© 2013 O’Brien & Gere

Volute Press Application on Water Treatment Residuals

2013 NYC Watershed / Tifft Science & Technical Symposium

September 19, 2013

#obgPresents

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City of Ithaca

Located on south end of Cayuga Lake in Finger Lakes Region

Population: 30,000 Average water demand: 3 MGD Greater Ithaca area is served by

three public water systems Existing 6 MGD conventional

water treatment plant was constructed in 1903

Last major upgrade was completed in 1951

City decided to replace its plant rather than buy water from another system

Ithaca

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Water Supply Project Elements

Dredging water supply reservoir

New gatehouse and intake Dam safety improvements Raw water transmission

maintenance Re-construction of 6 MGD

filtration plant with conventional pre-treatment and membranes

Interconnections with other utilities

Residual dewatering facility Distribution system

improvements

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Existing Lagoon Dewatering Operations

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Cleaning typically required 6 people and at least a week per lagoon

Some years, both lagoons are cleaned

Cleaning often occurs when resources are most valuable

Significant liner protection and maintenance required

Sludge is blended with compost and earth spoils to create manufactured topsoil

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Evaluation of Dewatering Options

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Strengths Weaknesses

Lagoon/Drying Beds Performance is somewhat

independent of solids loading Proven technology Flexible to operate in

both thickening and dewatering modes

Comparatively high visual and noise impacts

Intense / short duration labor needs

Not expandable if solids loads increase

Challenging site constraints

Volute Dewatering Press

Small footprint Good performance during

pilot testing Relatively easy start-up and

shutdown procedure Totally enclosed process

High wash water requirements for system cleaning

Fewer reference installations for similar applications

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PW Tech Volute Press

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Typical Installation

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PWTech Video

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PWTech Volute Press Pilot

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BDP Industries Pilot

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Piloting Results

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Description PWTech BDP Industries

Test Dates Oct. 2011 Nov. 2012

Hydraulic Loading (GPM) 3.3 – 8 10 – 12

Feed Solids (% wt.) 0.4 – 2.2 0.3 – 2.0

Cake Dryness (% wt.) 21.5 – 45 20 – 23

Polymer Dosage (lb. / dry ton) 15 – 32 28 – 33

Solids Capture Rate (%) 98.7 – 99.9 95 – 98

Test Unit Model ES132 3012DSP

Test Unit Capacity (lb./hr.) 38 380

*All tests performed using PACL sludge

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Raw Water Solids Data

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J F M A M J J A S O N D0

20

40

60

80

100

120

140

160

180

Monthly Average TSS mg/l

2011 2010 2009 2008 20072012

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Proposed Facilities

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Proposed Building – North Elevation

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Proposed Building – West Elevation

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Current Project Status

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Lessons learned

Coordinate pilot unit capacity with available sludge capacity

Consider the environmental conditions – polymer preparation is temperature dependent

Pilot all units under consideration at same time; Side-by-side pilot is much easier to evaluate

Pilot optional press features as needed to achieve performance

Water plant sludge is not the same as wastewater plant sludge

© 2013 O’Brien & Gere

QUESTIONS?