Sundaram, Vijay

Dr. Sundaram serves as AECOM’s Global One Water Practice Leader. Vijay has been at the forefront of advancing purified recycled water for drinking and groundwater recharge solutions within the US and around the world by developing treatment technologies and regulatory framework suitable for inland and coastal locations. Dr. Sundaram has 20 years of experience in addressing contaminants of emerging concern (CECs), disinfection byproducts, priority pollutants, and pathogens. He served as the Chair for the Water Reuse Roadmap, A Water Environment Federation (WEF) publication. He most recently won the McKee Groundwater Protection, Restoration or Sustainable Use Award.

Titles from this speaker

Description: Extended Investigation to Evaluate the Reliability of Ozone-BAC Treatment as a CEC...

Extended Investigation to Evaluate the Reliability of Ozone-BAC Treatment as a CEC Removal Barrier in Potable Reuse Applications

Abstract

Ozonation-Biological Activated Carbon (Ozone-BAC) process reliability in terms of contaminant removal over time is becoming increasingly important to the potable water industry. Field verification of ozone-BAC performance from startup to achieving steady state based on real-time tools is necessary for regulatory approval and develop operational protocols. Consequently, this study involved 19 months of continuous field-scale demonstration of two ozone-BAC systems with different Empty Bed Contact Times (EBCTs) with observations of removal of contaminants of emerging concern (CECs). Findings from this effort filled the gap in the literature regarding transition of granular activated carbon (GAC) to BAC in potable reuse applications. Lowering influent CEC concentrations to heavily loaded BAC resulted in significant desorption resulting in elevated levels of CECs in the BAC effluent which could be a serious concern if downstream polishing steps such as granular activated carbon (GAC) is not available.

SpeakerSundaram, Vijay

Presentation time

08:30:00

08:50:00

Session time

08:30:00

10:10:00

SessionAvoid the Brine: Achieving Potable Reuse Without RO

Session number328

TopicMicroconstituents, Water Reuse and Reclamation, Water Supply and Management

Author(s)

V. SundaramK. PagillaT.C. Guarin CL. LiR. Marfil-VegaS. DasguptaZ. Bukhari

Author(s)V. Sundaram1; K. Pagilla2; T.C. Guarin C2; L. Li2; R. Marfil-Vega3; S. Dasgupta4; Z. Bukhari4;

Author affiliation(s)AECOM Technical Services, Inc.1; University of Nevada 2; Shimadzu Scientific Instruments3; American Water Works Service Company Inc.4

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2020

DOI10.2175/193864718825157840

Volume / Issue

Content sourceWEFTEC

Word count19

How to Plan for PFAS in Carbon-based Potable Reuse Implementation

Abstract

PFAS are prime examples of how water recycling facilities can help break the circulation of these chemicals from the water cycle. Treatment technologies typically in use at WWTPs are ineffective for removing PFAS. While the most common technology for PFAS includes adsorptive, ion exchange, or RO membrane filtration processes, limited PFAS removal is expected across the ozone-biological activated carbon (Ozone-BAC) treatment steps within the carbon-based advanced treatment (CBAT) train. Granular Activated Carbon (GAC) is often included downstream of ozone-BAC for TOC removal. GAC provides reliable PFAS removal. However, utilizing a single GAC step for both TOC and PFAS removals may limit the full use of GAC adsorption capacity (i.e., PFAS breakthrough could occur ahead of TOC breakthrough). We will highlight our work on designing an advanced treatment train to achieve potable reuse standards, including an efficient approach for PFAS removal, and discuss the complexities of spent PFAS media management.

With impending finalization of Per-and-polyfluoroalkyl substances (PFAS) MCLs, removal of PFAS is becoming critical for potable reuse projects. However, removal of PFAS is expected to be minimal across Ozone-BAC treatment steps. Therefore, the path forward on how to plan for PFAS treatment/destruction within carbon-based potable reuse implementation will be presented.

SpeakerHunter, Amy

Presentation time

14:30:00

14:50:00

Session time

13:30:00

15:00:00

SessionMaking Forever Chemicals Gone Forever

Session locationRoom S405- Level 4

TopicAdvanced Level, Microconstituents and Contaminants of Emerging Concern (Non-PFAS), PFAS, Research and Innovation, Water Reuse and Reclamation

Author(s)

Hunter, Amy

Author(s)A. Hunter 1; V. Sundaram 2 ; A. Hunter 1;

Author affiliation(s)AECOM 1; AECOM 2 ; AECOM 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159094

Volume / Issue

Content sourceWEFTEC

Word count11

Potable Reuse from a Wastewater Operators' Perspective

Abstract

Potable reuse is becoming an attractive option for incorporating circular economy, resiliency, and the One Water approaches. As regulations for potable reuse get promulgated and projects get implemented, wastewater operators are being introduced to newer topics, such as Cryptosporidium parvum (Crypto) and Giardia lamblia (Giardia) inactivation; removal of Per- and polyfluoroalkyl substances (PFAS) and contaminants of emerging concern (CECs), such as hormones, and pharmaceuticals; and management of disinfection byproducts (DBPs) and their formation potential. The potable reuse project requirements from the perspective of a wastewater operator/utility will be discussed.

SpeakerSundaram, Vijay

Presentation time

14:36:00

14:51:00

Session time

13:30:00

15:00:00

SessionImplementation of Potable Reuse

Session number110

TopicDisinfection and Public Health, Policy and Regulation, Sustainability and Climate Change, Water Reuse and Reclamation, Water Supply and Management

Author(s)

Vijay Sundaram

Author(s)V. Sundaram1;

Author affiliation(s)AECOM Technical Services, Inc., Sacramento, CA1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2021

DOI10.2175/193864718825157989

Volume / Issue

Content sourceWEFTEC

Word count8

Quantification of Carbon Emissions in Potable Reuse Treatment Configurations

Abstract

Potable reuse commonly employs reverse osmosis (RO). However, RO has high energy requirements and generates a brine waste, making it better suited for coastal locations that allow for oceanic brine discharge. Carbon-based advanced treatment (CBAT) offers a more favorable option for inland regions, with lower capital costs, energy requirements, and no brine waste. This study quantified carbon emissions over a 50-year operational period for three configurations: RO with oceanic brine discharge, RO with zero-liquid discharge (ZLD) brine handling, and CBAT. Results showed that RO and pumping energy accounted for over 80% of Scope 2 emissions in RO trains, and ZLD brine treatment increased emissions by 60%. Alternatively, CBAT had 3x lower Scope 2 emissions, but Scope 3 emissions could be substantial depending on the type and replacement frequency of the granular activated carbon. By understanding carbon emissions, decision-makers can balance meeting potable reuse requirements while minimizing the carbon impact

Potable reuse provides numerous benefits and is being considered by utilities around the world, but the implementation of potable reuse requires significant infrastructure and power which may result in increased carbon emissions. Understanding the carbon emissions for reverse osmosis and carbon-based potable reuse treatment configurations is crucial in achieving the best balance between water sustainability and climate change adaptation.

SpeakerWagner, Brett

Presentation time

09:30:00

10:00:00

Session time

08:30:00

10:00:00

SessionWater Reuse: Challenges and Opportunities

Session locationRoom S403b - Level 4

TopicPotable Reuse, Water Reuse and Reclamation

Author(s)

Wagner, Brett

Author(s)B. Wagner 1; V. Sundaram 2 ; G. Bowden 3; B. Wagner 1;

Author affiliation(s)AECOM 1; AECOM 2 ; AECOM 3; AECOM 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159166

Volume / Issue

Content sourceWEFTEC

Word count10

Description: Rethinking Secondary and Tertiary Treatment Planning and Design for Potable Reuse...

Rethinking Secondary and Tertiary Treatment Planning and Design for Potable Reuse Applications

Abstract

Advancements in municipal wastewater treatment technologies started with removal of organics and nutrients (nitrogen and phosphorus) to meet stringent discharge limitations. Potable reuse is becoming an attractive option for incorporating circular economy, resiliency, water sustainability and the One Water approaches. Successfully implemented potable reuse projects have shown that membrane or reverse osmosis (RO) based Advanced Water Treatment (AWT) train and Ozone/biological activated carbon filtration (BACF) or carbon-based AWT train are suitable candidates. The selection of the AWT train will typically be based on project location (i.e., coastal vs inland), since the waste disposal method has the highest impact on the project lifecycle cost. As potable reuse projects get implemented, we have an opportunity to rethink the secondary and tertiary treatment design principles and strategies. The key aspects of transforming the secondary and tertiary treatment planning and design for potable reuse applications include: Sewershed source control Flow equalization Scalping plants and adaptive flow control Solids retention time (SRT) selection based on CEC removal requirements Nitrogen removal driven by nitrate MCL Phosphorus removal driven by RO fouling potential Pathogen log reduction across secondary and tertiary treatment unit processes
Sewershed source control is being required by the potable reuse regulations. Several case studies have shown that source control reduces the pollutant loads entering the WWTP. It is recommended that local limits be established with respect to certain chemicals entering the sewer so that the treatment plant is not overloaded with any one chemical. For example, industrial processes are limited to discharging 1.0 mg/L of 1,4-dioxane in the Orange County Sanitation District. A similar approach can be adopted for 1,4-dioxane and other chemicals to limit pollutants.
Flow Equalization: Maintaining a constant flow rate to the AWT system helps in operations and maintenance (O&M) of the system. With a constant flow operation, process performance such as pathogen log reduction and removal of CECs can be reliably achieved with greater certainty. Wastewater operators are already trained on the benefits of flow equalization on treatment performance.
Scalping Plants and Adaptive Flow Control: AECOM is currently designing the secondary treatment for East County Advanced Water Purification Project (Padre Dam). The main purpose of the secondary treatment which receives raw wastewater diverted from the existing sewer conveyance system is to deliver a consistent water quality to MF-RO-UVAOP AWT system. Most of potable reuse projects are being implemented in facilities that have oceanic or surface water discharges, therefore, flow to potable reuse AWT can be lowered or stopped for relatively short periods. Applying adaptive operational strategy in which the secondary effluent is not being utilized for potable reuse when its quality or other characteristics don't meet the criteria may further reduce the risk associated with potable reuse.
Selection of Solids Retention Time based on CEC removal: Past studies have shown that secondary treatment provides substantial removal of CECs. Therefore, the selection of secondary treatment SRT will be based on both nutrient and CEC removal requirements. WERF-03-CTS-22UR project findings have shown that 1) there are no significant difference in CEC removal between facilities operated at SRT = 5 days and SRT = 15 days, and 2) at least 5 days appears to be required minimum SRT needed to achieve 80% reduction of a wide range of CECs.
Nitrogen Removal to Meet Nitrate MCLs: Higher safety factors are typically applied in the case of primary drinking water contaminants such as nitrate. Consequently, treatment systems are designed with a maximum allowable concentration that is close to 50% of the maximum contaminant levels (MCLs). In wastewater compliance, nitrate is a part of the total nitrogen or dissolved inorganic nitrogen discharge compliance requirements. Biological secondary treatment with year-round nitrification to meet the nitrate MCL provides several additional benefits including: 1) nitrified effluent greatly improves UV and chlorine disinfection system performance, 2) improved Crypto and Giardia removal is expected with year-round biological nitrification, 3) increased diversity of biological microorganisms found in nitrification process tend to reduce bulk organics present in secondary effluent, and 4) biological nitrification process provides removal for certain types of CECs.
Phosphorus Removal to Address RO Fouling: In potable reuse facilities utilizing RO membranes, phosphate scaling of membranes is a major concern. Phosphate scaling can be reduced by lowering the feed pH. However, this requires a sizable and costly acid dose, and the lower feed pH also marginally increases the risk of silica scaling if marginally high concentration of silica is also present. Potential alternative strategies are to remove phosphorus biologically in the secondary treatment process and dose ferric chloride for phosphate removal. Reducing phosphate upstream of RO results in a more stable operating point with no acid dosing.
Pathogen Log Reduction across Secondary and Tertiary Unit Processes: Quantifying and demonstrating pathogen log removal across treatment steps, such as secondary biological and tertiary filtration processes, eliminates the need for inclusion of new and additional pathogen inactivation barriers, which could result in substantial savings in capital and O&M costs while meeting the pathogen inactivation requirements. From tertiary filtration planning and design perspective, the selection of dual-media filters over other alternatives such as disk filter can be leveraged for demonstrating log reduction values (LRVs) for Crypto, Giardia, and Virus. While a granular media filter is effective to some degree, its pathogen log reduction value (LRV) is greatly enhanced if the water is coagulated, flocculated, and clarified prior to filtration. This conventional filtration (i.e., dual-media filter with pretreatment) process is at the heart of most drinking water treatment facilities and is familiar to operators. The conventional filters with automated controls limiting effluent turbidity will achieve >2-log removal of the virus (TCEQ, 2019). Based on TCEQ guidance and Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), a conservative approach for conventional filters is to use LRV of 3.0 and 3.5 for Giardia and Crypto for regulatory compliance purposes when the filtration unit process has been optimized to achieve an 'individual filter turbidity of 0.15 NTU or less at each filter for at least 95% of the measurements recorded during a month, and has no individual filter producing water with turbidity above 0.3 NTU in any two consecutive 15-minute readings' (EPA, 2010; TCEQ, 2019).
Summary When planning and implementing potable reuse projects, wastewater facility planners, designers, and operators must understand the shift in requirements and what is expected from the facility planning design and operations teams in terms of achieving pathogen (virus, Giardia, and Crypto) log reductions, CEC removals and performance reliability. To assist the wastewater community with this transition, a clear understanding must be developed of ways to leverage secondary and tertiary treatment unit processes for cost-effective implementation of potable reuse projects.

Potable reuse is becoming an attractive option for incorporating circular economy and the One Water approaches. In potable reuse scenarios, collection system, primary, biological secondary, and tertiary treatment steps are considered as important aspects upstream of advanced water treatment. Improvements and enhancements that could be made in these upstream steps can have a profound impact on the overall safety, reliability, and cost-effectiveness of a potable reuse project.

SpeakerSundaram, Vijay

Presentation time

14:00:00

14:25:00

Session time

13:30:00

15:00:00

TopicFundamental Level, Facility Operations and Maintenance, Municipal Wastewater Treatment Design, Potable Reuse, Water Reuse and Reclamation

Author(s)

Sundaram, Vijay

Author(s)Vijay Sundaram1

Author affiliation(s)AECOM, Sacramento, CA1