Introduction. Spokane River DO TMDL: Proposed Restrictions. Waste Load Allocation: Based on 50µg/l Total P - Seasonal (Mar Oct) for final TMDL

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1 City of Spokane Riverside Park Water Reclamation Facility (RPWRF) Pilot Studies for Reducing Effluent TP for Discharge to the Spokane River in preparation for the NEXT LEVEL OF TREATMENT Larry A. Esvelt PhD PE, Lars Hendron PE, Wastewater Utilities, City of Spokane Mark H. Esvelt PE, Brian Walker, Water & Wastewater Services PNCWA, Bend OR October 25,

2 Introduction Spokane River DO TMDL: Proposed Restrictions Phosphorus (Total Phosphorus = TP) Ammonia Nitrogen (NH3-N) Carbonaceous Biochemical Oxygen Demand (CBOD) Waste Load Allocation: Based on 50µg/l Total P - Seasonal (Mar Oct) for final TMDL 2

3 Next Level of Treatment (NLT) Goal: Choose Best Technology(ies) for RPWRF to meet DO TMDL WLA + Other Water Quality Objectives Seeking 10 to 20 µg/l TP Correlated reduction in CBOD Reduce PCBs, Heavy Metals, PPCPs (to the extent feasible) 3

4 6 Technologies P-Pilot Project 3 Coagulation-Sedimentation Technologies 3 Coagulation-Filtration Technologies Conducting tests with technologies in series, with trains in parallel operation Evaluating P removal, costs, footprint, O&M considerations, etc. 4

5 General Guidelines for Pilot Peer Review Group 3 rd Party Experts for guidance and objectivity Oversight/Advisory Committee Local and Regulatory interests for transparency Public dissemination of data and pilot results Pilot Results will be used to inform Design, Construction and Operation of NLT improvements 5

6 Schedule for P-Pilots 2005 Preliminary Piloting - TMDL Collaboration 2006 Technology Selection and Procurement Process (All Pilot units purchased by City to eliminate vendor influence) 2007 Contracting and Infrastructure 2008 Installation and Startup 2009 Commissioning Initial Testing 2010 Focused Testing diurnal flow variations, transient testing, optimization 2011 Pilot Plant Report (Begin Engineering Report for RPWRF Upgrades) 6

7 Spokane s RPWRF

8 Riverside Park Water Reclamation Facility 44 MGD rated capacity avg. dry weather 130 MGD wet weather peak influent 100 MGD full treatment, limited duration excess to storage for post-storm treatment 1958: Primary Treatment 1977: Advanced Secondary Treatment : Next Level of Treatment (NLT)

9 Next Level of Treatment Address TP WLA to be in TMDL Currently (proposed) Limit = 42 µg/l Working on how to translate into Permit 95% ile concentrations are typically 2.5 to 4 times the Median or 50% ile Design for NLT may still be 10 to 20 µg/l to consistently meet 40 µg/l ±

10 RPWRF P-Pilot Study - Location Treatment Town P-Pilot Buildings P-Pilot Bldgs

11 Schematic Flow Diagram RPWRF P Pilot Program 11

12 Pilot Units Layout RPWRF P Pilot Program

13 P Pilot Buildings Treatment Town 13

14 Preliminary Process Considerations Scale of Pilot Plant Units As large as feasible to reduce the scale-up factor for NLT implementation as much as possible Two chemical precipitation steps in series - required to Provide Optimum Phosphorus Reduction (based on preliminary pilot testing results and review of other sites that are reducing phosphorus to low levels) Reduce chemical use, and resulting sludge production as much as feasible. 14

15 Construction Progress RPWRF P Pilot Program 15

16 Chemical Precipitation Processes Chemical Coagulation, Flocculation, Sedimentation Units 0.5 MGD each Conventional Coagulation, Flocculation, Sedimentation w/ Settling Tubes (2 units) Coagulation, Flocculation, Sedimentation Using Ballast for Settling Enhancement Silica Sand Ballast (Actiflo ) Magnetite Sand Ballast (Comag ) 16

17 S Bldg - Sedimentation Units 17

18 K Bldg - Sand Ballasted Sedimentation System 18

19 C Bldg Magnetite Ballasted Sedimentation System 19

20 Filtration Processes Filtration Units 3 Pairs: Downflow Dual Granular Media (Anthracite and Sand) Filters w/ Conventional Backwash mgd each. Upflow Sand Filters w/ Continuous Backwash 0.3 mgd each. Membrane Filters 0.15 mgd each. Each Filter System will accept feed from 1 or 2 Sedimentation Process units to the two parallel filter units for comparative performance. 20

21 F Bldg Granular Media Filter Units anthracite and sand 21

22 B Bldg Upflow Sand Filter Units 22

23 Z Bldg Membrane Filter Units 23

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27 Expected Permit Limit = mg/l 27

28 Preliminary Results Constituent Winter Average Summer Average PP Inf TP* 2.4 mg/l 0.4 mg/l PP Sed TP* 0.18 mg/l 0.06 mg/l PP Filt TP* 0.05 mg/l 0.03 mg/l RPWRF Winter Operation Activated Sludge Treatment RPWRF Summer Operation Alum coagulant added to activated sludge *PP = Pilot Plant; TP = total phosphorus; *Sed = Coagulation/Flocculation/Sedimentation; *Filt = Coagulation/Flocculation/Filtration

29 Preliminary P-Pilot Observations P removal depends on Coagulant Addition. Alum as coagulant and caustic (NaOH) as alkalinity have worked successfully. (Note: Currently doing runs with FeCl3 for comparison. Preliminarily there is no detectable difference in performance.) High Coagulant Dosages are needed to get TP to low concentrations 100 mg/l± (as Hydrated Alum) in each of 2 final stages (This is compared to approx 75 mg/l dosed in AS). Solids removal step may be limiting. 29

30 Preliminary P-Pilot Observations Analytical testing automated P test apparatus with 0.5 cm cell is not sensitive enough for low P concentrations 10 cm light path flow-through cells appear to give good results for Reactive (Ortho) P (at least to 10± µg/l). Use of Inductively Coupled Plasma Spectrometry (ICP) appears to be promising for TP, especially ICP/MS (at least to 10± µg/l). QA study indicates that data collected is sufficiently accurate to allow proper interpretation of differences between treatment alternatives. 30

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32 Data Analysis Data is observed to be distributed approximately log normally 2-week runs at constant operating parameters with daily flow proportional composite sampling Testing for each day composite samples. Analyze data from each run as a single data body - defining log distribution for comparison with data from other runs. (Thus a single data set consists of 12 daily data points analyzed for log-normal statistic.) 32

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36 RPWRF P-Pilot Study Thank You. For additional information please contact: 36

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39 Spokane RPWRF Technology Selection Protocol Pilot a variety of NLT technologies Identify which best serves City s needs Focus on P. Evaluate: PCBs, metals, etc. This step does not identify a particular Vendor Update the Facility Plan RFP for Design or Alternative Delivery Vendor(s) selected during design Proceed to construction Operate to verify performance

40 Technology Selection Protocol Objectivity & Transparency Prevent bias and undue influence(s) Keep City (RPWRF) operations at arm s length Hire an independent Pilot coordinator Purchase the pilot treatment units* Use contract operators & laboratories Engage recognized treatment experts Involve key Collaboration stakeholders Provide public access to the testing results * installed; with startup, training & technical support