anemute alemu

8/16/2019 ANEMUTE ALEMU

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CHAPTER ONE

INTRODUCTION ❖ Wastewater is the used water generated by the community

arious actiities!

❖ It contains im"urities or "o##utants in the $orm o$ so#ids%#i&u

or their combination in such concentration that is harm$u# i$

the enironment!

❖ The contaminants inc#ude sus"ended so#ids%biodegradab#e

organic com"ounds%inorganic so#ids%nutrients%meta#s and "

microorganisms!


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❖ The suspended solids are primarily organic particles composed

wastes(faeces),food waste and toilet paper.

❖ Inorganic solids include surface sediments and soil as well as sa

metals.

❖ The removal of suspended solids is essential prior to discharge

avoid settlement in the receiving water course.

❖ The design of wastewater treatment plant units,in general,means

determination of the determination of capacity(volume)and dimetreatment tanks.

❖ Wastewater treatment plants are designed on a unit operation co

which one operation is optimized to accomplish one task.the cho

treatment operations depends on the uality and variability of wa

treatment ob!ectives.


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❖ Wastewaters are normally treated by the combination of physicand biological operations.

❖ physical methods of treatment include the use of tanks and othe

designed to control the flow of wastewater and and to promote thcontaminants.

❖ The action of bacteria and other microorganisms are biological m

treatment,which play a vital role in the removal of pollutants whic

effectively achieved by other means.

❖ "hemical treatment methods enhance the efficiency of other pro

operations and provide specialized treatment as a result of their

various treatment stages.


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'OURCE' O( WA'TEWATER

❖ Wastewater can originate from the combination of domestic,indu

commercial activities.

❖ The source of wastewater will determine its its characteristics an

be treated.

❖

#omestic wastewater is the wastewater generated from homes,band institutions and contains pollutants such as,faecal and vege

matter,grease and scum,detergents,rags and sediments.$n the

wastewater from industrial processes may include to%ic chemica

strong organic wastes,radioactive wastes,large amounts of sedim

temperature wastes or acidic wastes.


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O)*ECTI+E' O( THE PRO*ECT

❖ The main ob!ective of this pro!ect is to maintain a healthy enviro

treating properly the wastewater before they find their way into wor agricultural lands and other possible reuse.

❖ To reduce the strength of wastewater,so that it may not pollute th

water.

❖ To reduce its volume in general.

❖ To destroy the pathogens

❖ To enable its safe and satisfactory disposal

❖

To produce methane gas


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,OCATION O( TREAT-ENT P,A


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DE'I.N PERIOD

&enerally, the design period of wastewater treatment plant is determ

considering the following facts'

❖ unds available for the construction of the treatment plant

❖ seful lifespan of materials that are used in the construction of wa

treatment plant

❖ *ate of interest on the loans taken to complete the pro!ect

❖ $peration and maintenance cost

❖

+nticipated e%pansion of the population


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❖ The consideration of the above factors in the se

design period serves two purposes.

(irst#y% it wi## not "ut on e/cessie $inancia# burden on the const

the wastewater treatment "#ant as it can be carried out in "hase

design "eriod is ery #ong% it wi## unnecessari#y increase the cosconstruction and the ca"acity o$ the treatment "#ant wi## remain

#onger "eriod o$ time! On the other hand% i$ the design "eriod is

ca"acity o$ the "#ant sha## be consumed $aster and wi## create a

e/"ansion!Thus% by considering the aboe cases% a design "erio

years inc#uding its construction "eriod is ado"ted $or this "ro3e


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POPU,ATION PRO*ECTION ❖ A$ter the design "eriod has been $i/ed% the "o"u#ation o$ the

area at the end o$ the design "eriod has to be determined! I

designing a wastewater treatment "#ant $or a new town4city%

dai#y wastewater $#ow is norma##y com"uted on the basis o$

dai#y water demand o$ the town 4city! This demand is usua##

on the basis o$ the "ro3ected "o"u#ation oer the end o$ the

"eriod!

❖ The estimation o$ $uture "o"u#ation de"ends on the conside

$actors that wi## goern the $uture growth and dee#o"ments

town4city in the s"heres o$ trade and

commerce%industries%education%socioeconomics%etc!


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❖ Thus $rom the data obtained $rom Communication Cor"orat

Directorate )ureau o$ Debre -ar5os Uniersity%the statisticastudents and sta$$ wor5ers are as $o##ows6

Tab#e 76 'tudents 'tatistica# data in 8229 E!C

irst

degree

econ

ddegree

Total

*egular

-/-0 112 -3/2

4%tension

5525 6/ 317

umm 206 670 251


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Table 8workers statistical data in 007 4."

9ale emale

Total

+cademicstaff

222 -62 --67

+dministrative staff

533 651 -/0

Technicalassistant

56 -3 7

"afeteria

-5


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