What is the Water/Energy Nexus?

When you use water, you use energy

When you make energy, you use water

Pumping, transport, treatment, lifting, sewage treatment

Energy: Centralized vs. Decentralized

The Solution to most sustainability issues is On-Site Solutions

Centralized Wastewater Plant

2 out of every 3 gallons of indoor water

Rule of thumb: 40 gallons / person /day

Adds up quickly to 50,000 gallons annually

*No toilet or kitchen waste

Greywater – 40+ years of “potential”

A remarkable, but little-used resource:• Found in every home

• ‘Motherlode’ of relatively clean water (2,000,000 acre-feet/year in California alone)

• Relatively easy to treat

The Obstacles:• Cobbled, engineered, DIY solutions abound

• No consistent standard or regulatory framework….untilNSF-350 became standard in California

California leads in Mainstreaming Greywater

1. Third-party certification standard: NSF-3502. Incorporated into California Plumbing code (2013)3. Whole-home, productized solutions (March 2015)4. Drought imperatives for more use of On-site Water

Resources (April 2015)5. Broad desire for home-based solutions6. Emergency Revisions to building standards, CalGreen and

Model Landscape Ordinance (June/July 2015)7. Local Codes emerging - San Francisco, LA, Silicon Valley

Water Quality Spectrum

500 450 400 350 300 250 200 150 100 50

Grey Water (untreated)

BOD5

50 45 40 35 30 25 20 15 10 5

BlackwaterSewage

PotableSecondary

Treated water

SepticDischarge

Tertiary Treated water

NSF/ANSI-350 Standard“NSF/ANSI Standard 350 is a revolutionary standard established to set clear, rigid, yet realistic guidelines for water reuse treatment systems. With a key focus on public health and appropriate water quality criteria for reuse applications….” NSF.org

Independently validated for system performance

Undergone rigorous 6-month test program

Verified to meet stringent water quality

Verified to produce no odor

Tested for electrical safety

Tested to maximum permitted sound levels

Tested for strength and integrity requirements

Maintenance-free for 6-month minimum

Approved with warranty and literature

Subjected to annual audit requirements

Systems certified to NSF/ANSI-350 are:

2 Categories of Greywater Emerge: Non-Certified vs. NSF-350 certified

Non-certified

NSF-350 Certified

Permitted by Plumbing code *

Outdoor water reuse Limited Unrestricted

Subsurface Irrigation

Drip Irrigation

Spray Irrigation

Fountains

Car Washing

Indoor water reuse

Toilet Flushing

Urinal Flushing

Storage of water allowed for on-demand reuse

Mandatory 2-year servicing included #

CA State and Local permissions (regulations vary across the US)

*Conditional approval based on suitability; including discharge basin, discharge parameters and bypass provision.# May be included by some manufacturers but is not typical.

Current Installations

Alamo Sacramento

Los Angeles

BeaumontLancaster

Orange County San Diego

Carmel

CNBC Business News

Mainstream Recognition:

Best in Show:

By:

Benefits of On-Site Water Recycling:For Builders & Homeowners• Permission to build• Lusher, more differentiated landscapes• “Drought resilience” protects landscape and home resale

valueFor Water and Sewer Agencies, Cities, Developers• Protect future city growth potential• Cut new home water usage almost in half• Build 2X homes with same water supply • Ensure little or no potable water used for Irrigation • Cut sewer volumes by 3 X – peak flows by 6 X• “Infra-Stretch”: Stretch existing infrastructure – save millions

on sewage treatment • Saves water today – not ten years from now

O3

Treatment Process

1. Grey Water Collection

2. Batch Treatment Process

– Coarse Filtration (~30 mesh)

– Hybrid Flotation (Aeration, Ozone and Electrolysis)

– Activated Carbon Contact

– Fine Filtration (<0.5µ)

– UV Disinfection

3. Storage and Reuse Management

4. Monitoring and Reporting

5. Fault Detection

Raw grey water enters NEXcollectorExcess overflows to sewer (automatic)10 gallon batch enters NEXtreaterCoarse FiltrationAerationOzone InjectionElectrolysisHybrid FlotationActivated Carbon ContactFine FiltrationUV DisinfectionDelivery to NEXservoirTop Up and Recirculation as needed

What the Homeowner Sees

“Seeing” Performance:

The MyNexus App

Total Potable Water Used Per Day – Family of 4

[ Each barrel = 60 gallons/day ]

New Homes

10 Year Old HomeCode Fixtures,

Spray Irrigation

WaterSense,

Microspray/Drip

WaterSense,

Microspray/Drip,

+ Recycling

150 gpc

45 gpc

75 gpc

120 gallons per capita daily

600 gal

0 gal

Each barrel equals 60 gallons

Water Recycling HomeHigh Efficiency Home

120,000

72,000

24,000

An

nu

al W

ater

Use

(Gal

.)

Outdoor Water Outdoor Water

Indoor Water Indoor Water

Water efficient homes use 66% more

water than recycling homes

6am noon 6pm midnight 6am noon 6pm midnight

TYPICAL SEWER FLOWS

Standard Home With Grey Water Reuse

Average

PeakAverage

Peak

70% lower wastewater and And much smaller peaking factors

allows lower CAPex and OPex

Best time to install tanks is during initial trenching

Lining up tanks

Tank lids peeking above ground before final landscaping

Pre-configured NEXbench

“Recycle-Ready Plumbing” – the new Best Management Practice (BMP)

• Up-grade pathway to Home Water Recycling

• Home sewers combine blackwater sewage with relatively clean greywater

• “Recycle Ready” -- separates grey from black and pre-configures home for the future

• On-site recycling potential at half the cost

• Takes away builder’s risk of new technology

“Recycle Ready Plumbing”–collection and storage tanks, and universal installation bench placed at time of construction

Home Energy Recycling from Greywater

• 18% of all California home energy use is for water heating (EIA)

• 24% for new California homes (RESNET)

• Water heating energy has been resistant to reduction – how to raise w/h efficiency?

• Water Heating energy goes “Down the drain” as grey water

• 75-80% reduction in Water Heating energy

Geothermal: Earth Energy Transfer

Home Energy Recycling –Everyman’s Geothermal

• The Home Water/Energy Nexus – resides in hot water that becomes greywater

• On-site “Home Water Recycling” raises water efficiency, addresses drought and protects lifestyle expectations

• “Home Energy Recycling” is the most effective way to cut Home Energy use in Water Heating

• Greywater Recycling addresses the Home Water/Energy Nexus

Key Points