Oxidation Ditch Upgrade Engery Savings While Increasing Peak Flows

Oxidation Ditch UpgradeEnergy Savings While Increasing Peak

Flows

November 19, 2014Ryan Brauen, P.E.

IWEA 2014 Oxidation Ditch Upgrade – Energy Savings While Increasing Peak Flows

Agenda

• Background• Improvements• Funding• O2 Ditch Rehab• Energy Findings• Performance• Lessons Learned• Questions

WWTP

WRRFWater Resource Recovery Facility


Location – Greentown, IN


Project Need

• Age• Enforcement

– Sewer Ban: 1997• Early Warning: 1994• Hyd. Overloading (112%)• Bypasses (38)• TSS, NH3, P

– Agreed Order: 2006• Hyd. Overloading• SSO’s• Bypasses (25)• E. Coli, NH3

Need

Age

AgreedOrder

SewerBan


Approach

2006: Collection System Field Investigations

2009: Collection System Rehabilitation

2009-2011: Flow Monitoring

2011-2012: WRRF Design

2013-2014: WRRF Construction


Design Constraints

• Design Data– ADF: 0.58 MGD– PHF: 2.85 MGD– cBOD5: 180 mg/l– TSS: 220 mg/l– NH3-N: 30 mg/l– P: 7 mg/l

• NPDES Limits– cBOD5: 10 mg/l– TSS: 12 mg/l– NH3-N: 1.1 mg/l

(summer), 1.6 mg/l (winter)

– P: 1.0 mg/l– pH, D.O., E. Coli


Existing Facility

• 1963: Original Facility

• 1990: O2 Ditch, Intra-Channel Clarifier, UV

• 2000: Screening, Raw Sewage Pumping, Surge Tank (EQ)


Improvements

• New Influent Sewer• Screening• Raw Sewage Pumping• Plant Piping• EQ Blowers & Flow

Control• Chem P• O2 Ditch Mods• Flow Splitter

• Secondary Clarifiers• RAS/WAS Pumping• UV & Post Air• Aerobic Digesters &

Blowers• Sludge Dewatering• SCADA• Generator


Funding

• SRF• Green Project Reserve

– Rain Gardens ($24,500)

– Riparian Buffer ($8,400)

– Plumbing ($900)

– D.I. Pipe ($325,000)

– Glass Block ($2,000)

– Lighting/Switches ($13,600)

– VFD’s ($51,200)

– O2 Ditch System ($161,000)


Existing O2 Ditch & Clarifier

• Installed 1990• 2 – 40 Hp Rotors• Intra-Channel

“Boat” Clarifier– Regular Solids

Washout– Limited Control– Reduced Tank

Volume


O2 Ditch Improvement – Option 1

• Replacement Rotors– 2 – 30 Hp Rotors– Sys. Eff. = 90%– VFD’s– D.O. Control


O2 Ditch Improvement – Option 2

• Bio-Loop®

– 3 – 25 Hp PD Blowers– Motor Eff. = 90%– VFD Eff. = 98%– Fine Bubble

Membrane– 2 – 2.7 Hp

Submersible Mixers• 49 rpm• ~6-ft. dia. Blades

– D.O. Control


O2 Ditch Improvement – Selection

• Bio-Loop® Selected– Past Rotor Issues– Energy Savings– Flexibility– Cold Weather Ops– Lower Capital Cost


O2 Ditch Energy Evaluation - Existing

• 2 – 40 Hp Rotors• 13 Hrs/day (6.5

hrs/rotor)• Eff. = 80% (est.)• $0.08/kWh• ~$39/day• $14,235/yr.


O2 Ditch Energy Evaluation – Option 1 Replacement Rotors

• Aeration Control– 2 – 30 Hp Rotors– 16.2 Hp req./rotor– VFD turn down– 24 Hr./day/rotor– Sys. Eff. = 90%– $0.08/kWh– ~$52/day– $18,900/yr.

• Mixing Control– 2 – 30 Hp Rotors– 9 Hp req./rotor– VFD turn down– 24 Hr./day/rotor– Sys. Eff. = 90%– $0.08/kWh– ~$29/day– $10,585/yr.


O2 Ditch Energy Evaluation – Option 2Bio-Loop®

• 2 Mixers – 24/7– Eff. = 90% (est.)

• SCADA– Blower Runtime– Blower Hz– 5/2014 – 9/2014

• $0.08/kWh• Avg. $16/day• $5,840/yr.


Oxidation Ditch – Energy Comparison

Existing Rotors(As Operated)

Replacement Rotors

(Aeration Limited)

Replacement Rotors

(Mixing Limited)

Bio-Loop(Actual)

Avg. Day $59 $52 $29 $25Avg. Month $1,770 $1,560 $870 $750Avg. Year $14,235 $18,900 $10,585 $9,12520 Years $284,700 $378,000 $211,700 $182,500

Annual Savings ($5,110) ($9,775) ($1,460) $020 Yr. Savings ($102,200) ($195,500) ($29,200) $0


Effluent Quality – Post Construction

Design

MRO2/2014 – 9/2014 %

RemovalInfluent EffluentInfluent (MGD) 0.580 0.303 --- --cBOD5 (mg/l) 180 182 4.9 97.3%TSS (mg/l) 220 227 3.2 98.6%NH3 (mg/l) 30 22 0.36 98.4%P (mg/l) 7 4.2 0.50 88.1%


Lessons Learned

• Existing Tankage• Baffle Walls• Air Curtain

– Scum/Foam• Blower Sizing


Summary

• Flows – Design: 0.42 MGD 0.58 MGD– Peak: 1.5 MGD 2.85 MGD

• 14-50% Energy Savings• Lower Capital Cost• Operational Flexibility• Compatible with Bio-P• Cold Weather Ops


Summary

Energy Savings Opportunities Existand Can Be Realized at Small Facilities


Questions?

Thanks to:Town of Greentown

Klein Enterprises, LLC

[email protected]

Oxidation Ditch Upgrade Engery Savings While Increasing Peak Flows

Engineering

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