Joint Water Purification ProjectColorado's First Planned Indirect. Potable Reuse

Transcription

1 Joint Water Purification ProjectColorado's First Planned Indirect Potable Reuse April 25, 2013 California WATEREUSE Central Valley Sierra Foothills

2 Project Overview Joint venture with two owners: 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

3 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

4 Alluvial / Indirect Potable Reuse Water Quality Issues Microbial Re-growth in Wastewater Water Quality Concerns

5 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

6 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

7 Overall System Configuration Alluvial Recharge Park/ Greenbelt Irrigation Dedicated Alluvial Wells Dedicated Alluvial Wells Potable Water Use JWPP WTP Water Brine Waste Discharges to Sewer Wastewater Brine to Discharge Deep Aquifer Wells

8 Project Timeline Project Initiation 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 2003 July 2005 Sept 2005 Jan 2006 June 2006 Oct 2007 Feb 2008 Aug 2009 June 2010

9 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

10 Technical and Institutional Issues Development in a high end commercial park Fouling of RO membranes due to wastewater colloidal particles 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

11 Comparison of System Configurations Advanced Wastewater Advanced Water Customers Alluvial/Aquifer Discharge and California IPR Systems Advanced Water Advanced Wastewater ACWWA/CWSD have little control over other WW discharges and urban runoff Alluvial/Aquifer Discharge and Joint Water Purification Project Customers

12 Potable Configuration Water Quality Monitoring Advanced Wastewater Alluvial Filtration/ 6 month Travel Time RO Skids Oxidation Reactors (UV/H2O2) Air Strippers Clearwell/ Disinfection

13 Plant Multiple Barrier Concepts TREATMENT PROCESS CONTAMINANTS OF CONCERN Pathogens/ Inorganic Microbial Alluvial Filtration X1 Reverse Osmosis X X Radionuclides X2 Advanced Oxidation Air Strippers X4 Chemical Disinfection Organics TOC VOC/SOC Emerging X1 X1 X1 X X3 X3 X X X5 X Will generally remove organics except volatiles with MW < Will remove radionuclides with the exception of radon gas Will remove light volatile organics Will remove radon gas only

14 Construction Cost Summary ITEM Bid Package 1Water Plant COST $27,500,000 Potable Processes $23,000,000 Concentrate System $4,500,000 Bid Package 2Pipelines $3,500,000 Bid Package 3Raw Water Supply Wells $2,000,000 TOTAL $33,000,000

15 Questions and Answer