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 Residual Solids Management Plan – RSMP (2014)  Pilot-Scale Screw Press Evaluation  Residual Disposal Options  Recommendations 2

West SideEast Side Crown PlantNottingham Plant Mark Petrie – PMDebbie Hanby – PM Capacity: 112 MGDCapacity: 125 MGD Parma Control Rich Papp - PM miles of pipe 1.3 million people Morgan PlantBaldwin Plant Tyrone Butler – PMFrank Woyma – PM Capacity: 150 MGDCapacity: 165 MGD 3

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Current Residuals Management Strategy Baldwin, Morgan Nottingham: Force main pumping to NEORSD sewer system of thickened solids from sedimentation basins and backwash clarifiers Permit limits  4,000 mg/L TSS  300 mg/L BOD5  12.5 tons/day Total Dry Solids  Flowrate 2 MGD to 4 MGD Crown: Beneficial reuse (through Emerald Environmental) of plate-and-frame press dewatered thickened solids from sedimentation basins and backwash clarifiers 5

Solids Production Rates Determined performing a solids mass balance at each plant and comparing to reported residual discharge and production rates Estimated Solids Production Rates: Morgan: 135 lbs/MG of water treated Baldwin: 162 lbs/MG Nottingham: 168 lbs/MG Crown: 172 lbs/MG 6

Evaluated Residual Solids Management Options StrategyBaldwinMorganNottinghamCrown Sewer DischargeXXX Liquid Sludge HaulingXXXX Drying Bed DewateringXXX Mechanical Dewatering (Screw Press) XXX Mechanical Dewatering (Plate & Frame Press) X 7

Estimated Costs (2014) OptionCapital CostAnnualEACTPW Baldwin Sewer Discharge$0$1,499,746$2,877,104$42,804,036 Liquid Tanker (9% Solids)$2,237,124$1,204,945$1,355,315$20,163,663 Drying Bed Dewatering$17,047,700$501,920$1,647,793$24,515,002 Mechanical Dewatering$7,774,510$388,250$910,819$13,550,689 Nottingham Sewer Discharge$0$1,212,078$2,290,232$34,072,864 Liquid Tanker$0$1,049,725 $15,617,257 Mechanical Dewatering$4,325,467$269,900$560,639$8,340,897 8

Estimated Costs (2014) OptionCapital CostAnnualEACTPW Morgan Sewer Discharge$0$811,970$1,568,510$23,335,461 Liquid Tanker$0$779,085 $11,590,818 Drying Bed Dewatering$11,280,000$261,418$1,019,611$15,169,240 Mechanical Dewatering$3,645,610$201,600$446,642$6,644,909 Crown Liquid Tanker$0$740,280 $11,013,497 Drying Bed Dewatering$17,945,000$308,142$1,514,328$22,529,375 Mechanical Dewatering$0$660,362 $9,824,519 9

RSMP Recommendations Consider screw press dewatering (assuming beneficial reuse will be available) Pilot-scale testing of screw press to determine:  Process efficiency  Pretreatment and chemical requirements  Design parameters Install screw presses at one plant (e.g., Morgan) Have a back-up plan for disposal/beneficial reuse of dewatered residuals Maintain sewer discharge as an alternative to dewatering Eventually replace Crown plate-and-frame presses with screw presses 10

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Pilot-scale Screw Press Evaluation Objectives Determine dryness (% solids) of sludge cake Pressate (filtrate) water quality Solids capture efficiency Polymer requirements (polymer type and dose) Optimal feed sludge concentration (hydraulic loading) Solids loading rate Screw size (diameter and length) Screw speed Discharge pressure Operation and maintenance requirements (e.g., lubrication, washing, etc.) 12

Pilot-scale Screw Press Evaluation Screw Press Evaluation was performed by MWH and AECOM Screw Presses Evaluated: A Schwing Bioset 300 screw press unit  Baldwin water works  Morgan water works A PWTech Volute ES201 unit  Morgan water works 13

Screw Press Comparison Schwing Bioset Press Average hydraulic feed capacity = 10 gpm (maximum hydraulic capacity = 30 gpm) Design dewatering rate = 100 dry lbs/hour PWTech Volute Press Hydraulic feed capacity = 15 gpm Maximum solids load = 80 dry lbs/hour 14

Schwing Bioset Press Flow Schematic 15

Schwing Bioset Press 16

Schwing Bioset Press 17

PWTech Volute Press Schematic 18

PWTech Volute Press 19

PWTech Volute Press 20

PWTech Volute Press 21

What you start with…. 22

Polymer addition/coagulation 23

Injected into the screw press… 24

What you hope for: 25-30% cake… 25

Pressate 26

Testing and Sample Analyses Polymers tested Schwing: Polydyne C-6266, 60% Charge - 41% Active Polydyne C-6286, 80% Charge - 41% Active Polydyne C-9530, 80% Charge - 41% Active PWTech: Ciba 8812 Ashland K111 27

Testing and Sample Analyses Sampling Locations /Parameters Analyzed Feed sludge Total Solids Sludge cake Total Solids Pressate (filtrate) Turbidity Organics (TOC, UV254, SUVA, TTHMFP, HAA5FP, etc.) Inorganics (heavy metals, sulfates, chlorides, nitrates, etc.) 28

Testing and Sample Analyses Sampling Locations/Parameters Analyzed (Cont.)* Operating parameters Polymer type and dose Feed sludge flow Operating press pressure Scroll speed Condition tank speed * Total Solids content in feed and dewatered sludge was determined both by the press operators (at trailer lab) and by CWD lab. For uniformity, the CWD lab data are reported. 29

Operating Conditions 30 Parameter Baldwin Schwing Morgan Schwing Morgan* PWTech Feed Flow (gpm)7 – 2910 – 2012 Feed Sludge TS (%)0.3 – Active Polymer (lbs/dt) Scroll Speed (rpm)0.17 – – – 2.4 Solids Throughput (lbs/hr)35 – 4450 – Cone Pressure (psi)10080 – 100n/a Cake Dry TS (%)25 22 * After Stabilization

Results 31

Results 32

Results 33

Results - Pressate 34 ParameterUnit Baldwin - Schwing Morgan - Schwing Morgan - PWTech Ironmg/L Supernatant*mg/L Manganesemg/L Supernatant*mg/L Aluminummg/L Supernatant*mg/L TOCmg/L DOCmg/L UV2541/m SUVAL/mg-m TTHMFPug/L

Screw Press Test Conclusions Both presses could be used to dewater CWD residuals The Schwing press operated effectively under a wide range of operating conditions (polymer selection bench-scale tests performed prior to pilot-scale testing) The PWTech press required more preparation (polymer optimization was performed during the pilot-scale study); after establishment of proper operating conditions, the press operated effectively Pressate quality was similar for both presses Pressate quality at Morgan was better than Baldwin because the Morgan sludge was fresh (residuals at Baldwin were stored for prolonged time resulting in decomposition of various compounds and solubilization of metals) Settling of the pressate prior to recycling would substantially improve its quality 35

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Screw Press Cost 37 DescriptionBaldwinNottinghamMorganCrown PWTech Screw Presses$7,608,769$4,053,524$3,899,817$5,371,856 Schwing Screw Presses$9,207,786$5,255,000$4,626,851$6,497,718

Residual Disposal Options Evaluated Discharge to the NEORSD sewer system Transport thickened residuals at solids contents of: 3% 6% 9% 12% 15% Installation of screw presses with disposal of the dewatered residuals: Through beneficial reuse To a landfill Plate and frame dewatering at Crown with beneficial reuse 38

Sewer Discharge Cost 39

Estimated Costs OptionCapital CostAnnualEACTPW Baldwin Sewer Discharge$0$1,926,788$3,316,157$49,336,036 Liquid Tanker (6% Solids)$2,237,124$1,507,425$1,657,795$24,663,802 Screw press dewatering (Beneficial reuse) $7,608,979$445,250$956,693$14,233,175 Screw press dewatering (Landfill) $7,608,979$1,360,250$1,871,693$27,846,064 Nottingham Sewer Discharge$0 $1,547,201$2,635,539$39,210,165 Liquid Tanker$0 $1,312,405 $19,525,272 Screw press dewatering (Beneficial reuse) $4,053,524$322,400$594,860$8,850,022 Screw press dewatering (Landfill) $4,053,524$1,117,400$1,389,860$20,677,615 40

Estimated Costs OptionCapital CostAnnualEACTPW Morgan Sewer Discharge$0 $1,046,440$1,809,262$26,917,247 Liquid Tanker$0 $785,055 $11,679,636 Screw press dewatering (Beneficial reuse) $3,899,817$233,600$495,729$7,375,196 Screw press dewatering (Landfill) $3,899,817$708,600$970,729$14,441,996 Crown Liquid Tanker$0$740,280 $11,013,497 Plate&Frame dewatering (Beneficial reuse) $0$660,362 $9,824,519 Screw press dewatering (Beneficial reuse) $5,371,856$255,900$616,973$9,179,001 Screw press dewatering (Landfill) $5,371,856$815,600$1,176,673$17,505,924 41

Typical Equiv. Annual Cost - Morgan 42 3% 9% 12% 6% 15% SP - Landfill SP - Reuse NEORSD

Equivalent Annual Cost - Crown 43 3% 6% 9% 12% 15% Plate and Frame - Reuse SP - Reuse SP - landfill

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Recommendations Discharge to the sewer system is already the most expensive option; implement an alternative means for residuals disposal Identify an alternative means for beneficial reuse of dewatered residuals Should an alternative option for beneficial reuse be identified, initiate installation of screw presses to all four water works in a staged approach Test gravity thickening to identify the maximum attainable solids content in the thickened sludge; if solids contents > 5% are possible, replace sewer discharge with liquid transport 45

Acknowledgements AECOM for assisting in operation, sample collection BissNuss, Inc. – Schwing representative Pelton Environmental Products, Inc. –PWTech representative Schwing Bioset PWTech Screw Press operators Baldwin and Morgan staff for their assistance CWD lab for sample analyses 46