Steinle-Darling, Eva

Dr. Eva Steinle-Darling is Director of the Water Reuse Technical Practice at Carollo and is also leading the company’s response to addressing clients’ challenges with per- and polyfluoro alkyl substances, or PFAS. Her areas of technical expertise include membrane processes, advanced oxidation, filtration, disinfection, and other advanced treatment processes for microconstituent removal and management of microbial risks and has been responsible for over $2 million in applied research on those topics

Titles from this speaker

Description: Demonstrating Real-Time Collection System Monitoring for Enhanced Source Control in...

Demonstrating Real-Time Collection System Monitoring for Enhanced Source Control in Potable Reuse

Abstract

WEFTEC, the largest water event of its kind in North America, offers water quality professionals the best in water quality education and training. With almost 200 technical sessions, workshops, mobile sessions, local facility tours and 1,000+ exhibitors, it is the premier water conference! The WEFTEC technical program is selected through a rigorous, peer-review process, ensuring that attendees experience the highest-quality education. WEFTEC speakers are experts and innovators, leading the way in water quality. The following paper was presented at WEFTEC 2020.

SpeakerSteinle-Darling, Eva

Presentation time

09:10:00

09:30:00

Session time

08:30:00

09:30:00

SessionReuse Water Quality: Control the Source

Session number533

TopicMicroconstituents, Water Reuse and Reclamation, Water Supply and Management

Author(s)

A. SalvesonP. CarloE. Steinle-DarlingE. Steinle-Darling

Author(s)A. Salveson1; P. Carlo1; E. Steinle-Darling2; E. Steinle-Darling2;

Author affiliation(s)Carollo Engineers, CA1; Carollo Engineers, TX2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2020

DOI10.2175/193864718825157498

Volume / Issue

Content sourceWEFTEC

Word count13

Ion Exchange Potable Reuse: Organics and Salinity Removal Without RO

Abstract

An innovative treatment train, coined ion exchange-based advanced treatment (XBAT), was developed and validated for potable reuse. XBAT combines suspended ion exchange (SIX) and lime softening, which are integrated by regenerating the spent resin using bicarbonate. XBAT simultaneously removes TOC and salinity without the use of RO and the resulting concentrate disposal challenges. As such, XBAT provides the cost efficiency of non-RO based purification and the salt reduction of RO based purification. Salinity is the result of all dissolved anions and cations in water, which is often characterized by total dissolved solids (TDS). For potable reuse, salinity represents a specific challenge because wastewater effluents are typically more saline than the conventional surface water or groundwater that supplies a given community, and often exceeding drinking water standards. RO-based advanced treatment (RBAT) and carbon-based advanced treatment (CBAT) are the two prevailing advanced treatment approaches for potable reuse. Although RO rejects most dissolved salts, the resulting RO concentrate constitutes a large portion of total feed flow and creates a challenging residual disposal problem. CBAT integrates multiple treatment barriers for chemical and pathogenic contaminants, but none of the unit treatment processes removes measurable amounts of ionic salts. Therefore, there is a pressing need for an alternative treatment approach that overcomes the limitations of RBAT and CBAT by removing salinity without the residual challenge. To provide the efficiency of CBAT while providing the salt removal of RBAT, through years of research, our team developed an innovative treatment concept, namely ion eXchange-Based Advanced Treatment (XBAT), that simultaneously removes TOC and salinity without RO. XBAT consists of (1) suspended ion exchange (SIX) for the removal of negatively charged constituents (TOC, nitrate, sulfate, chloride, bromide, phosphate, etc.), (2) resin regeneration using bicarbonate, and (3) lime softening for cation (i.e., Ca, Mg) and excess bicarbonate removal (figure 1). SIX is a steady-state ion exchange process that keeps a strong base anion (SBA) resin fluidized in the reactor. A significant feature of SIX is its high resin regeneration frequency, which keeps the resin's ion exchange capacity only slightly utilized, thus allowing spent resin to be regenerated by a weaker and less concentrated regenerant (4% NaHCO3 in lieu of 10% NaCl). Bicarbonate regeneration adds alkalinity into SIX effluent, making the treated water more suitable for hardness removal and further TDS reduction through calcium carbonate precipitation. Figure 1 - Conceptual diagram of XBAT (IX with SBA resin and bicarbonate regeneration + lime softening) We have successfully demonstrated XBAT at the bench scale and evaluated its performance for TOC and salinity removal from secondary and tertiary wastewater effluents. Four resin types, two resin doses, three contact times, and their various combinations were tested over up to 50 resin exhaustion and regeneration cycles to assess long-term XBAT performance. Results indicated in figure 2 show an average TOC removal rate of 50% regardless of the effluent type and initial TOC concentrations. Average percent removal rates for sulfate, nitrate, bromide, and chloride were 99%, 90%, 94%, and 74%, respectively. Subsequent lime softening resulted in 92% calcium removal and 96% magnesium removal. Taken together, TDS decreased from an average of 680 mg/L down to 370 mg/L, achieving about 50% salinity reduction. This level of TDS removal would be sufficient to return effluent salinity levels to that of conventional drinking water sources, thus enabling the implementation of potable reuse without concerns about up-cycling conservative ions. A pilot study demonstrating XBAT has recently concluded (January 2024); results will be shared as part of this presentation. Figure 3 shows the XBAT pilot. Figure 2 Bench-scale results of bicarbonate-form IX performance on a tertiary effluent with four different resins Table 1 Bench-scale results of XBAT (SIX + softening) on tertiary effluent Figure 3 - XBAT Pilot - SIX (L) and Pellet Softener (R)

SpeakerPickett, Melanie

Presentation time

14:30:00

15:00:00

Session time

13:30:00

15:00:00

SessionEffective Strategies for Managing Organics in IPR/DPR Systems

Session number216

Session locationRoom 340

TopicIntermediate Level, Water Reuse and Reclamation

Author(s)

Pickett, Melanie, Yu, Rosa, Steinle-Darling, Eva, Hart, Vincent

Author(s)M. Pickett1, R. Yu2, E. Steinle-Darling3, V. Hart4

Author affiliation(s)1Carollo Engineers, Inc.2Carollo Engineers, Inc.3Carollo Engineers, Inc. 4Carollo Engineers, Inc.

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159674

Volume / Issue

Content sourceWEFTEC

Word count11

Putting DPR Rules Into Context: Regulatory Developments Across the United States

Abstract

The United States has a long history of successful water reclamation driven by a combination of effluent diversion and water supply scarcity. Both drivers have more recently resulted in a number of states working to develop regulations for direct potable reuse (DPR). Active regulatory processes include: (1) Texas, where DPR has been implemented in the absence of rules since 2013, and the 2021 state legislature passed a bill requiring its regulators to develop guidelines that will streamline DPR permitting; (2) California, which has just released its proposed DPR rules for public comment; (3) Florida, where the stakeholder-driven Potable Reuse Commission guidance is now helping shape a series of draft DPR regulations published by the FDEP, (4) Colorado, where state regulators are currently holding stakeholder workshops to help draft the language for future DPR rules, and (5) Arizona, where stakeholder-driven guidance and rulemaking recommendations were delivered to state regulators, who are now gearing up to draft regulations of their own. All of these efforts are also ongoing within the little-known context of DPR being allowed and regulated in two other US states: Ohio (since 2015) and North Carolina (since 2014).
Many stakeholders in these states and elsewhere will find themselves asking: What is the basis and rationale behind various parts of my state's approach to DPR? While the authors claim no prescience with regard to regulator intent in drafting their respective DPR rules, all regulatory progress is incremental and builds on prior work. Thus, the basis of much of the current draft rules can be found in various forms of prior guidance or regulations. This presentation will walk through guidance developed by Carollo and others through the progression of stakeholder processes in various US states that have gotten us to this point. We'll start with the 2015 National Water Research Foundation (NWRI) 'Framework for Direct Potable Reuse' and discuss how the major topics in that framework have evolved through various phases of regulatory development. Starting with the overarching public health and regulatory priorities that are consistent across all US-based guidance to-date, we'll define the key components of a sustainable DPR program, and how those have evolved since the 2015 NWRI Framework. We'll answer questions including: How do various jurisdictions define DPR? How have expectations changed around source control? Why are there different microbial log removal value (LRV) targets and what is their basis? What are the requirements around advanced treatment and how can we account for constituents of emerging concern (CECs)? How does monitoring differ in DPR compared to IPR and other reclaimed application? Attendees will leave the presentation understanding the background behind current regulatory trends for DPR and better prepared to discuss the merits of various regulatory approaches as DPR rules are finalized in various states.

Water supply scarcity and the desire to divert effluent have recently resulted in several states working to develop regulations for DPR. Many stakeholders find themselves asking: What is the basis and rationale behind various parts of my state's approach to DPR? This presentation will walk through the progression of stakeholder processes starting with the 2015 'Framework for Direct Potable Reuse' and discuss how major topics have evolved through various phases of regulatory development.

SpeakerSteinle-Darling, Eva

Presentation time

08:30:00

09:00:00

Session time

08:30:00

09:15:00

TopicIntermediate Level, Disinfection and Public Health, Facility Operations and Maintenance, Potable Reuse, Water Reuse and Reclamation

Author(s)

Steinle-Darling, Eva

Author(s)Eva Steinle-Darling1

Author affiliation(s)Carollo Engineers, Inc., TX1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2022

DOI10.2175/193864718825158494

Volume / Issue

Content sourceWEFTEC

Word count12

Description: What Happens in Texas Doesn't Stay in Texas: How a Small-Town Texas DPR Study...

What Happens in Texas Doesn't Stay in Texas: How a Small-Town Texas DPR Study Inspired an International Award-Winning Carbon-Based Direct Potable Reuse Demonstration (in Florida)

Abstract

The City of Dripping Springs is located in Hays County, Texas, twenty-five miles southwest of the State capital, Austin. The Austin metropolitan area is one of the fastest growing metropolitan areas in the nation (U.S. Census Bureau, 2014a). In addition, the U.S. Census Bureau ranked Hays County as the 14th fastest growing county in the U.S with a population increase of twelve percent between 2010 and 2013 (U.S. Census Bureau, 2014b). Like much of Texas over the past several years, the City has experienced drought conditions ranging from moderate to severe (U.S. National Drought Mitigation Center, 2015). Drought conditions, along with an increase in population, have led to strain on the City’s water supplies. Due to this confluence of factors, the City of Dripping Springs, Texas commissioned a feasibility study for direct potable reuse (DPR) in 2014, which was completed in 2015.

This paper discusses the genesis a first-of-its-kind proposal to produce purified drinking water from treated effluent using a process train that comprises ozone (O3), biologically active carbon (BAC), ultrafiltration (UF), granular activated carbon (GAC), and high-dose UV disinfection prior to chlorination, storage and distribution. This carbon-based advanced treatment (CBAT) approach was first established in a feasibility study in Texas, followed by implementation in a permanent 20 gpm demonstration facility in Florida. Intensive monitoring and sampling proved the ability to produce drinking water with this approach that meets all regulatory standards and an equivalent water quality to reverse-osmosis based treatment (RBAT).

SpeakerSteinle-Darling, Eva

Presentation time

13:52:00

14:07:00

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)

Eva Steinle-Darling