Background. Need for more water:

(1)

Rainwater Harvesting from Tucson Rooftops:

Can we promote water conservation

and

and protect human health?

protect human health?

Nathan

Nathan Allen, Angela Knerl,

Allen, Angela Knerl, Jean

Jean McLain, Rob

McLain, Rob Root,

Root, and Leif Abrell

and Leif Abrell

University of Arizona

Tucson PAG, Mar 31, 2014

(2)

Background

• Need for more water:

–

Arid and semi-arid lands in U.S.

receive~300 mm of rain a year

–

Western U.S. has fast growing cities

that rely on finite water supply

–

Need to recycle water: wastewater & rain

harvesting

(3)

Background: Rooftop rainwater

• Cisterns as a tool

–

Capture and store water

, easy to install

–

May be promoted by utilities and local governments.

–

Reduce hydrologic problems

• Cisterns- a potential health and landscape hazard

–

Harvested water for garden and landscape irrigation,

yet

few water quality standards exist

.

–

Cisterns may concentrate atmosphere deposited

contaminants

–

_{Cisterns can host and incubate microorganisms of}

(4)

Background: gap and solution

• _{Knowledge gap:}

–

Harvested (recycled) water is most often used for garden

and landscape irrigation, yet no water quality standards

exist regarding the use of harvested rainwater.

• Solution

–

Monitor water quality over the 2013 monsoon season and

discern what homeowners should be wary of and when.

–

Assess ability of simple, cheap filters to change water

quality

–

Pass findings to utilities and municipalities in the western

U.S. to draft plans for safe rainwater harvest and recycling.

(5)

Cisterns 3 and 4

Water Resource

Research Center (WRRC)

Biosphere 2

Cisterns 1 and 2

2013 Data:

Experimental sites

(6)

2013 Data:

Description of Systems

Site Tank Location First flush Cap. (gal) Output Roof Area (ft2₎ Roof comp. Tank comp. B2

C1 S. East Yes 2500 Spigot 250

Built up white elastomeric

Fiberglass

C2 N. East Yes 2500 Dipper 935

Built up white elastomeric Fiberglass WRRC C3 North No 500 Spigot 750 Built up white elastomeric Galvanized Steel & Concrete C4 West No 300 Spigot 800 Built up white elastomeric Galvanized Steel & Concrete

(7)

2013 Data:

(8)

2013 Data:

Sample Preparation and Analysis

• Microbiology - Total coliforms, E. coli, and

Enterococcus by Colilert and Enterolert quanti-tray

technique (IDEXX).

• Metals analysis - samples filtered, acidified to pH<2;

ICP-MS analysis of 16 metals

• Organic contaminants - samples filtered, extracted by

SPE (solid phase extraction); LC-MSMS analysis of

(9)

2013 Data:

Coliform Results

• Water guidelines:

“# of indicator

bacteria/100mL”

• WHO guidelines for

“irrigation of crops

likely to be eaten

uncooked” < 1000

Fecal

Coliforms/100mL

• Sources: animals

(including birds),

humans

Microbiology

(10)

2013 Data:

Enterococcus

Results

Microbiology

• Enterococcus:

indicator for marine

bathing; correlates

with presence of

pathogens

• Enhanced survival in

the environment

• Sources: birds

(11)

2013 Data:

Indicator Reliability

Microbiology

Regulated indicators vs. disease-causing

indicators. What is causing selective survival of

one indicator but dieoff of the other?

(12)

Metals analysis

Arsenic

5 Cancer risk

Toxic

Barium

100 Increase Blood

pressure

Cadmium

1 Kidney

damage

Chromium

5 Toxic /

Dermatitis

Lead

5 Neurotoxin

Mercury

0.2 Kidney

Damage

Selenium

1 Hair

loss

Silver

5 Argyria

OSHA Regulated Elements (shaded)

(13)

Metals analysis

Arsenic

5 Barium

100 Cadmium

1 Chromium

5 Lead

5 Mercury

0.2 Selenium

*

1 Silver

5 *

*

(14)

2013 Data

(15)

Metals analysis

B2

WRRC

(16)

(17)

2013 Data

Metals analysis

Ba

Hg

Se

(18)

Liquid chromatography - tandem mass

spectrometry

(LC-MSMS) – PPCPs, EDCs,

(19)

Approach Moving Forward

• Completion of Organic contaminants analysis

Perfluorinated compounds (PFCs) – some distribution by

atmospheric deposition; new EPA monitoring rule.

Perfluooctanoic acid (

PFOA

) - non-stick surfaces on cookware

and waterproof, breathable membranes for clothing

Perfluooctane sulfonic acid (

PFOS

) - fire fighting foams and

various surfactant uses

PFOA PFOS

(20)

4 prong approach

1. Microbiological

2. Organic

3. Inorganic chemistry

4. Citizen science

Establishing chemical and microbiological indicators of safe, harvested rainwater to

promote water conservation and public health

Proposal submitted to EPA Feb 18, 2014

Chorover, Root, McLain, Allen, Abrell (Knerl, Eden)

$750K / 3 years

• EPA RFP: Human and Ecological Health Impacts Associated with

Water Reuse and Conservation Practices

• RFP focused on research that measures and quantifies health and

ecological impacts from unplanned and planned potable water reuse

by comparison to conventional systems.

(21)

Expected Outcomes

• Energy conservation,

• Water conservation,

• Nutrient management,

• AZ Gov has released a strategic water plan

• STEM is specifically noted in RFP,

–

we will use community science and students.

(22)

Thank you

Seed Grant:

The University of Arizona National Science Foundation

Water & Environmental Technology (WET) Center

(23)

Leaf Free

Critter Free

Insect Free

Light Proof

(24)

Rooftop Water Catchment Survey 1. Roof

•What type of roof (flat or pitched)?

•Age of roof (<5yr; 6-10yr; 11-20yr; 21-50 yr; >50yr; unknown)

•Roof material (coatings etc.)

•Overhanging trees: (Y N)

•Aspect: (N E S W)

2. Cistern

•Age of cistern: (<5yr; 6-10yr; 11-20yr; 21-50 yr; >50yr; unknown)

•Material: (Lined; unlined; plastic; metal; galvanized)

•Size: (____ gallons)

•Above ground: (Y N)

•Installation: (Contractor; Self; previous owner; unknown)

•How often does the cistern run dry? (____days per year)

•Water quality problems: (smell; fouling; cloudy; none) frequency

•Sediment buildup: (Y N)

•Treatments/cleaning: (Bleach; soap; water softener)

•Location: (________ GPS rounded to nearest 5 seconds)

•Do you have any of following within 200ft of the cistern?

(Septic tank; Underground storage tank; Animal lot; None; Other) 3. Gutters and water spouts

•Age (<5yr; 6-10yr; 11-20yr; 21-50 yr; >50yr; unknown)

•Material (plastic; metal; galvanized)