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Joint Water Purification Project- Colorado's First Planned Indirect Potable Reuse

April 25, 2013

Joint Water Purification Project- Colorado's First Planned Indirect Potable Reuse

April 25, 2013

California WATEREUSE – Central Valley Sierra Foothills California WATEREUSE – Central Valley Sierra Foothills

Project Overview Project Overview

• Joint venture with two
• wners:

– Arapahoe County W&WW Authority (ACWWA) – Cottonwood W&S District (CWSD)

• Location

– Southeast Denver metro area

• System Capacity

– Initial= 9 mgd – Build out= 12 mgd

Water Supply Sources Water Supply Sources

• Sources

– Non-renewable deep aquifer sources – Renewable Cherry Creek alluvial water

• The renewable alluvial water has

several water quality issues:

– High percentage of effluent form upstream WWTPs – (≈ 60% current, up to ≈ 80% in the future) – Emerging contaminants of concern – Aesthetics (Iron, color, hydrogen sulfide) – Uranium and radon gas

Cherry Creek and a typical alluvial well house

Alluvial / Indirect Potable Reuse Water Quality Issues Alluvial / Indirect Potable Reuse Water Quality Issues

Water Quality Concerns

Microbial Re-growth in Wastewater

Project Goals Project Goals

• Original Project Goals:

– Provide treatment for the alluvial water supply, thereby protecting its long term usability – Long-term implementation of Indirect Potable Reuse to the extent possible – Provide an appropriate level of treatment that would have public support – Maximize use of renewable alluvial supply – Address aesthetic concerns

→ Many of these are policy level decisions

Key Components of the Indirect Potable Reuse System Key Components of the Indirect Potable Reuse System

• Expansion and upgrades

to the Lone Tree Creek Water Reclamation Facility (LTCWRF)

• Development of a Raw

Water Delivery system that provided 6 months of travel time

• Development of a water

treatment facility and associated waste stream treatment processes

The LTCWRF, which includes tertiary treatment/ filtration, was placed into operation August 2009

Overall System Configuration Overall System Configuration

Water Treatment Brine Treatment Wastewater Treatment

Alluvial Recharge Deep Aquifer Wells Dedicated Alluvial Wells Dedicated Alluvial Wells Brine to Discharge

JWPP WTP

Park/ Greenbelt Irrigation Potable Water Use Waste Discharges to Sewer

Project Timeline

Project Initiation

2003 July 2005 Sept 2005 Jan 2006 June 2006 Oct 2007 Feb 2008 Aug 2009 June 2010

JWPP WTP Pre-Design Complete LTCWRF Pre-Design Complete LTCWRF Design Complete LTCWRF Construction Begins JWPP WTP Design Complete JWPP WTP Construction Begins LTCWRF Construction Complete JWPP Producing Water

Project Development Project Development

• Developed a Technical Advisory

Committee (TAC)

• Hired a Public Relations firm to assist

with developing the message

• Evaluation & comparison to CA Indirect

Potable Reuse Systems, site visits

• Implementation of multiple barrier

concepts

• Progress design meetings with Colorado

Dept of Public Health and Environment

• Presentations to engineering community
• Public participation and presentations
• Value Engineering during design

Technical and Institutional Issues Technical and Institutional Issues

• Development in a high end commercial park
• Fouling of RO membranes due to

wastewater colloidal particles

• Treatment of RO brine to remove

phosphorus and other permit requirements

• Impacts of waste streams to the sewer

system

• Accumulation of salts in the alluvium due to

RO brine discharge

• Challenges in developing the raw water

system, including yield and locating wells with acceptable water quality for membranes

Significant capital and O&M costs are realized for the RO brine treatment system

Comparison of System Configurations Comparison of System Configurations

Joint Water Purification Project

Advanced Water Treatment Advanced Wastewater Treatment Alluvial/Aquifer Discharge and Treatment Advanced Wastewater Treatment Advanced Water Treatment Alluvial/Aquifer Discharge and Treatment

California IPR Systems

ACWWA/CWSD have little control over

• ther WW discharges

and urban runoff Customers Customers

Potable Treatment Configuration Potable Treatment Configuration

Water Quality Monitoring RO Skids Oxidation Reactors (UV/H2O2) Air Strippers

Clearwell/ Disinfection Alluvial Filtration/ 6 month Travel Time

Advanced Wastewater Treatment

Plant Multiple Barrier Concepts Plant Multiple Barrier Concepts

1. Will generally remove organics except volatiles with MW < 200-300 2. Will remove radionuclides with the exception of radon gas 3. Will remove light volatile organics 4. Will remove radon gas only

TREATMENT PROCESS CONTAMINANTS OF CONCERN

Pathogens/ Microbial Inorganic Radionuclides Organics

TOC VOC/SOC Emerging

Alluvial Filtration X1 X1 X1 X1 Reverse Osmosis X X X2 X X3 X3 Advanced Oxidation X X Air Strippers X4 X5 Chemical Disinfection X

Construction Cost Summary Construction Cost Summary

ITEM COST

Bid Package 1- Water Treatment Plant $27,500,000 Potable Treatment Processes $23,000,000 Concentrate Treatment System $4,500,000 Bid Package 2- Pipelines $3,500,000 Bid Package 3- Raw Water Supply Wells $2,000,000

TOTAL $33,000,000

Questions and Answer Questions and Answer