Transcript S Civil Monroe L. Weber-Shirk Environmental Engineering

Monroe L. Weber-Shirk
School of Civil and
Environmental Engineering
Outline
Burden of unsafe water
Global Water Supply and Sanitation
Assessment 2000 Report
The Millennium Development Goals
Safe and Improved…
Cell phones vs. municipal water technology
Mortality and Morbidity From
Unsafe Drinking Water
 1.7 to 2.2 million persons die from
waterborne diseases each year
 Most of the victims are children
 1 billion episodes of gastroenteritis and
other infections are caused by unsafe
drinking water each year
 Equivalent to ______
22 245 passenger
Boeing 767-400 crashes per day
Daniele Lantagne, CDC
Global Water Supply and Sanitation
Assessment 2000 Report
 To meet the 2015 development target of halving the fraction of
the population without services in Africa, Asia, and Latin
America and the Caribbean, the number of people served by
water supply must increase by 1.6 billion (32%), and those
served by sanitation must increase by 2.2 billion (59%).
 For water, this means providing services for an additional
300,000 every day, until 2015. Considering that only 816 million
people gained access to improved water services during the
1990s, the pace has to be accelerated.
 For sanitation, the challenge is even greater, with services to be
provided for an additional 400,000 every day until 2015. During
the 1990s, only 750 million people gained access to improved
sanitation services.
Global Water Supply and Sanitation
Assessment 2000 Report
 Rapid urban growth means that more than half of the
additional services must be in urban areas, despite the
higher current levels of coverage.
 The lower levels of service in rural areas also mean that
nearly half of the improvements will need to come in rural
areas, even though the rural population will grow more
slowly than the urban population.
 Current progress is inadequate to meet the targets.
 Something will have to change dramatically if the targets
are to be met.
 A wide range of issues would need to be resolved, and the
majority of these are institutional and social, rather than
technical.
More on this view later!
The Millennium Development Goals
 The Millennium Development Goals are an ambitious
agenda for reducing poverty and improving lives that
world leaders agreed on at the Millennium Summit in
September 2000. For each goal one or more targets have
been set, most for 2015, using 1990 as a benchmark:
1. Eradicate extreme poverty and hunger
2. Achieve universal primary education
3. Promote gender equality and empower women
4. Reduce child mortality
5. Improve maternal health
6. Combat HIV/AIDS, malaria and other diseases
7. Ensure environmental sustainability
8. Develop a global partnership for development
Goal 7: Ensure environmental
sustainability
Targets
9. Integrate the principles
of sustainable
development into
country policies and
programmes and reverse
the loss of
environmental resources
10.Halve, by 2015, the
proportion of people
without sustainable
access to safe drinking
water
11.By 2020, to have
achieved a significant
improvement in the lives
of at least 100 million
slum dwellers
Indicator
25. Proportion of land area covered by forest
26. Land area protected to maintain
biological diversity
27. GDP per unit of energy use (as proxy for
energy efficiency)
28. Carbon dioxide emissions (per capita)
[Plus two figures of global atmospheric
pollution: ozone depletion and the
accumulation of global warming gases]
29. Proportion of population with sustainable
access to an improved water source
30. Proportion of people with access to
improved sanitation
31. Proportion of people with access to
secure tenure [Urban/rural disaggregation
of several of the above indicators may be
relevant for monitoring improvement in
the lives of slum dwellers]
Millennium Goal 4:
Reduce child mortality
 Diarrheal diseases claim the lives of around two million
children each year- 5,000 per day, and cause countless
more to fall ill.
 Children already suffering from poor diets and the ravages
of other diseases are the first to get sick and die from water
and sanitation-related diseases such as diarrhea, cholera
and typhoid
 Diarrhea spreads most readily in environments of poor
sanitation where safe water is unavailable – often areas that
have been hit by human made or natural disasters.
 Water-borne diseases are one of the major cases of
under-five mortality, along with pneumonia, malaria, and
measles.
How would you define
“improved water supply”?
Quantity
Quality
Proximity
Reliability
Schedule
Cost
Improved Water Supply
Reasonable access to at least 20 liters per
person per day from a source within one
kilometer of the user’s dwelling from one of
these sources
household connections
public standpipes
boreholes
protected dug wells
protected springs
rainwater collection
Quality?
Intermittent Supplies
 It is estimated that over one-third of the urban
water supplies in Africa, and in Latin America and
the Caribbean, and more than half those in Asia,
operate intermittently.
 Why are supplies intermittent? _______________
Rolling blackouts
 Crude form of rationing
 Lack of meters
 Leaking system
 Some sections of the city might never receive water
otherwise
 Elevation challenges!
 Home storage
Consequences of Intermittent
Supplies
 Intermittent water supply is a significant constraint
on the availability of water for hygiene
 And personal hygiene is very important!!!
 Encourages the low-income urban population to
turn to alternatives such as water vendors
 That are expensive and from dubious sources
 Point of Use Storage
 That create considerable risks of contamination
 Risks of distribution system contamination
Consequences of Intermittent
Supplies
 Contamination may also occur by intrusion of
contaminated water into the pipelines through
faulty joints, cracks, etc.
 Opportunity for contamination by siphoning
 Loss of chlorine residual in stagnant water
 The pipelines are subject to additional stress
caused by transient flows (water hammer),
affecting the durability of the system and
weakening pipes and joints (more leaks…)
 Water waste increases
 Complaints about metering air (if there are meters)
Point of Use Storage
 When there is frequent intermittence in the water
distribution system, the consumers are commonly
equipped with domestic storage tanks
 Although these devices help to reduce hourly
peaks in demand and mask short-term
interruptions for users, they are often neither
properly protected nor regularly cleaned and
disinfected
Eliminating Intermittency
Reduce demand – metering
Eliminate leaks
Eliminating intermittency may have a more
significant improvement in public health
than any steps taken to improve the water
quality
This might be a Monroe Myth!
The Technology is well Developed
 A common view held by many academicians,
community development workers, and funding
organizations
 Lack of safe water and sanitation infrastructure is
blamed on
 Weak institutions
 Corruption
 Weak Economies
 Poor education
Suppose distillation was the only method that environmental
engineers had developed to create clean water
 All water in pipes delivered to homes was unsafe
 What would you say is the limiting factor
preventing implementation of safe piped water?
 Weak institutions
 Corruption
 Weak Economies
 Poor education
 Inadequate technology
 What do you conclude?
Why aren’t there better technology
choices?
 We have a solution that works for strong
economies (conventional water treatment)
 Individual cities can’t afford to hire consulting
firms to conduct research to develop better
technologies
 Each city chooses conservative existing designs
 The same is true for countries in the Global South
(they can’t afford the R&D to develop better
technologies)
Continual optimization?
Cell Phones vs. Water Treatment
Why are cell phones continually getting
cheaper and better?
Why is conventional water treatment not
enjoying a similar optimization?
Vendors, Consultants, Municipalities
What does each entity strive to obtain?
Cell Phones vs. Municipal Water
Treatment
Global!
Cell phones
Municipal Water
100, 000, 000 people
yr
 2000 plants
Units per year
850,000,000
Companies
10?
100s?
Incentive
Improve
technology &
increase market
share
Successful
operation at
handover of each
customized plant
50, 000 people
year
plant
Why has the Private Sector Failed to
Optimize Municipal Water Treatment?






Low volume of units and customized designs for each site
Large number of firms
Long life of units
Vendors want to sell hardware
Consultants want to remove liability for design
Consultants use vendors and hence develop designs that
include equipment that can’t easily be purchased elsewhere
 Vendor designs must remain proprietary to prevent other
firms from benefiting
 Can’t risk failure on a unit – conservative design prevails
Examples of Technology Misfits in
the Global South
El Progreso, Honduras
Modular Package plant
Black box technology
Marcala, Honduras
No chemical feeds
Upflow filtration
Technology needs (see AguaClara)
Ethics of Engineering Experimentation
http://aguaclara.cee.cornell.edu/resources/research/
A Role for Universities
Develop new knowledge
Test the designs in full scale field trials
Make that knowledge available to the global
community
GNU open source engineering!
Capacity building: training the trainers
Course Overview
Setting the stage (Public Health)
Exploring treatment technology options
The question of scale: Point of Use vs.
Centralized systems
Theory and Design of water treatment
processes
Putting it all together: system design
PowerPoint speaker notes have the references
La 34: the first Cornell Designed
Water Treatment Plant in Honduras
Ojojona
Tegucigalpa
 The share of the population with
reasonable access to any of the following
types of water supply for drinking:
household connections, public standpipes,
boreholes, protected dug wells, protected
springs and rainwater collection.
Reasonable access is defined as the
availability of at least 20 liters a person
per day from a source within one
kilometer of the user’s dwelling
Photo by Chris Boone
Tegucigalpa
Photo by Chris Boone
Water Storage Tanks
Photo by Chris Boone
Vara de Cohete, Honduras
Water Source
Photo by Chris Boone