Evaluation of Powdered Activated Carbon Feed System For Taste and Odor Removal at City of Camden WTP. Jane Gan

Transcription

1 Evaluation of Powdered Activated Carbon Feed System For Taste and Odor Removal at City of Camden WTP Jane Gan

2 Outline of the Presentation 2 An Overview of Algae Related T&O Factors affecting algae growth and proliferation Taste & odor control goal setting Algae Source Management Techniques Treatment technologies for algae related T&O control Performance data Case Studies

3 Overview of Algae Related Taste & Odor 3 Taste & odor can be caused by a wide variety of types and species of algae: Chlorophyta (Green algae), e.g. Pandorina, Volvox Cyanophyta (Blue-Green Algae), e.g. Microcystis, Anabaena Chrysophyta (Yellow-Green Algae), e.g. Dinobryon, Synura Pyrrhophyta (Dinoflagellates), e.g. Ceratium, Peridinium Cryptophyta (Cryptomonads), e.g. Cryptomonas Geosmin and 2-methylisoborneol (MIB) are by far the most well known T&O causing algae metabolites, but by no means the only ones

4 The proliferation of algae in Ontario's Lakes Blue-green algae Green algae Data from Winter, J. (Ontario MOE)

5 Gaffney BPW Spartanburg Water Anderson Regional JWS Clinton WTP Camden WTP Lugoff Elgin WA Greenwood CPW Newberry WTP North Augusta WTP Charleston Water System Occurrence of T & O in SC Beaufort Jasper WSA

6 How do we measure Taste & Odor? 6 Humans have varying sensitivity to tastes and odors in drinking water With so many causes of T&O, a one size fits all approach to measurement is not possible Three main methods are used: 1. Measurement of specific compounds, e.g. MIB or geosmin 2. Threshold Odor Number (TON - Standard Methods) A fixed panel measures the intensity of odor (regardless of type) 3. Flavour Profile Analysis (FPA) A fixed panel measures both type and intensity of flavour

7 Water Source Ammonia mg-n/l Total Phosphorus 0.05 mg-p/l Camden WTP Intake Wateree Dam & Hydro Station Page 7

8 Concentrations of T&O compounds at Camden Intake 19.3 MIB Geosmin

9 So how do we deal with algae related T&O? 9 Management of Algae Growth at the Source Stop or suppress algae growing in the first place Kill algae at the source Management of Algae T&O at the Water Treatment Plant Remove live algae cells through treatment Kill live algae cells through treatment Directly treat T&O causing compounds after release

10 Management of Algae Growth at the Source 10 Several techniques have been considered: Select an alternative intake location Reduce nutrient input from point and non-point sources Precipitate nutrients in-lake using alum or lime Dredge sediment De-stratify water with artificial circulation Aerate the Hypolimnion Use algaecides (e.g. copper sulphate) as a growth inhibitor Bio-manipulate at the source Care is needed, as unintended results can occur, e.g.: Other environmental impacts (e.g. toxicity due to algaecide use) Proliferation of other species Enhanced release of intracellular compounds

11 Water Quality Sampling Plan with Duke Energy Sampling locations Wateree full pond Camden intake Lugoff intake Taste and Odor Occurrence at Camden WTP Page 11 Sampling schedule Low-level (baseline) High-level MIB/geosmin Sampling parameters In-situ Temperature Dissolved oxygen ph Conductivity Chlorophyll a fluorescence Blue-green fluorescence Turbidity Nutrient Total/Ortho phosphate Ammonia, nitrate, nitrite, and total Kjeldahl nitrogen Additional Analyses Algae Count MIB/Geosmin

12 mi above Camden Intake 4.3 mi above Camden Intake Camden Intake LEWA Intake LEWA & Camden Upper Intake ( ft) May 28, 2013 Elevation, ft Camden Lower Intake ( ft) Water Temperature, C

13 mi above Camden Intake 4.3 mi above Camden Intake Camden Intake LEWA Intake LEWA & Camden Upper Intake ( ft) September 10, 2015 Elevation, ft Camden Lower Intake ( ft) Water Temperature, C

14 mi above Camden Intake 4.3 mi above Camden Intake Camden Intake LEWA Intake LEWA & Camden Upper Intake ( ft) May 28, 2013 Elevation, ft Camden Lower Intake ( ft) Dissolved Oxygen, mg/l

15 September 10, mi above Camden Intake 4.3 mi above Camden Intake Camden Intake LEWA Intake LEWA & Camden Upper Intake ( ft) Elevation, ft Camden Lower Intake ( ft) Dissolved Oxygen, mg/l

16 May 28, 2013 Elevation, ft LEWA & Camden Upper Intake ( ft) 11 mi above Camden Intake 4.3 mi above Camden Intake Camden Intake LEWA Intake Camden Lower Intake ( ft) Fluorometry-estimated Chlorophyll a, µg/l

17 September 10, 2015 Elevation, ft LEWA & Camden Upper Intake ( ft) 11 mi above Camden Intake 4.3 mi above Camden Intake Camden Intake LEWA Intake Camden Lower Intake ( ft) Fluorometry-estimated Chlorophyll a, µg/l

18 Wateree locations 5000 Green Algae Diatoms Blue-green algae Others Density (units/ml) CAMDEN LEWA Location Total Algal Density (units / ml) Sample Date: September 10, 2015

19 Treatment Techniques 19 Removal of Live Algae Removal or Destruction of Extracellular T&O Compounds Pre-Treatment Techniques Oxidative Techniques Coag./Flocculation/Sedimentation Chlorine Coag./Flocculation/Ballasted Flocculation Potassium Permanganate Coag./Flocculation/DAF Advanced Oxidation Ozonation Filtration Processes Sorptive Techniques Granular Media Filtration Powdered Activated Carbon (PAC) Low Pressure Membrane Filtration Granular Activated Carbon (GAC) Cartridge and Bag Filters Biologically Active Filtration Strainers Reverse Osmosis or Nanofiltration

20 Treatment Process & Challenge KMnO 4 & PAC Alum, Lime, Polymer Cl 2 Cl 2 NH 3, PO 4, F -, Lime Source Water Pump Station Coag/Floc Sedimentation Filtration Cl 2 Contactor Clearwell Distribution Challenge - Seasonal spikes of Mn in source water - Prolonged periods of taste and odor problem in 2012 Treatment process - Pre oxidation with potassium permanganate - Chlorine on top of the filters - Powder activated carbon at the raw water pump station Page 20

21 Treatment Process & Challenge KMNO 4 & PAC Alum, Lime, Polymer Cl 2 Cl 2 NH 3, PO 4, F -, Lime Source Water Pump Station Coag/Floc Sedimentation Filtration Cl 2 Contactor Clearwell Distribution Process - KMnO4 and PAC have a neutralizing impact on each other Operation - Batch slurry system for potassium permanganate as well as carbon Page 21

22 Treatment Process & Challenge KMNO 4 & PAC Alum, Lime, Polymer Cl 2 Cl 2 NH 3, PO 4, F -, Lime Source Water Pump Station Coag/Floc Sedimentation Filtration Cl 2 Contactor Clearwell Distribution Optimization of T&O removal MIB and geosmin occurrence PAC type PAC dose Contact time prior to coagulation Actions Source water monitoring PAC process evaluation Alternative equipment selection Site layout Performance Most effective without interference from oxidant Alternative PAC feed system Capacity PAC feed system Page 22

23 Powdered Activated Carbon Process Evaluation 3-Step Jar Test Select carbon type Generate dose removal curve Pre coagulation contact time Page 23

24 Powdered Activated Carbon Process Evaluation 3-Step Jar Test Select carbon type Generate dose removal curve Pre coagulation contact time Water Characteristics Date 3/24/2015 Raw water ph 7.04 Raw water temperature 15.2 C Raw water TOC 4.54 mg/l Turbidity 10.2 NTU Alkalinity 30 mg/l % Removal 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% Set #1 Carbon Type : Best Performance Aqua Nuchar 68% 62% 60% 54% 44% 40% 48% 47% 38% 27% Jar Test Conditions Results Alum dose 49 mg/l (wet dose) Rapid Mix 250 rpm 76 sec Flocculation #1 29 rpm 13 min Flocculation #2 15 rpm 13 min Flocculation #3 12 rpm 17 min Setting 0 rpm 9 min 25 mg/l of Blank (regular coagulation) Price MIB Geosmin TOC $/lb ng/l ng/l mg/l HydroDarco Ex NA BF NA % HydroDarco Ex 20 BF Aqua Nuchar Water Carb Water Carb 800 Aqua Nuchar Water Carb MIB Removal Geosmin Removal Water Carb Page 24

25 Powdered Activated Carbon Process Evaluation 3-Step Jar Test Select carbon type Generate dose removal curve Pre coagulation contact time Set #2 MIB & Geosmin Dose Removal Curve by Aqua Nuchar % Removal 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Initial MIB 62 ng/l, Geosmin 69 ng/l. regular coagulation Geosmin Removal MIB Removal Aqua Nuchar Dose (mg/l) Page 25 What does it mean?? MIB is more difficult to remove. MIB & Geosmin removal is not affected by their initial concentration. Initial MIB in Source Water (ng/l) Target MIB in Finished Water (ng/l) Target % MIB Removal Scenario 1 Required PAC dose without contact time (mg/l) % % % % % 53

26 Powdered Activated Carbon Process Evaluation 3-Step Jar Test Select carbon type Generate dose removal curve Pre coagulation contact time Pre Coagulation Contact Time (minute) Flow Rate (MGD) 24 inch pipe (ft) Pump station to rapid mix Property Page line 26 to rapid mix

27 Powdered Activated Carbon Process Evaluation 3-Step Jar Test Select carbon type Generate dose removal curve Pre coagulation contact time 30 Set #3 Pre Coagulation Contact Time Initial MIB 46 ng/l 14 Set #3 Pre Coagulation Contact Time Initial Geosmin: 35 ng/l ppm 35 ppm ppm 35 ppm MIB Concentration (ng/l) Geosmin Concentration (ng/l) Pre Coagulation Contact Time (Minutes) Pre Coagulation Contact Time (Minutes) Page 27

28 Powdered Activated Carbon Process Evaluation 3-Step Jar Test Select carbon type Generate dose removal curve Pre coagulation contact time 30 Set #3 Pre Coagulation Contact Time Initial MIB 46 ng/l 14 Set #3 Pre Coagulation Contact Time Initial Geosmin: 35 ng/l ppm 35 ppm ppm 35 ppm MIB Concentration (ng/l) Geosmin Concentration (ng/l) Pre Coagulation Contact Time (Minutes) Pre Coagulation Contact Time (Minutes) Page 28

29 Powdered Activated Carbon Process Evaluation 3-Step Jar Test Select carbon type Generate dose removal curve Pre coagulation contact time Selected Powdered Activated Carbon: AquaNuchar Initial MIB in Source Water (ng/l) Target MIB in Finished Water (ng/l) Target % MIB Removal Scenario 1 Scenario 2 Required PAC dose without contact time (mg/l) Required PAC dose with ~30 min contact time (mg/l) % % % % % % % % % Page 29

30 Powdered Activated Carbon Feed Equipment Selection Batch Slurry System SuperSack Silo Concrete Slurry Tank Delivery 50-lb bag 500 to 900-lb sack Tanker truck (40,000 lb) Unit Price (AquaNuchar) Examples in SC Tank truck (40,000 lb) dry or slurry $ 1.05/lb $ 1.05/lb $ 1.00/lb $ 1.20/lb Camden WTP Spartanburg R.B. Simms WTP Greenwood W.R. Wise WTP Rock Hill WTP Columbia Canal WTP Page 30

31 Powdered Activated Carbon Feed System Layout Raw Water Pump Station Vs. Treatment Plant Site Pump House Control Building PAC, KMnO 4 Page 31

32 Powdered Activated Carbon Feed System Layout Raw Water Pump Station Vs. Treatment Plant Site Page 32

33 Powdered Activated Carbon Feed System Layout Raw Water Pump Station Vs. Treatment Plant Site Contact chamber Vs. No contact chamber Selected Powdered Activated Carbon: AquaNuchar Initial MIB in Source Water (ng/l) Target MIB in Finished Water (ng/l) Target % MIB Removal Scenario 1 Scenario 2 Required PAC dose without contact time (mg/l) Required PAC dose with ~30 min contact time (mg/l) % % % % % % % % % Page 33

34 Powdered Activated Carbon Feed System Layout Page 34 (AWWA WR Report: Optimization of Powdered Activated Carbon Application for Geosmin and MIB Removal

35 Powdered Activated Carbon Feed System Layout Design Criteria for Evaluation: 15 occurrences per year Page 35 (AWWA WR Report: Optimization of Powdered Activated Carbon Application for Geosmin and MIB Removal

36 Powdered Activated Carbon Feed System Layout Raw Water Pump Station Vs. Treatment Plant Site Contact chamber Vs. No contact chamber Assumptions Duration of T&O Spikes: 15 days per year Plant flow rate during T&O spikes: 2.5 MGD Unit carbon cost if plant uses super sack system: $1.05/lb Initial MIB in Source Water (ng/l) Target MIB in Finished Water (ng/l) Annual Carbon Cost to Treat T&O Spikes Target % MIB Removal Scenario 1 Scenario 2 Saving in PAC Required PAC Required PAC Cost by Annual PAC Annual PAC dose without dose with ~30 building a ~ 30 Cost for T&O Cost for T&O contact time min contact min contact Spikes Spikes (mg/l) time (mg/l) chamber % 27 $ 8, $ 5,911 $ 2, % 40 $ 13, $ 8,866 $ 4, % 53 $ 17, $ 11,494 $ 5, % 64 $ 21, $ 14,121 $ 6, % 74 $ 24, $ 16,091 $ 8, % 83 $ 27, $ 18,061 $ 9, % 90 $ 29, $ 19,703 $ 9,852 Page 36

37 Powdered Activated Carbon Feed System Layout Raw Water Pump Station Vs. Treatment Plant Site Contact chamber Vs. No contact chamber Contact Chamber Dimensions (Size similar to third stage flocculation basins at Camden WTP) Initial MIB in Source Water (ng/l) Saving in PAC Cost by building a ~ 30 min contact chamber 20 $ 2, $ 4, $ 5, $ 6, $ 8, $ 9, $ 9,852 Page 37 Stage Length Width Depth Volume G (ft) (ft) (ft) (ft 3 ) (s -1 ) Contact Time Length of 24 inch pipe (ft) Pre Coagulation Contact Time (minute) Flow Rate (MGD) Pump station to rapid mix Property line to rapid mix Contact Chamber Total Contact Time in WTP Contact Chamber Cost EQUIPMENT DESIGN NOTES QTY Units Mixer Mixer Concrete Vertical Turbine Flocculators VFD and Control Panel Concrete Base (On Grade) EQUIPMENT PRICE (UNIT) EQUIPMENT PRICE (TOTAL) CONST. PRICE (EQ *.50) PRICE 2 EA $ 21,000 $ 42,000 $ 21,000 $ 63,000 2 EA $ 10,000 $ 20,000 $ 10,000 $ 30, CY $ 350 $ 3,746 $ 1,873 $ 5,619 Concrete Concrete (Walls) 70.5 CY $ 500 $ 35,259 $ 17,630 $ 52,889 Total: 151,500

38 Powdered Activated Carbon System Design Parameters Carbon type: AquaNuchar Alternative feed system: Supersack system with 900-lb sack Alternative feed system capacity Place alternative PAC system at WTP Extend PAC injection point to the property line Keep KMnO 4 raw water pump station Plant Raw Water Flow (MGD) Powdered Activated Carbon Dry Feed Rate - Pounds per Hour Powdered Activated Carbon, mg/l Page 38

39 Estimated Construction Costs for Recommended System $416,000 Item Unit Cost Site Work $25,000 Shed $35,000 Equipment $120,000 Piping/Valves $10,000 Electrical $30,000 SCADA $10,000 Installation $90,000 Contingency (30%) $96,000 Total $416,000

40 Thank you. We re listening. Page 40