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CE 4312- Water andWastewater Engineering

LECTURE 1-INTRODUCTION

Nadeeka Miguntanna

[email protected]


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Learning Outcomes

On completion of this unit you should be able to:

•Understand the importance of water and wastewatertransfer and treatment.

•Understand the principles of unit processes in water andwastewater treatment including: physical, chemical, andbiological treatment principles and the impacts of waterpollutants on human health and the environment.

•Apply the fundamental principles of water andwastewater treatment in designing water and wastewatertreatment schemes to remove pollutants.

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Content

Wastewater collection and treatment

• Introduction and Terminology

• Wastewater flow rates

• Wastewater characteristics

• Wastewater composition

• Wastewater characterization studies

•

Primary and secondary treatment of wastewater3


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Introduction and TerminologyTopics

•Beneficial uses of water

• Objectives

• Necessity of Water and Wastewater Treatment?

•

Global situation• Water cycle

• Water Sources

• Aims of water treatment

• Water Quality & Quantity

• A typical surface water treatment plant

• Water quality Guidelines & Standards4


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Basic needs – Human Life

Air Shelter

Water

Food “Many Live

with out

Love but

none with

out water”5


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Beneficial uses of Water

• Aquatic life and wildlife support

• Fish/shellfish consumption

•

Recreation• Agriculture

• Industry/hydropower/landscaping

• Drinking water supply

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Aquatic life and wildlife support

• The waterbody provides suitable habitat for

survival and reproduction of desirable fish,

shellfish, and other aquatic organisms

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Beneficial uses of Water Contd:

• Landscaping

• Hydro Power generation

•Industrial processing and/or cooling

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Water Consumption

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Objectives- Environmental Engineering

• To supply water safe/portable in QUALITY andadequate QUANTITY to population.

• To COLLECT, TREAT AND DISPOSE the

wastewater generated in the community.

• To put in place the methods for pollution

prevention in industries and to treat and

dispose of industrial wastes.11


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Objectives- Environmental Engineering Contd:

• To control air pollution from indoor, work

environment as well as from the industries.

• To collect, transport and safely dispose of

municipal and hazardous solid wastes.

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Why Treat Water and Wastewater?

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Concern to the Public Health


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Historical Development of Public

Health

• In the early 19th century, the growing towns of

Britain were characterised by overcrowding, poor

housing, bad water and disease.

• Edwin Chadwick (1800-1890)argued that diseasewas the main reason for poverty, and that

preventing disease would reduce the poor rates.

•

In 1848, a cholera epidemic terrified thegovernment into doing something about

prevention of disease -through both public and

individual health measures.14


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Sir Edwin Chadwick(In 1842)

“Aid to be sought from the science of the Civil

Engineer, not from the physician”

He identified that solutions for Environmental

medical problems would be come from

Engineering but not from medical community.

Public Health Act and the Nuisances removal

and Diseases Prevention Act were passed in 1848.15


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The Observations of Dr John Snow

(1813-1858)• In 1854, within 10 days some 500 people living in or

around Broad Street died. Snow lived in the area of FrithStreet, so he decided to intervene. He patrolled thedistrict, interviewing the families of the victims .

• His research led him to a pump on the corner of BroadStreet (now Broadwick) and Cambridge Street

• Nearly all the deaths had taken place within a shortdistance of the pump.

Dr John Snow, a surgeon (later, considered pioneer of thescience of epidemiology), speculated that it was spread bycontaminated water.

an idea neither the authorities nor the

medical profession accepted. 16


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Broad Street Pump & JohnSnow‟s proof of cholera‟stransmission of the 530inmatesof the Poland Street workhouse,only 5people had contractedcholera; building had its ownwell.

the 70workers in a Broad Streetbrewery, where the men weregiven an allowance of free beer

every day and so never drankwater at all, there were novictims at all

• Snow recommended toremove the pump handle.

• When they did so, the spreadof cholera stopped.

However, Snow's 'germ' theory of disease was

not widely accepted until the 1860s.

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• The most advanced and elaborate eighty-twomiles of sewage system in the entire world wasoperational by 1865

It remains the backbone of

London’s waste-management

system to this day.

In 1875 a Public Health Act enforced

laws about slum clearance, provision of

sewers and clean water, and theremoval of nuisances.

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HEALTH IN A SOCIETY

• Today researchers express the incidence ofdisease as a rate relative to the population orto the population within age cohorts (e.g.,

deaths per 1,000 population)

• Health in a society is usually measured by

three main indicators: the infant mortalityrate, the childhood mortality rate and the lifeexpectancy.

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(Sources * WHO, 1999 ; ** WHO, 2000)20


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February 2010- Cholera in Papua New

Guinea (in 50 years).

2109 cases have been confirmed nationwide.

50 dead as of 1March 2010

East Sepik's main river was contaminated with

Vibrio cholerae, the bacteria which cause

cholera. Mainly a water-borne disease, though it

can become food-borne.

cholera treatment centre At Angau Hospital,

Lae http://www.msf.org.au

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CHOLEARA OUTBREAK IN SRILANKA

• Sri Lanka is suffering from a cholera outbreak

which started at the end of September

1997. A total of 431 cases were reported for

1997. As of 13 November 1998, the totalnumber of cases notified for 1998 is 1 264,

with 36 deaths. On average, 125 cases per

month, with a case-fatality rate of 2.7 %.(WHO records-1998)

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Preventable Deaths

LACK OF CLEAN WATER AND SANITATION ARE

TWO OF THE MOST IMPORTANT FACTORSRESPONSIBLE FOR THE POOR HEALTH

CONDITIONS.

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Water treatment aims to ensure that

water is:

•Pleasant to consumers (Aesthetics).Free from colour, taste, odor and pleasing.

(Physical perception-Subjective)

•

Safe for human consumption (Safety).Free from Bacteriological (Free from

pathogens-Disease causing microorganism)

and other chemical constituents.

•Provided at a reasonable cost (Economics).

PORTABLE AND PALATABLE WATER 25


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Limited amount of fresh water on earth thathumans can use.

To some degree the earth's fresh water supplies areconstantly refreshed through a natural process- we

call the water cycle

Therefore a renewable resource.

It's very important that we use fresh water

thoughtfully.

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The Hydrological Cycle (Water Cycle)

The recycling of water between the Earth and theatmosphere.

It is the movement of water involving

• Evaporation,• Transpiration,

• Condensation,

•

Precipitation,• Infiltration

• Run-off

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The Urban Water Cycle

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QUANTITY OF WATER

WATER SOURCESGround Water

Surface Water

Lake Water

Sea WaterTreated Effluent - Wastewater treated to the

highest standard to remove contaminants andimpurities.

Provide economic benefits by reducing demandon water reserves.

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Pollution Level (PL) and Carrying

Capacity(CC)

Prior to Industrial and Green Revolution,

quantum of pollution was less.

River’s self cleaning capacity (Carrying

Capacity) was greater than pollution load.

CC>PL32


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At Present................

Intensive industrialization population explosion

and modernization leads

PL>CC

Therefore intervention by Environmental

Engineers (EE) is Essential.

EE- Engineers the natural process to

amplify the rates such that the process

occurs rapidly.

TREATMENT PLANT33

TREATMENT PLANT


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TREATMENT PLANT

Water is continuum. No difference between

water and wastewater (except in biodegradableorganic matter).

Similar Treatment technologies (Unit operation

and processes ) can be employed.

Selection of Treatment technology depends on

nature of pollutant.

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1. Before water is supplied to communityquality should be enhanced so as to meet

WATER QUALITY STANDARDS.

2. Simultaneously the wastewater quality to be

enhanced since untreated effluent causesdeterioration of water quality (This is calledsource protection.

3. Source protection is an effective method of maintaining high quality resulting inreduction in water treatment cost.

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Typical Engineered system of

Treatment

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