Water distribution system

[Hearts]

For our assignment, we have to design a system that will draw water from a source, calculate it's quality, treat it and then distribute it.

I'm not really sure where to start or what to do and would really appreciate guidance on what to do.

[CaptainPanic]

I'll ask you some questions. The answers might point you in the direction that I think is the right one (if I understand your assignment well).

 

1. How do you draw water from a source? What do you need? What pieces of equipment?

2. How do you measure how much it is? Would you measure the absolute amount you have (m3), or rather the flow (m3/s)?

3. How do you treat relatively clean water? How can you upgrade it to drinking water? Is there more than 1 method? Why did you make the choice you made? Money? Ecology? Something else?

4. What's needed to distribute it? Pipes? How many? Can the amount of piping be minimized, while maximizing the distribution?

5. Would you need a storage or a buffer tank?

 

First put all the major blocks in a row. Work them out individually... because in reality they are all connected, but still individual units in the supply.

 

Of course, after working them out individually, it should connect. I.e. the flow of water coming out of one part must be the same size as the flow going into the next (because in reality it IS the same flow).

[Mr Skeptic]

Each of those steps is separate but depends on information from the previous steps. To get started, just start any of the steps, but include for calculations the info you will need from the previous steps.

[Hearts]

I think I'll start with estimating the water demand first~

how would I know if the population growth follows an arithmetic or a geometric progression? (I can get past data, not much of it though,)

and If I want the system to last for a long time, how far ahead can I safely predict the numbers?

I have to leave room for possible development of the area in the future too. How can I do this practically?

Did try googling them, but only very simple cases (involves nothing more than just plugging numbers into the equation) turned up.

[michel123456]

I think you are making things too complicated. Stick to your question, do not amplify it. In real world, you should begin by making a market research, make a feasibility study, find investors, create a society, get authorizations and a lot more that were not asked.

Read the question, ask the question, proceed.

[Hearts]

Mined some really useful notes from a forgotten part in my computer. Happy

@michel123456 : Unfortunately, estimating population growth IS part of the question

 

Predicting water demand due to future development of the area wasn't really asked but the lecturer did mention the importance of it in one of his classes.

Estimating the water demand has been taught, but we only know it in theory.

The lecturer will give us the data soon.

The business aspect of it is something I don't want to go into either (and it's not asked anyway). Had a brief course on engineering entrepreneurship back a while ago, but due to general disinterest in the subject, I came away with nothing more than a slide show and format for a business plan.

 

 

@CaptainPanic :

 

Due to the little resource we have (Google and books from the library we hardly understand), We are allowed to make some of the data up. It must be believable though. Here's a map of the area. A, (kampung ulu pauh) is the village we want to provide water for. The river doesn't look feasible from here, too many obstacles. The lake though..hmm..wad do u think?

Anyway I think the village should already has its own water supply and distribution system and I'm still looking it up. Nothing relevant appeared yet though.

[michel123456]

So you have to find the source first?

In this case you need other kind of data. Relief map and geological.

 

It is getting complicated.

If it is an autonomic system for the village, a political map showing the village district is a must.

[CaptainPanic]

I think I'll start with estimating the water demand first~

how would I know if the population growth follows an arithmetic or a geometric progression? (I can get past data, not much of it though,)

and If I want the system to last for a long time, how far ahead can I safely predict the numbers?

I have to leave room for possible development of the area in the future too. How can I do this practically?

Did try googling them, but only very simple cases (involves nothing more than just plugging numbers into the equation) turned up.

It's just a matter of 'overdimensioning'. Make the system so large that it can cope with the 99% of all predictions regarding growth within a reasonable time.

 

It's a very common principle in engineering. It's better to make stuff too strong, too large, too robust. At least it will survive if your predictions turn out wrong.

@CaptainPanic :

 

Due to the little resource we have (Google and books from the library we hardly understand), We are allowed to make some of the data up. It must be believable though. Here's a map of the area. A, (kampung ulu pauh) is the village we want to provide water for. The river doesn't look feasible from here, too many obstacles. The lake though..hmm..wad do u think?

Anyway I think the village should already has its own water supply and distribution system and I'm still looking it up. Nothing relevant appeared yet though.

Water supplies for such a small village are a matter of connecting to the main grid, if there is one.

I would not connect to that little lake in the picture you showed. It's too small, and possibly stagnant water. The river is likely better, especially if it never dries up. Obstacles are no problem, because all you need is a pipe, which can go under ground. But your best option is ground water. Drill a well, and get the water from over 100 meters deep. That often requires very little treatment.

 

Anyway, since we're dealing with such a small place, it's important to find out if the neighbors already have something. Google for "malaysia water company", or "malaysia water supply company", and you'll find some real companies. Perhaps it's worth it to send a short email to them?

[Hearts]

The full question~

WATER SUPPLYFOR THE PROPOSE HOUSING AND PUBLIC DEVELOPMENT PROJECT IN PAUH, PERLIS

 

 

1. Introduction

 

 

As engineer in the consultantfirm, your group are assigning to design a water supply system for the proposedhousing and public development project in Pauh, Perlis.

 

 

2. Scope of Work

 

 

The scope of work shallcomprise the following;

 

 

(a) ProjectDescription

 

(b) Populationprojection

 

© Computationof water demand

 

(d) ProposeWater Intake Collection and Water Intake Structure

 

(e) Determination of Water Quality Index (WQI)

 

(f) Proposeand design water treatment plant

 

(g) Proposewater distribution layout

 

 

3. Project Description

 

 

Shouldincludes; the purpose of design project, study of project area (such as projectlocation and existing environment i.e. land use, topography, geology and meteorology (wind profileand rainfall)) and projectelements (electricity, telecommunication, access road, drainage and sewerage.)

 

 

4. Population Projection

 

 

Previousdata from thepopulation and housing census done by Department of Statistics in Pauh, Perlis isgiven in the following table.

 

 

 

Year

 

1980

1990

2000

2010

Population

 

3000

5700

6400

9600

 

 

 

 

Assume the design years of the watersupply scheme. Choose one of the following methods of population projection andestimate your population:

 

 

i) arithmetic growth

 

ii) geometric growth

 

iii) incremental increase

 

iv) decreasing rate of increase

 

 

5. Water Demand

 

 

The daily water demand for thewhole development is ………….. L/day and is computed based on guideline providedby JBA Perlis:

 

 

 

 

Housing and Public Development

 

People/Unit of Development

Water Demand per person (L/capita/day)

Total Water Demand (L/day)

1.

 

Terrace house

 

Assume

5

1500

2.

 

Semi-D

 

Assume

Assume

2000

3.

 

Bungalow

 

Assume

Assume

2000

4.

 

Apartment

 

Assume

5

1500

5.

 

Mosque

 

1 unit

Assume

50

 

6.

 

Daily school

 

1 unit

20% per population

50

 

7.

 

Boarding school

 

1 unit

Assume

250

 

8.

 

Kindergarten

 

2 unit

20% per population

30

 

 

Total

 

 

 

 

Trade Development

 

Unit of development

Water Demand per unit (L/day)

Total Water Demand (L/day)

1.

 

Shop lots (single-storey)

 

Assume

2000

 

2.

 

Petrol station

 

2

50000

 

3.

 

Wet market

 

1

25000

 

4.

 

Light industry workshop

 

1

1500

 

 

Total

 

 

 

 

6. Water Demand Fluctuations

 

 

Average annual demand is not sufficient for design ofwater systems due to water demand fluctuations. Generally, monthly fluctuation is used for design of damand storage tank. Flow of water required during maximum daily demand can beused to design water treatment plant, while flow required at peak hour demandcan be used for design of water distribution system (pumping, service tank,water mains).

 

 

Given:

 

Maximum daily demand = 180% of annual average demand

 

Maximum weekly demand = 148% of annual average demand

 

Maximum monthly demand = 128% of annual average demand

 

Maximum hourly demand = 150% of maximum daily demand

 

 

6. Propose Water Intake Collection and WaterIntake Structure

 

 

- Type of water collection: justify your selection

 

-Type of water intake structure: justify your selection

 

 

7. Determination of Water Quality

 

 

Water quality studyis an important criterion in the design of water treatment plant. Therefore,each group of student is needed to carry out field work by collecting “river water sample”for the analysis of its waterquality. All the parameters that been selected should can be calculated for the WaterQuality Index (WQI). Therefore, each group of student is required to classifythe water quality level for the selected “river water sample” based on theresult obtained from the WQI.

 

 

8. Propose Water Treatment System

 

 

Prepare a design for the proposed water treatment systemat new housing and public development project in Pauh, Perlis. A design should include an estimate of the flow tobe treated, the water quality of the water, specification of the unit processesto be included in the treatment system, the size of the treatment units (i.e.,dimensions, flow capacities, etc.), and an estimate of the water quality thatwould result from the system.

 

 

9. Propose Water DistributionSystem

 

 

Should includes, description ofmethod and layout water distribution system, description of material used indistribution system and prepare overall layout of water distribution.

 

 

[michel123456]

It would not be the first time a Professor ask his students to resolve a case he his engaged to solve for a third party in real life.

Does your Professor maintain a consulting office out of academics?

[Hearts]

Michel: Nope, I don't think so. Not this particular one anyway. Anyway it's a she and she's not a professor yet, still studying for it I think.

Sent an email to the guys responsible for the water distribution in the state. Still awaiting reply.

Meanwhile I'm googling stuff here and there~

I dread calculating head loss.

Anyway why is political map important? Can we pretend there's no red tape?

 

Captainpanic: about 'overdimensioning', I found..

 

Excessive capacity

The system should not have excessive capacity (which will result in long transit

times) unless this excess capacity is required to meet a known increase in future

demand.

 

source : http://www.who.int/water_sanitation_health/dwq/en/piped3.pdf

 

3. Design and operation of distribution networks

3.2 DESIGN AND OPERATION OF PIPED NETWORKS

3.2.1 Hydraulics

second paragraph.

 

Distribution pipes

..Since water pipes will be used for at least 50 years, most communities look ahead to expanded service and often use bigger pipe than the minimum. Too large a pipe, however, can lead to water quality problems. If water stands too long in large pipes, the chlorine residual diminishes, metals can dissolve in the water, and biological films can grow.

 

 

source: http://ohioline.osu.edu/b910/b910_13.html

 

Thx for the replies..it helped to get the ball rolling

Edited March 12, 2011 by Hearts

[michel123456]

If this exercise is meant to ressemble real life, you need a political map first. All installations must be inside the district perimeter (see edit).

-you need a plot (a piece of land) at the source. You need land for the ducts till the village: that can be under some roads, or next to roads, it is difficult and costly to expropriate land for ducts on kilometers (that depends on your political regime of course). You need a large plot near the consummation point for the water treatment plant. If you don't care of these elements, the cost will be outrageous.

 

_theoretically, you should use gravity. The source should be at an elevated point. Then you can use open air ducts (canals) to transport raw water until the treatment plant that will be the closest possible to the village. The path must then be drawn on a topographical map with contour lines. In between, you should care for storage in open air tanks, or lake,(on communal plot) to buffer the demand. This can be an existing lake, if you have one. After cleaning water, use mechanical devices (pumps) to raise water in elevated tanks (water towers), in order to deliver clean water under pressure. Each water tank must be on a communal plot, that can be on squares or traffic circles for example. That's the easy part.

If source is not elevated (the river), you must use pumps right from the beginning, ducts under pressure, and several points for re-pressure (I don't know the technical terminology), which mean cost in installation & maintenance.

 

_I suppose modern design should include water recycling, since a huge amount of clean water is usually wasted. So your design should not stop at consummation.

 

I am not an expert, I strongly suggest to get any possible information from other older students. If not available, bring flowers or sweets to your professor. Tell her from Michel.

 

---------------

Basically, you need an urban survey. If there is no (you can't establish one by yourself), it will remain very theoretical, and maybe easier.

 

---------------

edit.

If the developpment is part of a large governmental (national) project, the municipality border is not an issue.

Edited March 13, 2011 by michel123456

[Hearts]

hmm..okay..thanks for the pointer,

but why open air ducts (canals) are used? wouldn't it risk even more contamination?

The water recycling part is a good idea.. there are some paddy fields around the village that could use irrigation~

unproductive week anyway, got addicted to Heroes 5, and I suspect that I won't get any reply from 'guys responsible for the water distribution in the state'

hmm, underground pipes? They don't interfere with anything above ground cause they are well, underground, but should any of the pipe leak along the way, they will be a pain to detect and replace/repair, especially if something has already been built on top of it.

how do they do that anyway? Do they insert some sort of radioactive substance with short half lives and then check with a gieger counter?

 

 

[michel123456]

From source to treatment plant there may be several kilometers. the water in those ducts (or canals) is 'dirty'. This same water will go into the lake; it is not drinkable water. But it must be protected from contamination like pesticide & other chemical products. It means the whole area that concerns the lake must be under supervision, no industries, no settlement, maybe no agriculture, in other words, nothing at all in a restricted closed area.

_Canals are used when possible, it is not easy to design, you may need bridges (aqueducts) and other technical works. Water In Athens -Greece (4millions inhabitants) comes from 192 km away through such a canal crossing mountains.

 

Underground pipes are possible, but you will never allow to build anything upon it, except road. Pressure meters at intervals will indicate the leak quite easily. Also, because water is under pressure (closed pipes), the leak may appear as a regular fountain.

http://www.youtube.com/watch?feature=player_embedded&v=Qz-AqE725ao

[Hearts]

Forgive me but you haven't mention the reason why canals are preferred. I found out the closest river to the village is 4.6 kilometers away. I don't think it makes economic sense to cordon off that much length of land. (The people here use it to plant paddy/rice).

 

Btw I cant watch the video you linked.

My university believes youtube is bad for us.

 

 

 

[michel123456]

Forgive me but you haven't mention the reason why canals are preferred. I found out the closest river to the village is 4.6 kilometers away. I don't think it makes economic sense to cordon off that much length of land. (The people here use it to plant paddy/rice).

 

Btw I cant watch the video you linked.

My university believes youtube is bad for us.

 

The video is showing a leak in a small town road, producing a 10 m high jet.

I am not an expert. I suppose on long distance and for large debit open air canals are more efficient. But you have to begin from an elevated source, like a barrage in a mountain somewhere.

I would say first make the quantitative estimate of the demand, so you can get an idea of the dimensions you need. Maybe I drive you in the wrong direction, I have no idea how big this developement is.

[Hearts]

It's okay =) you've been a great help~

Really appreciate your efforts.

Thanks.

Other than your pressure-meter-at-regular-intervals (I can't believe I didn't think of that ), I also found out that they use a sensitive sound measuring/hearing device to detect underground leaks. Simple concept but I think determining the exact location of the leak depends largely on the skill of the person operating the device.

http://www.nrc-cnrc....s/ctus-n40.html

 

A person in my country on average consume around 300 litres of water a day!

Source: http://www.competiti...s/mcr05/lee.pdf (pg 6) and the words of my lecturer.

Assuming water demand haven't increased significantly for the last 5 years..

Pretty scary when considering that 6 litres of drinking water can keep me hydrated for a few days.

Btw, about the size of the project..

The system is to last for around 50 years.

 

Past data

 

year population

 

1980 3000

 

1990 5700

 

2000 6400

 

2010 9600

 

The village include

 

few Terrace houses

few Semi-D s

few Bungalows

few Apartments

one Mosque

one Daily school

one Boarding school

two Kindergartensfew Shop lots (single-storey)

two Petrol station

one Wet market

one Light industry workshop

 

I haven't actually calculated the water demand yet..I'm sorry for not making clear the size of this project.

Hope this gives you a rough idea ~

Going to see a lecturer with actual experience in this later =D

Wish me luck~ he can be a little unforgiving sometimes, especially to the ones that did not do their homework.

Edited March 14, 2011 by Hearts

[michel123456]

Good luck.