Reducing Spokane Riverside Park Water Reclamation Facility ... PNCWA...• B-units (Centra-Flo (by Blue Water Technologies) - upflow-continuous backwash sand filters) –Good consistent

Reducing Spokane Riverside Park Water Reclamation Facility (RPWRF) Effluent TP for Discharge to the Spokane River

Larry A. Esvelt PhD PE BCEE, Esvelt Environmental EngineeringMark H. Esvelt PE, Esvelt Environmental Engineering

Brian Walker, Water & Wastewater Systems

1

Brian Walker, Water & Wastewater SystemsLars Hendron PE, Wastewater Utilities, City of Spokane

Water Environment FederationPacific Northwest Clean Water Association

2009 Annual Conference, Boise, IdahoSeptember 15, 2009

Spokane’s WWTP in 1958

Spokane’s RPWRF in 2009



“Treatment Town”P-Pilot Buildings

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• 2014: Next Level of Treatment (NLT)

Next Level of Treatment

• Address TP WLA to be in TMDL• Previously (proposed) TMDL - 8 – 10 µg/L

– No definition of how these WLA would be translated into Permit limits

• Currently (proposed) WLA = 42 µg/L• Currently (proposed) WLA = 42 µg/L– Still no definition on translation 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

Spokane RPWRF Pilot Studies 08-10

Underlying Principles• Open and Transparent Process & Procedures• Consider Unique Needs to Guide Pilot Process Selection –

Size, Site Limitations, Other Constituents (HM, PCBs, etc.)

8

• Purchased all units – vendor installation & startup• Independent Project Guidance• Qualified Operation of Pilots w/ NO Bias or Perceived Bias• Peer Review of Approach and Protocol, and of Results• Local Oversight and Advisory Guidance


Preliminary Process Considerations• Systems Likely to Approach ‘Goal’ of 10 µg/L • Systems Implementable for ‘Large’ Treatment Plants

(RPWRF Average Wastewater Flow is now about 40 MGD).

9

• Type of systems based on earlier Pilot Plant data and experience elsewhere.

• Unlikelihood that a Single Stage Process will achieve optimal results – therefore 2 compatible stages will be a criteria. Compatibility must be confirmed during studies.


Considerations For NLT Recommendations• Implementation Cost: First, Operation, Life Cycle• Implementability on the Site• Effectiveness for ALL Potential Pollutants of Concern

10

• Effectiveness for ALL Potential Pollutants of Concern• Compatibility with other policies for overall water

quality enhancement (e.g., other parameters and limitations)

• Flexibility for Further Improvements if/when Feasible

Spokane RPWRF Pilot Studies 08-10Preliminary Specific Process Considerations

• Chemical Coagulation, Flocculation, Sedimentation Units – 0.5 MGD each or greater to reduce the scale-up factor as much as possible– ‘Conventional’ Coagulation, Flocculation, Inclined Plate

11

– ‘Conventional’ Coagulation, Flocculation, Inclined Plate Settler

– Coagulation, Flocculation, Sedimentation Using Ballast for Settling Enhancement (‘Ballasted’ Sedimentation), 2 Unique System Presented themselves – Both Selected

Spokane RPWRF Pilot Studies 08-10Preliminary Specific Process Considerations

• Filtration Units – 3 Pairs– ‘Conventional’ Downflow Dual or Multi Media Granular

Media Filters w/ Conventional Backwash– Upflow Continuous Backwash Filters

12

– Upflow Continuous Backwash Filters– Membrane Filters

• Each Filter System will accept feed from 2 Settlers simultaneously (parallel filter units) for comparative performance

Schematic Flow Diagram RPWRF P Pilot Program

13

Pilot Units Layout RPWRF P Pilot Program

Construction Progress RPWRF P Pilot Program

15


16


Operation and Monitoring Considerations• Control and Track Flow to each unit• Control and Track Chemical Feed to each unit• Track Feed Water Quality

17

• Track Intermediate Water (Settler Effluent) Quality• Track Final Effluent Water Quality• Quality Parameters: TP, RP, FTP, FRP (F=0.45µ) • BOD, NH3-N, Heavy Metals, PCBs and other

Persistent Bioaccumulative Toxins as appropriate

Testing for Low Concentrations of Phosphorus

• P-Pilot Lab: Standard Methods 4500-P E Spectrophotometer @880 nm, 10 cm Light Path.

• Anatek Lab: Standard Methods 4500-P G Flow Injection Spectrophotometer @880 nm, Flow Injection Spectrophotometer @880 nm, 0.5 cm Light Path. Now changing to 10 cm LP

• RPWRF Lab: EPA Method 365.3 Spectophotometer @ 650 nm, 10 cm Light Path.

18

Testing ScheduleSUN MON TUES WED THU FRI SAT

P-Pi

lot

Ana

tek

RPW

RF

P-Pi

lot

Ana

tek

RPW

RF

P-Pi

lot

Ana

tek

RPW

RF

P-Pi

lot

Ana

tek

RPW

RF

P-Pi

lot

Ana

tek

RPW

RF

P-Pi

lot

Ana

tek

RPW

RF

P-Pi

lot

Ana

tek

RPW

RF

INFL

UEN

T(1

SA

MPL

E)

pH X X X X X X X X X X X

Temp. X X X X X X X

Turb. X X X X X X X

Alk. X X X X X X X X X X X

OP X X X X X X X X X X X X X X X

TP X X X X X X X X

SOP X X X

STP X X X

Ca X X X

Al/Fe X X X

NH3-N X X X

BOD X X X

TSS X X X

Metals* X* X*

19

Metals* X* X*

EFFL

UEN

T(1

0 SA

MPL

ES)

pH X X X X X X X X X X X

Temp. X X X X X X X

Turb X X X X X X X

Alk. X X X X X X X X X X X

OP X X X X X X X X X X X X X X X

TP X X X X X X X X

SOP X X X

STP X X X

Ca X X X

Al/Fe X X X

NH3-N X X X

BOD X X X

TSS X X X

Metals* X* X*

REJE

CT(1

0 SA

MPL

ES)

pH X X X X X X X

OP X X

TP X X X

TSS X X X

Al/Fe X X X

Metals* X* X*

* Metals will only be analyzed every other week on effluent, ea. 4 wks on Reject

* Metals include Cd, Cu, Cr, Pb, Ni, Zn

Now For Some Data

(long awaited)↓

20

60

70

80

90

100

2.5

3

3.5

4

Alum Dose, m

g/l

P, m

g/l

P-Pilot Influent - RPWRF EffluentA-Inf TP A-Inf OP P-Inf OP Alum Dose

210

10

20

30

40

50

0

0.5

1

1.5

2

2/20 3/20 4/20 5/20 6/20 7/20 8/20

Alum Dose, m

g/l

P, m

g/l

100

1000

1

10

Alum Dose, m

g/l

P, m

g/l

P-Pilot Data S-unit EffluentA-S1 TP P-S1 OP A-S2-TP P-S2 OP S1 Alum Dose S2 Alum Dose

220.1

1

10

0.001

0.01

0.1

2/20 3/20 4/20 5/20 6/20 7/20 8/20

Alum Dose, m

g/l

P, m

g/l

100

1000

0.1

1

Alum Dose, m

g/l

P, m

g/l

P-Pilot Data K-unit and C-unit EffluentA-C1 TP P-C1 OP A-K1 TP P-K1 OP K Alum Dose C Alum Dose

231

10

0.001

0.01

2/20 3/20 4/20 5/20 6/20 7/20 8/20

Alum Dose, m

g/l

P, m

g/l

100.1

1

Alum Dose, m

g/l

P, m

g/l

P-Pilot Data B-unit EffluentA-B1 TP P-B1 OP A-B2 TP P-B2 OP B1 Alum Dose B2 Alum Dose

100

240.01

0.1

1

0.0001

0.001

0.01

2/20 3/20 4/20 5/20 6/20 7/20 8/20

Alum Dose, m

g/l

P, m

g/l

10

100

0.1

1

Alum Dose, m

g/l

P, m

g/l

P-Pilot Data F-unit EffluentA-F1 TP P-F1 OP A-F2 TP P-F2 OP F1 Alum Dose F2 Alum Dose

250.1

1

0.001

0.01

2/20 3/20 4/20 5/20 6/20 7/20 8/20

Alum Dose, m

g/l

P, m

g/l

100

1000

0.1

1

Alum Dose, m

g/l

P, m

g/l

P-Pilot Data Z-unit EffluentA-Z1 TP P-Z1 OP A-Z2 TP P-Z2 OP Z1 Alum Dose Z2 Alum Dose

260.1

1

10

0.0001

0.001

0.01

2/20 3/20 4/20 5/20 6/20 7/20 8/20

Alum Dose, m

g/l

P, m

g/l

Preliminary P-Pilot Observations

• P removal depends on Coagulant Addition –exact relationship to be determined.

• High Coagulant Dosages are needed to get P to low concentrations – up to 100 mg/l (as P to low concentrations – up to 100 mg/l (as Alum) in each of 2 or 3 stages.

• Solids removal step appears to be limiting –following coagulant addition, solids may be a surrogate for P removal efficiency.

27


• S-units – (Corix sedimentation units - settling tubes)– Reliable and easy to operate.– Solids removal protocol appears to be critical to

effectiveness. effectiveness. – Adjustment of duration and frequency of solids

withdrawal has resulted in more consistent results.– Approximately 10% reject– Relatively straight forward design and installation

28


• K-unit (Kruger Actiflo – sand ballasted sedimentation)– Operating time to date is inadequate to make many specific

observations– Appears to produce high quality effluent equivalent to

S-unitsS-units– Operation and adjustments more complicated than S-units.– Very sensitive to Coagulant and Polymer dose – out of

adjustment results in immediate upset, including loss of a major quantities of sand

– Uncertain complication for full scale design and installation

29


• C-unit (Cambridge Comag – magnetite ballasted

sedimentation)– Operating time to date is inadequate to make very many

specific observations– Appears to produce high quality effluent equivalent to

S-units, perhaps better– Operation and adjustments more complicated than S-units.– Very sensitive to Coagulant and Polymer dose – out of

adjustment results in immediate upset, including loss of major quantities of magnetite

– Some magnetite loss on a continuing basis– Relatively complicated design and installation 30


• B-units (Centra-Flo (by Blue Water Technologies) -

upflow-continuous backwash sand filters)– Good consistent quality effluent– Accept high Coagulant Dose – Accept high Coagulant Dose – Relatively easy to operate– Approximately 10% reject– Relatively simple design and installation

31


• F-units (Corix conventional backwash dual media filters)– Good consistent quality effluent– Accept high Coagulant Dose – Relatively easy to operate– Relatively easy to operate– Backwash frequently at high coagulant dose,

possibly resulting in higher than 10% reject (we’re still evaluating how to extend filter runs)

– Relatively easy design and installation

32


• Z-units (GE Zenon – membrane filter units)– Operating time to date is inadequate to make very many

specific observations – especially since initial installation could not meet “design flow” rating

– Produces a high quality effluent– Produces a high quality effluent– Appears to accept a high coagulant dose – but must be re-

evaluated after mods to bring capacity up to design– Reject quantity being evaluated– Relatively complicated design and installation

33


• Pilot units installation and startup has been longer than was anticipated

• All pilot units, once installation was complete, and following operator training, have been and following operator training, have been relatively easy to operate

• Operator time is a premium with 10 treatment plants to operate, and monitor

34


• Alum as coagulant and caustic (NaOH) as alkalinity have worked successfully

• Analytical testing has been a trial. Low sensitivity of automated P test apparatus using sensitivity of automated P test apparatus using SM4500 P G with 0.5 cm cell is not adequate

• 10 cm flow through cells appear to give good results for Reactive P

35


• Precipitate forms in high velocity pipe and fitting sections with high Alum dosages.high Alum dosages.

• Precipitate in an in-line pH probe

• Following Slide –– in a static mixer,– blown out of mixer

36

Preliminary P-Pilot ObservationsStatic Mixer Solids from Mixer

37

Normalized TP Data Distribution After Treatment

1

Breckenridge, Iowa Hill 2003

Influent Arith Mean = 3.59 mg/lInfluent Log mean = 3.35 mg/lInf Log 95%ile = 6.40 mg/lInf log 99%ile = 8.36 mg/l

Biol Eff Arith Mean = 1.74 mg/lBiol Eff Log mean = 1.54 mg/lBiol Eff Log 95%ile = 3.53 mg/lBiol Eff Log 99%ile = 4.99 mg/l

38

0.001

0.01

0.1

P, m

g/l

Influent Biol Eff Chem Eff Final Eff Inf Stat Biol Stat Chem Stat Final Stat

50% 99.8%99.5%99%98%95%90%80%70%60%40%30%20%10%5%2%1%0.5%0.2%

Chem Eff Arith Mean = 0.031 mg/lChem Eff Log mean = 0.020 mg/lChem Eff Log 95%ile = 0.073 mg/lChem Eff Log 99%ile = 0.125 mg/l

Final Eff Arith Mean = 0.0091 mg/lFinal Eff Log mean = 0.0065 mg/lFinal Eff Log 95%ile = 0.026 mg/lFinal Eff Log 99%ile = 0.046 mg/l

RPWRF P-Pilot Study

Thank You.

[email protected]@[email protected]

[email protected]@spokanecity.org

39


40

Spokane RPWRF Pilot Studies 08-09Expected Coagulant Dose & Performance

• Existing Seasonal Dose – AlumEffluent TP

• Stage 2 (Chem Precip)

• MR = 1.0 – 1.5 75± mg/l0.5 – 0.8 mg/l P

• MR = 10 – 20

41

• Stage 2 (Chem Precip) Dose – as AlumObjective Eff. TP

• Stage 3 (Filtration)Dose – as AlumObjective Eff. TP

• MR = 10 – 2050 – 100 mg/l0.05 – 0.08 mg/l

• MR = 50 – 10030 – 100 mg/l0.005 – 0.015 mg/l

Documents

Reducing Spokane Riverside Park Water Reclamation Facility ... PNCWA...• B-units (Centra-Flo (by Blue Water Technologies) - upflow-continuous backwash sand filters) –Good consistent