Localized Treatment for DBP s using Spray Aeration and Online Monitoring

Transcription

1 Localized Treatment for DBP s using Spray Aeration and Online Monitoring Tom Williams twilliams@aquametrologysystems.com Tom.Williams@enebio.com

2 Who are we? Worked in DBP s since 2008 AMS is US based company with R&D and Technical Support in Sunnyvale, CA and manufacturing in Lowell, MA Privately held with European and US private investors Founded in 2007 to focus on TTHM Monitoring now also HAA and Trace Metals Monitoring Established presence across the USA and in UK and Spain with multiple units at several clients THM-100 has been extensively tested independently by leading laboratories and water utilities in USA and Europe Enabling the Optimization of THM Control 2

3 Disinfection By-Product Formation DBPs Naturally-Occurring Organic Matter (NOM) e.g. - Humic Acids - Fulvic Acids Chlorine Based Compounds for Microbiological Disinfection e.g. - Chlorine - Hypochlorite - Chlorine Dioxide Disinfection By-Products* e.g. - Trihalomethanes - Haloacetic Acids -Bromate - Chlorite Disinfection By-Products* - Several thousand are known - More than 500 have been toxicologically reviewed - Several classes and compounds are regulated in drinking water: Trihalomethanes Haloacetic Acids 3

4 Typical Surface Water Source Enabling the Optimization of THM Control 4

5 DOC or TOC Detection Enabling the Optimization of THM Control 5

6 Hydrophilic or Hydrophobic? Enabling the Optimization of THM Control 6

7 Typical Humic compound the methanes Enabling the Optimization of THM Control 7

8 Halogens the Halo s in THM s halogen molecule structure model d(x X) / pm (gas phase) d(x X) / pm (solid phase) fluorine F chlorine Cl bromine Br iodine I Enabling the Optimization of THM Control 8

9 Bromine sources Mining areas salt/coal Fire retardants Drugs and Pharmaceuticals DBDMH Cooling towers/pulp and paper mills Dyes Organobromine Biocides water treatment Salt Water Intrusion Enabling the Optimization of THM Control 9

10 Trihalomethanes in Drinking Water chloroform bromodichloromethane dibromochloromethane bromoform 10

11 Stage 1 Disinfection By Product Rule Source: EPA, 40 CFR Parts 9, 141, and 142 National Primary Drinking Water Regulations Stage 2 Disinfectants and Disinfection Byproducts Rule; Final Rule, p

12 Stage 2 Disinfection By Product Rule Source: EPA, 40 CFR Parts 9, 141, and 142 National Primary Drinking Water Regulations: Stage 2 Disinfectants and Disinfection Byproducts Rule; Final Rule, p

13 Standard Method for DBP Analysis Operator collects a water sample Physically delivers it to the lab A skilled technician prepares the sample The sample is analyzed on an expensive piece of lab equipment (GC-MS) Results are reported to the water treatment plant in 3-10 days Operator makes an educated adjustment to the treatment process Water utility puts the report in a binder 13

14 Operating a Plant Without a Monitor Is Like Driving a Car Without a Speedometer Enabling the Optimization of THM Control 14

15 AMS THM-100 Another Option First commercial in-line instrument for TTHM and CHCl 3 monitoring with manual sampling capability Installed at multiple water utilities with excellent correlation to lab results Unattended 24/7 results in 1 hour which can immediately be used to modify the process Self calibrating no need for skilled operator intervention at anytime (in μg/l) range for TTHM and Chloroform 2 (W) x1.3 (D) x 5 (H) 100 lbs 15

16 Organization of THM-100 System W 2.0 (610mm), D (406mm) H 5.0 (1,524mm) Weight 100lbs (45.3kg) Electronics Cabinet Process Cabinet Chemical Reagents and Standards 16

17 THM-100 Principal of Operation Analysis Steps THM-100 Process Flow Draw Finished Water Sample Fill Reservoir (Purge Vessel) Extract THMs Purge Reservoir and Trap THMs Concentrate THMs Desorb Trap and Dissolve THMs into Reagents React THMs with Reagents Initiate the Fujiwara Reaction Measure change in Absorbance Spectrophotometric Detection at 540 nm Determine Concentration of the dominant THM and TTHM Quantitative Determination of dominant THM and TTHM Concentrations Report total THM and Chloroform results Make Results Available on the System and via 4-20 ma and the Ethernet 17

18 Rates of the Colorimetric Reactions Rates of Colorimetric Reactions Chloroform reacts more slowly than brominated THMs to form the Fujiwara reaction The THM Speciation of each water sample is deduced from the kinetics of the Fujiwara reaction Optimized Fujiwara Reaction Kinetics for the Four THMs Absorbance.e Cl3 Br2Cl BrCl2 Br Time / secs 18

19 Data Reliability: Labs vs. Online (Spiked Samples) 5 US-EPA Accredited Labs & 3 THM-100 Monitors (current studying 60 labs nation wide) Sample Water Spiked at TTHM 79.5 ug/l (60% CHCl 3 ) Lab 1 Lab 2 Lab 3 Lab 4 Lab 5 THM THM THM % Error CHBr % Error CHBr % Error CHCl3 % Error CHCl3 19

20 70 THM Measuremnts Online vs Three Analytical Labs CHCl3 Conc Lab [ALS] 60 TTHM Conc Lab [ALS] TTHM Lab [Microbac Harrisburg] TTHM Lab [Benchmark] 50 CHCl3 Conc Online TTHM Conc Online TTHM and % CHCl /14 11/28 12/12 12/26 1/9 1/23 2/6 2/20 20

21 What Influences THM Formation? Time (increase in water age = increase in THMs) Temperature (increase in temperature = increase in THMs) ph Disinfectant dose Natural organic matter (NOM) Seasonal effects high temperature, changes in water quality 21

22 Managing TBP Formation at the WTP Remove precursors at the water treatment plant Enhanced coagulation Optimizing coagulant type (alum, ferric chloride, PACl) and dosage based on source water quality GAC adsorption Engineered Bio filtration Membranes RO filtration Delay introduction of disinfectant Use alternate disinfectants Chlorine dioxide Chloramines Ozone 22

23 Distribution System DBP Management Techniques Reduce water age / chlorine demand Promote system turnover Operational changes Mixing systems Dead end elimination Water quality based flushing program 23

24 What is Happening in the Tank? Instability due to short circuiting (no fresh chlorine in upper layers) Chlorine residuals decay rapidly Buoyant warmer water floats persistently DBPs / Nitrification Biofilm grows in warmer layers Instability due to lack of turnover (no fresh chlorine 24 in upper layers)

25 Tank Mixing Results East Tank June July

26 Localized Removal of THMs in the Distribution System External aeration systems Packed tower or forced draft Tray aerator In tank / reservoir aeration systems Surface aeration Spray aeration Diffused bubble aeration 26 GAC contactors Chlorine booster station required

27 Typical In Tank / Reservoir Aeration Systems Recirculation and Surface Spray System Diffused Bubble Aeration System Surface Mechanical Aerator System THM removal via liquid / gas transfer

28 Case Study - Full Scale Demonstration Ongoing Projects Spray Tank Aeration 28

29 Case Study- Full-Scale Aeration System 29

30 Case Study - Full-Scale Aeration System /15/14 12:00 AM 6/20/14 12:00 AM 6/25/14 12:00 AM 6/30/14 12:00 AM 7/5/14 12:00 AM 7/10/14 12:00 AM 7/15/14 12:00 AM 7/20/14 12:00 AM TTHM (ug/l) Tank Level (ft) Mashantucket Pequot Tribal Nation Water Treatment Simulation Study Results Aeration System Aeration System On TTHM Level During Tank Fill TTHM Level During Tank Drain Tank Level

31 Independence Tank - NKWD 1 million gallon capacity Source = FTTP/TMTP Blend Demand 2 MGD Influences 2 THM compliance sites 3 drain/fill cycles daily 450,000 gallon per day turnover ~20% flows through tank Booster chlorine up and downstream

32 Case Study low mixing energy (velocity contour plot) > 0.1 ft/s 0.1 mgd spray spray pattern (blue) 1.1 mgd fill

33 Case Study Low mixing energy (tracer concentration plot) 100% new water 50/50 blend t = 5 min t =30 min 100% old water t =60 min t =120 min

34 NKWD Lab Results vs. On Line Analyzer TTHM Concentration (ug/l) Lab Total AMS Total /25/2013 8/14/ /3/ /22/2013 1/11/2014 3/2/2014 4/21/2014 6/10/2014 Date

35 City of Phoenix South Mountain Reservoir Enabling the Optimization of THM Control 35

36 Optimizing Energy Use for THM Remediation System installed May 2012 Location is the last point in the network where remediation can occur TTHM levels too close to MCL without remediation ug/l daily swing aeration, pumping, temperature, demand 8 15-HP aerators which can only be turned on or off 8 15-HP aerators, using 784MWH/year ug/l /2/12 9/4/12 9/6/12 9/8/12 9/10/12 9/12/12 9/14/12 9/16/12 9/18/12 9/20/12 % TTHM TTHM %CHCl3 Enabling the Optimization of THM Control 36

37 Castelldefels Water Storage Spain B A A B Near Barcelona 330k gals/tank A - aerated B - control Enabling the Optimization of THM Control 37

38 THM Mitigation by Aeration, RO, & Monitoring TTHM (ug/l) Reservoir filling between midnight and 6am (lower energy costs) Aeration reduces TTHM by ~30% daily Aeration changes THM speciation Extent of aeration and RO reduced on Sept 14 th Reduction in Extent 40 of THM Mitigation Sep TTHM % Bromoform 9 Sep 10 Sep 11 Sep 12 Sep 13 Sep 14 Sep 15 Sep 16 Sep 17 Sep 18 Sep 19 Sep 20 Sep % Bromoform 38

39 Contract Compliance Monitoring - Agbar THM / ug/l THMs at Service Reservoir in NE Spain (#1) CHBr3 CHBrCl2 + CHBr2Cl CHCl Mar 21 Mar 28 Mar 4 Apr 11 Apr 18 Apr 25 Apr 2 May 9 May 16 May Source: Miquel Paraira Faus, Director Water Quality

40 City of Benicia Water Treatment No. CA 12 MGD Seasonally variant local sources Blending and enhanced coagulation Enabling the Optimization of THM Control 40

41 THM SUMMARY Quarterly Average Running Annual Average THM conc. ug/l Jan-08 Feb-08 Mar-08 Apr-08 May-08 Jun-08 Jul-08 Aug-08 Sep-08 Oct-08 Nov-08 Dec-08 Jan-09 Feb-09 Mar-09 Apr-09 May-09 Jun-09 Jul-09 Aug-09 Sep-09 Oct-09 Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 Apr-10 May-10 Jun-10 Jul-10 Aug-10 Sep-10 Oct-10 Nov-10 Dec-10 Jan-11 Feb-11 Mar-11 Apr-11 May-11 Jun-11 Jul-11 Aug-11 Sep-11 Oct-11 Nov-11 Dec-11 Jan-12 Feb-12 Mar-12 Apr-12 May-12 Jun-12 Jul-12 Aug-12 Sep-12 Oct-12

42 DAILY THM-100 DATA Daily Average TTHM, ppb Total THM, ppb /01/12 10/15/12 10/29/12 11/12/12 11/26/12 12/10/12 12/24/12 01/07/13 01/21/13 02/04/13 02/18/13

43 SOURCE WATER CHANGES Blend PSC NBA Avg Daily THM Total THM, ppb

44 Old Bridge Municipal Water Authority - NJ Enabling the Optimization of THM Control 10M gal tank fed from a consecutive source Few homes / low demand Variable THMs 44

45 Source Blend Variability in a Consecutive System System Features, Functions, Benefits Enabling the Optimization of THM Control 45

46 Why monitor THM s in real time? THM100 enables Real-Time Monitoring of THMs in Drinking Water THM s can vary dramatically over a few hours WHO: Engineers designing capital or operational changes need to accurately map the fluctuations in the system to provide best solution Wholesalers and Purchase Water Systems - Contract compliance between consecutive systems. Operators can test automatically at any location and also bring grab samples from around the network. WHY: Capital and operational savings can be in the $millions Operational Benefits: Reduced operating costs with process optimization of THM remediation Performance can be improved with correct blending Save Energy on aeration To identify when Bromo based THM s occur in systems Regulatory Benefits: Enables Compliance Management Archival to Proactive Minimizes Public Health Hazards from exposure to contaminants Minimizes Potential Regulatory Breaches, and Fines based on Violations 46

47 Other Products available HAA monitor currently being tested by Scottish Water Trace Detect Online trace metals monitors arsenic, selenium, iron, manganese, chromium, many more metals Enabling the Optimization of THM Control 47

48 Questions Rex Sistek Aqua Metrology Systems (602) Tom Williams Enabling the Optimization of THM Control 48