WRF Webcast Optimizing Engineered Biofiltration (#4346)

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1 No part of this presentation may be copied, reproduced, or otherwise utilized without permission. WRF Webcast Optimizing Engineered Biofiltration (#4346)

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3 Focus Area Research Program Objectives: Guidance Biofiltration: Defining Benefits and Developing Utility Guidance For implementation, enhancement, monitoring, and optimization Communication Attributes of biofiltration Enhancement of drinking water treatment effectiveness Water Research Foundation. ALL RIGHTS RESERVED.

13 Optimizing Engineered Biofiltration (#4346) October 7 th, 2014

14 Acknowledgements Coauthors: Carollo Engineers: Kara Scheitlin, P.E., Giridhar Upadhyaya, Ph.D., and Jess C. Brown, Ph.D., P.E. University of Michigan: Lutgarde Raskin, Ph.D. and Tzu-Hsin Chiao University of Glasgow: Ameet Pinto, Ph.D. Project Co-Sponsors: Dallas Water Utilities Tampa Bay Water Leopold-Xylem, Inc. Project Advisory Committee: Hsiao-Wen Chen (PM), Mary Jo Kirisits, Jim Smith, and Yachi Tsao Others Corinne Duckworth, P.E., Carollo Engineers Pam London-Exner, Veolia Water City of Arlington, TX LuminUltra Technologies Ltd Intuitech, Inc.

15 Project Overview A review of the DWU Bachman WTP and Tampa Bay Water Regional Surface Water Treatment Plant Project Conclusions and Misc. Studies Results Biological Filtration Enhancement Improving Hydraulic and Water Treatment Performance Validate Biofilter Peroxide Enhancement Validate Biofilter Nutrient Enhancement Identify potential limitations (and resolutions) for nutrient enhancement

16 This research project included over 9 months of piloting at two water treatment facilities

17 Advanced pilot-scale systems closely modeled fullscale operations

18 Dallas Water Utilities Services over 2.4 million 900 MGD of treated water capacity 699 miles of service area Undergoing process changes at all 3 WTPs Testing performed at the 150 MGD Bachman Water Treatment Plant

19 Chlorine + Ammonia Bachman WTP Current Ozone Lime Polymer Ferric Polymer Ferric BWW Effluent Preozonation Contactor Flocculation Sedimentation Flocculation Sedimentation Filtration BW Disinfection 77 MGD AADF

20 Bachman WTP Design Ozone Ferric Polymer Lime BWW Lime Chlorine Ammonia Effluent Preozonation Flocculation Contactor Sedimentation Filtration BW Disinfection 77 MGD AADF

21 Tampa Bay Water New Port Richey Pinellas Co. Pasco Co. Tampa St Petersburg Hillsborough Co. 2.3 Million Residents Served 230 mgd Average Daily Demand

22 Tampa Bay Water Supplies and Facilities 22

23 Tampa Bay Water s Supplies Wellfields 11 Consolidated WUP Wellfields 4 Separately Permitted Wellfields Water Treatment Plants 9 Groundwater Treatment Plants 1 Surface Water Treatment Plant 1 Seawater Desalination Plant Pump Stations 3 Raw Surface Water Withdrawals 2 Large Finished Water High Service Stations Several Raw and Finished Water Boosters

24 Surface WTP Background 99 MGD firm/120 MGD max Highly variable surface water sources Seasonal predictable variability with rapid, short term changes due to rainfall events TOC, color, turbidity, alkalinity, hardness, bromide, manganese, fluoride Conventional treatment using enhanced coagulation for color removal, ozone for primary disinfection, biological filters, free chlorine/chloramines New(er) plant; green field in 2001, expansion 12/2010

25 Source Water Variability TOC ranges from 4 to 32 mg/l Color ranges from 40 to 300 PCU Alkalinity swings from 40 to 160 mg/l Bromide levels range from 50 to 600 ug/l MIB and geosmin seasonally present as high as 300 ppt

26 1999 Ozone/Biofiltration Pilot Five gpm flow Rapid mix, flocculation, tube settlers, ph adjustment, ozone contactor, three filter columns Spiked with MIB and geosmin Ambient bromide levels (70 ug/l) during testing Demonstrated bromate formation control and T/O removal

27 % REMOVAL TOC Removal by Process Unit % REMOVAL (ACTIFLO) % REMOVAL (ACTIFLO-FILTERS) % REMOVAL (TOTAL)

28 Tampa Bay Water Surface WTP Ferric Polymer Microsand Ammonia ph Adj Lime Ozone Lime BWW Hypo Effluent High Rate Ballasted Sedimentation Intermediate Ozone Contactor Filtration BW Disinfection 99 MGD AADF

Acclimation Hydraulic loading rate Backwashing

29 Typical biofiltration design and operational considerations Media selection (design) Temperature Acclimation Hydraulic loading rate Backwashing strategy Passive variables + variables driven by particle removal

Average Filter Run Volumes (gal/sqft/run) Challenges can be expected when only filtration is considered Decreased filter productivity Underdrain failures

30 Average Filter Run Volumes (gal/sqft/run) Challenges can be expected when only filtration is considered Decreased filter productivity Underdrain failures 14,000 12,000 10,000 8,000 Biofiltration Implemented Nozzles 6,000 4,000 2, Year of Operation Filter Floor Uplift from Above

32 EPS can be beneficial and detrimental within the biofilter Positive Impacts to Bacteria Negative Impacts to Biofilter Biofilm (EPS) Adhesion Protection Biofilm (EPS) Clogging Headloss Granular media Granular media

33 Coag/flocc/sed processes upstream of biofilters typically leads to nutrient limitations which can stress bacteria, often causing excess EPS production

34 Implementation of nutritional ratio reduces biological stress Carbon : Nitrogen : Phosphorus 100 : 10 : 1

35 Maintaining a nutrient balance requires only small concentrations of N & P 1 mg/l DOC Consumed mg/l Ammonia-N x mg/l Orthophosphate P

36 Dallas and Tampa pilot biofilters both exhibited nutrient limitation Dallas Filter Influent Conditions 1.5 mg/l DOC Consumed 0.28 mg/l Ammonia-N x <0.006 mg/l Orthophosphate P X

37 Nutrient limitation was overcome by Background (Influent) Nutrients adding phosphoric acid 1.5 mg/l DOC Consumed Supplemented Nutrients 0.28 mg/l Ammonia-N x mg/l Orthophosphate P x mg/l Orthophosphate P X PO 4 -P dose increased to >0.06 mg/l to ensure substrate limitation

38 In WRF TC 4215, nutrient enhancement decreased headloss and increased filter run time 7 Headloss (ft) % decrease in terminal headloss 15% increase in filter run time Filter Run Time (hr)

39 Headloss (ft) At Dallas and Tampa Bay Water, nutrients provided little benefit to biofilter performance during initial operation Location: Dallas Filter Run Time: 24 hours Loading Rate: 2.5 gpm/ft 2 Control Nutrient Enhanced Date

40 The primary operational difference at Dallas and Tampa Bay was the use of ferric as the coagulant.

41 MineQL modeling suggests phosphate adsorption on ferric hydroxides ph before adjustment Total PO 4 ADS PO 4 Dissolved PO 4 41

42 MineQL modeling suggests phosphate adsorption on ferric hydroxides ph after adjustment Total PO 4 ADS PO 4 Dissolved PO 4 42

43 Headloss (ft) The benefits of ph and nutrient enhancement have been validated for multiple water sources Location: Dallas Loading Rate: 2.5 gpm/ft 2 Phosphate Dose: 0.2 mg/l as P Control Nutrient

44 Microbial enzymes mediate reduction of peroxide. H 2 O 2 enzyme enzyme enzyme enzyme enzyme enzyme Granular media

45 As peroxide is reduced, EPS and other organics are oxidized. H 2 O + O 2 Granular media

46 Average Terminal Headloss Reduction Relative to Control (%) Biofilter hydraulic improvements were realized at low peroxide doses at Dallas 40% 35% 30% 25% 20% 15% 10% 5% 0% Location: Dallas Filter Run Time: 24 hours Loading Rate: 2.5 gpm/ft 2 Peroxide Dose: Varies 0.10 mg/l 0.50 mg/l 1 mg/l 2 mg/l Peroxide Dose

47 Average Decrease in Headloss Relative to Control Higher dose requirements at Tampa Bay suggest plant-by-plant optimization may be necessary 40% 35% 30% 25% 20% 15% 10% 5% Location: Tampa Bay Filter Run Time: 24 Loading Rate: 4.0 gpm/ft 2 Peroxide Dose: Varies 0% 0.5 mg/l 0.75 mg/l 1 mg/l 2 mg/l Peroxide Dose

48 DOC Removal Peroxide supplementation does not appear to impact biological activity 100% 90% 80% Location: Tampa Bay Control Peroxide 70% 60% 50% 40% 30% 20% 10% 0% 0 mg/l 0.5 mg/l 0.75 mg/l 1 mg/l 2 mg/l Note: Error bars represent standard deviation. Peroxide Dose

49 Peroxide inhibits algae growth at Tampa Bay and Dallas pilots Control (algae) Peroxide (no algae) Control (algae) Nutrients (algae) Control (algae) Dallas Tampa Bay

50 Underdrain Delta P (in) Underdrain cap mitigation study provided encouraging results UD Mitigation - Unenhanced UD Mitigation - 10 mg/l Peroxide 10 Max ΔP During High Rate BW Max ΔP During High Rate BW Number of Backwashes

51 Cap EPS (µg EPS/in 2 cap) 100x more EPS observed on surface of clogged cap Clogged Cap (ΔP>10 in) Clean Cap (ΔP<3 in)

52 Headloss (ft) Anthracite versus GAC as biofilter support media Control Headloss Anthracite Headloss Pilot Location: Dallas Loading Rate: 2.55 gpm/ft /03/11 11/04/11 11/05/11

53 Decrease in headloss accrued over a filter run compared to the GAC control filter Enhancement strategies improved hydraulic performance of the anthracite 70% 60% 50% 40% 30% 20% biofilter at Dallas Location: Dallas Filter Run Time: 24 hours Loading Rate: 2.5 gpm/ft 2 10% 0% 100:11:1 C:N:P 100:50:3 C:N:P 100:27:15 C:N:P 100:14:13 C:N:P (no P Dosed) (0.026 mg/l P dosed) (0.26 mg/l P dosed) (0.21 mg/l P dosed) Pre-Enhancement Nutrient Nutrient/pH Nutrient/pH/Peroxide

54 Reduction in Terminal Headloss with Peroxide Addition Relative to Control Hydraulic performance of Tampa Bay s Anthracite biofilter improved with peroxide supplementation 60% 40% 20% Location: Tampa Bay Filter Run Time: 48 hours Loading Rate: 4.0 gpm/ft 2 0% -20% 0 mg/l 0.5 mg/l 1 mg/l 2 mg/l -40% -60% -80% -100% -120% Note: Error bars represent a 75% confidence interval Peroxide Dose

55 Microbial Activity of Anthracite Filter (pg ATP/mL media) Hydrogen Peroxide Dose (mg/l) Biological activity of anthracite filters may be more sensitive to peroxide supplementation 2.0E+6 4 ATP - Start of filter run 1.5E E E E+0 0 2/22/11 6/2/11 9/10/11 12/19/11 3/28/12

56 Effluent water quality from GAC control biofilter was better than anthracite biofilter Location Average DOC Removal* GAC Control Anthracite Dallas 38% 28% Tampa Bay 26% 15% *Filters operated under control conditions (no enhancements)

57 TOC Removal Anthracite biofilters exceed TOC removal goals at Dallas 70% 60% 30 mg/l Ferric Sulfate * 9H 2 O 50% 40% 30% Enhanced Coagulation Rule - 35% TOC Removal 20% 10% 0% GAC Biofiltration TOC Removal Floc/Sed TOC Removal Anthracite

58 Implementation of Engineered Biofiltration Conceptual Integration Schematic for Bachman WTP, Dallas

59 Implementation Considerations Nutrient Enhancement Upstream coagulation/sediment ation process operations Coagulant selection Biofilter feed ph adjustment Peroxide Enhancement Optimize upstream processes Avoid overdosing hydrogen peroxide Evaluate biofilter media selection Design concentration of bulk hydrogen peroxide

60 Conclusions Engineered biofiltration strategies showed hydraulic benefits Effectiveness of strategies impacted by upstream processes ph/coagulant type Carryover GAC may be more robust support media compared to anthracite Optimized biofiltration may yield cost savings and water quality benefits across multiple processes

61 Future Work Evaluate holistic biofilter and full treatment train enhancement strategies Quantify phosphorus concentrations on carryover floc at ambient and adjusted ph values Demonstrate enhancement strategies at the full-scale (TC 4525) Study the long-term impacts of engineered biofiltration on distribution system stability Further evaluate the impacts of ph optimization on biofilter performance, specifically manganese removal (TC 4448)

62 Future Work (Continued) Identify potential deleterious effect of using liquid ammonium sulfate (LAS) as an NH 4 -N source on biofilter hydraulic performance Perform additional biofilter microbial characterization to help define the functionality of the present microbial communities and identify their roles in EPS production and contaminant cycling

63 Thank you for attending No part of this presentation may be copied, reproduced, or otherwise utilized without permission.