Conclusions from Water Quality Testing at the DPR Project in Big Spring, TX Eva Steinle-Darling, Ph.D., P.E. with Justin Sutherland, PhD. P.E. and Andrew Salveson P.E. (Carollo) Erika Mancha (Texas Water Development Board), and John Burch, John Womack, and Cole Walker (Colorado River Municipal Water District) WateReuse Florida Workshop May 26, 2016

The Motivation for DPR in Texas April 19, 2016 Shown here is the US Drought Monitor map for Texas on October 4, 2011, the peak of the recent and ongoing drought that started in October 2010 (according to the State Climatologist). Almost the entire state is classified as in “exceptional drought.” While this most recent drought has led many people to consider potable reuse, including direct potable, the projects I’m going to talk about today originated long before that, in communities already used to periods of extended drought and looking to plan ahead. Projects spawned by the recent drought are just starting to come into the project pipeline. [[click for animation]] Shown here is the most recent drought map for the state. As you can see, many places are still under drought conditions, but the severity has eased substantially, especially in the eastern part of the state, where rains over the last few months have brought relief. An exception to this general trend is the area of exceptional drought near the Oklahoma border, which is home to one of the three DPR projects I will discuss today. But [[next slide]]

Reservoir Levels as of April 15, 2016 Still Tell a “Tale of Two States” Wichita Falls Big Spring … just because rainfall is starting to approach normal levels in many places, doesn’t mean the effects of the drought are not still being felt across the state. Both aquifers and surface water reservoirs across the state are still playing catch-up. This map shows all the major surface water reservoirs across the state. The colors indicate how full they are, with deep blue indicating nearly full, and red indicating 20% or less full. This map really shows that the effects of the drought are still being felt in the western part of the state. Five reservoirs are officially empty, being recorded as 0% full, and six more are less than 5% full. It is in these areas, which have been prone to previous drought, that the three currently approved DPR projects are located. DPR Project WaterDataForTexas.org

Carollo Team Led In-Depth Water Quality Evaluation of Big Spring DPR Facility Facility Designed by Freese & Nichols 4 1 2 3 5 6 Moss Creek Lake H2O2 Filtered Effluent from Big Spring <50% blend E.V. Spence Pipeline Microfiltration Reverse Osmosis UV To drinking water plants RO concentrate 1 Sample locations For 2013, the Texas Water Development Board devoted 100% of its research funding to a DPR grant aimed at understanding the water quality produced by the RWPF at Big Spring. The ongoing study consists an in-depth water quality study of both the effluent “raw water” from the RWPF, as well as many points within the process. We will be looking at pathogens, and trace chemicals (like pharmaceuticals and personal care products). As part of this water quality we will develop a list of surrogate measures that will help monitor DPR processes like the one at Big Spring to ensure that high-quality water is delivered 100% of the time. We have assembled a team of experts from teams leading the bulk of the DPR research on a national level, including Trussell Technologies, the Southern Nevada Water District, the National Water Research Institute and several others. Study Sponsored by: Research Partners: Trussell Technologies University of Texas Southern Nevada Water Authority Nalco Company Hazen & Sawyer

Water Quality TESTING SHOWS EXCELLENT RESULTS To date, two major water quality sampling events have been conducted under the program, in July 2014 and February 2015. This is in addition to more regular monitoring and reporting required by the TCEQ. Water Quality TESTING SHOWS EXCELLENT RESULTS

Fluorescence Images Tell a Good Story Effluent RO Permeate Moss Creek Lake

ATP Tests Confirm Significant Removal of Microbial Activity The high microbial quality of the finished water can also be seen in terms of the ATP results… Actual numbers: Plant Influent 171.37 MF Feed (post-chloramines) 70.24 MF Filtrate 51.70 RO Permeate 0.17 AOP Product Water 0.15 Deionized Water 2.98 .1 .01

Virus Results Support Conclusion that Product Water is Safe for Drinking How so? Drinking Water Goal = 2.2 x 10-7 MPN/L 2000-liter field-filtered RO permeate samples are non-detect:  < 2.0 x 10-3 MPN/L Minimum log removal (drinking water validated) of downstream UV system = 4-log:  < 2.0 x 10-7 MPN/L in product water

RO Achieves Robust Removal of Trace Organics (Pharmaceuticals etc.) Similar resuls are seen with trace chemicals, such as pharmaceuticals. This data set shows concentrations on a log scale, and each color bar represents the concentration after a certain level of treatment. Red = secondary effluent, ….

AOP Finishes the Job Similar resuls are seen with trace chemicals, such as pharmaceuticals. This data set shows concentrations on a log scale, and each color bar represents the concentration after a certain level of treatment. Red = secondary effluent, ….

DPR Finished Water Improves Blended Water Quality wrt Trace Organics Similar resuls are seen with trace chemicals, such as pharmaceuticals. This data set shows concentrations on a log scale, and each color bar represents the concentration after a certain level of treatment. Red = secondary effluent, ….

The Story is Similar for Nitrosamines…

… and Estrogens…

… and Perfluorinated Chemicals…

… but not for Trihalomethanes (THMs) Here we see what is essentially an expected result: Due to disinfection actions, likely both at the upstream WWTP and due to chloramines fed to control biofouling at the RWPF, we see some THMs, which are conventional disinfection byproducts in the product water. These concentrations are still well below regulatory limits (80ug/L for total THMs). We see none in the conventional raw water because this water has not yet been disinfected.

Formation Potential Tests Illustrate the Advantage of DPR Water While the actual DBPs formed at the RWPF are relatively low, the real advantage of the water produced at RWPF is that it has a very low potential to form DBPs during the conventional water treatment plants downstream. This graph shows a comparison of the formation potential of the conventional surface water from Moss Creek lake to the very low levels (light blue bars) formed with RWPF product water under the same conditions.

Surrogate TESTING PROVIDES ADDITIONAL CONFIDENCE AT EACH PROCESS STEP

Particle Size Distribution Data Demonstrate > 2-log Removal of “Protozoa” by MF Influent ~ 2-log MF Filtrate “Protozoa” = 5-15um sized particles

Trasar(R) Tested as Surrogate for RO Integrity Fluorescent dye fed with anti-scalant (Nalco) Size ~ 600 g/mol Testing completed at Ventura, CA pilot site in cooperation with WRF 4536

Discrepancy between Actual Removals and LRV Credit Drives Studies (RO membranes)

Pilot Work in Ventura, CA WRRF 14-10 / WRF 4536 2:1 pilot test in Ventura, CA CSM RE404-FEN (4”-elements) Concentrate Feed Feed Sample Combined Permeate Sample Stage 1 Permeate Sample

Results with Intact Membranes: Trasar has Much Higher LRV than EC * *Limit of detection based on feed concentration.

Cut O-Ring Results in Bulk Flow Breach Concentrate Permeate Feed Membrane Element Stage 1 Cut O-ring

Membrane Elements were Oxidized Prior to Testing Exposed 2 elements to free chlorine feed prior to test Oxidized membranes NaCl rejection reduced from 99.7% to 72% and 77%, respectively Normalized permeate flow increased 2% & 8% Concentrate Permeate Feed Stage 1 Oxidized Elements

Results with Oxidized Membranes Show Measurable Change in Trasar LRV * * *Limit of detection based on feed concentration.

Fouled Stage 2 Provided Additional “Real World” Test Condition

In Summary: Trasar EC Yes Lower LRV than phage under normal and damaged conditions Yes

In Summary: Trasar EC Yes Lower LRV than phage under normal and damaged conditions Yes Instantaneous Response

In Summary: Trasar EC Yes 3 to 4 1.5 Lower LRV than phage under normal and damaged conditions Yes Instantaneous Response Demonstrated LRV (on CSM RE404-FEN Membranes) 3 to 4 1.5

In Summary: Trasar Outperforms EC! Lower LRV than phage under normal and damaged conditions Yes Instantaneous Response Demonstrated LRV (on CSM RE404-FEN Membranes) 3 to 4 1.5 Maintains useful LRV under some damaged conditions No

Chloramines Serve as Valuable Indicator of UV Performance

Summary of Observations from Big Spring DPR product water quality is (much!) better than the raw water used for blending. Conventional DBPs are a big issue in DPR, too! Better monitoring means (even) more confidence in the treatment processes. She looks pretty normal, doesn’t she?

Eva Steinle-Darling, Ph.D., P.E. esd@carollo.com Thank You Eva Steinle-Darling, Ph.D., P.E. esd@carollo.com