J. Garrison 6; S DeBoses 6;

Author affiliation(s)Black & Veatch 1; Black & Veatch 2 ; Black & Veatch, Los Angeles, CA 1; Black & Veatch 3; Black & Veatch 4; Clemson Wastewater Treatment Facility 6; Clemson Wastewater Treatment Facility 6;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159162

Volume / Issue

Content sourceWEFTEC

Word count12