WRF Webcast. Enhanced Removal of Nutrients and Trace Organic Contaminants in Pilot- Scale Stormwater Treatment Systems.

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1 No part of this presentation may be copied, reproduced, or otherwise utilized without permission. WRF Webcast Enhanced Removal of Nutrients and Trace Organic Contaminants in Pilot- Scale Stormwater Treatment Systems October 24, 2017

2 Enhanced Removal of Nutrients and Trace Organic Contaminants in Pilot- Scale Stormwater Treatment Systems Brief Introduction Presentation Dr. Richard Luthy, Stanford University Q&A Dr. Richard Luthy, Stanford University Dr. Negin Ashoori, Stanford University Dr. Marc Teixido Planes, UC Berkeley Water Research Foundation No Water Environment & Reuse Foundation Project No. Star N4R14 Environmental Protection Agency Grant Agreement No. RD The Water Research Foundation (WRF) received funding from Water Environment & Reuse Foundation (WE&RF) under Project No. Star N4R14. WE&RF Project No. Star N4R14 was part of Grant Agreement No. RD with the U.S. Environmental Protection Agency (EPA). WRF, WE&RF, and EPA assume no responsibility for the content of the research study reported in this publication or for the opinions or statements of fact expressed in the report. The mention of trade names for commercial products does not represent or imply the approval or endorsement of either WRF, EPA, or WE&RF. This report is presented solely for informational purposes.

5 Please Type Your Questions Here! Slides and recording will be available to WRF subscribers WITHIN 24 hours after the webcast!

6 No part of this presentation may be copied, reproduced, or otherwise utilized without permission. Enhanced Removal of Nutrients and Trace Organic Contaminants in Pilot- Scale Stormwater Treatment Systems October 24th, 2017 Project Team: N. Ashoori, M. Teixido, D. Dillard, B. Halaburka, D. Sedlak and R. Luthy

7 WRF final report published (September 2017) Final report can be found at: 2

8 Take-home Messages Woodchip reactors are very effective for nitrate removal (both stormwater and ww) Select types of biochar are effective in removing TrOCs from stormwater Iron-sand filters and Mn-coated sands were ineffective & require more study Woodchip-biochar combinations show promise in treating stormwater & likely also in polishing ww effluents for nitrate & TrOCs

9 Capture, Treat, and Recharge System 3

pyrethroids, fipronil Vehicle-related compounds PAHs, benzothiazoles & alkylphenols

10 Urban Stormwater Smart Urban Water Grids Pathogens E. coli, enterococci Urban-use biocides diuron, triazines, chlorophenoxyacetic acids, pyrethroids, fipronil Vehicle-related compounds PAHs, benzothiazoles & alkylphenols (rubber) benzotriazoles (anti-freeze) Energy Positive Systems Diuron Fipronil Mercaptobenzothiazole Benzotriazole 4

11 Field Site/Testbed: Location Sonoma County Water Agency (SCWA), Sonoma Valley WWTP, Sonoma, CA Aerial view of field site Water collection trailer and storage tank 5

12 Field Site/Testbed: Construction 6

13 Field Site/Testbed: Water Collection 500 gallons were collected every 4 weeks Water was filtered through stainless steel filter (mesh 20 x 20) Water was allowed to settle overnight 7

14 Woodchip Column Setup in Sonoma Woodchips Woodchip Biochar Woodchips Straw Woodchips To Drain Sample Ports x 3 x 3 x 3 x 3 From iron filter From stormwater tank Hypotheses: (1) Addition of woodchips can denitrify stormwater for prolonged periods of time (2) Introduction of geomedia (biochar) will enhance the removal of trace organic and metal contaminants (3) An assimilable C source (e.g., woodchips, straw) can enhance biodegradation of TrOCs 8

Biochar-MnOx Column Setup at SCWA 4 different column configurations: Mixed Layer A Layer B Sand MnOx+biochar (1%, w/w) Hypotheses: (1) Addition of geomedia (biochar and MnOx) will enhance the removal

15 Biochar-MnOx Column Setup at SCWA 4 different column configurations: Mixed Layer A Layer B Sand MnOx+biochar (1%, w/w) Hypotheses: (1) Addition of geomedia (biochar and MnOx) will enhance the removal of stormwater trace organic contaminants and metals. (2) The contaminant removal capacity (via adsorption/oxidation processes) of the geomedia will decrease with time. (3) Different pre-treatments will have an effect on the column performance (hydraulic properties and pollutant removal). Higher nutrient content in the influent may enhance biodegradation of trace organics Water Research Foundation. ALL RIGHTS RESERVED.

16 Test Bed Configuration: Sonoma Field Work Geomedia columns with Mn-oxide and biochar Nitrate test columns with woodchips alone, and with biochar and with straw 10

17 Study Overview Large lab-data set collected on DO, nitrate & TOC in replicate columns Varied flow rates Varied nitrate concentrations Varied temperatures Field conditioning & testing for eight months column acclimation with urban runoff Measured water quality parameters: ph, T, conductivity (EC), dissolved O 2 (DO), Dissolved Organic Carbon (DOC) and major ions (NO 2-, NO 3-, PO 4 3- and SO 4 2- ). Measured hydraulic performance parameters: porosity, hydraulic retention time (HRT), hydraulic conductivity (Ksat) and flow rate. Field challenge tests for four months with trace organics 11

18 Sonoma Nutrient Removal 12

19 Average Water Quality Parameters for Influent Water from Fryer Creek Parameter Value Phosphate 0.17 mg/l ( ) Nitrate 2.74 mg/l ( ) Dissolved organic carbon 4.29 mg/l ( ) Temperature o C ( ) Dissolved oxygen 7.99 mg/l ( ) ph 7.76 ( ) Total dissolved solids 132 mg/l ( ) 13

20 c/c Water Research Foundation. ALL RIGHTS RESERVED. Results for Nitrate Removal Nitrate Woodchips Control Woodchips Woodchips + Straw 1.0 Woodchips + Biochar Mar-16 Apr-16 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17 Influent Nitrate range: mg/l 14

Phosphate Removal Inconsistency The iron filings were able to effectively remove influent phosphate only during the first two months of operation. After 3.

$A large fraction of the previously adsorbed phosphate remobilized after the 4th month.$

21 Phosphate Removal Inconsistency The iron filings were able to effectively remove influent phosphate only during the first two months of operation. After 3.5 months, the phosphate-adsorption capacity of the iron filings was negligible. A large fraction of the previously adsorbed phosphate remobilized after the 4th month. The system failed due to suspended solids, media agglomeration and possibly flow rate. The clogging of this unit might have been avoided with smaller flow rates, installing a pretreatment system before this unit to reduce TSS load, and proper maintenance (e.g., scrapping off the top layer every one or two months of operation). 15

22 c/c Water Research Foundation. ALL RIGHTS RESERVED. Results for DOC in Field Columns Dissolved organic carbon 20.0 Woodchips Control 15.0 Woodchips Woodchips + Straw 10.0 Woodchips + Biochar Mar-16 Apr-16 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 *Range of values: Influent ( mg/l) Woodchips ( mg/l) Woodchips + Biochar ( mg/l) Woodchips control ( mg/l) Woodchips + Straw ( mg/l) 16

25 Sonoma Challenge Tests 19

26 Schematic Overview of the Field Experimental Setup 20

27 Contaminants for the Challenge Test Contaminant Benzotriazole Diuron 2,4-Dichlorophenoxy-acetic acid (2,4-D) Bisphenol A Tris (2-chloroethyl) phosphate (TCEP) Fipronil Atrazine Origin / Use Anti-corrosive (coolant, brake fluid) Urban use herbicide Urban use herbicide Plastics, epoxy resins Flame retardant Pesticide/insecticide Urban use herbicide 21

28 Results of Woodchip/Biochar Test for Trace Organic Contaminants After four months (300PV) of challenge test with 50ppb of each contaminant injected into synthetic stormwater each week Note: 12% by volume (33% by weight) biochar gives 100% removal 22

29 Results of Biochar/Manganese Oxide Test for Trace Organic Contaminants 1% biochar (by weight) and manganese oxide columns effectively removed over 80% of TrOCs, but manganese oxide by itself did not. Breakthrough of all TrOCs was achieved after 200 PV with sand alone. After 200 PV, the breakthrough (i.e., contaminant removal <90%) order was 2,4-D, TCEP, fipronil, atrazine and BPA, while diuron and benzotriazole showed no breakthrough. The greater DO consumption observed in biochar and manganese oxide containing columns highlights the importance of biodegradation as a removal mechanism due to greater microbial activity. 23

30 Results of Biochar/Manganese Oxide Test for Trace Organic Contaminants After 200 PV N without pretreatment W with pretreatment 24

31 Experimental Lab Setup for N-kinetic Studies 3 columns, 3 flow rates Varied NO3- concentration (2, 5, 11 mg/l) Varied temperature (4, 15, 21, 30 C) Sample column profiles (oxygen, TOC, nitrate) 25

36 Sonoma WWTP Holding Basins R1: 138,000 m 3 R2: 324,000 m 3 R3: 189,000 m 3 R4: 231,000 m 3 30

37 Percent of days treatment target acheived 2017 Water Research Foundation. ALL RIGHTS RESERVED. Size Requirements to Meet Upcoming Nitrogen Treatment Targets Sonoma would need a reactor 100,000 m 3 Size of holding basins: R1: 138,000 m mg-n/l target 4 mg-n/l target 2 mg-n/l target Reactor Size (m 3 ) # 10 4 R2: 324,000 m 3 R3: 189,000 m 3 R4: 231,000 m 3 31

38 Nitrate Removed (Kg-N yr -1 ) 2017 Water Research Foundation. ALL RIGHTS RESERVED. Cost Effectiveness of WBRs 5 # 10 4 $2.12/kg-N $5.58/kg-N Reactor Size (m 3 ) # 10 4 Assumptions Woodchips acquisition $26.50/m 3 (Schipper, 2010) Woodchips lasts 10 yrs.(robertson et al., 2008) (Maybe some sources of wood chips are essentially free) 32

39 Nitrate (mg-n L -1 ) 2017 Water Research Foundation. ALL RIGHTS RESERVED Predicted N Concentrations Using Sonoma Plant Data Effluent N with 20k m 3 reactor Effluent N with 60k m 3 reactor Effluent N with 100k m 3 reactor Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 33

40 Summary New knowledge of data sets and specific recommendations for optimizing material selection and operations for stormwater treatment Woodchips in passive infiltration systems with local, low-energy and low-cost carbonaceous adsorbents (e.g., biochar) is a promising technology to remove nitrate and trace organics in the studied urban area. The results of the woodchip bioreactor indicated that under field conditions woodchips could continually remove nitrate from the system. Even at lower concentrations of biochar at 1% by weight, the study columns were effective in removing the trace organic contaminants, whereas the manganese oxide lost reactivity after the aging period Laboratory experiments show woodchip reactors could be modeled with zeroorder kinetics and predict performance with variable flow, N and temp. 34

41 Future Work - LA Biochar Treatment with Modified Dry Well (Assess treatment and infiltration) - Pilot study at Geyserville, CA to test effluent polishing for recharge - Optimization of nitrogen trading as a innovative water management strategy 35

42 Thank you 36

44 No part of this presentation may be copied, reproduced, or otherwise utilized without permission. Comments or questions, please contact: For more information visit:

Enhanced Removal of Nutrients and Trace Organic Contaminants in Pilot-Scale Stormwater Treatment Systems. Project #4567

Enhanced Removal of Nutrients and Trace Organic Contaminants in Pilot-Scale Stormwater Treatment Systems Project #4567 Enhanced Removal of Nutrients and Trace Organic Contaminants in Pilot-Scale Stormwater