Kumar, Pranjali

Pranjali Kumar is a Senior Engineer with Carollo Engineers and serves as their Southeast Reuse Lead. Her work focuses on reclaimed water and potable reuse, from feasibility, planning, and regulatory analysis, to design and implementation. She is registered as a professional engineer in Florida and serves as a Trustee on the WateReuse Florida Board in addition to serving on WEF's and AWWA's Water Reuse Committees.

Titles from this speaker

A (Nearly) Full Public Reuse Regional Utility Evaluates Potable Reuse as an Alternative Water Supply

Abstract

Clay County Utility Authority (CCUA), serving the greater Clay County area in Northeast Florida, is a substantial water and wastewater service provider catering to 55,000 customers. The County is growing rapidly and is expected to double in population in the next 20-25 years. CCUA operates 7 Water Reclamation Facilities, five of which produce public access reclaimed water, and 22 water treatment plants. CCUA is situated in a region with limited groundwater resources. In response to the growing need to allocate water resources efficiently and limit groundwater withdrawals from the Floridan aquifer, the primary source of water supply, CCUA has embarked on a PAR optimization program while concurrently investigating alternative water supply (AWS) solutions such as potable reuse. Currently operating at 70% water reuse (non-potable reuse, known as public access reuse or PAR), CCUA is committed to achieving 100% PAR by 2030, and is evaluating potable reuse as an alternative water supply to expand the water portfolio. CCUA's potable reuse project is called 'Project Quench,' which uses reclaimed water (tertiary treated filtered and disinfected wastewater effluent) as source water for treating to drinking water standards. While there are other water sources in the area, such as surface water from the ocean, the St. Johns River and Black Creek, and stormwater, reclaimed water remains the most reliable from a quality and quantity perspective. Potable reuse takes careful early planning and piloting to demonstrate the feasibility of treatment techniques and multi-barrier treatment. With this goal, CCUA has completed several steps in the long-range planning efforts for potable reuse:

*Source Water Characterization: A comprehensive water quality sampling program was conducted at several of CCUA's interconnected treatment plants producing reclaimed water, which allowed an understanding of the quality and composition of available sources to ascertain their suitability as an AWS. Sampling was conducted for several regulated and unregulated contaminants, such as perfluoroalkyl substances and chemicals of emerging concern and pathogens. Data suggested that the Mid-Clay Water Reclamation Facility's reclaimed water was best suited for potable reuse from two perspectives: (i) proximity to areas of growth/development and the anticipated increase in water demand in the near future, and (ii) quality of reclaimed water due to lack of industrial wastewater contribution in the collection system and superior wastewater treatment. Reclaimed water quality at this facility averaged (n=4) at 2.5 mg/L total organic carbon (TOC), 350 mg/L total dissolved solids (TDS), 6.6 ng/L perfluorooctanoic acid (PFOA), 2.2 ng/L perfluorooctanesulfonic acid (PFOS), and 1.8 mg/L total nitrogen. Figure 1

*Selection of Treatment Train: Several factors were considered in the process of selecting the optimal treatment barriers for potable reuse at CCUA. These factors included the efficiency of treatment in removing pathogens and chemicals, associated treatment residuals handling, operational complexity, ability to permit a potential future facility, and cost considerations. Two primary treatment types were compared: reverse osmosis-based advanced treatment (RBAT) and carbon-based advanced treatment (CBAT). The selected processes to treat reclaimed water to drinking water standards include ozonation, biologically activated carbon (BAC) filtration, ultrafiltration (UF), granular activated carbon GAC) adsorption, UV disinfection, and chlorine disinfection. The table below shows the results of the different factors considered during process selection. Figure 2 Figure 3

*Design/ Construction, Test Plan, and Commissioning: Potable reuse project planning involves the development of a comprehensive roadmap encompassing design, construction, meticulous testing protocols, and commissioning stages for the potable reuse system. A 20 gallons per minute (gpm) demonstration pilot is currently under construction at the Mid-Clay Water Reclamation Facility site. Construction completion, facility startup, and commissioning will occur in the first quarter of 2024. Figure 4 Public Outreach A key component of potable reuse projects is the early engagement of internal and external stakeholders with clear and consistent messaging. During the facility's construction phase, CCUA developed several public engagement products, including a project website, handouts and brochures, a PowerPoint presentation slide deck, infographics for the pilot facility building, school and classroom resources, and a project video. Having a uniform theme for Project Quench and using clear, consistent, and correct messaging set CCUA up for success in communicating project details, its current investigative stage, and its future. Figure 5 The demonstration facility/evaluation of potable reuse is one element of CCUA's One-Water water supply planning approach. This abstract and presentation will encapsulate Project Quench's stages of comprehensive evaluation, outlining CCUA's vision to leverage reclaimed water as a superior AWS while navigating the complexities of water source integration and quality assurance.

Clay County Utility Authority (CCUA) in Florida serves 55,000 customers & operates multiple water reclamation & treatment facilities. With the population expected to double in 25 years & limited groundwater resources, CCUA must maximize water reuse & explore alternative water supplies. They launched Project Quench to pilot potable reuse as a long-term strategy. Key steps include source water characterization, selecting treatment methods, & engaging the public.

SpeakerSteinbrecher, Paul

Presentation time

11:30:00

12:00:00

Session time

10:30:00

12:00:00

SessionAdvancements in Non-RO Treatment for IPR/DPR: Exploring Cutting-Edge Solutions

Session number530

Session locationRoom 235

TopicIntermediate Level, Microconstituents and Contaminants of Emerging Concern (Non-PFAS), Sustainability and Climate Change, Water Reuse and Reclamation

Author(s)

Steinbrecher, Paul, Kumar, Pranjali, Assouline, Jason

Author(s)P. Steinbrecher1, P. Kumar2, J. Assouline3

Author affiliation(s)1Clay County Utility Authority, FL, 2Carollo Engineers, FL, 3Carollo Engineers, CO

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159631

Volume / Issue

Content sourceWEFTEC

Word count16

Redefining FAT in Potable Reuse: The Skinny on CBAT

Abstract

For many years, reverse osmosis (RO)-based advanced treatment (RBAT) using membrane filtration, RO, and UV advanced oxidation process has been an established standard for treating municipal wastewater effluent to drinking water standards for potable reuse. However, most inland water service providers and others with limitations on RO concentrate disposal will require alternative potable reuse approaches. Building upon the success of the full-scale facility in Windhoek, Namibia, nearly half a dozen years ago, the City of Altamonte Springs' pureALTA project piloted the first carbon-based advanced treatment (CBAT) train for direct potable reuse using ozonation, biological activated carbon filtration (O3/BAC), UF, granular activated carbon (GAC) adsorption, and UV disinfection. This award-winning project offered a market-changing innovative solution to inland utilities looking for sustainable approaches to water augmentation. The yearlong pilot demonstrated the use of several process control measures for optimized performance, such as ozone dose control based on influent total organic carbon (TOC) and nitrite concentration, empty bed contact time in the BAC filter for maximum TOC removal, and analysis of simultaneous removal of TOC and per- and polyfluoroalkyl substances (PFAS) in the GAC adsorber. Challenge testing using non-pathogenic surrogate organisms confirmed log removal values for Cryptosporidium, Giardia, and enterovirus at 10.6-log, 10.6-log, and 12.7-log, respectively, far exceeding the site-specific goals of 3.9-log, 4.2-log, and 11.2-log, respectively. This permanent demonstration facility has also been leveraged for public education and has hosted multiple tours for other water purveyors interested in similar solutions, and the presentation will highlight the cascading effect of the City's bold vision. Similar projects are developing across the US: The City of South Jordan in Utah, and inland utility, is currently piloting a similar treatment train for DPR downstream of membrane bioreactors (MBRs) and working with state regulators to pave the path for potable reuse in Utah. Colorado Springs Utilities' PureWater Colorado Mobile Demonstration Project, a traveling DPR demonstration system, meets stringent drinking water regulations and provided valuable data to the Colorado Department of Public Health and Environment in developing DPR rules for the State. Hampton Roads Sanitation District's SWIFT project in Virginia aims at performing managed aquifer recharge for eliminating effluent discharge to the Chesapeake Bay and mitigating saltwater intrusion, and is advancing the design and construction of full-scale CBAT for over 100 mgd of managed aquifer recharge. Clay County Utility Authority (CCUA) in Northeast Florida is exploring CBAT for indirect potable reuse with groundwater injection at Project Quench to meet future water demands in this growing part of the State, and is constructing a permanent demonstration facility. Polk County Utilities' (PCU) One Water Polk project is exploring CBAT for DPR in their northwest region which has limited groundwater supply. This project is testing the need for pre-treatment for enhanced TOC removal within a CBAT train using enhanced coagulation, and their permanent demonstration facility is currently in operation. The knowledge base generated by comparing the technical and implementation experiences of these projects can be used to inform a robust foundation for wide-spread adoption of CBAT. This presentation will offer highlights for each project, compare technical similarities and differences, and discuss lessons learned in CBAT application for potable reuse. Attendees will learn about the alternatives available to RBAT if brine management is not feasible for their service area, giving them the tools needed to evaluate the feasibility of implementing potable reuse schemes for addressing future water supply challenges.

California's success with potable reuse has popularized the term 'Full Advanced Treatment' or 'FAT', but it may undervalue other methods like carbon-based advanced treatment (CBAT). Inclusive terminology is essential. This paper demonstrates CBAT's equivalency using data from several CBAT projects across geographic regions, and suggests the use of 'reverse osmosis-based advanced treatment' (RBAT) outside California.

SpeakerKumar, Pranjali

Presentation time

10:30:00

11:00:00

Session time

10:30:00

12:00:00

SessionAdvancements in Non-RO Treatment for IPR/DPR: Exploring Cutting-Edge Solutions

Session number530

Session locationRoom 235

TopicIntermediate Level, Microconstituents and Contaminants of Emerging Concern (Non-PFAS), Sustainability and Climate Change, Water Reuse and Reclamation

Author(s)