Water Reuse

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Water Reuse

Bruce Lesikar

Texas Cooperative Extension

University Curriculum Development

for Decentralized Wastewater

Management


NDWRCDP Disclaimer

This work was supported by the National Decentralized Water

Resources Capacity Development Project (NDWRCDP) with

funding provided by the U.S. Environmental Protection Agency

through a Cooperative Agreement (EPA No. CR827881-01

01-0) 0)

with Washington University in St. Louis. These materials have

not been reviewed by the U.S. Environmental Protection

Agency. These materials have been reviewed by

representatives of the NDWRCDP. The contents

of these materials do not necessarily reflect the views and

policies of the NDWRCDP, Washington University, or the U.S.

Environmental Protection Agency, nor does the mention of trade

names or commercial products constitute their endorsement or

recommendation for use.


CIDWT/University Disclaimer

These materials are the collective effort of individuals from

academic, regulatory, and private sectors of the

onsite/decentralized wastewater industry. These materials have

been peer-reviewed reviewed and represent the current state of

knowledge/science in this field. They were developed through a

series of writing and review meetings with the goal of formulating

a consensus on the materials presented. These materials do not

necessarily reflect the views and policies of University of

Arkansas, and/or the Consortium of Institutes for Decentralized

Wastewater Treatment (CIDWT). The mention of trade names or

commercial products does not constitute an endorsement or

recommendation for use from these individuals or entities, nor

does it constitute criticism for similar ones not mentioned.


Citation

Lesikar, B.J., B. Lee and D. Waller 2005. Water

Reuse - PowerPoint Presentation. in (M.A.

Gross and N.E. Deal, eds.) University

Curriculum Development for Decentralized

Wastewater Management. National

Decentralized Water Resources Capacity

Development Project. University of Arkansas,

Fayetteville, AR.


Reclaimed Water IS a Resource

Water is necessary to sustain life

• Human consumption

• Food production

• Many daily tasks

‣Current supplies are not sufficient given

increased demand

Reuse water has the capacity to augment

current potable water supplies for various

tasks

‣Higher demand = Less available supplies


Hydrologic Cycle

‣ Natural system of water recycling

Water moves back and forth between the

Earth and the atmosphere

‣ Evapotranspiration takes water into the

atmosphere; precipitation returns water to

the Earth’s surface

‣ On-site system catches water after use

and allows the water to be used again

before release


Hydrologic Cycle


Earth’s Water Resources

Salt Water (97%)

Frozen Fresh Water

(2%)

Other 3%

Ground and

Surface Waters

1%

Frozen Fresh Water

2%

Ground and Surface

Waters (1%)

Salt Water

97%


Water Demand in the U.S.

‣ U.S. water demands in 1995

• Source: USGS Survey - Estimated Use of Water in

the United States in 1995 (1998).

• Average 402 billion gallons per day withdrawn

• 90% (362 billion gallons per day) was for

agricultural/industrial purposes

• 33.3% (134 billion gallons per day) was for irrigation

• 10% (40 billion gallons per day) was for household:

75 to 80 gallons per person per day


Water Reuse Stabilizes Demand

500

1.2

450

400

1

Total Water Withdrawals, 1000 mgd

350

300

250

200

150

0.8

0.6

0.4

Reclaimed Wastewater, 1000 mgd

100

50

0.2

0

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995

Year

0

Total Water Withdrawal

Reclaimed Wastewater


Typical Water Reuse Cycle


Another View of the Cycle


Chapter 2

Applications for

Reclaimed Water


Applications for

Reclaimed Water

‣ Greywater * Recovery

‣ Greywater * Recycle

‣ Greywater * Reuse

*Greywater

is water captured from sinks, showers, baths,

clothes washing machines, laundry tubs and dishwashers,

but NOT from toilets or urinals.


Greywater

‣ Various sources of contamination

Biological

• Microorganisms

• Biological

• Chemical

• Dissolved salts – sodium, nitrogen, phosphates,

chloride

• Chemicals – oils, fats, milk, soap, detergents

• Physical

• Soil

• Food

• Lint


Greywater Recovery

‣ Greywater Reuse

• May be treated or untreated

• Diverted or collected, treated, stored, and reused

‣ Use Sudsaver *

* a setting on some washing machines that retains water

from the rinse cycle and uses that water in the following

wash cycle.


‣ Direct

Greywater Reuse

• Divert water

• Filter before use for irrigation

• No kitchen water used

• No storage of untreated water

‣ Collect, treat, store, and use

• Treatment processes vary

• With disinfection, may be used for surface

irrigation


Greywater Diversion Devices

‣ Greywater has a potential of

pathogens and therefore is generally

kept below ground surface

‣ Direct application to soil

‣ Kitchen wastewater - excluded

‣ No storage

‣ Must pass Coarse screen


Greywater Diversion Example


Using Sudsaver

‣ Sudsaver – a setting on some clothes

washing machines that holds used rinse

water and reuses it for the next washing

cycle

‣ Saves ~20 gallons of water per cycle

‣ Caution for usage


Typical Sudsaver


Greywater Recycle

‣ In-facility Use

• Use greywater for toilet and urinal flushing

• Two levels

• Individual buildings

• Cluster water reuse system

‣ Total Recycle/Non-Discharging/Closed Loop

• No water enters or leaves the system

• Drawback: potential accumulation of contaminants

due to repeated passage of water through the

system


In-Facility Use

‣ Used for toilet and urinal flushing

‣ Common in highly populated areas

‣ Two (2) types

• Individual building

• Cluster systems


Individual Building System

‣ Collect wastewater from sinks

separately

‣ Each building has its own reclamation

system

‣ Each building has dual plumbing

system


Cluster System

‣ Treat wastewater from block(s)

‣ Transfer treated (reclaimed)

wastewater back to buildings for

flushing

‣ Blocks and buildings have dual

plumbing system


Cluster System

Irvine Ranch Water District, CA


Total Recycle/

Non-Discharging/Closed Loop

‣ Use wastewater for beneficial purposes without

discharging – closed loop wastewater reuse

• This type of reuse is generally not allowed in the US

‣ Accumulation of certain constituents due to

repeated passage of water through the system

may be a problem

‣ Denver Potable Water Demonstration Project

• Feasibility study incorporating the highest form of

advanced technology under management by highly

skilled people


Denver Potable Water

Demonstration Project

‣ 1985 – 1992

‣ 0.1 MGD treated wastewater to produce

drinking water

‣ Multiple barrier approach

Water met or exceeded drinking water

standards

‣ No adverse health effects detected


Potential Reclaimed Water Uses

‣ Irrigation

Water Features

‣ Parks

‣ Artificial Snow-Making

‣ Groundwater Recharge

‣ Preventing Salt Water Intrusion

‣ Aquifer Storage and Recovery (ASR)

‣ Foundation Stabilization

‣ Fire Protection


Irrigation

‣ Agricultural

‣ Landscape

‣ Golf Courses

• Highest Risk for public health (Asano,(

et al.)

‣ Sport Fields


Agricultural Irrigation

‣ A well established practice

‣ U.S. EPA illustrated the guidelines in

Manual - Guidelines for Water Reuse

(EPA/625/R-92/004, 1992)


Application of Reclaimed Water for

Crop Production

‣ Protected from any possible diseases

‣ Specific regulations


Landscape (Turf) Irrigation

‣ Applications

‣ Two (2) types

• Irrigation of restricted areas 1

• Irrigation of open access areas 2

Water quality standards

‣ St. Petersburg,Florida

‣ Hawaii

1. Areas where the public has limited access or exposure to

reclaimed water (e.g., freeway landscapes)

2. Areas where the public has full access (e.g., golf courses,

playgrounds, parks, schoolyards, residential landscapes)


Golf Courses

‣ A popular application of reclaimed water

‣ In Florida, 419 golf courses had been

reported to use 110 MGD of reclaimed

water in 2001

‣ Many states in U.S. have this application


Sport Fields

‣ Irrigate sport fields by reclaimed water

‣ Reclaimed water must be highest quality

to protect the public

‣ In Hawaii, subsurface irrigation system

(drip system) is used


Sprinkler system

Drip System


Important Water Quality

Parameters for Irrigation Water

‣ Salinity

‣ Specific Ion Toxicity

‣ Long-Term Decreased Water

Infiltration Rates

‣ Nutrients


Salinity

‣ Electrical Conductivity (EC)

• decisiemens per meter (dS/m(

dS/m),

mmho/m or mgTDS/L

‣ TDS (mg/L) = EC x 640

‣ Adverse effects on plant growth

• Increases osmotic pressure


Specific Ion Toxicity

‣ High concentration of specific ions

affects plant growth

‣ Ions: sodium, chloride and boron

‣ Boron - most prevalent

‣ In arid regions – high

evapotranspiration accelerates the

problem


Decreased Water Infiltration Rates

‣ Sodium deteriorates soil physical

characteristics

• Formation of crusts

Water logging

• Reduced soil permeability

‣ Sodium adsorption ratio (SAR) and

Adjusted SAR (adj(

R Na ) help to predict the

impact of sodium on soil especially for

surface irrigation systems


SAR and Adjusted SAR

SAR

=

Ca

Na

2+

+

+ Mg

2

2+

adjR

NA

=

Ca

Na

2+

x

+

+ Mg

2

2+


Nutrients

‣ N, P, K, Zn, B and S act as beneficial plant

nutrients in correct doses

‣ High content of nutrients may reduce crop

quality

‣ Nitrogen - most excessive nutrient

‣ Measure to balance nutrients


Water Features

‣ Use for aesthetic purposes

‣ Examples: decorative pools,

fountains, ponds, etc.

‣ Variable

water quality

standards


Parks

‣ Use reclaimed water to create green

spaces in arid areas

‣ Reclaimed water quality requirements

depend on human access to the property

‣ Japanese Garden in Los Angels

metropolitan area


Japanese Garden

in Los Angles Area, CA


Created Park in

Los Angeles County, CA


Artificial Snow-Making

‣ Making snow in winter

‣ High quality required

‣ Snow melt feeds

surface water and

becomes irrigation

water in summer

The Snow Valley Ski Resort, CA

from Water Environment & Technology, Feb. 1993


Groundwater Recharge

‣ Purposes

• Retard saltwater intrusion

• Provide further treatment

• Augment aquifers

• Provide storage

• Control or prevent ground subsidence


Recharge Methods

‣ Surface Spreading

‣ Direct injection


Surface Spreading

‣ Replenishing groundwater by spreading

reclaimed water over ground

Water enters the ground and percolates

through the soil

‣ Rapid Infiltration Basins (RIBs(

RIBs) ) are the

fastest way to move water into soil


Percolation

‣ Greywater spread across ground

‣ Additional treatment provided by

soil

‣ Factors for treatment requirements

Percolation Field in Orange County, CA


Rapid Infiltration Basins (RIBs(

RIBs)

‣ Infiltrating reclaimed water

‣ Requires highly permeable soils

‣ The soil for RIBs can be the

following:

- sandy loam, loamy sand, fine

sands

‣ Basins must be rotated


RIB Site in Orange County, FL


Direct Injection

‣ Practiced where surface spreading

is NOT possible

‣ Injecting reclaimed water into a

confined aquifer

‣ Creating Salinity Barrier System

‣ Highest quality of reclaimed water


Problems with Groundwater

Recharge

‣ Large surface land requirement for

percolation

‣ High cost to inject reclaimed water

‣ Possible contamination of groundwater

‣ Large affected area

Water right issues


Saltwater Intrusion

‣ Zone of brackish water between salt

and fresh water along coastlines due

to withdrawal of fresh water from

aquifers

‣ Saltwater may be drawn into

freshwater supplies to replace

overdrawn freshwater supplies

‣ Occurs in many coastal communities


Saltwater Intrusion


Salinity Barrier System

‣ Establishing a fresh water barrier by

injecting reclaimed water back into

the aquifer

‣ Safe distance away from potable

water wells

‣ Specific regulations

Water quality required: highest


Aquifer Storage and Recovery

(ASR)

‣ Inject reclaimed water into a

subsurface formation

‣ Store water for later use

‣ Eliminate large surface water storage

requirement and associated

environmental and economic

problems


Considerations associated with

ASR

Water quality changing during

storage

‣ Contamination of existing

groundwater

‣ Treatment and disinfection upon

water recovery

‣ State of Florida


Foundation Stabilization

‣ Use reclaimed water

for construction

activities

• Foundation compaction

• Dust control

• Mixing of concrete

‣ Reclaimed water

quality issues


Fire Fighting & Protection

‣ Use for fire fighting and protection

‣ Creating greenbelt to prevent forest

fire

‣ Main issues:

• Reclaimed water storage

Water transportation cost


Fire Fighting

‣ Structural fire fighting – requires

the highest water quality

‣ Nonstructural fire fighting – lower

water quality requirements


Fire Protection

‣ Hydrants, sprinkler system ONLY in

commercial and industrial buildings

‣ Sprinkler system in residential

buildings - requires the highest water

quality


Greenbelts

‣ Layer of vegetation surrounding a property

that acts as a fire barrier

‣ Reclaimed water is used to maintain the

vegetation, especially in arid areas

‣ Between five and ten feet thick


Storage

‣ Storage tanks generally located uphill of

the site

‣ Must have enough capacity for all

demands, including fire protection

‣ Must account for operational and seasonal

storage and disposal

‣ Open reservoir or closed tank

‣ Problems with each type of tank need to

be considered


Problems with Open

Reservoirs

‣ Odors – hydrogen sulfide

‣ Temperature stratification

‣ Loss of chlorine residual and DO

‣ Excessive growth of algae

‣ High level of turbidity and color

‣ Regrowth of microorganisms

Water quality deterioration


Open Reservoir


Problems with Closed Tanks

‣ Release odors – hydrogen sulfide

‣ Stagnation

‣ Loss of chlorine residual

‣ Regrowth of microorganisms


Closed Tank for Reclaimed Water


End of Slide Show


Greywater Reuse

‣ Greywater sources?

‣ Contamination of Greywater and its

reuse

- How contaminated?

- Reuse methods


Greywater Reuse Methods

‣ Reusing on site.

‣ Methods

- Greywater diversion devices

-Domestic greywater treatment

systems


Domestic Greywater Treatment

Systems

‣ Treating greywater

‣ Kitchen wastewater – included

‣ a variety of wastewater treatment

systems can be used

‣ Implementation of disinfection.


Greywater Treatment & Reuse


Common measures to solve

‣ Aeration

problems

‣ Injecting chemicals

‣ Recirculation by mixers


Chapter 3

Water Reuse Design

Considerations


Design Considerations

‣ System reliability and redundancy

‣ Site loading

‣ Performance of reclamation plants

‣ Safe design procedures


System Reliability and

Redundancy

‣ Performance of reclamation plant

• Need consistently high quality water,

regardless of the circumstances

‣ Regulations for water reclamation

plant – requires specific design

practices and equipment


Site Loading

‣ Considerations for irrigation

(especially agricultural)

• Hydraulic loading

• Organic loading

• Nutrient loading

• Salinity


Hydraulic Loading

‣ Limits on systems that use land

application to treat water for disposal

‣ Hydraulic loading is the limiting factor

‣ Generally set by site conditions

‣ Example: Nebraska sets maximum at

4 inches/week


Organic Loading

‣ High organics in water clog soil with a

biological mat

• Prevents oxygen transfer

• Creates anaerobic conditions

‣ Organic loading is a main design factor in

land treatment system for raw wastewater

‣ Organic loading is generally not a design

factor for irrigation with reclaimed water


Nutrient Loading

‣ Reclaimed water provides necessary

nutrients to crops

‣ Major nutrients

• Nitrogen

• Phosphorus

‣ Excessive nitrogen at the end of the

growing cycle may damage crops


Nitrogen in Reclaimed Water

‣ Nitrogen is often an excessive

nutrient

‣ Methemoglobinemia (“Blue Baby”

Syndrome) caused by nitrate

‣ Must NOT exceed 10 mg nitrate-

nitrogen/L (Florida state standard)


Salinity

‣ Affecting soil structure, texture and

plant growth

‣ Adjusted Sodium Adsorption Ratio

(R adj )

‣ State of Idaho Requires less than 2

mmho/cm Electrical Conductivity


Chapter 4

Management


Management

‣ Record Keeping

‣ Signage

‣ Cross-connection control


Record Keeping

‣ Recording all operational data

‣ Data recorded

• Analyses

• Records of operational problems

• Unit processes and equipment breakdowns

• Diversions to emergency storage or disposal

• Corrective or preventive actions taken


Signage

‣ Inform public that reclaimed water is being

used

‣ Locations of signage

• Use areas

• Valves

• Storage facilities

• Outlets

‣ Signs generally colored purple

‣ Example wording on sign: “DO NOT

DRINK”


Typical Signage


Typical Signage


Typical Signage


Cross-Connection Connection Control

‣ No cross-connection connection allowed between

reclaimed water and potable water

‣ Practices to prevent cross-connection

connection

• Back flow prevention devices

• Air gap separation

• No reclaimed water use in residential

building unless residents are denied

access


Chapter 5

Operation


Operation

‣ Capable operator present in plant

‣ Monitoring reclaimed water quality


Certified Operator

‣ Certification of water/wastewater

treatment operators

‣ Certified operator presence

requirements


Sampling and Testing

‣ Sampling frequencies and analyses

determined by the type of reuse

‣ Requirements vary from state to state

• Arizona – daily sampling for fecal coliforms for

unrestricted urban reuse

• California, Florida and Washington require on-

line turbidity monitoring


Chapter 6

Public Health

Considerations


Inorganic & Organic

Constituents in Wastewater

‣ Conventional/Common Constituents

‣ Nonconventional

‣ Emerging


Public Health Considerations

‣ Protection of the public in reclaimed

water use. See

www.epa.gov/scipoly/oscpendo/

• Website about endocrine disruptors

‣ Inactivation of infectious agents

‣ Removal of endocrine disrupters


Emerging Organics

‣ Synthetic chemicals

‣ May disrupt the hormonal systems of

humans and wildlife

‣ Four (4) types

• Veterinary and human antibiotics

• Human prescription and nonprescription

drugs

• Industrial and household waste products

• Sex and steroidal hormones


Pathogenic Organisms

‣ Types

• Bacteria

• Parasites

• Viruses

‣ Viruses are of most concern

‣ Complete list available in:

Manual - Guidelines for Water Reuse

EPA/625/R-92/004 (1992)


Infective Dose

‣ Dosed number of microorganisms

starting immunological response by a

host

‣ Number of microorganisms required

to show signs of a disease could be

higher than the infective dose

‣ Susceptibility is highly dependent on

the individual

• Higher for infants, elderly people and

malnourished people


Inactivation of Pathogens

‣ Pathogens must be destroyed during

the reclamation process

‣ Typical disinfectants

• Chlorine

• Ozone

• Ultraviolet (UV)


Chlorine

‣ The most typical disinfectant

‣ Efficiency depends on various

factors

‣ The order of resistance:

Parasite ova > Virus > Bacteria

‣ Can maintain a residual


Chlorine Contact Chamber


Requirements for Chlorine

Disinfection

‣ Low organic materials and ammonia

nitrogen

‣ Low Total Suspended Solids (TSS)

concentrations


Disinfection Byproducts (DBPs(

DBPs)

‣ Produced by Chlorination

‣ Typical DBPs

• Trihalomethanes (THMs(

THMs)

• Haloacetic Acids (HAAs(

HAAs)

‣ Probable human carcinogens

(USEPA)


Ozone (O 3 )

‣ A powerful oxidant

‣ Must be generated on-site

‣ Requires electricity and complex

O&M

‣ No DPBs and ozone residues


Ultraviolet (UV)

‣ Wave length 254 nm

‣ Mechanism of UV disinfection

‣ No DBPs and no residues

‣ Destruction of Endocrine Disrupters

‣ Gaining popularity


Interferences with Ultraviolet Light

‣ TSS

• Blocks UV rays

‣ Dirty Tubes

Disinfection

• Requires frequent cleaning

‣ UV Light Intensity

• Voltage drops decrease effectiveness

‣ Flow Rate

• High flow rates decrease time of exposure for

treatment


UV


Chapter 7

Public Education


Public Education

‣ Wastewater reuse issues

Water source requirements

• Environmental impact and cost

• Saving water sources

‣ Early involvement of the public

‣ Redundancy and extensive

monitoring program presence


Definitions

‣ Reclamation (water reclamation)

Reuse (water/wastewater Reuse )

‣ Color coding

‣ Reclaimed Water

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