Public Health Engineering 3r3d2s

PUBLIC HEALTH ENGINEERING (CE-355)

Saadat Ali Phone: 0333-2386630 Email: [email protected]

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Course Introduction • Water demand, sources, quality, sampling, analysis,

treatment, distribution network design • Wastewater generation, quality, effects on

environment and health, treatment • Solid waste management • Air and noise pollution control • Environmental Impact Assessments & Environmental

legislations

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Course Objectives • To give students basic concepts about public

health engineering • To give you idea about mitigation of environmental

issues that affect the public health • To make you aware about health and

environmental issues related with civil engineering • To make you aware about present environmental

status of the country and the work going on • To make you aware about legislations

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Recommended Books and Materials • Text Book: Water Supply and Sewerage. By

E.W. Steel, 6th edition.

Reference Book: • All lectures handouts will cover all the topics. • If out of books, reading material would be

provided to students as hard copy.

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Marks Distribution • 2 OHTs • 1 final exam • 4 assignments • 4 quizzes

• Term project • Total

= 30 (2 x 15) = 30 = 10 = 10 = 20 (10 write up + 10 presentation) = 100

• Practical

• Viva voce= 20 • 10 Assignments = 50 • 2 quizzes = 10

• Field visit = 20 (10 visits + 10 reports) • Total = 100

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Introduction to Public Health Engineering

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The Concept “Many diseases are preventable through simple, non-medical methods”

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Public Health? “the science of preventing disease, prolonging life and promoting health through the organized efforts of society, communities and individuals”

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History of Public Health • From the beginnings of human civilization, it was

recognized that polluted water and lack of proper waste disposal spread communicable diseases (Moin-ja-darro and Harrapa civilizations) • Roman times, it was well understood that proper

diversion of human waste was necessary for public health in urban areas. • During the 14th century Black Death in Europe, it was

believed that removing bodies of the dead would further prevent the spread of the bacterial infection.

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The Water

• Water covers 70.9% of the Earth's surface, and is vital for all

known forms of life. • Oceans hold 96.5% of surface water, glaciers and polar ice caps

2.4%, and other land surface water such as rivers, lakes and ponds 0.6% • Approximately 70% of the fresh water which is actively handled by

humans, is consumed by agriculture.

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The Water • Clean drinking water is essential to humans and

other life forms. • Scientists have estimated that by 2025

more than half of the world population will be facing water-based vulnerability

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Water Cycle

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The water cycle – dynamics does the trick Instant snap shot:

Shortage of freshwater !

Clouds 0.001%

8 days

” but, H2O is always on the move ...”

A dynamic perspective gives a better description:

Renewable rain gives in 2000 years as much water as is in the oceans!!! Rivers 0.0002%

Groundwater 0.7%

Lakes 280 0.007% days 4 600 years

Oceans 96.5% 3 000 years

16 000 years Ice caps 2.7%

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Water Chemistry • Water appears in nature in all three common states of matter,  As vapor in clouds;  As solid in glaciers and

 As liquid in aquifers in the ground. • Water has high specific heat capacity of 4200 J/(kg·K) due to hydrogen

bonding between its molecules.

This property allows water to moderate Earth's climate by buffering large fluctuations in temperature. • The maximum density of water occurs at 3.98 °C (39.16 °F).

It has the anomalous property of becoming less dense, when it is cooled down to its solid form. Ice expands to occupy 9% greater volume and floats over water.

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• Water is miscible with many liquids, such as ethanol, in all

proportions, forming a single homogeneous liquid. On the other hand, water and most oils are immiscible usually forming layers according to increasing density from the top. • Water is a universal solvent. Substances that dissolve in water,

e.g., salts, sugars, acids, alkalis, gases are known as hydrophilic (water-loving) substances, while those that do not mix well with water (e.g., fats and oils), are known as hydrophobic (waterfearing) substances. • The boiling point of water is dependent on the barometric

pressure. On the top of Mt. Everest water boils at 68 °C (154 °F), compared to 100 °C (212 °F) at sea level. Conversely, water deep in the ocean near geothermal vents can reach temperatures of hundreds of degrees and remain liquid.

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Water and Human Human body contains from 55% to 78% water. Most scientists agree that approximately 2 liters (6 to 7 glasses) of water daily is the minimum to maintain proper hydration.

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Potable Water • Water fit for human consumption is called drinking water or

potable water. • Some five million deaths a year are caused by polluted drinking

water. The World Health Organization (WHO) estimates that safe water could prevent 1.4 million child deaths from diarrhea each year • It takes around 3,000 liters of water, converted from liquid to

vapour, to produce enough food to satisfy one person's daily dietary need

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Water Scarcity

Pakistan available water = 1200 m3/c/year

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Sanitation • Sanitation is the hygienic means of promoting health

through prevention of human with the hazards of wastes. Hazards can be either physical, microbiological, biological or chemical agents of disease. • These includes human and animal feces, solid wastes,

domestic wastewater (sewage, sullage, greywater), industrial wastes and agricultural wastes

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Sanitation – ‘the silent crises’  2.4 billion people (40% of the world's population) lack so

called adequate sanitation  18% of the world's population lack safe water supply

 10% of all wastewater in developing countries is treated  Malnutrition is a major factor making us more vulnerable

to disease and death, thus food security is important  The combined effects of poor personal and domestic

hygiene and lack of safe water and good environmental sanitation is considered the most important risk factor for disease and death

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What sanitation is about Traditional interpretation: • Personal and household hygiene • Clean environment incl. water • Solid waste management

• Greywater disposal and treatment • Safe excreta disposal • Stormwater handling

Additional perspectives:

• Acceptance, affordable, convenience and pride • Environmentally sustainable arrangements

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Strategies for sanitation improvements Principle: • Organic ≠ other solid waste

• Stormwater ≠ sewage • Industrial ≠ household wastewater

• Black toilet water ≠ greywater

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Why do we often act as if we were only a few hundred million people on earth? v

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What is Wastewater Reuse? Terminology • Water reuse • The beneficial use of treated wastewater for agriculture, industry, etc. • Water reclamation • Reclamation involves all processes used to treat wastewater so that it can be beneficially reused • Water recycling • Recycling generally means reuse of wastewater back in the same cycle where it is generated. Hamid Iqbal

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What is Wastewater Reuse? Categories of Water Reuse • Indirect Reuse • Reuse of wastewater within the context of natural water systems (rivers, aquifers, etc.). The ultimate indirect reuse is through the global hydrologic cycle • Other : Indirect potable reuse • Direct Reuse • The direct beneficial reuse of treated wastewater for agriculture, industry, etc. • Direct potable reuse: the reuse of reclaimed water for potable uses Hamid Iqbal

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Driving Factors for Water Reuse • Water Availability • Water Consumption • Water Quality

Hamid Iqbal

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Benefits of Water Reuse • Important element of integrated water

resources utilization and management • Treated effluent is used as a water resource for many possible beneficial purposes • Pollution control e.g. for many Arab coastal cities, wastewater would not be discharged to the sea thus reducing pollution to the marine environment and not creating public health issues

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Public Health and Water Quality Considerations • Physical water quality considerations  Turbidity, color, etc. • Chemical water quality considerations  Chemical constituents including solids, metals, nitrogen,

phosphorus, etc.

• Biological water quality considerations  Pathogens including bacteria, helminths, virus, etc. • Emerging water quality considerations  Pharmaceuticals, hormonal products, personal care products

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Water Reuse Design Criteria • Water quality requirements • Monitoring requirements • Treatment process requirements

• Treatment reliability requirements • Operational requirements • Cross-connection control provisions

• Use area controls

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Treatment Reliability • Standby power supply • Multiple or standby unit processes • Emergency storage/disposal provisions

• Provisions for continuous disinfection • Non-design features

• Qualified personnel • Monitoring • O & M program

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Solid Waste • Waste: Anything which is not useful for a person is

called as waste. • However waste is a relative terminology and a useless thing for a person-could be useful for others, e.g. Scavengers collect the solid waste from streets and sell it to waste buyers and earn money. • Solid Waste (SW): Solid waste is the waste arising from all human and animal activities and is normally solid, semi solid or liquid discarded as unwanted material.

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Problems in SWM • The problems associated with the management of

solid waste in Pakistan are due to the quantity and diverse nature of waste. • The development of extensive urban areas • The engineering limitations of the impacts of

technology, energy and raw materials • So, to achieve a goal of proper solid waste

management in an efficient and orderly manner, the fundamental aspects and relationships involved must be identified and understood early.

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Present status in Pakistan • It is estimated that presently, 56,000 tons per day of

solid waste is generated in Pakistan. • No weighing facilities are installed at any disposal sites • Open burning of waste or open disposal • Collection 51-69 % • No Disposal facilities • A lot of potential for recycling and involvement of private sector which is overlooked • Hazardous hospital and industrial wastes are being simply treated as ordinary waste

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Air and Noise

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Danger in the air we breathe • At rest, human beings

breathe in and out at every 4 seconds, … • 16 times in a minute…and • 960 times an hour …or… • 8.5 million times of air intake in a year. • This adds up to I million gallons a year (4 million liters) of oxygen-related air in a year Hamid Iqbal

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Natural sources of air pollution • Ash and smoke from lightning-triggered

forest fires • Ash and dust from volcanic eruptions • Salt spray from sea waves • Methane from decaying organic matter • Pollen from plants • Dust from windstorms

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Air Pollution: regional & global problems • Acid rain • Photochemical Smog • Industrial Smog • Greenhouse effect and global warming • Depletion of stratospheric ozone • Eutrophication

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Common health effects of air indoor pollution

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We never know the worth of water till the well is dry. ~Thomas Fuller,

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