Today's Presentations

concretecakeUrban and Civil

Nov 29, 2013 (3 years and 10 months ago)

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Today’s Presentation


Piping

Storage, Treatment, and
Distribution

Source

Water Sources and Collection

Developing sources of Surface
Water


Rainfall Catchments


Ponds and Lakes


Streams and Rivers


Springs and Seeps


Rainfall Catchments


Quality


Disinfection necessary


Quantity


Seasonal


Accessibility


In yards of users


Reliability


Must rain; some maintenance
required


Cost


low


Ponds and Lakes


Quality


good for large bodies of water, poor for
small bodies of water


Quantity


decrease during dry season


Accessibility


intake needed, pumping and
storage required


Reliability


good; needs knowledge of
maintenance, pumping, and treatment to operate


Cost


high because of pumping and treatment


Ponds and Lakes Diagram

Streams and Rivers


Quality


depends on elevation. The higher,
the better.


Quantity


Seasonal


Accessibility


Needs intake


Reliability


maintenance required


Cost


treatment is expensive


Streams and Rivers Diagrams

Streams and Rivers Diagrams

Streams and Rivers Diagrams

Springs and Seeps


Quality


good; must disinfect and protect the
source


Quantity


variable for gravity
-
driven springs
(seasonal)


Accessibility


storage needed; gravity flow
makes delivery easier


Reliability


Good for gravity flow


Cost


Low, but will rise with the amount of
piping needed.


Springs and Seeps Diagram

Dams

Types of dams


Earth dam


Cast in place concrete


Concrete block


Dependent on:


Available resources


Size of dam


Placement of dam


Dams

Pros & Cons

Earth dam


Cheep, local resources


Must be closely watched


Not entirely waterproof


Require spillway


Cast in place concrete


Durable


Requires some skill


More expensive

Concrete block


Durable


No formwork


More expensive


Not entirely waterproof

Piping

Purpose:

To move water from source to village


Gravity feed

Configurations


Buried:


Pros: Protected from elements (Sunlight, rockfall,
Landslides)


Cons: Labor intensive and harder to maintain


Open:


Pros: Easy to install and maintain


Cons: Susceptible to elements


Suspended:


Used over gorges, streams, and bad terrain

Pressure in pipe


Large elevation drops can cause high
pressure in pipes



Certain pipes can withstand high pressure



Build structures to reduce pressure along
pipeline

Kinds of Pipes


PVC


Used for low
-
pressure stretches. Deteriorate
with sunlight


usually buried



Galvanized Iron


used for high
-
pressure stretches and in areas
where pipes can’t be buried. Expensive



Kinds of Pipes


HDPE


Can withstand high pressures, sunlight. Less
expensive than GI.



Local Materials


Bamboo Trunks


Low pressure, inexpensive


Deteriorate rapidly, difficult to connect.

Maintenance ?


Need inspections and upgrades



Install valves along length of pipe.

Water Treatment



Effective


Inexpensive


User friendly

Goals:

Water Treatment Options


Centralized Treatment


Chlorination


Slow Sand Filtration


Solar Pasteurizers


Murunga Seeds


Household Treatment


Storage


Solar Disinfection


Biosand

Chlorination


Most familiar treatment method


Concentrated solid is dangerous to transport and
store, dilute liquid is too bulky in large quantities


Production of Trihalomethanes


Requires regular, trained maintenance and
monitoring


Can also be done on a small, individual scale

Chlorination


Pot Chlorination



Requires bleach powder


Hung in well, refilled
weekly


Doesn’t meet WHO
standards


MIT is researching


On
-
site production of
dilute Cl by electrolysis


Requires energy! and more
training, maintenance

Slow Sand Filtration


Easy & cheap to
construct


Easy to clean


scrape
off top layer of sand


Expensive to test
effectiveness


Using cheap pass/fail
test, this will fail


More detailed results
cost 20x more

Solar Pasteurizers


Boils Water without Fuel


Very effective at
disinfection


Reduces deforestation


Higher Initial Cost


Requires Sunlight &
Warm Climate


Back up burner available


Very Low Maintenance


Runs automatically


Long lifetime


Biological Flocculants


Seeds from Moringaceae family trees,
Tuna Cactus, Potato Starch…


Often grow indigenously


Multiple uses


Murunga plants provide food, oil, and
firewood


Not as well known or studied

Storage


Storing water settles out particulates and
kills microorganisms


Very Easy to set up and maintain, Very
Inexpensive


Small scale, personal responsibility


Should not use clay pots


For best results there is a long lag time


2 weeks storage usually optimal

Solar Disinfection


Small scale version of solar pasteurization


Very small quantities


Very easy, individual control


Reliant on climate


Time consuming

Biosand


Biofilm forms on sand and is used to
remove nutrients from the water


Requires time for biofilm to form


Low maintenance


Needs more research


Successful in Nepal, problems in Sudan


Not sure why it failed in some locations

Water Treatment Summary


There are many different methods available


Many of these are simple and inexpensive


Treatment can be done at almost any scale


Unfortunately, often rely on pre
-
existence
of some very specific features (climate,
local plants, groundwater source)

Distribution in the Village

Hydraulic Ram


Water required uphill from source


Pump water uphill along supply system


No electricity required

Example: Fleming Hydro
-
Ram


A. Drive pipe


B. Poppet valve


C. Check valve


D. Compression
chamber

Water pumping process


A. Drive pipe


Falling water enters the
drive pipe at point A
until a required volume
is reached.


Water pumping process


B. Poppet Valve


Water continues
through the system
until it reaches a
poppet valve


Water escapes through
the waste valve until
the build
-
up of
pressure seals the
opening

Water pumping process


C. Check Valve


Water forces open the
one
-
way check valve
because the other exit
is sealed


Water passes the check
valve and begins to
compress the trapped
air in the vertical
compression chamber

Water pumping process


D. Compression
Chamber


Water pushes against
the trapped air in the
vertical compression
chamber


The trapped air acts
like a piston, forcing
the water back down
the compression
chamber

Water pumping process


E. Delivery Pipe


With the one
-
way
check valve closed, the
water enters the
delivery pipe attached
at (E) after it is forced
out of the ram.

Water pumping process


Cycle Repeats


A slight vacuum is
formed when the check
valve closes


The waste valve poppet
drops open again,
allowing water out of
the valve.


Approximately 60
cycles occur per
minute.

Design Requirements


Head of water supply


Size of the pump


Flow rate to the pump


Height of water
discharge


Vertical fall


Vertical lift


Rate of ram pulsation


Length of pipe on
intake and discharge

Output Range


1
-
inch ram = 700


1,800 gallons/day


1.5
-
inch ram = 700


3,000 gallons/day


2
-
inch ram = 700


4,000 gallons/day


3
-
inch ram = up to 16,000 gallons/day

Efficiency


With a ratio of 1
-
foot drop to 10
-
foot lift,
the pump delivers approximately 15


20%
of the water it uses


Practical only if need to pump water uphill

Delivery Methods:

Centralized Location


Advantages


One installation


Easy maintenance



Disadvantages


Overdemand due to population growth


Reliance on one source

Delivery Methods:

Distributed Location


Advantages


More than one source


Easier to upgrade



Disadvantages


Increased installation time and money


Higher maintenance