Trends In Indirect and Direct POTABLE REUSE IN THE UNITED STATES - - PowerPoint PPT Presentation

Trends In Indirect and Direct POTABLE REUSE IN THE UNITED STATES California WateReuse Association Central Valley/Sierra Foothills Chapter Central Valley/Sierra Foothills Chapter

July 18, 2013 George Tchobanoglous

Department of Civil and Environmental Engineering University of California, Davis

Topics

• Types of reuse accepted worldwide
• Reuse: Projected worldwide growth
• Indirect and direct potable reuse
• Treatment technologies
• Treatment technologies
• A Southern California Case Study
• Regulatory framework
• Need for uniform accepted vocabulary

TYPES OF REUSE ACCEPTED WORLDWIDE AND PROJECTED AND PROJECTED GROWTH

Types of Reuse Worldwide

• Agricultural irrigation (seasonal demand)
• Landscape irrigation (seasonal demand)
• Industrial (constant demand, site specific)
• Non-potable urban uses (limited volumes)
• Recreation/environmental uses (site specific)
• Recreation/environmental uses (site specific)
• Indirect potable use through groundwater

recharge (requires suitable aquifer)

• Indirect potable use through surface water

augmentation (availability of reservoir sites)

• Direct potable use (best option, but public

perception issues must be dealt with)

Reuse Market Size and Growth 2008

15 20 25 30

mand, 10

6 m 3/d

East Asia and Pacific North America Middle East and Africa

Source: GWI Global Water Market 2008

5 10

2006 2008 2010 2012 2014 2016 2018 Water dem Year Western Europe

Driving Forces for Direct and Indirect Potable Reuse

• The value of water will increase significantly in the

future (and dramatically in some locations)

• De facto indirect potable reuse is largely

unregulated (e.g., secondary effluent, ag runoff, urban stormwater, highway runoff)

• Infrastructure requirements limit reuse opportunities
• Infrastructure requirements limit reuse opportunities
• Existing and new technologies can and will meet the

water quality challenge

• Population growth and global warming will lead to

severe water shortages in many locations. A reliable alternative supply should be developed

• Must think differently about water

De Facto Indirect Potable Reuse

Courtesy City of San Diego

Definition of Planned Indirect and Direct Potable Reuse

De Facto and Indirect Potable Reuse

(existing in fact, whether recognized legally or not)

OCWD Groundwater Buffer Upper Occoquan, San Diego, CA (Proposed) Surface Water Buffer

TYPES OF PROJECTS

Infiltration Basin, Florida, USA

Kraemer/Miller Spreading Basins, OCWD and Legacy Regulations

Barrier Injection Wells

Groundwater Injection Wells

Indirect Potable Reuse Through Surface Water Augmentation: San Diego, CA

Courtesy City of San Diego

San Vincente Reservoir, San Diego County

San Vincente Reservoir, San Diego County

TRENDS IN TREATMENT TECHNOLOGIES

Existing and New Treatment Technologies

• Technologies for the removal of BOD,

TSS, nutrients, and pathogens

• Technologies for the removal of TDS,

trace constituents, and unknowns

• Brine management for inland locations
• TREATMENT IS NOT THE ISSUE

What Are Others Doing?

• Windhoek, Namibia
• Pure Cycle Corporation
• International Space Station
• Cloudcroft, New Mexico
• Big Spring, Texas
• Orange County Water District
• Alternative Treatment Processes

Treatment Process Flow Diagram Windhoek, Namibia

Treatment Process Flow Diagram Pure Cycle Corporation (c.a. late 1970s)

Treatment Process Flow Diagram Pure Cycle Corporation (c.a. late 1970s)

Urine Treatment Process Flow Diagram International Space Station (c.a. 2011)

Treatment Process Flow Diagram Cloudcroft, NM (c.a. 2011)

Treatment Process Flow Diagram Big Spring, Texas (c.a. 2011)

Technologies for the Removal of TDS, Trace Constituents, Unknowns

Adapted from OCWD

Microfiltration, Cartridge Filters, Reverse Osmosis, and Advanced Treatment (UV), OCWD

Impact of Recycle Flows on Nitrogen Removal

Return flows contain nitrogen

Brine Management: Concentration with Falling-Film Evaporator

Technologies for the Removal of Trace Constituents and Unknowns

Adapted from Sundaram et al., 2009

Comparison of Technologies for the Removal of Trace Constituents & Unknowns

Item MF-Ozone-BAC MF-RO-UV/Peroxide Fate of trace organics Degraded Removed and degraded Reject/side streams Minor (periodic backwash water) Major (up to 20%) Salinity Unchanged Decreased significantly

Adapted from Sundaram et al., 2009

Salinity Unchanged Decreased significantly Corrosivity Unchanged Increased (requires buffering) Energy consumption without MF 0.03 - 1.0 kWh/m3 8 - 10 kWh/m3

Alternative DPR Flow Diagrams With and Without Reverse Osmosis With Engineered Buffer

SOUTHERN CALIFORNIA CASE STUDY CASE STUDY

DPR Opportunities for the Future: The Southern California Example

Electric Power Consumption in Typical Urban Water Systems

System Power consumption, kWh/Mgal Northern California Southern California

Supply and 150 8,900 Supply and conveyance 150 8,900 Water treatment 100 100 Distribution 1200 1200 Wastewater treatment 2,500 2,500 TOTAL 3,950 12,700

DPR Opportunities for the Future: The Southern California Example

Water Use By County in Southern CA

Item

Quantity, Mgal/d

Los Angeles Orange San Diego Riverside San Bernardino

Population, 9,935 2988 2933 1946 1964 Population, 1000’s 9,935 2988 2933 1946 1964 Groundwater 331 49 75 86 77 Surface water 1529 335 356 349 287 Total 1860 384 431 435 364

Wastewater Management Infrastructure

Benefits of the Southern California Example

• Reliable alternative source of supply, more secure

from natural disasters

• Lower cost and reduced energy usage
• More water available for agricultural use, especially

during drought periods during drought periods

• Environmental benefits for bay delta habitat

restoration

REGULATORY REQUIREMENTS

Science Versus Regulations

Pre 1880s Physical observations - No Science - Common sense practices (regulations) Enlightenment 1880-1980s Science develops - Semi-scientific, observational, and empirical regulations follow empirical regulations follow Post 1980s Science leaps ahead - Science based regulations have evolved, but have not kept pace - Semi-empirical and empirical legacy regulations persist. .

NEED FOR UNIFORM ACCEPTED TERMINOLOGY TERMINOLOGY

Need for Accepted Vocabulary

Issues

• There is a need to speak with one voice
• Not everyone agrees that indirect potable reuse is

acceptable

• Little standardization of terms (e.g., indirect and

direct potable reuse) direct potable reuse) Consequence

• Everyone says whatever suits their particular interest
• The public is confused, especially about the safety of

reclaimed water.

• A uniform vocabulary is of critical importance, if reuse

projects are to be discussed rationally

Closing Thoughts

• Direct (and indirect) potable reuse will be a critical

element in the development of sustainable strategies for water resources management

• Technology is now available to produce water for

any use including direct potable pipe to pipe reuse any use including direct potable pipe to pipe reuse

• Must resolve disconnect between existing

standards and regulations and scientific findings

• In promoting water reuse, the profession must

speak with a unified vocabulary

THANK YOU FOR LISTENING LISTENING