ENGINEERING A NEW DRINKING WATER SUPPLY · 5 East Expansion I $7,167,350 6 West Main Service II and East Expansion I $5,336,350 7 East Expansion II $8,650,000 8 East Expansion III

IGNACIO CADENA, P.E. – PROJECT MANAGER

NOVEMBER 3, 2011 – SHERMAN, TEXAS

ENGINEERING A NEW DRINKING WATER SUPPLY

HOW LONG DOES IT TAKE TO DEVELOP A NEW DRINKING WATER SUPPLY?

26 years

PROJECT LOCATION

SOMERVELL COUNTY WATER DISTRICT

• Glen Rose, Texas

• Somervell County Water District Incorporated in 1985

• Selling Water November 2011

• Dinosaur Valley

• Fossil Rim Wildlife Center

• Paluxy River

• Comanche Peak Nuclear Plant


Overview

OVERVIEW

• Current Water Supply

• Water Supply Evaluation

• Supply Facilities

• Demand Projections

• Water System Hydraulic Analysis

• Capital Improvements Plan

• Treatment Facilities


Current Water Supply

CURRENT WATER SUPPLY

• Somervell County Water Supply

• Groundwater Wells from the Trinity Aquifer

• Declining Water Table Elevations in Municipal Wells

Figure 1.1

Depth to Water - Glen Rose Municipal Well #2

0

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40

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100

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180

Jan-60 Jan-65 Jan-70 Jan-75 Jan-80 Jan-85 Jan-90 Jan-95 Jan-00

Dep

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CURRENT WATER SUPPLY

• Increasing Demands

• Uncertainty to meet Future needs Figure 1.2

Historical and Projected Municipal Water Use

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1980 1990 2000 2010 2020 2030 2040 2050 2060

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Glen Rose Historical Glen Rose Projected Somervell County Historical Somervell County Projected


Water Supply Evaluation

WATER SUPPLY EVALUATION

• Mid 80’s Recommended Alternate Supply

• Diversion from Paluxy River

• Off-Channel Reservoir on Wheeler’s Branch

• Conservation Storage Capacity 4,118 acre-ft

• Diversion up to 2,000 acre feet/ yr for Municipal, Industrial and Irrigation

• Impound up to 5,000 acre feet/yr of Runoff

WATER SUPPLY EVALUATION

• Will not affect flow through Dinosaur Valley State Park

• Environmental impacts

• Archeological Impacts

• Is economically feasible and provides an adequate water supply

• Water quality suitable for municipal use


Channel Dam

CHANNEL DAM

• Upstream of Big Rocks Park on Paluxy River

• Diversion Dam 8-feet high & 100–feet long

• Constructed with reinforced concrete to allow overtopping

• Channel Dam Construction Completed 2007

• Channel Dam Cost - $1,351,000

CHANNEL DAM

CHANNEL DAM


Wheeler Branch Reservoir

WHEELER BRANCH RESERVOIR

• Located 2 miles NW of Glen Rose

• Constructed as earthen embankment

• 1,750–feet in length & max height of 90-feet

• Conservation capacity of 4,118 acre-feet

• Raw water supply 24-inch pipeline

• Reservoir Completed in 2007

• Construction Cost $9,869,000




Raw Water Pump Station

and Pipeline

RAW WATER PUMP STATION

• Raw Water Pump Station upstream of Channel Dam

• Designed variable diversion rates up to 50 cfs

• Operation contingent upon flow limits

• Pump Station and Pipeline Completed 2008


• 36-inch Pipeline approximately 2.0 miles long

• Pipeline Construction Cost $1,900,00

RAW WATER PUMP STATION & PIPELINE


Demand Projections

• Somervell County Population approx. 7,900

• Steady Growth Rate of 2.28% annually

Year Glen Rose Rest of County Total

2010 2,721 5,090 7,811

2015 2,914 5,706 8,620

2020 3,107 6,322 9,429

2030 3,493 7,889 11,382

POPULATION PROJECTION

• Somervell County average day demand estimated 85 gallons per capita day.

• Maximum Peaking Factor of 2.5

• Peak hour to max day peaking factor of 2.0.

Year

City of Glen Rose Served

(%)

Somervell County Served

(%)

Served Avg Day Demand

(MGD)

Served Max Day Demand

(MGD)

Served Peak Hour Demand

(MGD)

2010 100% 10% 0.99 1.82 3.22 2015 100% 30% 1.17 2.29 4.15 2020 100% 50% 1.39 2.83 5.23 2030 100% 70% 1.75 3.73 7.03

WATER DEMANDS


Water System Hydraulic

Analysis

• Water System Model

• Model Analysis using Maximum Day Demands

• Model using Adequate Pressures and Fire Flow Demand of 500 gpm

• Model used to Develop CIP for 2030 Improvements

WATER SYSTEM HYDRAULIC ANALYSIS


Capital Improvements Plan

• Phases

Project Description Total Project

1 WTP and Transmission to Glen Rose and Luminant $18,352,569

2 East Main Service I $5,730,000

3 East Main Service II $1,950,000

4 West Main I $2,701,350

5 East Expansion I $7,167,350

6 West Main Service II and East Expansion I $5,336,350

7 East Expansion II $8,650,000

8 East Expansion III $7,100,000

9 Heights/ Methodist Encampment Improvements $8,459,350

10 South Expansion $12,008,000

11 West Expansion II $6,876,750

12 West Expansion III $6,756,500

13 East IV and South II Expansion $8,937,550

TOTAL $100,033,769

CAPITAL IMPROVEMENTS PLAN




Treatment Planning

• Paluxy River Quality

• Low Salts Concentration

• Low Organics

• Clear water low in particulates except following rain events

• Non-corrosive

• Hardness compared to Groundwater

WATER QUALITY ANALYSIS

• Paluxy River Water Sampling December 2001

ENGINEERING A DRINKING WATER SUPPLY

• Remove / Inactivate Pathogens, including Cryptosporidium and Giardia

• Remove Colloidal Particulates

• Remove Organics

• Provide Hardness similar to Groundwater (Secondary Objective)

• Primary Drinking Water Quality Standards

TREATMENT OBJECTIVES

• Five Treatment Alternatives Evaluated:

–Alternative # 1: Solids Contact Clarifiers with Conventional Filtration Treatment

–Alternative # 2: Package Water Treatment Plant with Ion Exchange Sidestream Treatment for Softening

–Alternative # 3: Conventional Treatment with MF/UF-Membranes & NF-Membrane Sidestream Treatment for Softening.

TREATMENT ALTERNATIVES

• Treatment Alternatives Evaluated (Cont…):

–Alternative # 4: Direct MF/UF-Membranes Filtration & NF-Membrane Sidestream Treatment for Softening.

–Alternative # 5: Direct MF/UF-Membranes Filtration with Ion Exchange Sidestream Treatment for Softening.

–Alternative # 6: Direct MF/UF-Membranes Filtration (No Softening)



Clearwell

Backwash Pump

Disinfection

Distribution System

High Service Pumps

Wheeler Branch

Reservoir

Waste Discharge

Micro-Filtration Membranes

Reservoir

To Brazos Tributary

RWPS

Paluxy River

Channel Dam

River Water

MF/UF

• Selected Treatment Alternative

–Alternative # 6: Direct MF/UF-Membranes Filtration (No Softening)


Water Treatment Plant

Design

• Per 30 TAC Chapter 290.42 (g) Membrane Technology is Innovative or alternate treatment techniques.

• Pilot Study included Two (Preselected) Membrane Manufacturers

• Pilot Study Pretreatment

• Pilot Study conducted Inside Raw Water Pump Station

TREATABILITY STUDY – MEMBRANES

• Protocol Submitted to TCEQ for Approval

• Pilot Study Protocol Described a 3 Stage Evaluation

–Stage 1: Membrane system optimization flow rates, backwash rates, chemical doses, etc.

–Stage 2: Performance Stage using optimum conditions for 30 days (uninterrupted)

–Stage 3: Evaluation of Membrane Irreversible Fouling

TREATABILITY STUDY – PILOT STUDY

MEMBRANE PILOT STUDY

• Membrane Treatment Capacity 2.5 MGD

• Design Parameters: – Membrane Flux: 45 GFD

– Membrane Recovery: 96% Recovery

– Membrane Modules: 108

– Membrane Backwash: 20 Minutes

– Enhanced Flux Maintenance: 24 Hours

– Clean in Place Cleaning: 30 – 60 Days

WATER TREATMENT PLANT DESIGN

• Raw Water Feed System:

• Y-Strainers & Self-Cleaning Strainers

• Reverse Filtration Pumps

• Compressed Air System:

• Chemical Dosing System

• Neutralization System


• Membrane Equipment September 2011


• Residual Handling Lagoons (TPDES Permit)

• Disinfection Strategy

• Two 125-Gallon Concrete Clearwells

• High Service Pump Station

–Firm Capacity 3.75 MGD

–Horizontal Split-Case Centrifugal Pumps

• Construction Completed in November 2011



• Membrane Building November 2011


QUESTIONS ?


THANK YOU


Ignacio Cadena, P.E. Ph: 817 735 7283 E-mail: [email protected]

ENGINEERING A NEW DRINKING WATER SUPPLY · 5 East Expansion I $7,167,350 6 West Main Service II and East Expansion I $5,336,350 7 East Expansion II $8,650,000 8 East Expansion III

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