Dipankar Sen, PhD, PE Santa Clara Valley Water District Professor, Virginia Tech Civil & Env Engr

Transcription

1 Dipankar Sen, PhD, PE Santa Clara Valley Water District Professor, Virginia Tech Civil & Env Engr

2 Outline Changes in wastewater in our industry How it affects the wastewater treatment plant Advanced Wastewater Treatment Configurations and their Operation Recycled water production Configurations Managing Risk how will operations change? Ways to plan for the future Climate change, drought cycle, wet weather

3 Upgrade for Nitrogen Removal Nitrogen removal is typically required for discharge to sensitive Bays Chesapeake Bay Ocean discharges and Estuaries have not required this In biological systems, typical pathway is: Nitrification Denitrification Alternate pathways Nitritation, Annamox mediated denitrification

4 What do you have to do to Nitrify at your plant? MCRT MLSS Temperature Oxygen requirement Alkalinity requirement

5 What do you have to do to Denitrify? Organic Carbon requirement Create anoxic condition Amount of biomass Supplemental C?

6 Upgrade for Nitrogen Removal Santa Rosa Source: Google Maps

7 Upgrade for N Removal - Redlands MBR Slide: Courtesy of City of Redlands; Dave Commons; Membrane GE Zenon 7 Activated Sludge Tank Membrane Tank

8 Slide: Redlands MBR Plant Slide: Courtesy Redlands Dave Commons; Membrane GE Zenon GE Zenon Membranes 8

9 Phosphorus Removal Chemical P Removal Biological Excess P Removal

10 Westminster WWTP, MD Anoxic Anaerobic Source: Google Maps

11 IViewOps Screen, Westminster Ref: WEFTEC 2013, 2016

12 Four Tanks, two different types of diffusers serviced by one or two blower systems

13 View of Tank with Parkson Panel Diffusers

14 Setup at a Plant (adjacent to SCADA computer)

15 Westminster secondary effluent Plant was able to remove P through BEPR alone when effluent permit was 1 mg/l

16 Tertiary Effluent BNR, to be upgraded to ENR (4 mg/l TN, 0.3 TP)

17 Wet Weather Operations Management Even if you have upgraded your plant for recycled water production to adapt for climate change, you have to manage for wet weather operations Santa Rosa, CA Wants to avoid discharge to stream because it requires operating to a more stringent TP permit Westminster, MD Wants to be able to sustain nutrient removal, septage and sludge processing operations during wet weather Plant has flows from areas served with combined sewers

18 Provide intelligence to anticipate, plan and adapt for wet weather operations

19 Upgrade for N Removal Impact of Solids Handling Can your solids dewatering operations affect effluent ammonium-n and nitrate-n?

20 42 mgd AADF 54 mgd MMDF 75 mgd PWDF 128 mgd PDF 185 mgd PIF UOSA Millard H. Robbins, Jr. Water Resource Recovery Facility

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22 Centrate PE Flow, MGD PE NH4N, mg/l SE NO3N, mg/l Centrate, gpm /5/2012 4/6/2012 4/7/2012 4/8/2012 4/9/2012 4/10/2012 4/11/2012 4/12/ PE Flow, MGD SE NO3N, mg/l PE NH4N mg/l Centrate, gpm /12/2013 2/13/2013 2/14/2013 2/15/2013 2/16/2013 2/17/2013 2/18/2013 2/19/2013 Nitrate-N Probe Average Error Probe = 10.2; Model =15.1 ; Lab Sec Eff 15.9 mg/l. Measured values Simulated trend Fluctuation Error - NO3N probe readings tend to fluctuate more widely than lab readings Centrate Recycle No Centrate Recycle Flow weighted average = 15.1 mg/l Centrate recycle causes values to increase Centrate Recycle Centrate Recycle No Centrate Recycle Note how timing of peaks & valleys of simulation match Data from probe. Based on this, simulator used for optimization Simulation matches the roller coaster effect on effluent NO3N. Modelling identified the causes of the roller Figure 6. Fifteen minute Secondary Effluent Nitrate-N, Actual and Simulated for Calibration Periods in Table 2 coaster effects. Simulations can determine if probes need calibration; after calibration can test ways to improve

23 IViewOps Application at UOSA

24 Plant Simulation Scenarios, Views, Sub Views in IViewOps3 CSS CDS ESS Winter Opt Views Main HW ET WT SC SH

25 Are there other effects of digestion and dewatering operation on recycled water? Dewatering Polymer Coagulant Refra ctory organic nitrogen Anaerobic digestion Thermal hydrolysis

26 What helps generate better water quality for recycled water production? Higher MCRT? Nitrification? Denitrification? Type of coagulant? Alum, ferric PPCPs? Consistency in TSS? For Agricultural reuse? Groundwater recharge? RO operation? Carbon filter operation?