搜索
PART1INTRODUCTIONTOENVIRONMENTALENGINEERINGUnit1Text:EnvironmentalEngineeringWhatIsThisBookAbout?Theobjectiveofthisbookistointroduceengineeringandsciencestudentstotheinterdisciplinarystudyofenviroomentslproblems:theircauses,whytheysreofconcern,andhowwecsncontrolthem.Thebookincludes:?Descriptionofwhatismeantbyenvironmentsndbyenvironmentalsystems?Informationonthebasiscausesofenvironmentaldisturbances?Basisscientificknowledgenecessarytounderstandthenatureofenvironmentalproblemsandtobeabletoquantifythem?Currentstateofthetechnologyenvironmentalcontrolinitsapplicationtowater,airandpollutionproblems?Considerablegapsinourcurrentscientificknowledgeofunderstandingandcontrollingmanyofthecomplexinteractionsbetweenhumanactivitiesandnature?Manyenvironmentalproblemswhichcouldbeeliminatedorreducedbytheapplicationofcurrenttechnology,butwhicharenotdealtwithbecauseofsociety’slackofwilltodoso,orinmanyinstancesbecauseofalackofresourcestodoso.SomeImportantDefinitionsWheretheyarefirstusedinthisbook,definitionsareintroducedinblockform,asshownhere,orprintedinboldtype.Environmentisthephysicslandbiotichabitatwhichsurroundsus;thatwhichwecansee.hear,touch,smell,andtaste.System.accordingtoWehster’sdictionaryD,isdefinedas“asetorarrangementofthingssorelatedorconnectedastoformaunitororganicwhole;as,asolarsystem,irrigationsystem,supplysystem,theworldoruniverse”.Pollutioncanbedefinedasanundesirablechangeinthephysical,chemical,orbiologicalcharacteristicsoftheair,water,orlandthatcanharmfullyaffectthehealth,survival,oractivitiesofhumansorotherlivingorganisms.Whenthegoalofimprovingenvironmentalqualityistakentobeimprovinghumanwellbeing.theword“environment”broadenstoincludeallkindsofsocial,economic,andculturalaspects.Suchbroadnessisunworkableinmanyrealsituationsandimpracticalinatextbookdesignedforaone-semestercourse.Ourexaminationofenvironmentalproblemsisthereforelimitedbyourdefinitionof“environment”.InteractionofSystemsAnumberofdifferentenvironmentalproblemsareassociatedwithwater,air,orlandsystems.Manyoftheseproblemswillapplyonlywithinoneofthesesystems,justifyingthebreakdownintothesecategories.Suchaclassificationisalsousefulforeasiercomprehensionofrelatedproblemswithinonesystem.Moreover,itissensiblebecause,formanagerialandadministrativereasons®,suchsubfieldsasairpollution,watersupply,wastewaterdiaposal,andsolidwastedisposalareoftendealtwithseparatelybygovernmentalagencies.Unfortunately,manyimportantenvironmentalproblemsarenotconfinedtoanair,water,orlandsystem,butinvolveinteractionsbetweensystems.Acurrentexampleistheacidrainproblemstemmingfromtheemissionofsulfurdioxideandnitrogenoxidegasesintotheatmospherefromthestacksofgeneratingstations®,smelters,andautomobileexhausts.Thesegasesarethentransportedbyaircurrentsoverwideregions,Rainfall“washesthemout”,creatingacidrainwhichisharmfultoaquaticlife,forests,andagriculturalcrops.Twoexamplesofinteractionbetweensystemsthatcausemajorenvironmentaldisturbancesarepresented-thebuildupofatmosphericcarbondioxide,aglobalproblem.andtheacidrainproblem.normallyofregionalnature.EnvironmentalDisturbancesManymajorimprovementstoourstandardoflivingcanbeattributedtotheapplicationofscienceandtechnology.Afewexamplesarenotedhere.Canyouthinkofothers?•Theproductionofmoreandbetterqualityfood•Thecreationofhousingasprotectionfromextremesfromclimatesandaslivingapace•Thebuildingoffastandreliablemeansoftransportation•Theinventionofvarioussystemsofcommunication•Theinventionofmachinestoreplacehumanoranimalpower•Thesupplyofsafewaterandthedisposalofwastes•Theeliminationofmanyinfectiousdiseases•Theeliminationofmostwater-bornediseasesinthedevelopedworldthroughimprovedwatertechnology•Theavailabilityofleisuretimethroughgreaterproductivity,providingtheopportunityforculturalandrecreationalactivities•Theprotectionfromtheworsteffectsofnaturaldisasterssuchasfloods,droughts,earthquakes,andvolcaniceruptions.Withtheseimprovements,however,havecomedisturbingsideeffects,suchaslostarableland,disappearingforests,environmentalpollution,andneworganismsresistanttocontrols.Manyeffectsoriginallyconsideredtobejustnuisancesarenowrecognizedaspotentialthreatstonatureandtohumana.Inanagrariansociety,peoplelivedessentiallyinharmonywithnature,raisingfood,gatheringfirewood,andmakingclothingandtoolsfromtheland.Thewastesfromanimalsandhumanswerereturnedtothesoilasfertilizer.Few,ifany,problemsofwater,land,orairpollutionoccurred.Thecitiesofancienttimes,particularlythoseoftheRomanEmpire®hadsystemstosupplywaterandtodisposeofwastes.TheaqueductssupplyingtheancientcityofRome(populationabout1million)withsafewaterfromtheCloacaMaxims©,thebestknownandoneoftheearliestsewerstobebuilt,areexamplesofsuchsystems.ThemunicipaltechnologyofancientcitiesseemstohavebeenforgottenformanycenturiesbythosewhobuiltcitiesthroughoutEurope.Watersupplyandwastedisposalwereneglected,resultinginmanyoutbreaksofdysentery,cholera,typhoid.andotherwaterbornediseases.Untilthemiddleofthenineteenthcentury,itwasnotrealizedthatimproperwastesdisposalpollutedwatersupplieswithdisease-carryingorganisms.Theindustrialrevol