The Relevance of Low Molecular Weight Compounds on Monitoring for Direct Potable Reuse

Transcription

1 The Relevance of Low Molecular Weight Compounds on Monitoring for Direct Potable Reuse 20 October 2017 Jeff Neemann Jay DeCarolis Shane Snyder Ian Pepper

2 Low Molecular Weight Compounds (LMWC) What are they? Why are they important? What are the treatment implications? What are the monitoring gaps? An alternative monitoring concept 2

3 Low Molecular Weight Compounds (LMWC) Low boiling point chemicals Organic solvent extractable chemicals Fraction of natural organic matter (NOM) Related to size <900 Daltons Rapidly diffuse across the cell membrane Most drugs are small molecules 3

4 Many Familiar Compounds in Water Industry NDMA, chloroform, 1,4 dioxane, acetone, aldehydes, Some are known, many are unknown Disinfection byproducts (DBPs) Chlorine, chloramines, ozone, AOP, etc. Typically at low/trace concentrations <0.1 mg/l of TOC Typically ppb or ppt 4

5 Why are They Important? They are present and. removal/formation varies 5

6 What Is The DPR Challenge? DPR could contain contaminants that Represent health risks Impact aesthetics (taste/odor) Undesirable consequences (impact residual disinfectants) It is critical to monitor/detect these contaminants Few by real-time Most require off-line analytical analysis Some surrogates/indicators Takes time Is the water safe to deliver? When should I act? 6

7 Monitoring Chemical Contaminants Sources could be traced back to commercial or industrial activities that discharge into WW Concern for small concentrations we can t detect Concern for peak discharges Two categories of to think about Chemicals that are not easy removed by treatment Chemicals that could be at high concentrations Don t forget about DPBs NDMA, chloroform, etc. 7

8 Peak Events Are One Concern Cited in Expert Panel Final Report 8

9 Does This Happen More Than We Expect? Cited in Expert Panel Final Report 9

10 Other LMWC That Are Present At Trace Concentrations Concentrations could be less than determined by monitoring such as online TOC Present at ppb or ppt Strong source water control programs Some might be byproducts or impurities not specifically listed More frequent sampling during startup Characterize a wide range of compounds? 10

11 What Are The Treatment Implications? 11

12 A Lot Of The LMWC Fall Into A Category Of Not High Removal RO is moderately effective for range of LMWC RO cut off 150 to 300 Daltons Removal ranges from 40 to 90% on many Other technologies vary by compounds AOP effective for NDMA, 1,4 dioxane Ozone for some organics How does this change with a peak? Multiple barriers when we can 12

13 Removal Of Compounds By Treatment Technologies Compound RO Ozone GAC AOP Ibuprofen High High Low Moderate Sucralose High Low Moderate Low Carbamazepine High High High Moderate Gemfibrozil High High Moderate Low DEET Moderate Moderate Moderate Low PFOA Moderate Low Low Low PFOS Moderate Low Low Low Sulfamethoxazole High High Moderate High TCPP Moderate Low Moderate Low Atenolol High High Moderate Moderate Iopamidol High Moderate Moderate Moderate Triclocarban High High Moderate High Meprobamate High Moderate Moderate Low Fluoxetine High High Moderate High NDMA Moderate High Moderate High Estrone High High High High 17-α ethynylestradiol High High High High 13

14 What If No RO? Some utilities are considering non-ro DPR treatment trains No brine disposal Other local conditions More frequent monitoring Sensors in the sewershed How to address compounds that are not detected by TOC analyzer 14

15 Disinfection Byproducts Chlorine and chloramines Chloroform tip of iceberg? NDMA Ozone Bromate Aldehydes AOP Consider other treatment steps RO rejection, GAC/BAC adsorption 15

16 What Are The Monitoring Gaps? 16

17 Analytical Methods Usually physiochemical technique GC, HPLC Research Recommendation #4-2: Research is needed to develop more comprehensive methods to identify low molecular weight unknown compounds. Expert Panel DPR Report Need better understanding of the remaining fraction NOM/TOC Potential for biosensor analysis Specific compounds or non-specific 17

18 We Also Need To Think About Other Ways Indicators Individual compound that represents the characteristics of a family Ideally conservative removal But not one size fits all Surrogates Physical or chemical property that correlates with LMWC removal TOC or conductivity rejection of RO membranes Change in UV254 for Ozone 18

19 Is Online TOC The Answer? It is not the Only Answer Online TOC is a great real-time method to see general organics, which includes LMWCs But.. There are LMWCs that are not detected by online TOC, such as PFOS limited reactivity Some concentrations would be within the detection accuracy of a TOC analyzer More challenging to measure before RO TOC plus others UV254 19

20 Commercially Available Online Surrogate Sensors For LMWC Parameter Sensor ph Many Conductivity Many TOC/DOC [TOC] GuardianBlue Event Detection System (HACH Homeland Security Technologies) [TOC/DOC] Spectro::lyser (s::can Messtechnik GmbH) [TOC] Sievers 5310 C Online TOC Analyzer (GE Analytical Instruments) UVA 254 or UVT 254 Real Tech Real UVT (1375 Hopkins Street Whitby ON L1N 2C2 Canada) IQ SensorNet (NiCaVis 705 IQ) (Xylem Analytics) Fluorescence SAFire (WET Labs) Turbidity Many (Source: Progress Report) F-EEM of Colorado river water collected via Central Arizona Project (CAP). 20

21 An Alternative Monitoring Concept 21

22 We Live In A Word Where Over 100 Billion credit card transaction in 2015 (source creditcards.com) Use machine learning and data mining 20+ Emotion Recognition applications Joy, Sadness, Anger, Fear, Surprise, Contempt, and Disgust Used for national security The Day a Computer Writes a Novel Artificial intelligence written short story Passed first round of competition (source Futurism.com) 22

23 We Work In An Industry That Has prevalent data silos How many people do you have to talk to? Thousands of points go unused but are saved Lives in a spreadsheet world Uncontrolled copies Manual updating for current answer Our idea of monitoring is High/High-High alarm Low/Low-Low alarm 23

24 Data Analytics = Value Cost Size Availability Function Cost of Storage Cost of Sensors Computing Power Access Technology will transform how to make better informed operational decisions 24

25 Water Quality Event Detection WE&RF Decision Support Tool Tool Detector Detector Detector Detector Detector WQ Sensors Operational Performance Data Off-line WQ Data Event Data Maintenance Data Focus on wide definition of sensor and data 25

26 So How Might We Detect LMWC In DPR? Decision Support Tool AI Detector Sewer WQ Sensors WRF WQ Sensors DPR WQ Sensors Off-line WQ Data Operational Data Use a collection of data to know when to act 26

27 Final Thoughts 27

28 Final Thoughts A lot of positive aspects of DPR and potable reuse Need to consider occurrence of LMWC Trace concentrations present Potential for peak events Removal with treatment and formation of DBPs Monitoring Online TOC good tool How do we know for other situations? Think of all data sources 28

29 The Relevance of Low Molecular Weight Compounds on Monitoring for Direct Potable Reuse 20 October 2017 Jeff Neemann Jay DeCarolis Shane Snyder Ian Pepper