November 17, 2015

Charting the Future of Water Reuse for the City of Raleigh

Sheryl D. Smith, P.E. – CDM SmithEileen M. Navarrete, P.E., PMP – City of Raleigh

2015 Annual Conference Raleigh, NC

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Presentation Overview

Water Resources Background and Reuse Master Plan Objectives

Existing Reuse Program Options for Expanding Non-Potable Reuse Program Consideration of Potable Reuse Utility Perspectives and Next Steps

Water Resources in Raleigh

Regional Utility 190,000 metered customers 525,000 citizens Average Rainfall: 46 inches Drought of Record: 33 inches

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50 Year Raleigh Service Area Future Water Demand Projections (MGD)

2011 2020 2030 2040 2050 2060

Surface Water Supply 77.3 77.3 77.3 77.3 77.3 77.3

Service Area Demand 51.0 64.4 78.2 91.3 102.7 115.0

Future Water Supply Need -- -- 0.9 14.0 25.4 37.7

Future Water Sources

Conservation “Traditional” reclaimed water Infrastructure rehabilitation/replacement Reallocation of existing reservoir storage New reservoir Quarry storage River intake

Regulatory Restrictions on Potable Reuse

Reclaimed Water as a Source Water Unplanned indirect potable reuse occurs throughout the State and

the U.S. Draft Legislation – Written early 2013 with NCDENR

Neuse River Study to inform the underlying conditions and assumptions of the Bill.

Prohibition against potable reuse was removed by NC legislature in August 2014

Legislation Requirements

Reclaimed water treated to highest standard (Type 2) Reclaimed water and source water are combined in an

impoundment, sized for 5 days storage (20% reuse) Conservation measures Unbilled leakage is maintained below 15% Reuse Master Plan Public Participation

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Informing NC Bill – Project Objectives Baseline Neuse River water quality What happens in the river?

Pixie Dust Syndrome

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Master Plan Project Objectives

Determine role of reuse in meeting the City utility’s water resources needs Define best reuse strategies to reduce demands on the potable water

system Define acceptable balance of reuse costs and revenue

Provide data to support proposed potable reuse legislation

Existing Reuse Program

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Existing Reuse Distribution Systems

Southeast Raleigh Distribution System

Zebulon Distribution

System

Bulk Distribution at Treatment Plants

Smith Creek WWTP

Neuse River RRF

Little CreekWWTP

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Southeast Raleigh Distribution System

Approx. 23 miles of pipe (6 to 24-inch) 0.75 MG elevated storage tank June 2015 Demand = 900,000 gpd

Uses On-site treatment plant WW pump stations Parks & rec irrigation Other municipal facility irrigation Golf course irrigation Industrial cooling tower

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Zebulon Distribution System

Approx. 4 miles of 12-inch pipe 0.25 MG elevated storage tank June 2015 Demand = 90,000 gpd

Uses WW pump stations Athletic field irrigation Municipal facility irrigation Industrial cooling towers,

toilet flushing, irrigation Concrete production

Options for Expanding Non-Potable Reuse

Options for Expanding Non-Potable Reuse

Expand water reuse distribution system from treatment plant(s) Existing Southeast Raleigh system New distribution system from Smith Creek WWTP

Decentralized reuse facilities Wetlands/streamflow augmentation Stormwater storage

Approach to Reuse Distribution System Expansion Identify reuse demand “nodes” High density of non-residential water demand Anchored by large user

Help justify cost of pipeline construction Ideally non-irrigation uses to shave peaks Phone/in person interviews conducted to gauge interest

Potential future development corridors considered Proximity to existing reuse distribution system

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Reuse Node Identification

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Reuse Node Identification

Reuse node

Potential anchor customer

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Raleigh Distribution System Expansion

20 miles of new pipe

Additional demand ADD ~ 0.9 mgd MDD ~ 2.3 mgd

~30% irrigation ~70% cooling,

toilet, other New booster pump station

New Smith Creek Distribution System

Industrial & institutional users New residential development 5 miles of new pipe Additional demand

ADD ~ 0.3 mgd MDD ~ 0.8 mgd

Decentralized Reuse Options

Satellite treatment facilities significantly more $$ than pipeline options

Irrigation supply capacity limited since irrigation peaks coincide with low WW flows

Consideration of Potable Reuse

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Neuse River Study Conducted to Inform NC Legislation Objectives

Baseline Neuse River water quality What happens in the river?

Constituents 6 microorganisms 110 chemical constituents

Including conventional parameters, pharmaceuticals, hormones, and other trace chemical constituents

Bulk genotoxicity Sampling

3 events during low streamflow conditions

Eight Sites

Summary – General findings

River had acceptable water quality; similar to historical quality

Anthropogenic influence seen at all sites Neuse River RRF is not a significant source of microbial

contamination

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10

100

1000

A B C D E F G H

Log

(Uni

ts/1

00 m

L)

Clostridium perfringens Coliphages, Total E. coli

Enterococci Fecal coliforms

Summary – Chemicals

Methods capable of detection at low concentrations (1 ppt) Site C – greatest # of detections of chemicals Mean of the # of detections per event for site C were not

statistically different than those for sites D, E, and F

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A B C D E F G H

Num

ber o

f de

tecti

ons

Pharmaceuticals Sterols & Hormones Flame retardants

PFCs DBPs Metals

Pest/Herb/Fung Consumer products WW Tracer

72% of the chemicals tested were detected at site C

WTP WWTP 2 WTPs

Neuse River Study Conclusions

1. The Neuse River has acceptable water quality for a drinking water supply source.

2. The river is not degrading or removing most of the detected microbial indicators or trace chemical constituents.

3. No technical difference exists between reclaimed water as a source water than Neuse River water downstream.

Utility Perspectives and Next Steps

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Potable Reuse – Potential Option

Decommissioned EB Bain WTP

Decommissioned Raw Water Main

Next Steps

Cost /Benefit analysis Phasing Include potable reuse in Reuse Master Plan update

Basic structure of a pilot program Evaluate potable reuse as another alternative for a reuse project

Questions?