Introduction to sustainable water management systems

7/29/2019 Introduction to sustainable water management systems

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Introduction

Water is a scarce commodity. The increase in population being seen across the country and

indeed, all over the world, coupled with increased industrial output, continues to place an increased

strain on this valuable resource. This is the prime motivation for the water conservation movement,

which is part of the larger sustainable development effort. Water conservation is an urgent matter,

requiring the input of various professional practices and industries.

Water conservation within the building industry is achieved by efficient use which in itself

integrates policy with technology. Some of the policies cost little, if anything, to implement while some,

particularly those that are technology heavy, might have a large capital outlay but the savings in regards

to water bills will offset the expense in the mid to long term.

Best Management Practices for Water Conservation (non-domestic use)

i. Water management planningii. Information and education programmes

iii. Distribution System Audits, Leak Detection and Repairiv. Water-Efficient Landscaping and irrigationv. Water-Efficient sanitary ware

vi. Water efficient kitchen systemsvii. Alternate water sources

i. Water management planning

This basically involves developing a comprehensive projection of a buildings potential water

requirements, and coming up with policies and solutions that will conserve water. It is best included in

the design stage of a building but can be used on those that are already up and operational as a retrofit

measure.

ii. Information and education programmes

The human element is an important consideration when choosing to implement water

efficiency technologies and methods. New operation procedures, retrofits, and replacementsare most effective when employees, contractors, and the public know what the new technology

or methods are and how to use them properly. Information is also important in helping mold

public opinion, steering it towards being positive. Human beings tend to be resistant to change.

Providing information makes the transition seem less harsh.


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iii. Distribution system Audits, leak detection and repair

Facilities with large campus settings and expansive distribution systems can lose a significant amount of

total water production and purchases to system leaks. Leaks in distribution systems are caused by a

number of factors, including pipe corrosion, high system pressure, construction disturbances, frost

damage, damaged joints, and ground shifting and settling. Regular distribution system leak detectionsurveys can generate substantial benefits including:

Reduced water losses: Reducing water losses stretch existing supplies to meet increasingdemand. This could defer the construction of new water facilities such as wells, reservoirs, or

treatment plants.

Reduced operating costs: Repairing leaks saves money by reducing power costs to deliver waterand chemical costs to treat water.

Increased knowledge of the distribution system: Becoming more familiar with the system,including knowing the location of mains and valves empowers personnel to respond faster to

emergencies such as main breaks.

Reduced property damage: Repairing system leaks prevents damage to property and safeguardspublic health and safety.

Improved justification for water management: Conducting routine water audits and verifyingproduction and end point meters results in better accounting and helps validate the need to

reduce water losses.

A distribution system audit helps to quantify system losses and target leak detection and repair. A leak

detection survey then identifies leak locations, pinpointing the exact location so the leak can be

repaired.1

Case study: Kirtland Air Force Base Leak Detection and Repair Program

Overview

Kirtland Air Force Base (AFB) performed an award winning leak detection and repair program in 2006.

The results of the project are saving Kirtland AFB 179 million gallons each year, which is over 16% of the

total water use at the base. Kirtland AFB is located on 52,000 acres, southeast and adjacent to

Albuquerque, New Mexico. The area is a high altitude desert, only receiving about 8 inches of rain each

year. Kirtland AFB draws water from an underground aquifer via seven production wells throughout the

base. The base also has access to water from the City of Albuquerque. The underground water supply is

declining, which has spurred Kirtland AFB to develop a water conservation program, including the leakdetection and repair program featured in this case study.

Project summary

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October 2011
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Two leak detection approaches were considered by Kirtland AFB: passive survey and active survey.

These two methods are described below:

1) Passive survey involves installing listening devices on water lines at regular intervals to recordthe acoustic signatures that are used to identify leaks. Where leaks are identified, additional

equipment is applied to find the specific leak locations. Passive surveys are best suited for apermanent installation and long term monitoring of water lines. The benefits include accurate

leak location and size determination; good option for long-term monitoring of water lines. The

disadvantages are that the survey equipment can only hear one leak at any given point in time

and installation can be time consuming over long water lines

2) Active survey involves leak detection crews using acoustic listening devices, while walking eachwater line to find leaks. This method is best suited for a large network of water lines in areas

where multiple leaks are suspected. The benefits include allowing for a relatively rapid survey of

extensive water lines and providing exact leak locations as the survey progresses. The primary

disadvantage is that this method gives a one-time snapshot of system leaks which does not

provide on-going leak detection options.

Kirtland AFB decided on the active survey method. In total, 108 miles of water distribution lines

were investigated in the survey; this represents about 90% of the water distribution lines on the

base. Through the survey it was determined that nearly 16% ofthe bases water use was lost

through the water distribution system leakage. A total of 31 leaks were identified with an estimated

average water loss of 333 gallons per minute. The study found that major leaks were primarily

caused by offset joints (i.e., joints that are misaligned), while smaller leaks were caused by corrosion

of the pipe material.

Figure 1 Minor leak found during inspection

Figure 2 Major leak found during inspection


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Cost and savings summary

The cost of the survey itself was approximately $75,000 (or roughly $695 per mile) and the repairs cost

an additional $514,000. The survey and repairs saved the site over 179 million gallons annually,

representing over 16% of the bases total water use, valued at more than $330,000 annually.

iv. Water efficient Landscaping and Irrigation

Water is necessary for plant life. The technical interventions employed in conserving water in

landscaping fall into two broad categories:

Landscaping choicesThese include, but are not limited to:

Implementing the use of porous paving; porous paving includes gravel andloose aggregate paving as well as permeable concrete pavers. It includes a

range of materials and techniques for paving roads that allow the

movement of water and air around the paving material. All these pervious

materials allow storm water to percolate and infiltrate through areas thatwould traditionally be impervious to the soil below. By allowing rainwater to

seep into the ground, pervious paving can be instrumental in recharging

groundwater and reducing stormwater runoff. This capability can reduce

the need for retention ponds, swales, and other stormwater management

devices. Pervious paving integrates hardscape surfaces with stormwater

management. Types include:

Pervious concrete: made from carefully controlled amountsof water and cementitious materials mixed to create a paste

that forms a thick coating around aggregate particles.

Unlike conventional concrete, the mixture contains little or

no sand, creating a substantial void contentbetween 15%

and 25%. This allows for water to drain through quickly.

Both the low mortar content and the high porosity reduce

strength compared to conventional concrete, but sufficient

strength is readily achieved for many applications.
http://en.wikipedia.org/wiki/Impervious_surfacehttp://en.wikipedia.org/wiki/Impervious_surface


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Figure 3 Figure 4

Porous asphalt: is mixed at conventional asphalt plants, butfine (small) aggregate is omitted from the mixture. The

remaining large, single-sized aggregate particles leave open

voids that give the material its porosity and permeability.

Under the porous asphalt surface is a base course of single-

sized aggregate.

Single sized aggregate: uniformly graded aggregate e.g.loose gravel or stone chippings


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Figure 5

Porous turf: using grass

Figure 6 open blocks combined with turf Figure 7 open jointed blocks allow water to percolate to

the sub surface

Open jointed blocks: allow water to percolatethrough the spaces between the joints

Use of appropriate plants: indigenous plants tend to require less water thanexotic species. Xeroscopic plants are also water efficient.


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Mulching: reduces water lost to the environment through evaporation Avoid the use of decorative water features Design the landscape so plants with similar water needs are grouped

together (hydrozoning). This allows for more efficient irrigation

Eliminate "strip grass" to the greatest extent possible. Small strips of grass,common in parking islands and between sidewalks and the roadway, are

hard to maintain and difficult to water efficiently. Use bushes, mulch, or

permeable hardscape in these areas instead.

Recirculate water in decorative fountains, ponds, and waterfalls. Shut offthese features when possible to reduce evaporation losses. Check water

recirculation systems annually for leaks and other damage. Consider using

non-potable water in these systems

Implement low-impact development techniques, such as making parking lotislands depressions instead of raised curb areas to capture and retain storm

water

Irrigation choices Irrigation control systems that water plants only when needed should be implemented.

There are many available technologies that use weather or soil moisture information to

schedule irrigation according to plant needs. Below are a few options:

Weather-based irrigation controls use real-time or historical weatherinformation along with landscape parameters entered by the vendor to

schedule or allow for irrigation when plants need water.

Soil-moisture-based irrigation controls are inserted into the soil to measuremoisture. They can be connected to an existing controller or add-on device,

enabling irrigation when only the plants need water.

Complete central control systems utilize demand-based controls and enablea water manager to centrally operate and manage multiple irrigation

systems at multiple locations using various means of communication.

o Implement low-flow, low-volume irrigation, also called micro-irrigation or dripirrigation. Many plant beds do not require the spray heads traditionally used to

water turf areas. Drip irrigation can be more efficient due to slow and direct water

application to plant root zones, minimizing evaporation and runoff.


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Figure 8 drip irrigation


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Case study: PACIFIC NORTHWEST NATIONAL LABORATORY GROUNDS MAINTENANCE

Overview

The laboratory is located in an arid region of Washington State, receiving only eight inches of

precipitation annually. It has more than 100 acres of turf and landscaped areas and nearly 50 acres of

wild, undeveloped areas. PNNL has developed a comprehensive grounds maintenance program, which

began in 2000. The program encompasses sound landscape design and maintenance of the plants and

efficient application of water to these plants. The original goal of the program was to rejuvenate the

existing landscape while saving water and energy.

The ProjectPrior to the comprehensive landscape management program at PNNL, many of the sites trees were

watered with an outdated flood irrigation technique. The bubble-style irrigation heads watered trees at

the base of the trunk, causing the tree roots to clump around the trunk instead of developing a broad

root network. As part of the program, this system was replaced with sprinklers. Trees naturally have a

small network of roots, called feeder roots that spread just below the surface of the ground outwards

beyond the outer leaves of the tree. This perimeter is called the dripline. The feeder roots capture and

soak up rain that falls beyond the dripline. By replacing the old style bubbler irrigation with sprinklers,

PNNL replicates how trees naturally receive water from rain. The trees are now more disease and

drought resistant and water used for irrigation has been reduced by 40%.

Turf

PNNL has extensive lawns throughout the campus totaling more than 100 acres. Through the master

planning process, PNNL found that the turf was being overwatered; frequent and shallow watering

created a highly compacted and water resistant soil. The compacted soil created an anaerobic condition

in the root zone, which stunted the roots.

Anaerobic soil is devoid of oxygen. In compacted and wet areas, the oxygen gets squeezed out of the

soil. When organic materials in the soil break down in anaerobic conditions, hydrogen sulfide isproduced, causing a harsh environment for the plants root system, a foul smell, and black soil.

To fix this problem, the lawns are now aerated and then topdressed with sand, which breaks up the

compacted soil to allow oxygen and water to penetrate. The frequency of aeration and topdressing

depends on the condition of the

soil. Flat areas are typically aerated annually. But for areas with high traffic and compacted soil or areas

that have steep slopes, aeration and topdressing is applied more frequently throughout the growing

season. Aeration and topdressing has created a much longer root depth, improving the health of the

lawn and decreasing the amount of water needed by 30%.

Other better management techniques used on PNNL grounds include:

Cutting the grass with mulching mowers, which reduces the need for fertilizers, helps retain moisture,

reduces labor time for bagging and disposing of turf clippings, and also limits soil compaction

because the mulching mowers are significantly lighter than the industrial mowers previously used.

Allowing grass to grow longer between 3 and 3.5 inchesin the summer months. This is beneficial

because the longer grass shades roots and slows evaporation by keeping the root system cool.

Testing soils to determine the exact fertilizer needs.

Applying a 10% solution of mild liquid dish soap to the soil periodically to correct its water resistant

nature. The soap helps the water molecules bind to the soil, thereby allowing the soil to retain


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moisture. The frequency of application is driven by the soil condition. For most areas, the soap

solution is sprayed on once per year. For areas with steep slope or compacted soil, more frequent

application is needed.

Xeric and Native Landscaping

PNNL grounds personnel are converting water-intensive and problematic landscaping into xeric and

native areas. Xeric landscapes use native and low-water consuming plants that require minimalirrigation.

A particular challenge for the PNNL groundskeepers was the high-water-use landscaping adjacent to

parking lots and streets. These areas have been changed to low-water landscaping. The groundskeepers

planted urbanite ash trees in such areas because this species of tree can tolerate the summer heat and

is very drought resistant. Evergreen shrubs in parking medians have been replaced with bunchgrass,

which is well adapted to the local climate because of its low water requirements and high resistance to

diseases.

In addition to being inefficient, the old sprinkler system had high maintenance costs because the

sprinkler heads were vulnerable to damage from passing cars. The new sprinkler systems have heads

that deliver water directly to the plants roots and are not placed on the edge of the turf area, making

them less vulnerable to damage.

To further reduce water use while maintaining aesthetics, PNNL is creating gardens to feature native

plants from eastern Washington. In addition, the laboratory is adding walkways throughout the campus

to encourage staff and visitors to walk from one building to another instead of driving. Thus, the

laboratory hopes to reduce its overall carbon footprint and promote healthy physical activity at the

same time.

Irrigation System Improvements and Controls

PNNL performed a comprehensive maintenance program to upgrade the campus-wide irrigation system.

Water output was tested along with sprinkler coverage so that the system could be fine-tuned to ensure

broken sprinkler heads were repaired and all sprinkler heads were set correctly for efficient and

effective coverage.

The laboratory has also begun installation of a smart watering system that allows grounds

maintenance workers to control irrigation to all landscaping zones from one central location.

Maintenance workers set an optimal water schedule for each landscape zone at the central office, from

which control signals are sent out via a wireless network to sprinklers. This centralized system also

allows for quick changes based on weather conditions. The system will be enhanced with a weather-

based system that will download weather data from a local weather station. Data such as rainfall

amounts, wind speed, and humidity will be taken into account to determine the optimal water needs for

the plants in real time.

Cooling Pond Water Reuse

PNNL has large cooling ponds that are used as heat reservoirs for a portion of the campus airconditioning system in the summer months. About 15 times during the summer months, these ponds

reach a maximum operating temperature of 85F. At this point, warm water from the pond must be

removed and replaced with cool water from the Columbia River. This cool makeup water volume varies

with cooling needs, but in some cases can approach 1 million gallons per day. Instead of dumping this

warm pond water into the local sewer system, PNNL reuses it for irrigation. The pond water is checked

for safety then pumped into the irrigation system to water the grounds. It is estimated that 15 million

gallons of fresh river water is diverted from turf irrigation by reusing the pond water.


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v. Water efficient sanitary ware

A great proportion of the water used can be attributed directly to sanitary ware. For the purpose of

clarity, this report will break it down into two major sections:

Water efficient toilets and urinals Water efficient taps and showerheads

Water efficient toilets and urinals

Toilets and urinals can account for nearly one-third of building water consumption. Old and

inefficient toilet and urinal fixtures can be a major source of water waste in buildings, making the

savings potential in this area rather significant. Of the appliances that use water, the WC uses the most;

about 3040% of domestic water use and up to 90% for offices and public conveniences.

The best way to achieve efficiency in these restroom fittings is by using low flow appliances and

implementing the double flush system in toilets. Waterless urinals are also a good option for enhancing

water conservation.

Early closure or valve insert or replacement devices can reduce flush volumes by 2.25 to 7.5

litres per flush. However, they often require frequent replacement or adjustment, may lead to clogging

and other flush performance problems, and may void warranties on the fixture itself. This makes them a

poor choice.

N.B.Infrared or ultrasonic sensors for automatically flushing, flushometer valve-type toilets and urinals

should not be considered a water-saving device. Rather, these devices make toilet and urinal operationfully "hands free" and sanitary. This is because they do not, in and of themselves, reduce the amount of

water used by the appliance. They may, in fact, increase the water use in the facility if not properly

calibrated.

i. Low-flow appliancesLow-flow toilets, also sometimes called ultra-low flow toilets (ULFTs), usually use one of two

methods to clear waste: gravity or pressure-assisted. However, they all use 6 liters of water or less

per flush. Gravity toilets clear waste when you move the flapper and water is released, dropping

from the tank and flushing through the bowl. Gravity drives the waste out of the bowl.

Pressure-assisted toilets, by contrast, compress a pocket of air, which acts to energize the water

that's released into the bowl with each flush. The air is compressed within a vessel inside the tank

each time it refills. Pressure-assisted toilets are a little noisier than gravity-fed models and they

usually are more expensive as well, starting at more than $150 versus $75 or more for gravity-fed

models.


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Since 1999, some toilets have been made available that use even less water per flush than the

typical low-flow toilets. These are called high efficiency toilets (HETs) and utilize about 20 percent

less water than the average low-flow toilets, or about 1.28 gallons (4.8 liters) per flush.

Figure 9 low flow toilet: pressure assisted type Figure 10 low flow toilet: gravity assisted type

ii. Double flush systemsDouble flush systems work on the premise that solid and liquid waste would require different

volumes of water to be cleared, thus when one button is pushed and solid waste disappears, and

when the other is pushed liquids are disposed of. Solid waste is cleared with 6 litres of water per

flush, while urine is flushed away with only 3 litres. This means that when the latter is flushed in the

traditional system, 3 litres of water are unduly spent. Some studies have shown that that on average

only 1 out of 5 toilet visits actually require the full 6 litre capacity of toilets, which means that the

other 4 visits waste about 12 litres of water.

Figure 11 double flush toilet


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iii. Waterless urinalsThough somewhat controversial, waterless urinals do have a significant impact on the water

consumption of a building. Water is used in conventional urinals to wash the bowl and flush the trap.

The waterless urinal may employ the following methods to that end:

a) Valve Waterless Urinal Systems

Urine passes through a one-way 'plastic' valve that, when closed, prevents odours from

being emitted into the washroom. These generally require some regular maintenance to clear

urine crystals and debris, including hair. It is important not to allow the valve to become stuck

open, especially if the urinal trap the previously prevented odours has been replaced with a

"right-angled" straight-through connection. The idea of removing the trap is that the flow of

urine alone will carry the hair and other debris in to the main drain. Valve systems can work very

well if properly maintained and they are available to retrofit most types of standard urinal

bowls. Some models include a scented or microbiological block to complement the valve.

The main problem of this type is that the valve can be left open due to hair and debris clogging

the outlet.

Figure 12 Smell stop valve of the valve waterless urinal system

b) Barrier Waterless Urinal Systems

Urine and debris passes through an oil-based barrier fluid which forms the seal to

prevent odours reaching the washroom. In some systems, the barrier fluid is contained

within a replaceable cartridge that also captures debris which would otherwise fall into the

waste pipes. Cartridges typically need to be replaced every 2 to 5 months, dependent on

usage. The barrier fluid can be swiftly degraded if the correct cleaning chemicals are not

used. Otherwise, barrier systems work very well, although those that use replaceablecartridges can be expensive to run for busy washrooms.


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Figure 13 Barrier system cartridge Figure 14 Waterless urinal

c) Microbiological Waterless Urinal SystemsUrine comes into contact with a block, often housed within a dome inserted into the

urinal waste outlet. The block contains anumber of active ingredients, including surfactants,

but the most important of these is the microbialspores.Once taken down into the trap with

the urine, the spores become active beneficial bacteria that 'feed' upon the urine and then

multiply. By breaking down the urine into components, the bacteria from the block prevent

the build-up of sludge and crystals that are a major contributing cause to blockages. They

also generate an environment hostile to the 'bad' bacteria that cause odours. Providing

that some block is present and it contains the appropriate ingredients, then there is no

requirement for "odour lock" mechanisms or valves. Appropriate cleaning chemicals must

be used and simple but regular maintenance is required. Most importantly, the microbes

cannot break down hair, grit and other debris that inevitably finds its way into the urinal

trap and thence the waste runs. Therefore to push the debris down to the main drain before

it can collect and cause a blockage, it is essential to pour some fluid down each urinal at

regular intervals, usually once per week. This "dosing" process is most effective when a

mixture of warm water and an appropriate chemical is used


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Figure 15 microbiological dome

Figure 16 Microbiological waterless urinal

Water efficient taps and showerheads

Water efficient taps and showerheads are those that allow a smaller volume of water through

them at a given time in order to reduce the amount of water wasted. According to the WaterSense

criteria the maximum flow rate should be in the 7.5 litres per minute range. Flow may be regulated

using a rubber ring known as a flow restrictor or may be implemented in the appliances heads design.

Figure 17 Showerhead with and without a flow restrictor.


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CASE STUDY: Huntington Veterans Affairs Medical CenterFaucet and Showerhead

Replacement ProjectOverview:

The Huntington Veterans Affairs (VA) Medical Center implemented an award winning faucet andshowerhead water efficiency program in 2007. The efficiency improvements save the medical center

more than 1.5 million gallons of water each year.

Project Summary

The Huntington VA Medical Center implemented a large retrofit of faucets and showerheads in

its 1-South section, which contains offices, clinics, a surgery unit, patient rooms, and laboratories.

Conducted in 2007, the retrofit was part of the medical centers Green Environmental Management

Service (GEMS) initiative.

New 1.5 gallon per minute (gpm) laminar flow faucets replaced 178 outdated 2.5 gpm models. A laminar

flow head delivers tiny side-by-side streams of water, that provide a continuous flow while maintaining

a low flow rate. Laminar faucets tend to have less splashing and lend a smooth feel to the water.

The GEMS initiative also converted 33 showerheads from 2.2 gpm to 1.75 gpm models with flow

restrictor style heads. The retrofit utilized the existing pressure and temperature compensating valves in

the shower stalls. The efficient retrofits perform well while providing an adequate flow rate for both

patients and staff.

The Huntington VA Medical Centre also implemented additional fixture efficiency retrofits, including

converting 87 toilets to both 1.6 gallon per flush (gpf) and dual flush toilets. Dual flush toilets have a full

and partial flush option with average water use of approximately 1.3 gpf.

Cost and Savings Summary

Retrofitting faucets and showerheads save the Huntington VA Medical Centre 1,538,000 gallons of

water each year. This data is based on actual pre- and post-retrofit metered data and was derived based

on average patient and staff occupancy rates over the year. Huntington VA Medical Centre enjoys an

annual cost savings of $12,900 based on combined water and sewer costs of $10 per thousand gallons.

In addition, using less hot water saves energy resulting in an annual energy savings of 5,800 therms per

year creating an additional $7,200 in annual cost savings. The centre spent $771 for total material costs

and $2,637 for in-house labour to install the features. As a result of combined water and energy savings,

the Huntington VA Medical Centre achieved a project payback in less than two months. Since

completing the plumbing fixture retrofits in 2008, Huntington staff evaluated water use and found thatconsumption decreased 11 per cent from fiscal year 2006 compared to 2008. This reduction includes

faucet and showerhead retrofits described in this case study as well as other conservation efforts, such

as a toilet retrofit done during the same time period. The bar chart above right shows actual water use

at the medical centre in fiscal year 2006 through 2008, revealing more than three million gallons of

annual water savings.


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vi. Water efficient commercial kitchen systems

Water efficiency for commercial kitchen equipment is especially important because high volume

applications typically use mostly hot water. Ensuring commercial kitchen equipment uses waterefficiently affords both significant water and energy savings.

Water-using commercial kitchen equipment include pre-rinse spray valves, wash tanks and sinks,

commercial dishwashers, food steamers, steam kettles, commercial ice makers, and combination ovens

(combination oven/steamer).

Garbage disposals can waste significant amounts of water. Eliminate or minimize the use of garbage

disposals by using strainers or traps that employ a mesh screen to collect food waste.

When installing dishwashing machines, only install dishwashers with rack sensors to allow water

flow only when dishes are present. Also ensure that they are energy efficient for maximum impact.

vii. Alternate water sources

Alternate water sources refer to the use of recycled or grey water as well as rainwater to

supplement the use of fresh water in non-potable applications. This will have been discussed under

waste water management.


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RESOURCES/ REFERENCES

http://www1.eere.energy.gov/femp/program/waterefficiency_basics.html as retrieved on Sunday, 23rd

October 2011

http://www.greenbuildingstore.co.uk/page--water-saving-products.html as retrieved on Sunday, 23rd

October 2011

http://en.wikipedia.org/wiki/Permeable_paving as retrieved on Sunday, 23rd October 2011

http://www.concretethinker.com/Papers.aspx?DocId=10 as retrieved on Sunday, 23rd October 2011

http://www.waterlessurinals.co.uk/about-waterless-urinals/ as retrieved on Friday 28th October 2011

http://tlc.howstuffworks.com/home/low-flow-toilet2.htm as retrieved on Friday 28th October 2011

IMAGES

Figure 1 Minor leak found during inspection courtesy ofhttp://www1.eere.energy.gov/femp/pdfs/water_cs_kirtland.pdf

Figure 2 Major leak found during inspection courtesy ofhttp://www1.eere.energy.gov/femp/pdfs/water_cs_kirtland.pdf

Figure 3 courtesy ofwww.concretenetwork.com Figure 4 courtesy ofwww.concretethinker.com Figure 5 courtesy ofwww.eot.state.ma.us Figure 6 open blocks combined with turf courtesy ofwww.crestock.com Figure 7 open jointed blocks allow water to percolate to the sub surface courtesy of

www.level.org.nz Figure 8 drip irrigation courtesy ofwww.jains.com Figure 18 low flow toilet: pressure assisted type courtesy ofwww.joanspear.wordpress.com Figure 19 low flow toilet: gravity assisted type courtesy ofwww.daviddarling.info Figure 11 double flush toilet courtesy of www.cmhc.ca Figure 12 Smell stop valve of the valve waterless urinal system courtesy of

www.waterlessurinals.co.uk

Figure 13 Barrier system cartridges courtesy ofwww.waterlessurinals.co.uk Figure 14 Waterless urinal courtesy ofwww.waterlessurinals.co.uk Figure 15 Microbiological waterless urinal courtesy ofwww.waterlessurinals.co.uk Figure 16 microbiological dome courtesy ofwww.waterlessurinals.co.uk Figure 20 Showerhead with and without a flow restrictor courtesy ofwww.mx-group.com
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Introduction to sustainable water management systems