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compare the two alternatives and see which alternative would have the highest number. The

highest number outcome would be the recommendation of the alternative.

D. Design Goals and Weights

This was our rank ordering of goals from report 3

Rank Ordering of Goals

Performance

Sustainability Acceptability

Safety Economic

Performance - 0.5 1.0 0.0 0.5 2.0

Sustainability 0.5 - 1.0 0.0 1.0 2.5

Acceptability 0.0 0.0 - 0.5 0.5 1.0

Safety 1.0 1.0 0.5 - 1.0 3.5

Economic 0.5 0.0 0.5 0.0 - 1.0

Next we weighted our goals on a scale from one to one hundred. We then divided it

into three parts

being optional (1-30), important (31-70), and critically important (71-100). The

results are as follows:

Performance 75

Sustainability 85

Acceptability 55

Safety 95

Economic 50

E. Method Used to Generate Alternative:

Water Supply source:

Alternative 1:

a.) Description:


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Extend the Southern Nevada water distribution system via water main extensions: The South

Valley Lateral water providers have identified a selected alternative to supply approximately

130,000 gallon / day to Utopian homes. The Horizon Ridge Reservoir alternative is selected

because it is in 20 mile reach and water delivery will be effective and efficient. The system shall

have sufficient capacity to maintain 40 psi at the building entrance for one- and two-family

dwellings. For other development provide minimum pressure of 35 psi at the building side of the

meter during periods of maximum use, and to provide sufficient volumes of water at adequate

pressures to satisfy the expected daily consumption plus fire flows of 20 psi. Normal working

pressure in the distribution system should be approximately 60 psi with a range of 40 psi to 100

psi. Where installation of dead-end water mains cannot be avoided, a hydrant or a valve of

adequate size for flushing shall be installed at the terminal end of the line. The flush valves shall

have an above ground discharge and shall be protected from contamination. Trenching, pipe

laying, and backfilling shall be accomplished in a manner to prevent damage and misalignment

of the pipe. Water mains shall be buried to a depth below the frostline or to a depth sufficient to

provide a minimum of 30 inches cover, whichever is greater. There are many benefits of a

existing system it is a reliable source of water, assured quality of water, better overall

management, and more skilled technical operational capabilities. This water system meet all goal

of sustainability. This project will not produce any CO2, will meet the goals of environmental

sustainability of potable water supply and no waste or pollution will be produced.

b.) Goal Achievement and Ranking factor:

This Alternative will satisfy all goal of water supply system. This system will have better

performance than water well and it will also be cost-effective.

Sustainability 4

Safety 6


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Acceptability 2

Economic 7

Performance 8

Alternative 2:

a.) Description:

Install and develop Pumping stations: The location of the pump station and intake structure, and

the anticipated heads and capacities are the major factors in the selection of pumps. Main

pumping stations which supply water to the distribution system will be located near the water

treatment facility or a potable water storage facility and will pump directly into the piping

system. Booster pump stations will also be located in the system to increase the pressure in the

pipeline. Major planning factors are: availability of electric power, roadway access for

maintenance and operation purposes, and adverse impact, if any, upon surrounding occupancies.

Pump drives for water supply and distribution pumps will be electric motors. Diesel or other

fuels will be considered as a power source only for emergency use. The total energy consumption

charges associated with a pump operation can be decreased by improving the efficiency of

individual pumps or combination of pumps. However, such measures have little impact on

reducing the costs associated with time of day energy rate schedules. A pump operating policy is

a schedule of water levels that should be maintained and a series of rules that dictate when

different pumps should be operated in response to different system conditions. The pumping

equipment will be located so as not to be subject to flooding. The site will be graded to drain

surface water away from structures. Roadway access for maintenance vehicles will be provided

at all equipment locations with space provided for vehicle turn around. Pumping station can be

sustained by limiting the drawdown of ground water level only to level that will be replenished

by future recharge.


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Undergr

ound Reservoir And Pump Station

Above figure shows the pump supplying the distribution system

b.) Goal Achievement and ranking factor:

This alternative will meet the performance goal but it is inadequate to meet the Economic and

Sustainability goal which is the aim of the system.

Sustainability 3

Safety 5

Acceptability 3

Economic 5

Performance 7

Water Treatment facility:

Alternative 1: Onsite Treatment (Primary, Secondary, and Tertiary)


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Fig 1

a.) Description

With this alternative, we suggest to build a treatment facility onsite. The treatment facility will

include three stages of treatment, which are the Primary, Secondary, and Tertiary stages. Primary

treatment includes those components that are designed to remove solids and oils from the waste

stream. This could include bar screens, grit chambers, and primary sedimentation tanks. When

the wastewater stream leaves this treatment area, it is assumed that the wastewater is relatively

free of solids. Secondary treatment is a biological process designed to remove soluble,

biodegradable wastes from the water. Tertiary wastewater treatment is used after the secondary

units to clean the wastewater prior to its final discharge. This area of the process may include

further solid removal through sand beds, or even further reduction of organic matter through an

activated carbon system.

b.) Goal Achievement and Rating Factors


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This alternative will fulfill all the goals and requirements of the system as stated in report three,

but is unsatisfactory in an economic standpoint. This will be discussed more in depth in the

tradeoff analysis section of this report. Rating factors that were considered when evaluating this

alternative include its ability to meet the relevant laws, the acceptability to the stakeholders, and

the cost of the facility. We rated on a scale of 1 to 10, with 10 being superior, in each of the goals

from report three. The results are as follows;

sustainability 7safety 9acceptability 4economic 2

performance 9

Alternative 2: Use existing treatment facility

Fig 2

a.) Description

Las Vegas has an existing treatment facility for all waste water that runs constantly. In this

alternative we assume that we attach to the existing system which will allow for use of the

pretreated water. It is located at 6005 East Vegas Valley Drive (see picture above). In regard to


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treatment, the facility treats 100 million gallons of wastewater on a daily basis, through

physical, biological, and chemical treatment systems, to be reused or returned to the Las Vegas

Wash.(CCWRD)

b.) Goal Achievement and Rating Factors

This alternative will satisfy all goals and excel in some. It will be able to perform at the rate that

is needed as well as save money over alternative one. When evaluating and rating this alternative

we found must better results. They are as follows;

sustainability 7safety 9

acceptability 9economic 10performance 9

Water Storage Facility:

Alternative 1: Ground Level Storage:

b) Description

Water ground storage tanks shall be provided with a light-proof and insect-proof cover of

concrete, steel or equivalent material approved by the Division. The construction joints between

side walls and the covers of concrete tanks or reservoirs shall be above ground level and above

flood level; except that clearwells constructed below filters may be excepted from this

requirement when total design, including waterproof joints, gives equal protection. The access

manholes for finished water storage tanks or reservoirs shall be framed at least four inches above

the tank or reservoir covers at the opening and shall be fitted with solid covers of materials that

overlap the framed openings and extend down around the frames at least two inches. The covers

for the openings shall be hinged at one side and fitted with a locking device. The tanks or

reservoirs shall have vents with screened, downward directed openings. The vent and screen


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shall be of corrosion resistant material. Water supply inlets and outlets of storage tanks and

reservoirs shall be located and designed to provide circulation of the water. All tanks and

reservoirs shall be equipped with drain valves. Ground Storage tanks have lower initial cost of

construction, a lower maintenance cost, the ease with which water quality can be tested, greater

safety, and a greater aesthetic value.

A plan of the reservoir with all dimensions as shown in Figure 9. This plan shows a top, side andend view.


If the storage facility is needed then ground level storage will be the one to choose. It will able to

fulfill the goal of performance, safety with being cost-effective.

Sustainability 6

Safety 9

Acceptability 4

Economic 6

Performance 9


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Alternative 2: Elevated Storage Tank:

a) Description

The specifications for elevated tanks, stand-pipes, towers, paints, coatings and other

appurtenances shall meet the appropriate ANSI/AWWA Standards D 100 84 and D 101-53(R86)

of the American Water Works Association, Inc., which are hereby incorporated by reference

including any subsequent amendments and editions. Elevated tanks do not require the continuous

operation of pumps. Short term pump shutdown does not affect water pressure in the distribution

system since the pressure is maintained by gravity. And strategic location of the tank can

equalize water pressures in the distribution system. However, precise water pressure can be

difficult to manage in some elevated tanks. The optimal pressure is achieved at only one depth.

http://water.me.vccs.edu/courses/ENV110/lesson10.htm

The length of the standpipe causes continual and highly unequal pressures on the distribution

system. In addition, a significant quantity of the water in a standpipe is required to produce the

necessary water pressure. The water below a certain level is therefore used only as a support,

unless booster pumps are available for emergency use of this water.


This alternative will not satisfy the performance goal of this system.
http://water.me.vccs.edu/courses/ENV110/lesson10.htmhttp://water.me.vccs.edu/courses/ENV110/lesson10.htm


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Sustainability 4

Safety 6

Acceptability 2

Economic 6Performance 5

F. Evaluation

1. Decision Matrix

Water Supply Alternative:

sustainability(85)

safety(95)

acceptability(55)

economic(50)

performance(75)

DF=WF*RF

Existing

System 340 570 110 350 600Water Well 255 475 165 250 525

Treatment Alternatives

Sustainabilit

y (85)

Safety

(95)

Acceptabilit

y (55)

Economic

(50)

Performance

(75)

DF=WF*RF

Onsite Facility 595 855 220 100 675 2445

Existing

Facility

595 855 495 500 675 3120

Storage Alternative:

sustainability safety acceptability economic performance DF=WF*RF

Ground Level

ElevatedStorage

These numbers were achieved by multiplying the goal weights from report three by each of the

alternatives ratings in that category. The result was then added in each alternative to reveal the

numbers on the far right of the table. These numbers will allow a decision in regard to which

alternative is best suited to this project.


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2. Rankings for Treatment Alternatives

The table above shows that the existing facility came out above that of building an onsite

facility. The results show how each alternative is equal with respect to sustainability, safety, and

performance. The difference lies within that of acceptability and economic. The reason for this

will be discussed in the tradeoff analysis section of this report.

G. Tradeoff Analysis

1. Sustainability Vs Performance and Economic Goals for Treatment

Alternatives

In regard to treatment the important factor to look at is that of economics. Since each of the

alternatives is relatively similar in regard to performance, cost will be the biggest factor. There is

an existing facility in Las Vegas that treats all water and is most beneficial to the proposed

system. So the only cost for that alternative will be that of materials and construction. On the

other hand, if the alternative that proposes a new facility is constructed is chosen, the costs will

be significantly higher.

2.The Top Ranking Alternative Versus Other Alternative:

3.Sensitivity of Result to Design:

H. Preliminary Design Study Recommendations


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1. Achievement of Sustainable Design

For this project we recommend using alternative two (the existing facility) for its ability to

achieve sustainability, performance, and economic goals. By implementing this alternative, no

new materials will be needed which can save money. The savings from this alternative can allow

research and use of new water conservation techniques.

2. Achievement of Performance

Water Supply Source: Alternative 1 Water supply from existing source was the

recommended alternative. The advantages of this alternative in relation to the others are:

a. Provides residents access to the highest quality water available,

b. Can be implemented relatively quickly,

c. Eliminates homeowner operation and maintenance responsibility,

d. Offers the highest level of fire protection,

e. Protects public welfare,

f. Minimizes environmental impact on and would be the most protective

against any potential future impacts to the existing aquifer supply.

g. Provides a redundant, reliable water supply.

Treatment Facility: If using the existing treatment facility to supply clean water to the

community, performance can be expected to match that of existing communities of Las Vegas.

Water Storage Facility: The alternative is generally non-structural. The construction of new

storage facilities will not be required. The only construction anticipated is associated with a new

ditch for pipe installation.

3. Achievement of Economic and Other Goals


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Assuming the existing water system is a viable water system, there are obvious economies of

scale both initially and ongoing which generally results in less overall cost to consumers of the

new system. The total capital cost of Horizon Ridge Reservoir and related pumping station and

pipeline is estimated to range between approximately $33.6 million and $46 million. We

anticipate that energy costs for this alternative would be about $18 for 325 851 gallon of water

pumped to the reservoir. Alternative two promotes use of the existing treatment facility. By using

this alternative, the cost of the project will be significantly lower than that of alternative one.

4.Strengths and Shortcomings of the Preliminary Design Study:

6. Summary of Further Research, Analysis and Design Needs

Over the last three reports, the water team has been researching a proposed water system so that

the needs of the decision maker are met. The next step in the category of further research will

include the things such as the quantity of materials needed, location of materials for construction,

and the design plans from the remaining teams. Water conservation techniques should also be

researched for the future in order to better meet sustainability goals. Design considerations and

project costs require updating. Also, an assessment of on-site environmental conditions is

needed.

References:

Hornby, Lawrence E., Devising Wastewater Treatment Strategies.

4/27/2010.http://www.p2pays.org/ref/02/01336.pdf

Clark County Water Reclamation District. 4/27/2010.

http://www.cleanwaterteam.com/home.html
http://www.cleanwaterteam.com/home.htmlhttp://www.cleanwaterteam.com/home.html


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City of Las Vegas. Wastewater treatment. 4/27/2010.

http://www.lasvegasnevada.gov/information/5397.htm

Fig 1. From google/images. 4/27/2010.

http://saferenvironment.files.wordpress.com/2008/11/image2.gif

Fig 2. CCWRD. 4/27/2010. http://www.cleanwaterteam.com/aboutus_rev.html
http://saferenvironment.files.wordpress.com/2008/11/image2.gifhttp://saferenvironment.files.wordpress.com/2008/11/image2.gif

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