© 2014 Evoqua Water Technologies LLC INTRODUCING THE CAPTIVATOR George Smith; Director of Biological Processes

WHAT IS THE CAPTIVATOR? Uses a DAF for a primary clarifier WAS blended with influent in aerated contact tank prior to DAF Up to 80% combined solids (primary/WAS and absorbed) thickened in DAF and removed

Benefits: up to 40% more biogas 40% less aeration energy 20% less capital New plants and retrofits Conventional Plant The Captivator System improves a conventional process by replacing primary clarification and separate sludge thickening with a VLR® Contact Tank and a Folded Flow® DAF applied to the liquid stream. The Captivator™ System for activated sludge plants with anaerobic digestion VLR Contact Tank Folded Flow DAF Aeration Tank Final Clarifier Anaerobic Digester Controls

Conventional Plant The Captivator System offers significant saving on foot print for a new plant compared with a conventional activated sludge system. DAF smaller than primary sedimentation Smaller aeration basins Less aeration equipment The Captivator™ System saves footprint for new plants VLR Contact Tank Folded Flow DAF Aeration Tank Final Clarifier Anaerobic Digester Controls

The Captivator™ System can easily be applied to an existing plant Capacity expansion More biogas production Less aeration energy demand Easy operation The Captivator System can easily be applied in to any existing plant with anaerobic digestion with minor modifications. VLR Contact Tank Folded Flow DAF Aeration Tank Final Clarifier Anaerobic Digester Primary Sedimentation Thickener Controls

VLR® Aeration Contact Tank Folded Flow® DAF TIW™ Integrated Control System Captivator™ System deploys proven technologies Captivator is a combination of very well known and proven technologies - Biosorption and Solid/Liquid Separation. Higher BOD/COD and TSS removal can be achieved than primary sedimentation with Captivator. Extracted TSS can also be thickened up to 6% by a folded flow DAF and no need for extra thickener.

Folded Flow® DAF efficiently removes and thickens the majority of biomass and incoming SS Very high surface loading rate can be applied (5000 gpd/sf) compared with primary sedimentation, which can accept up to gpd/sf High TSS removal efficiency – 85 % Very high loading Remove and thicken sludge Lower energy: 6 hp/MGD No polymer/chemical required for most conditions Captivator™ System employs an unique DAF VLR Contact Tank Folded Flow DAF Aeration Tank Final Clarifier Anaerobic Digester Controls

Short reaction time Efficient organic removal Optimized energy usage with Vertical Loop Reactor and Disc Aerator Biosorption takes place in the Contact Tank The biomass in the VLR contact tank absorbs the majority of the soluble, colloidal and particulate organic matter in the floc This biosorption occurs over a short, 20 to 30 minute contact time The organic matter extracted from the raw wastewater is then transferred to Anaerobic Digestion within the activated sludge floc Adsorption t = 0 min Microbial Floc Adsorption t = 20-30min Microbial Floc VLR aerated contact tank drives efficient biosorption VLR Contact Tank Anaerobic Digester Controls

Easy operation and control of the system as one process One interface with operator Process and energy optimization for fluctuations Balances power input to influent loadings between day/night, and average/peak flowrate. Optimizes BOD extraction under fluctuation of raw wastewater characteristics. Maximizes transfer of BOD to Anaerobic Digester Integrated control system fine tunes performance of the Captivator System VLR Contact Tank Folded Flow DAF Aeration Tank Final Clarifier Anaerobic Digester Controls

Benefits: Less aeration energy demand More energy generation through increased biogas production Whereas a 30 MGD conventional AS plant might use 1000 kW of energy for aeration, and only produce 500 kW energy from biogas a plant with Captivator System would need only 600 kW aeration energy and could generate 700 kW energy from biogas The Captivator™ System: a step toward net zero energy consumption *Total WWTP power not factored Only power for aeration * *

100% A.T. 20.9% Oxidized F.C. 6% Final Effluent AD Inflow WAS 15.5% 39.0% 32.2% Biogas Excess Sludge C.T. 42.4% D.A.F. DAF Sludge 71.2% 1.9 % Oxidized 113.6% COD balance of Captivator System demonstrates the benefits over conventional AS process Less aeration energy Less aeration volume More energy generation through increased biogas More heat or waste heat potential through energy generation Conventional AS Captivator

100% A.T. 20.9% Oxidized F.C. 6% Final Effluent AD Inflow WAS 15.5% 39.0% 32.2% Biogas Excess Sludge C.T. 42.4% D.A.F. DAF Sludge 71.2% 1.9 % Oxidized 113.6% COD balance of Captivator Less aeration energy Less aeration volume More energy generation through increased biogas More heat or waste heat potential through energy generation Conventional AS Captivator

PILOT STUDIES Bethlehem, PA … folded-flow 5000 gpsfd overflow Oconomowoc, WI … folded-flow 5000 gpsfd overflow Singapore … folded-flow DAF with aerated contact

BENCH TEST SS REMOVAL Various combinations of WAS and polymer 74% no additive WAS only WAS and polymer Polymer only 52% 66% 32%

BETHLEHEM STUDY DAF WITH 108 SF DAF surface overflow rate 5000 gpsfd but as high as 10,000 gpsfd overflow Recycle 25% but as low as 16% Floated solids concentration above 6% 1mg/l polymer added (for thickening purposes) … one run without polymer (same results)

BETHLEHEM RESULTS SS REMOVAL DAF with 72% SS Removal Floc tank Floc tank DAF 201 mg/l mg/l mg/l (effective 56 mg/l % removal) WAS To aeration process

BETHLEHEM RESULTS BOD REMOVAL DAF with 52% BOD Removal Floc tank Floc tank DAF 201 mg/l mg/l mg/l 90 mg/l mg/l mg/l (25% removal) 111 mg/l mg/l mg/l effective 96 mg/l % removal) WAS To aeration process

OVERALL (MAIN GATE) Singapore Pilot Study

Top View from Digester DAF Tank with Floc Tank DAF Installation Control Panel 40,000 gpd treatment system

SUMMARY FOR HIGH SOLIDS LOAD High Solids Loading Conditions Biosolids TSS Loading /Influent BOD Loading DAF performance, Removal Efficiencies, % TargetedActualTSSBODCOD Base Case Base Case +10 ppm FeCl Base Case + 5 ppm FeCl DAF System DAF Influent Biosolids Flow, TSS Source Q Inf = 30 gpm, BOD = 400 mg/L TSS = 375 mg/L Q R = 6 gpm, TSS = 6000 mg/L DAF Float Sludge, 3.5% DAF Effluent, to Aeration Tanks BOD = 50 mg/L, TSS = 35 mg/L FeCl 3, ppm Primary Clarifier Contact Tank Influent Flow Q DAF = 18 gpm, Directly To Aeration Tanks Q = 18 gpm BOD = 320 mg/L TSS = 210 mg/L

Primary 133 mg/l DAF 17 mg/l (87% removal)

Results for Aqua Nueva WRF Pima County, AR 32 mgd Six 65’ x 20’ Folded-Flow DAF (with 8 minute aerated contact in front) May-June SS: 300 mg/l – 480 mg/l – 120 mg/l … 75% SS removal (90 mg/l effective SS) sCOD 30% – 35% Estimated BOD removal: 55% Note: Difficult wastewater … chemical additions were required

CAPTIVATOR WITH FLOATED SOLIDS RECYCLE … REMOVES MORE BOD … BUT Requires more DAF surface area and more aerated contact time Higher pressurized recycle rates Results in the return of less WAS … although … Provides independent biomass for higher BOD removal Elevated MLSS allows for higher SS removal

NORMAL SOLIDS BALANCE Digester 80,000 lbs destroyed 110,000 lbs to be dewatered Activated Sludge Process 90,000 lbs 140,000 lbs BOD Primary 100,000 lbs Primary clarifiers 200,000 lbs BOD 190,000 lbs

SOLIDS BALANCE WITH CAPTIVATOR Digester 110,000 lbs destroyed 110,000 lbs to be dewatered Activated Sludge Process DAF 100,000 lbs (75,000/0.75) 90,000 lbs BOD 220,000 lbs DAFContact 200,000 lbs BOD

SOLIDS BALANCE WITH CAPTIVATOR WITH RECYCLE Digester 125,000 lbs destroyed 110,000 lbs to be dewatered Activated Sludge Process DAF 45,000 lbs (41,000/0.9) 70,000 lbs BOD 565,000 lbs 235,000 lbs 300,000 lbs DAFContact 200,000 lbs BOD

Comparison of performance Lbs to aeration Lbs destroyed Primary 140,000 80,000 Captivator 90, ,000 Captivator/recycle 70, ,000

To Aeration VLR contact 175’ x 20’ … 750 mg/l MLSS 24 mgd Influent 2 mgd WAS and FSR Conversion of existing primary clarifiers 80’ x 20’ VLR contact 175’ x 20’ … 1350 mg/l MLSS ’

Piloting Recommended for plants with existing activated sludge systems One 16’ x 4’ Folded-Flow DAF and 10,000 gallon VLR Contact tank will pilot a a treatment flow of 250,000 gpd to 300,000 gpd … with WAS borrowed from the existing activated sludge system

Summary: The Captivator system extracts high levels of BOD from the mainstream process It can be used in existing plants or new plants Pilot testing has confirmed up to 80% SS removal and 60% BOD removal 35% sCOD removal has been shown in full-scale plant

© 2014 Evoqua Water Technologies LLC QUESTIONS?