Water unit 3 notes b.arch Sem 4 according too anna university regulation
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Sep 23, 2024
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About This Presentation
Unit 3 drainage revised notes water b arch sem 4
Slide Content
UNIT 3
DRAINAGE AND WASTE
MANAGEMENT
NOTES PREPARED BY:
Ar. Manju Maathavan
MEASI Academy Of Architecture
DRAINAGE AND WASTE
MANAGEMENT
NOTES PREPARED BY:
Ar. Manju Maathavan
MEASI Academy Of Architecture
DRAINAGE AND WASTE MANAGEMENT
Storm water drains at city level.
Types of pipe.
Storm water gutter.
Drainage systems in small building/campus.
Roof drainage.
Rain water harvesting and storage sumps.
Solid waste- types, segregation and refuse
collection.
Disposal - Incinerator, composting, vermi-
composting, sanitary land Filling, bio gas
system, modern renewable energy system.
Storm water drains at city level.
Types of pipe.
Storm water gutter.
Drainage systems in small building/campus.
Roof drainage.
Rain water harvesting and storage sumps.
Solid waste- types, segregation and refuse
collection.
Disposal - Incinerator, composting, vermi-
composting, sanitary land Filling, bio gas
system, modern renewable energy system.
STORMWATER DRAINAGE
SYSTEMS
SYSTEMS
STORMDRAINS
WHAT IS A STORMDRAIN?
•Drains in the ground that conduct water that collects
during and after rain and snow storms on streets and
sidewalks to other locations to reduce puddling and
flooding.
•In Berea, our storm drains are directed into the East
Branch of the Rocky River and eventually flow into
LakeErie.
•Drains in the ground that conduct water that collects
during and after rain and snow storms on streets and
sidewalks to other locations to reduce puddling and
flooding.
•In Berea, our storm drains are directed into the East
Branch of the Rocky River and eventually flow into
LakeErie.
STORM DRAIN POLLUTION
•Our biggest water quality problems don’t
come from a discharge pipe. They comefrom
stormwater washing off the land—roads and
rooftops, lawns and construction sites,
parking lots anddriveways.
•The problems include the flooding volumes
of water that flow off the hard, impervious
surfaces of our urban and suburban
landscapes, as well as all the pollutantsthat
are washed off thesesurfaces.
•Our biggest water quality problems don’t
come from a discharge pipe. They comefrom
stormwater washing off the land—roads and
rooftops, lawns and construction sites,
parking lots anddriveways.
•The problems include the flooding volumes
of water that flow off the hard, impervious
surfaces of our urban and suburban
landscapes, as well as all the pollutantsthat
are washed off thesesurfaces.
WHAT SHOULD GO DOWN A STORMDRAIN?
Stormwater, ofcourse!
Stormwater, ofcourse!
VARIOUS STYLES OF STORM DRAINS
WHAT SHOULD GO DOWN A SANITARYSEWER?
•Humanwaste
•Dishwater
•Laundrywater
•Reasonable garbagedisposal
waste
•Bathwater
•Humanwaste
•Dishwater
•Laundrywater
•Reasonable garbagedisposal
waste
•Bathwater
COMBINED STORM DRAINS & SANITARY SEWERS–
COMBINED SEWER OVERFLOWS
Storm drain on top ofsanitarysewer.Notice thereis
no top to the sanitarysewer.
StormDrain
SanitarySewer
COMBINED SEWER OVERFLOWS
Storm drain on top ofsanitarysewer.Notice thereis
no top to the sanitarysewer.
StormDrain
SanitarySewer
RAIN WATER
HARVESTING
HARVESTING
HarvestingSystem
Broadly rainwater can be harvested for twopurposes-
•Storing rainwater for ready use in containers above or below ground,
•Charged into the soil for withdrawal later (groundwaterrecharging)
Broadly rainwater can be harvested for twopurposes-
•Storing rainwater for ready use in containers above or below ground,
•Charged into the soil for withdrawal later (groundwaterrecharging)
RAIN WATER HARVESTING
TECHNIQUES :
There are two main techniques of rain waterharvestings.
•Storage of rainwater on surface for futureuse.
•Recharge to ground water. The storage of rain water on surface is atraditional
techniques and structures used were underground tanks, ponds, check dams,
weirsetc
Recharge to ground water is a new concept of rain water harvesting and the
structures generally used are:-
Pits:-Rechargepitsareconstructedforrechargingtheshallowaquifer.Theseare
constructed1to2m,wideandto3m.deepwhicharebackfilledwithboulders,
gravels,coarsesand.
•Trenches:-These are constructed when the permeable stram is available at
shallow depth. Trench may be 0.5 to 1 m. wide, 1 to 1.5m. deep and 10 to 20 m.
long depending up availability of water. These are back filled with filtermaterials.
•Dug wells:-Existing dug wells may be utilised as recharge structure and water
should pass through filter media before putting into dugwell.
TECHNIQUES :
There are two main techniques of rain waterharvestings.
•Storage of rainwater on surface for futureuse.
•Recharge to ground water. The storage of rain water on surface is atraditional
techniques and structures used were underground tanks, ponds, check dams,
weirsetc
Recharge to ground water is a new concept of rain water harvesting and the
structures generally used are:-
Pits:-Rechargepitsareconstructedforrechargingtheshallowaquifer.Theseare
constructed1to2m,wideandto3m.deepwhicharebackfilledwithboulders,
gravels,coarsesand.
•Trenches:-These are constructed when the permeable stram is available at
shallow depth. Trench may be 0.5 to 1 m. wide, 1 to 1.5m. deep and 10 to 20 m.
long depending up availability of water. These are back filled with filtermaterials.
•Dug wells:-Existing dug wells may be utilised as recharge structure and water
should pass through filter media before putting into dugwell.
Handpumps:-Theexistinghandpumpsmaybeusedforrechargingthe
shallow/deepaquifers,iftheavailabilityofwaterislimited.Watershouldpass
throughfiltermediabeforedivertingitintohandpumps.
Rechargewells:-Rechargewellsof100to300mm.diameteraregenerally
constructedforrechargingthedeeperaquifersandwaterispassedthrough
filtermediatoavoidchokingofrechargewells.
Spreadingtechniques:-
When permeable strata starts from top then this technique is used.
Spread the water in streams by making check dams, bunds, cement plugs,
gabion structures or a percolation pond may beconstructed.
Recharge Shafts :-For recharging the shallow aquifer which are located below
clayey surface, recharge shafts of 0.5 to 3 m. diameter and 10 to 15 m. deep
are constructed and back filled with boulders, gravels & coarsesand.
Lateral shafts with bore wells :-For recharging the upper as well as deeper
aquifers lateral shafts of 1.5 to 2 m. wide & 10 to 30 m. long depending upon
availability of water with one or two bore wells are constructed. The lateral
shafts is back filled with boulders, gravels & coarsesand.
shallow/deepaquifers,iftheavailabilityofwaterislimited.Watershouldpass
throughfiltermediabeforedivertingitintohandpumps.
Rechargewells:-Rechargewellsof100to300mm.diameteraregenerally
constructedforrechargingthedeeperaquifersandwaterispassedthrough
filtermediatoavoidchokingofrechargewells.
Spreadingtechniques:-
When permeable strata starts from top then this technique is used.
Spread the water in streams by making check dams, bunds, cement plugs,
gabion structures or a percolation pond may beconstructed.
Recharge Shafts :-For recharging the shallow aquifer which are located below
clayey surface, recharge shafts of 0.5 to 3 m. diameter and 10 to 15 m. deep
are constructed and back filled with boulders, gravels & coarsesand.
Lateral shafts with bore wells :-For recharging the upper as well as deeper
aquifers lateral shafts of 1.5 to 2 m. wide & 10 to 30 m. long depending upon
availability of water with one or two bore wells are constructed. The lateral
shafts is back filled with boulders, gravels & coarsesand.
1
Reasons of Shortage of
Water•Populationincrease
•Industrialization
•Urbanization
(a)Increase in per capitautilization
(b)Less peculationarea
•Decrease in surface area ofLakes.
•Deforestation
Reasons of Shortage of
Water•Populationincrease
•Industrialization
•Urbanization
(a)Increase in per capitautilization
(b)Less peculationarea
•Decrease in surface area ofLakes.
•Deforestation
What is the
solution?
•Rain water is the ultimate source of fresh
water
•Potential of rain to meet water
demand is tremendous
•Rain water harvesting helps to overcome
water scarcity
•To conserve ground water the aquifers
must be recharged with rainwater
•Rain water harvesting is the ultimate
answer
solution?
•Rain water is the ultimate source of fresh
water
•Potential of rain to meet water
demand is tremendous
•Rain water harvesting helps to overcome
water scarcity
•To conserve ground water the aquifers
must be recharged with rainwater
•Rain water harvesting is the ultimate
answer
Why Rain water be
harvested•To conserve & augment the storage of
groundwater
•To reduce water tabledepletion
•To improve the quality of groundwater
•To arrest sea water intrusion in coastalareas
•To avoid flood & water stagnation in urban
areas
Therefore rain water harvesting is-
•It is the activity of direct collection of rainwater,
•Rain water can be stored for direct use or can be recharged into
theground wateraquifer
harvested•To conserve & augment the storage of
groundwater
•To reduce water tabledepletion
•To improve the quality of groundwater
•To arrest sea water intrusion in coastalareas
•To avoid flood & water stagnation in urban
areas
Therefore rain water harvesting is-
•It is the activity of direct collection of rainwater,
•Rain water can be stored for direct use or can be recharged into
theground wateraquifer
Rain WaterHarvesting…..
•Rain Water Harvesting RWH-process of collecting,
conveying & storing water from rainfall in an area –for
beneficialuse.
•Storage –in tanks, reservoirs, undergroundstorage-
groundwater
•HydrologicalCycle
•Rain Water Harvesting RWH-process of collecting,
conveying & storing water from rainfall in an area –for
beneficialuse.
•Storage –in tanks, reservoirs, undergroundstorage-
groundwater
•HydrologicalCycle
Rain WaterHarvesting…….
•RWH -yield copious amounts of water. For an
average rainfall of 1,000mm, approximately four million
liters of rainwater can be collected in a year in an acre
of land (4,047 m
2),post-evaporation.
•As RWH -neither energy-intensive nor labour -
intensive
•It can be a cost-effective alternative to otherwater-
accruing methods.
•With the water table falling rapidly, & concrete
surfaces and landfill dumps taking the place of water
bodies, RWH is the most reliable solution for
augmenting groundwater level to attainself-sufficiency
•RWH -yield copious amounts of water. For an
average rainfall of 1,000mm, approximately four million
liters of rainwater can be collected in a year in an acre
of land (4,047 m
2),post-evaporation.
•As RWH -neither energy-intensive nor labour -
intensive
•It can be a cost-effective alternative to otherwater-
accruing methods.
•With the water table falling rapidly, & concrete
surfaces and landfill dumps taking the place of water
bodies, RWH is the most reliable solution for
augmenting groundwater level to attainself-sufficiency
•Roof Rain Water Harvesting
•Land based Rain WaterHarvesting
•Watershed based Rain Water harvesting
For Urban & Industrial Environment–
Roof & Land based RWH may be usedin
•Public, Private, Office & Industrialbuildings
•Pavements, Lawns, Gardens & other openspaces
RWH –Methodologies
•Land based Rain WaterHarvesting
•Watershed based Rain Water harvesting
For Urban & Industrial Environment–
Roof & Land based RWH may be usedin
•Public, Private, Office & Industrialbuildings
•Pavements, Lawns, Gardens & other openspaces
RWH –Methodologies
Rain Water Harvesting–Advantages
1.Provides self-sufficiency to water supply
2.Reduces the cost for pumping of ground water,
3.Provides high quality water, soft and low inminerals
4.Improves the quality of ground water through dilution whenrecharged,
5.Reduces soil erosion & flooding in urbanareas
6.The rooftop rain water harvesting is less expensive & easy to
construct, operate andmaintain,
7.In desert, RWH onlyrelief
8.In saline or coastal areas & Islands, rain water providesgood
qualitywater
1.Provides self-sufficiency to water supply
2.Reduces the cost for pumping of ground water,
3.Provides high quality water, soft and low inminerals
4.Improves the quality of ground water through dilution whenrecharged,
5.Reduces soil erosion & flooding in urbanareas
6.The rooftop rain water harvesting is less expensive & easy to
construct, operate andmaintain,
7.In desert, RWH onlyrelief
8.In saline or coastal areas & Islands, rain water providesgood
qualitywater
AppropriateTechnology
Water conservation
and groundwater
rechargetechniques
Water harvesting
cum supplementary
irrigationtechniques
Water conservation
and groundwater
rechargetechniques
Water harvesting
cum supplementary
irrigationtechniques
The roof catchment are selectively cleanerwhen
compared to the ground levelcatchment
•Losses from roof catchment areminimum
•Built & Maintained by localcommunities
•No Chemical contamination & only required
filtration
•Available at door step with leastcost
Rain water harvestingsystem-
The typical roof top rain water harvesting system comprises
of –or components-
•Roofcatchment
•Gutters
•Down pipe & first flushingpipe
•FilterUnit
•StorageTank
compared to the ground levelcatchment
•Losses from roof catchment areminimum
•Built & Maintained by localcommunities
•No Chemical contamination & only required
filtration
•Available at door step with leastcost
Rain water harvestingsystem-
The typical roof top rain water harvesting system comprises
of –or components-
•Roofcatchment
•Gutters
•Down pipe & first flushingpipe
•FilterUnit
•StorageTank
24
Size of Storage
Tank
•Basedon
–No. of person in the Household
–Per capita waterrequirement
–No. of days for which water is
required
Size of Storage
Tank
•Basedon
–No. of person in the Household
–Per capita waterrequirement
–No. of days for which water is
required
25
Water available from
Roof
Annual rainfall (in mm) x roof area (in sq. m)
x co-efficient of run off forroof
co-efficient of run off-
GI
sheet
Asbesto
sTiled
Plasteron bricks/
Concrete
0.9
0.8
0.7
5
0.7
Water available from
Roof
Annual rainfall (in mm) x roof area (in sq. m)
x co-efficient of run off forroof
co-efficient of run off-
GI
sheet
Asbesto
sTiled
Plasteron bricks/
Concrete
0.9
0.8
0.7
5
0.7
36
How the problem can be
minimized
1By providing pipe water system with source
(electric based)
(a)Surfacewater
(b)Deep tubewells
2Recharging strata through rainwater
harvesting methods
(No. of villages of lower range concentration
can be decreased)
3Storing rain water for drinkingpurpose
(a)In areas where electricity problem ismore
(b)In areas where concentration ismore
(c)In areas where dependable source is not
available
How the problem can be
minimized
1By providing pipe water system with source
(electric based)
(a)Surfacewater
(b)Deep tubewells
2Recharging strata through rainwater
harvesting methods
(No. of villages of lower range concentration
can be decreased)
3Storing rain water for drinkingpurpose
(a)In areas where electricity problem ismore
(b)In areas where concentration ismore
(c)In areas where dependable source is not
available
Advantages of
groundwater:
•There is more ground water than surfacewater
•Ground water is less expensive and economicresource.
•Ground water is sustainable and reliable source of watersupply.
•Ground water is relatively less vulnerable topollution
•Ground water is usually of high bacteriologicalpurity.
•Ground water is free of pathogenicorganisms.
•Ground water needs little treatment beforeuse.
•Ground water has no turbidity andcolour.
•Ground water has distinct health advantage as art alternative for lower
sanitary
quality surfacewater.
•Ground water is usually universallyavailable.
•Ground water resource can be instantly developed and used.There is no
conveyance losses in ground water basedsupplies.
•Ground water has low vulnerability todrought.
•Ground water is key to life in arid and semi-aridregions.
•Ground water is source of dry weather flow in rivers andstreams.
groundwater:
•There is more ground water than surfacewater
•Ground water is less expensive and economicresource.
•Ground water is sustainable and reliable source of watersupply.
•Ground water is relatively less vulnerable topollution
•Ground water is usually of high bacteriologicalpurity.
•Ground water is free of pathogenicorganisms.
•Ground water needs little treatment beforeuse.
•Ground water has no turbidity andcolour.
•Ground water has distinct health advantage as art alternative for lower
sanitary
quality surfacewater.
•Ground water is usually universallyavailable.
•Ground water resource can be instantly developed and used.There is no
conveyance losses in ground water basedsupplies.
•Ground water has low vulnerability todrought.
•Ground water is key to life in arid and semi-aridregions.
•Ground water is source of dry weather flow in rivers andstreams.
Basictermsrelatedtosolidwaste
Sewer:
Sewersareundergroundpipesorconduitswhichcarrysewagetopointsofdisposal.
Sewage:
TheLiquidwastefromacommunityiscalledsewage.Sewageisclassifiedintodomesticand
non-domesticsewage.Thenondomesticsewageisclassifiedintoindustrial,commercial,
institutionalandanyothersewagethatisnotdomestic.
Sewerage:
Theentiresystemusedforcollection,treatmentanddisposalofLiquidwaste.Thisincludes
pipes,manholes,andallstructuresusedfortheabovementionedpurposes.
Garbage:
Garbageisthewasteproduceddailyinourhomes.Itincludesdifferentwastelikevegetable
peels,chemicalsubstances,polythenes,paper,metals,etc.Sometimes,itisalsoreferredto
aswetwaste.Thesewasteisusuallyoforganicnatureandbiodegradablemeaningit
decomposesquickly.
Sullage;
Kitchenwastes,bathroomwastes,wastewaterfromhousewhichdoescreatesmell.
Stormwater:
WasteRainwater.
INTRODUTION
Sewer:
Sewersareundergroundpipesorconduitswhichcarrysewagetopointsofdisposal.
Sewage:
TheLiquidwastefromacommunityiscalledsewage.Sewageisclassifiedintodomesticand
non-domesticsewage.Thenondomesticsewageisclassifiedintoindustrial,commercial,
institutionalandanyothersewagethatisnotdomestic.
Sewerage:
Theentiresystemusedforcollection,treatmentanddisposalofLiquidwaste.Thisincludes
pipes,manholes,andallstructuresusedfortheabovementionedpurposes.
Garbage:
Garbageisthewasteproduceddailyinourhomes.Itincludesdifferentwastelikevegetable
peels,chemicalsubstances,polythenes,paper,metals,etc.Sometimes,itisalsoreferredto
aswetwaste.Thesewasteisusuallyoforganicnatureandbiodegradablemeaningit
decomposesquickly.
Sullage;
Kitchenwastes,bathroomwastes,wastewaterfromhousewhichdoescreatesmell.
Stormwater:
WasteRainwater.
INTRODUTION
1.Ash:thenon-combustiblesolidby-productsofincinerationorotherburningprocess.
2.Bulkywaste:largewastessuchasappliances,furniture,andtreesandbranches,that
cannotbehandledbynormalMSWprocessingmethods.
3.Co-disposal:thedisposalofdifferenttypesofwasteinoneareaofalandfillordump.
Forinstance,sewagesludgesmaybedisposedofwithregularsolidwastes.
Basictermsrelatedtosolidwaste
4.Biodegradablematerial:anyorganicmaterialthatcanbebrokendownby
microorganismsintosimpler,morestablecom-pounds.Mostorganicwastes(e.g.,food,
paper)arebiodegradable.
5.Compost:thematerialresultingfromcomposting.Compost,alsocalledhumus,isasoil
conditionerandinsomeinstancesisusedasafertilizer.
6.Composting:biologicaldecompositionofsolidorganicmaterialsbybacteria,fungi,and
otherorganismsintoasoil-likeproduct.
7.Disposal:thefinalhandlingofsolidwaste,followingcollection,processing,or
incineration.Disposalmostoftenmeansplacementofwastesinadumporalandfill.
2.Bulkywaste:largewastessuchasappliances,furniture,andtreesandbranches,that
cannotbehandledbynormalMSWprocessingmethods.
3.Co-disposal:thedisposalofdifferenttypesofwasteinoneareaofalandfillordump.
Forinstance,sewagesludgesmaybedisposedofwithregularsolidwastes.
Basictermsrelatedtosolidwaste
4.Biodegradablematerial:anyorganicmaterialthatcanbebrokendownby
microorganismsintosimpler,morestablecom-pounds.Mostorganicwastes(e.g.,food,
paper)arebiodegradable.
5.Compost:thematerialresultingfromcomposting.Compost,alsocalledhumus,isasoil
conditionerandinsomeinstancesisusedasafertilizer.
6.Composting:biologicaldecompositionofsolidorganicmaterialsbybacteria,fungi,and
otherorganismsintoasoil-likeproduct.
7.Disposal:thefinalhandlingofsolidwaste,followingcollection,processing,or
incineration.Disposalmostoftenmeansplacementofwastesinadumporalandfill.
10.Garbage:ineverydayusage,refuseingeneral.
someMSWMmanualsusegarbagetomean"foodwastes,"althoughthisusageisnot
common.
11.Landfilling:thefinaldisposalofsolidwastebyplacingitinacontrolledfashionina
placeintendedtobepermanent.TheSourceBookusesthistermforbothcontrolled
dumpsandsanitarylandfills.
13.MSW:municipalsolidwaste.
14.MSWM:municipalsolidwastemanagement
15.Putrescible:subjecttodecompositionordecay.Usuallyusedinreferencetofood
wastesandotherorganicwastesthatdecayquickly.
16.Refuse:allkindsofwastesinsolidstateexceptingexcretafromresidential,
commercialandindustrialarea.
Basictermsrelatedtosolidwaste
someMSWMmanualsusegarbagetomean"foodwastes,"althoughthisusageisnot
common.
11.Landfilling:thefinaldisposalofsolidwastebyplacingitinacontrolledfashionina
placeintendedtobepermanent.TheSourceBookusesthistermforbothcontrolled
dumpsandsanitarylandfills.
13.MSW:municipalsolidwaste.
14.MSWM:municipalsolidwastemanagement
15.Putrescible:subjecttodecompositionordecay.Usuallyusedinreferencetofood
wastesandotherorganicwastesthatdecayquickly.
16.Refuse:allkindsofwastesinsolidstateexceptingexcretafromresidential,
commercialandindustrialarea.
Basictermsrelatedtosolidwaste
Conservancysystems
•Oldsystem
•Collectioninseparatevessels
•Depositioninpools&pits
•Removaloncein24hoursatleast
•Drysystem
•Invillagesandsmalltowns
WaterCarriagesystem
•Watermedium
•Dilutionratioshouldbehigh
•CollectioninsewersthroughWC
•Garbagenotpermitted
•Initialcosthigh
•Largeamountofwaterrequired
Methodsofcarryingrefuse:
➢Conservancysystem
➢Watercarriagesystem
•Oldsystem
•Collectioninseparatevessels
•Depositioninpools&pits
•Removaloncein24hoursatleast
•Drysystem
•Invillagesandsmalltowns
WaterCarriagesystem
•Watermedium
•Dilutionratioshouldbehigh
•CollectioninsewersthroughWC
•Garbagenotpermitted
•Initialcosthigh
•Largeamountofwaterrequired
Methodsofcarryingrefuse:
➢Conservancysystem
➢Watercarriagesystem
TYPESOFSEWERAGESYSTEM TheSewerageSystemcanbeofFollowingThree
Types:
1.combinedsystem,
2.separatesystem
3.&partiallyseparatesystem
1)COMBINEDSYSTEM:
Incombinedsystemalongwithdomesticsewage,therun-offresultingfromstormsiscarriedthroughthe
samesewersofseweragesystem.IncountrieslikeIndiawhereactualrainydaysareveryfew,thissystem
willfacetheproblemofmaintainingselfcleansingvelocityinthesewersduringdryseason,asthesewage
dischargemaybefarlowerascomparedtothedesigndischargeafterincludingstormwater.
Advantagesanddisadvantagesofcombinedsystem
Advantages
•Inanareawhererainfallisspreadthroughoutayear,thereisnoneedofflushingofsewers,asselfcleansing
velocitywilldevelopedduetomorequantitybecauseofadditionofstormwater.
•Onlyonesetofpipewillberequiredforhouseplumbing.
•Incongestedareasitiseasytolayonlyonepiperatherthantwopipesasrequiredin
othersystems.
Disadvantages
•Notsuitablefortheareawithsmallperiodofrainfallinayear,becausedryweatherflowwill besmalldueto
whichselfcleansingvelocitymaynotdevelopinsewers,resultinginsilting.
•Largeflowisrequiredtobetreatedatsewagetreatmentplantbeforedisposal,henceresultinginhigher
capitalandoperatingcostofthetreatmentplant.
•Whenpumpingisrequiredthissystemisuneconomical.
•Duringrainsoverflowingofsewerswill spoilpublichygiene.
Types:
1.combinedsystem,
2.separatesystem
3.&partiallyseparatesystem
1)COMBINEDSYSTEM:
Incombinedsystemalongwithdomesticsewage,therun-offresultingfromstormsiscarriedthroughthe
samesewersofseweragesystem.IncountrieslikeIndiawhereactualrainydaysareveryfew,thissystem
willfacetheproblemofmaintainingselfcleansingvelocityinthesewersduringdryseason,asthesewage
dischargemaybefarlowerascomparedtothedesigndischargeafterincludingstormwater.
Advantagesanddisadvantagesofcombinedsystem
Advantages
•Inanareawhererainfallisspreadthroughoutayear,thereisnoneedofflushingofsewers,asselfcleansing
velocitywilldevelopedduetomorequantitybecauseofadditionofstormwater.
•Onlyonesetofpipewillberequiredforhouseplumbing.
•Incongestedareasitiseasytolayonlyonepiperatherthantwopipesasrequiredin
othersystems.
Disadvantages
•Notsuitablefortheareawithsmallperiodofrainfallinayear,becausedryweatherflowwill besmalldueto
whichselfcleansingvelocitymaynotdevelopinsewers,resultinginsilting.
•Largeflowisrequiredtobetreatedatsewagetreatmentplantbeforedisposal,henceresultinginhigher
capitalandoperatingcostofthetreatmentplant.
•Whenpumpingisrequiredthissystemisuneconomical.
•Duringrainsoverflowingofsewerswill spoilpublichygiene.
TYPESOFSEWERAGESYSTEM
2)SEPARATESYSTEM:
Inseparatesystem,separateconduitsareused;onecarryingsewageandothercarryingstormwaterrun-off.
Thestormwatercollectedcanbedirectlydischargedintothewaterbodysincetherun-offisnotasfoulas
sewageandnotreatmentisgenerallyprovided.Whereas,thesewagecollectedfromthecityistreated
adequatelybeforeitisdischargedintothewaterbodyorusedforirrigationtomeetdesiredstandards.
Separatesystemisadvantageousandeconomicalforbigtowns.
Advantagesanddisadvantagesofseparatesystem
Advantages
•Assewageflowsinseparatepipe,hencethequantitytobetreatedatsewagetreatmentplantissmall,
resultingineconomyoftreatment.
•Thissystemmaybelesscostlyasonlysanitarysewageistransportedinclosedconduitandstormwater
canbecollectedandconveyedthroughopendrains.
•Whenpumpingisrequiredduringdisposal,thissystemiseconomicalduetolessflow.
Disadvantages
•Selfcleansingvelocitymaynotbedevelopedatcertainlocationsinsewersandhenceflushingofsewers
mayberequired.
•Thissystemrequireslayingtwosetsofpipe,whichmaybedifficultincongestedarea.
•Thissystemwillrequiremaintenanceoftwosetsofpipelinesandhencemaintenance
costismore
2)SEPARATESYSTEM:
Inseparatesystem,separateconduitsareused;onecarryingsewageandothercarryingstormwaterrun-off.
Thestormwatercollectedcanbedirectlydischargedintothewaterbodysincetherun-offisnotasfoulas
sewageandnotreatmentisgenerallyprovided.Whereas,thesewagecollectedfromthecityistreated
adequatelybeforeitisdischargedintothewaterbodyorusedforirrigationtomeetdesiredstandards.
Separatesystemisadvantageousandeconomicalforbigtowns.
Advantagesanddisadvantagesofseparatesystem
Advantages
•Assewageflowsinseparatepipe,hencethequantitytobetreatedatsewagetreatmentplantissmall,
resultingineconomyoftreatment.
•Thissystemmaybelesscostlyasonlysanitarysewageistransportedinclosedconduitandstormwater
canbecollectedandconveyedthroughopendrains.
•Whenpumpingisrequiredduringdisposal,thissystemiseconomicalduetolessflow.
Disadvantages
•Selfcleansingvelocitymaynotbedevelopedatcertainlocationsinsewersandhenceflushingofsewers
mayberequired.
•Thissystemrequireslayingtwosetsofpipe,whichmaybedifficultincongestedarea.
•Thissystemwillrequiremaintenanceoftwosetsofpipelinesandhencemaintenance
costismore
TYPESOFSEWERAGESYSTEM
PARTIALLYSEPARATESYSTEM:
Inthissystempartofthestormwaterespeciallycollectedfromroofsandpavedcourtyardsofthe
buildingsisadmittedinthesamedrainalongwithsewagefromresidencesandinstitutions,etc.The
stormwaterfromtheotherplacesiscollectedseparatelyusingseparateconduits.
Advantagesanddisadvantagesofpartiallyseparatesystem
Advantages
•Economicalandreasonablesizesewersarerequired.
•Workofhouseplumbingisreducedasrainwaterfromroofs,sullagefrombathsandkitchen,etc.are
combinedwithdischargefromwaterclosets.
•Flushingofsewersmaynotberequiredassmallportionofstormwaterisallowedto
enterinsanitarysewage.
Disadvantages
•Increasedcostofpumpingascomparedtoseparatesystemattreatmentplantsandintermediatepumping
stationwhereverrequired.
•Indryweatherself-cleansingvelocitymaynotdevelopinthesewers.
PARTIALLYSEPARATESYSTEM:
Inthissystempartofthestormwaterespeciallycollectedfromroofsandpavedcourtyardsofthe
buildingsisadmittedinthesamedrainalongwithsewagefromresidencesandinstitutions,etc.The
stormwaterfromtheotherplacesiscollectedseparatelyusingseparateconduits.
Advantagesanddisadvantagesofpartiallyseparatesystem
Advantages
•Economicalandreasonablesizesewersarerequired.
•Workofhouseplumbingisreducedasrainwaterfromroofs,sullagefrombathsandkitchen,etc.are
combinedwithdischargefromwaterclosets.
•Flushingofsewersmaynotberequiredassmallportionofstormwaterisallowedto
enterinsanitarysewage.
Disadvantages
•Increasedcostofpumpingascomparedtoseparatesystemattreatmentplantsandintermediatepumping
stationwhereverrequired.
•Indryweatherself-cleansingvelocitymaynotdevelopinthesewers.
PATTERNSOFCOLLECTIONSYSTEM
PERPENDICULARPATTERN
➢Theshortestpossiblepathismaintainedfortherainscarryingstormwaterandsewage(Figure2.1).
➢Suitableforseparatesystemandpartiallyseparatesystem.
➢Thispatternisnotsuitableforcombinedsystem,becausetreatmentplantisrequiredtobeinstalledat
manyplaces;otherwiseitwillpollutethewaterbodywherethesewageisdischarged.
PERPENDICULARPATTERN
➢Theshortestpossiblepathismaintainedfortherainscarryingstormwaterandsewage(Figure2.1).
➢Suitableforseparatesystemandpartiallyseparatesystem.
➢Thispatternisnotsuitableforcombinedsystem,becausetreatmentplantisrequiredtobeinstalledat
manyplaces;otherwiseitwillpollutethewaterbodywherethesewageisdischarged.
PATTERNSOFCOLLECTIONSYSTEM
INTERCEPTORPATTERN
➢Sewersareinterceptedwithlargesizesewers(Figure2.2).
➢Interceptorcarriessewagetoacommonpoint,whereitcanbedisposedoffwithorwithouttreatment.
➢Overflowsshouldbeprovidedtohandleverylargeflow.
INTERCEPTORPATTERN
➢Sewersareinterceptedwithlargesizesewers(Figure2.2).
➢Interceptorcarriessewagetoacommonpoint,whereitcanbedisposedoffwithorwithouttreatment.
➢Overflowsshouldbeprovidedtohandleverylargeflow.
PATTERNSOFCOLLECTIONSYSTEM
RADIALPATTERN
➢Itissuitableforlanddisposal.
➢Inthispatternsewersarelaidradiallyoutwardsfromthecentre,hencethispatterniscalledasradial
pattern(Figure2.3).
➢Thedrawbackinthispatternismorenumberofdisposalworksisrequired.
RADIALPATTERN
➢Itissuitableforlanddisposal.
➢Inthispatternsewersarelaidradiallyoutwardsfromthecentre,hencethispatterniscalledasradial
pattern(Figure2.3).
➢Thedrawbackinthispatternismorenumberofdisposalworksisrequired.
PATTERNSOFCOLLECTIONSYSTEM
FANPATTERN
➢Thispatternissuitableforacitysituatedatonesideofthenaturalwaterbody,suchasriver.
➢Theentiresewageflowstoacommonpointwhereonetreatmentplantislocated(Figure2.4).
➢Inthisnumberofconvergingmainsewersandsub-mainsareusedformingafanshape.
➢Singletreatmentplantisrequiredinthispattern.
➢Thedrawbackinthispatternisthatlargerdiametersewerisrequiredneartothetreatmentplantasentire
sewageiscollectedatacommonpoint.
➢Inaddition,withnewdevelopmentofthecitytheloadonexistingtreatmentplantincreases.
FANPATTERN
➢Thispatternissuitableforacitysituatedatonesideofthenaturalwaterbody,suchasriver.
➢Theentiresewageflowstoacommonpointwhereonetreatmentplantislocated(Figure2.4).
➢Inthisnumberofconvergingmainsewersandsub-mainsareusedformingafanshape.
➢Singletreatmentplantisrequiredinthispattern.
➢Thedrawbackinthispatternisthatlargerdiametersewerisrequiredneartothetreatmentplantasentire
sewageiscollectedatacommonpoint.
➢Inaddition,withnewdevelopmentofthecitytheloadonexistingtreatmentplantincreases.
PATTERNSOFCOLLECTIONSYSTEM
ZONEPATTERN
➢Morenumbersofinterceptorsareprovidedinthispattern(Figure2.5).
➢Thispatternissuitableforslopingareathanflatareas.
ZONEPATTERN
➢Morenumbersofinterceptorsareprovidedinthispattern(Figure2.5).
➢Thispatternissuitableforslopingareathanflatareas.
Composting
TreatmentanddisposalofsolidwasteSeveralmethodsare
usedfortreatmentanddisposal.Theseare:
➢Itisaprocessinwhichorganicmatterofsolidwasteisdecomposedand
convertedtohumusandmineralcompounds.
Compostistheendproductofcomposting,whichusedasfertilizer.
Threemethodsofcomposting:
(a)compostingbytrenching
(b)openwindrowcomposting
(c)mechanicalcomposting
Composting
Composting
usedfortreatmentanddisposal.Theseare:
➢Itisaprocessinwhichorganicmatterofsolidwasteisdecomposedand
convertedtohumusandmineralcompounds.
Compostistheendproductofcomposting,whichusedasfertilizer.
Threemethodsofcomposting:
(a)compostingbytrenching
(b)openwindrowcomposting
(c)mechanicalcomposting
Composting
Composting
Compostingby trenching
➢Trenches3-12mlong,2–3mwideand1-2mdeepwithspacing2m.
➢Drywastesarefilledupin15cm.Ontopofeachlayer5cmthicksandwichinglayerof
animaldungissprayedinsemiliquidform.
➢Biologicalactionstartsin2-3daysanddecompositionstarts.
➢Solidwastestabilizein4-6monthsandchangedintobrowncoloredodourlesspowdery
formknownashumus.
➢Trenches3-12mlong,2–3mwideand1-2mdeepwithspacing2m.
➢Drywastesarefilledupin15cm.Ontopofeachlayer5cmthicksandwichinglayerof
animaldungissprayedinsemiliquidform.
➢Biologicalactionstartsin2-3daysanddecompositionstarts.
➢Solidwastestabilizein4-6monthsandchangedintobrowncoloredodourlesspowdery
formknownashumus.
➢Open windrow composting
➢Largematerialslikebrokenglass,stone,plasticarticlesareremoved.
➢Remainingsolidwastesisdumpedongroundinformofpilesof0.6–1mheight.
➢Thewidthandlengthofpilesarekept1-2mand6mrespectively.
➢Moisturecontentmaintainedat60%.
➢Temp.increasesinsidepile.
➢Afterpileforturnedforcoolingandaerationtoavoidanaerobicdecomposition.
➢Thecompleteprocessmaytake4-6week.
➢Largematerialslikebrokenglass,stone,plasticarticlesareremoved.
➢Remainingsolidwastesisdumpedongroundinformofpilesof0.6–1mheight.
➢Thewidthandlengthofpilesarekept1-2mand6mrespectively.
➢Moisturecontentmaintainedat60%.
➢Temp.increasesinsidepile.
➢Afterpileforturnedforcoolingandaerationtoavoidanaerobicdecomposition.
➢Thecompleteprocessmaytake4-6week.
Mechanicalcomposting
➢Itrequiressmallareacomparetotrenchingandopenwindrowcomposting.
➢Thestabilizationofwastetakes3-6days.
➢Theoperationinvolvedare
▪receptionofrefuse,
▪segregation,
▪Shredding(cutortornoff),
▪Stabilization,
▪marketingthehumus(darkbrownororganicsubstancesofsoil).
➢Itrequiressmallareacomparetotrenchingandopenwindrowcomposting.
➢Thestabilizationofwastetakes3-6days.
➢Theoperationinvolvedare
▪receptionofrefuse,
▪segregation,
▪Shredding(cutortornoff),
▪Stabilization,
▪marketingthehumus(darkbrownororganicsubstancesofsoil).
Whycomposting?
•about70%ofmunicipalwasteisnormallyorganic
•organicwastecancauseproblemsofsmell,gas,andstrayanimalsin
landfills
•recyclingatsourceismosteconomicandenvironmentfriendlymethod
ofwastemanagement
•simplemethodsavailable
•compostisvaluableresourceforfarmers
•compostingatsourcekeepsinorganicwastecleanandmakesiteasier
forrecycling
Composting
•about70%ofmunicipalwasteisnormallyorganic
•organicwastecancauseproblemsofsmell,gas,andstrayanimalsin
landfills
•recyclingatsourceismosteconomicandenvironmentfriendlymethod
ofwastemanagement
•simplemethodsavailable
•compostisvaluableresourceforfarmers
•compostingatsourcekeepsinorganicwastecleanandmakesiteasier
forrecycling
Composting
Concept
•processofdecompositionoforganic
wastebymicro-organism
•naturalprocess(bemadefasterand
moreeffectivebymixingvarioustypes
ofwasteandadjustingmoisture,
temperatureandaeration)
•containsNPKandotherplantnutrients
includingmicro-organisms
stepsofcomposting:
•prepaeration(convertingwasteintoraw
material)
•productionofcompost
•marketing
Composting
•processofdecompositionoforganic
wastebymicro-organism
•naturalprocess(bemadefasterand
moreeffectivebymixingvarioustypes
ofwasteandadjustingmoisture,
temperatureandaeration)
•containsNPKandotherplantnutrients
includingmicro-organisms
stepsofcomposting:
•prepaeration(convertingwasteintoraw
material)
•productionofcompost
•marketing
Composting
Preparation
•wastecollection
•sortingintoorganicandinorganic
•reducesizeifnecessary
•adjustmoisturecontent
•starters/additives
•adjustC:Nratio
Composting
•wastecollection
•sortingintoorganicandinorganic
•reducesizeifnecessary
•adjustmoisturecontent
•starters/additives
•adjustC:Nratio
Composting
41
Source:adaptedfromENPHO
Compostpreparation
•placepreparedwasteinpiles,windrows,chamberorbins
•turnthecompostregularlyorarrangeotherwaystoaeratethewaste
•regularlymonitortemperature&moisture
Composting
Source:adaptedfromENPHO
Compostpreparation
•placepreparedwasteinpiles,windrows,chamberorbins
•turnthecompostregularlyorarrangeotherwaystoaeratethewaste
•regularlymonitortemperature&moisture
Composting
Source:adaptedfromENPHO
42
Homecompostingoptions
Composting
42
Homecompostingoptions
Composting
43
Compostingatcommunity&municipal
level
Composting
Compostingatcommunity&municipal
level
Composting
44
•separatewasteatsource.Glassinthewastecan
resultininjuries
•ensureproperC/N-ratio&chopwasteinsmallpieces
•ensureproperamountofwaterandairtoavoidsmell
•prepareandimplementpropermarketingstrategy
(mostcompostprojectsfailbecauseofpoor
marketing)
•regularlymonitorcompostingprocess
Composting
Importantpointstoremember
•separatewasteatsource.Glassinthewastecan
resultininjuries
•ensureproperC/N-ratio&chopwasteinsmallpieces
•ensureproperamountofwaterandairtoavoidsmell
•prepareandimplementpropermarketingstrategy
(mostcompostprojectsfailbecauseofpoor
marketing)
•regularlymonitorcompostingprocess
Composting
Importantpointstoremember
45
Vermicomposting
Vermicomposting
Source:http://www.yelmworms.com/_images/vermicomposting.gif
46
Vermicomposting
Concept
46
Vermicomposting
Concept
47
Howtodoathome
Source:adaptedfromENPHO
•preparevesselorbin
•add2inches(5cm)ofbeddingmaterials
•addworms
•cutwasteintosmallpiecesandputinthebin
•keepbincoveredwithamoistcloth
•putbinawayfromdirectsunlight
•regularlycheckmoisture
•harvestvermicompostevery3to4months
•storeharvestedcompostfor2-3weeksandthen
removetheyoungworms
Vermicomposting
Howtodoathome
Source:adaptedfromENPHO
•preparevesselorbin
•add2inches(5cm)ofbeddingmaterials
•addworms
•cutwasteintosmallpiecesandputinthebin
•keepbincoveredwithamoistcloth
•putbinawayfromdirectsunlight
•regularlycheckmoisture
•harvestvermicompostevery3to4months
•storeharvestedcompostfor2-3weeksandthen
removetheyoungworms
Vermicomposting
48
Composting
Disadvantages:
•wastesegregationrequired
Advantagesanddisadvantages
Vermicomposting
Advantages:
•seeabove
•sellingofworms
Disadvantages:
•maintainproperenvironmental
conditionsforworms
Advantages:
•recyclingatsource
•economicandenvironmentfriendly
wastemanagement
•simplemethodsavailable
•compostisvaluableresourcefor
gardeners/farmers
Composting
Disadvantages:
•wastesegregationrequired
Advantagesanddisadvantages
Vermicomposting
Advantages:
•seeabove
•sellingofworms
Disadvantages:
•maintainproperenvironmental
conditionsforworms
Advantages:
•recyclingatsource
•economicandenvironmentfriendly
wastemanagement
•simplemethodsavailable
•compostisvaluableresourcefor
gardeners/farmers
Vermicomposting
LANDFILLING
LANDFILLING
LANDFILLING
LANDFILLING
LANDFILLING
LANDFILLING
LANDFILLING
LANDFILLING
LANDFILLING
Biogas
WhatisBiogas?
•Clean,efficientsourceof
renewableenergy(1)
•Madefromorganic
waste
•Producesmethane
•Anaerobicdigestion(2)
•Replacesnon-renewable
energy
•Digestedinanairtight
container
•Clean,efficientsourceof
renewableenergy(1)
•Madefromorganic
waste
•Producesmethane
•Anaerobicdigestion(2)
•Replacesnon-renewable
energy
•Digestedinanairtight
container
MODERNRENEWEBLEENERGYSYSTEM
SewerSystems
Contents
1.Concept
2.HowitcanoptimiseSSWM
3.ConventionalSewers
4.SeparateSewers
5.SimplifiedSewers
6.Solids-freeSewers
7.PressurisedSewers
8.VacuumSewers
9.Channels
10.SewerPumpingStations
11.TransferandSewer
DischargeStation
Alargesewersystem.Source: RiverSides(n.y.)
1.Concept
2.HowitcanoptimiseSSWM
3.ConventionalSewers
4.SeparateSewers
5.SimplifiedSewers
6.Solids-freeSewers
7.PressurisedSewers
8.VacuumSewers
9.Channels
10.SewerPumpingStations
11.TransferandSewer
DischargeStation
Alargesewersystem.Source: RiverSides(n.y.)
WhatisaSewerSystem?
•A piped system to transport wastewater (and sometimes storm water)
fromthe source(households,industry,runoff)to atreatmentfacility.
•Thereareseveraldesigns,dependingontopography,amountandkindof
wastewater,sizeofcommunity,etc.
198
1.Concept
“Flush and forget”: in
many cases, sewers lead
intosurfacewatersources
withoutanytreatment.
Source:STAUFFER(2010)
•A piped system to transport wastewater (and sometimes storm water)
fromthe source(households,industry,runoff)to atreatmentfacility.
•Thereareseveraldesigns,dependingontopography,amountandkindof
wastewater,sizeofcommunity,etc.
198
1.Concept
“Flush and forget”: in
many cases, sewers lead
intosurfacewatersources
withoutanytreatment.
Source:STAUFFER(2010)
WhatKindsofSewer SystemsExist?
•Thereexistseveraldifferentsewersystems:
•ConventionalSewers
•SeparateSewers
•SimplifiedSewers
•Solids-freeSewers
•PressurisedSewers
•VacuumSewers
•Channels
•Someofthemrequiresupportingelementssuchas:
•SewerPumpingStations
•TransferStations
1.Concept
•Thereexistseveraldifferentsewersystems:
•ConventionalSewers
•SeparateSewers
•SimplifiedSewers
•Solids-freeSewers
•PressurisedSewers
•VacuumSewers
•Channels
•Someofthemrequiresupportingelementssuchas:
•SewerPumpingStations
•TransferStations
1.Concept
UseaSewerSystem
2.HowitcanOptimise(SSWM)sustainable sanitation&watermanagement
Rooftoprainwater
harvesting as a
watersource.
Urinefertilisation
Urinediversion
flushtoilet
•Inmany countriesaroundtheworld,flushtoiletsandsewersystemsarethe
commonsanitarysystems.
•However,thereareseveralpossibilitiesto keepyourwastewater low and
provideasustainabletreatment:
Simplifiedsewer
system
Compostfilter(pre-
treatment)
Verticalconstructedwetland
2.HowitcanOptimise(SSWM)sustainable sanitation&watermanagement
Rooftoprainwater
harvesting as a
watersource.
Urinefertilisation
Urinediversion
flushtoilet
•Inmany countriesaroundtheworld,flushtoiletsandsewersystemsarethe
commonsanitarysystems.
•However,thereareseveralpossibilitiesto keepyourwastewater low and
provideasustainabletreatment:
Simplifiedsewer
system
Compostfilter(pre-
treatment)
Verticalconstructedwetland
DesignPrinciple
3.ConventionalSewers
•Largenetworksofundergroundpipes,mostlyinurbanareas.
•Collectionof blackwater,brownwater,greywaterandstormwater.
•Thesystemcontainsthreetypesofsewerlines:
oMainline(primary):thecentreof
thesystem,allotherlinesempty
intoit.
oBranchlines(secondary):extend
fromthemain.
oHouse laterals (tertiary): bring
wastwaterfromthehousestothe
branchlines.
Mastersewersystemmap.
Source:USAID(1982)
3.ConventionalSewers
•Largenetworksofundergroundpipes,mostlyinurbanareas.
•Collectionof blackwater,brownwater,greywaterandstormwater.
•Thesystemcontainsthreetypesofsewerlines:
oMainline(primary):thecentreof
thesystem,allotherlinesempty
intoit.
oBranchlines(secondary):extend
fromthemain.
oHouse laterals (tertiary): bring
wastwaterfromthehousestothe
branchlines.
Mastersewersystemmap.
Source:USAID(1982)
Design
•Wastewateristransportedtoacentralisedtreatmentfacility bygravity.
•Dependingon topography,sewerpumpingstationsarenecessary.
•Thelinesarein adepthof1.5to 3m andmanholes provedaccessfor
maintenance.
•Itmust bedesignedtomaintain“self-cleansing”velocitythatno particles
accumulate
3.ConventionalSewers
Cross-section of a
conventionalsewerina
commonurbanset-up.
Source:EAWAG/SANDEC (2008)
•Wastewateristransportedtoacentralisedtreatmentfacility bygravity.
•Dependingon topography,sewerpumpingstationsarenecessary.
•Thelinesarein adepthof1.5to 3m andmanholes provedaccessfor
maintenance.
•Itmust bedesignedtomaintain“self-cleansing”velocitythatno particles
accumulate
3.ConventionalSewers
Cross-section of a
conventionalsewerina
commonurbanset-up.
Source:EAWAG/SANDEC (2008)
Costs
Initialcostsarehighbecause:
•Excavationand refillingoftrenchesto laythepipes;
•Requiresspecialisedengineersandoperators;
•Maintenancecostsarehighcomparedtodecentralisedsystems;
•Extensionofthesystemcanbedifficultandcostly(redesignofthewholesystem)
3.ConventionalSewers
Maintenance and
operation of the City's
water system is quite a
costlytask.Source:THECITY OF
MADERA(n.y.)
Initialcostsarehighbecause:
•Excavationand refillingoftrenchesto laythepipes;
•Requiresspecialisedengineersandoperators;
•Maintenancecostsarehighcomparedtodecentralisedsystems;
•Extensionofthesystemcanbedifficultandcostly(redesignofthewholesystem)
3.ConventionalSewers
Maintenance and
operation of the City's
water system is quite a
costlytask.Source:THECITY OF
MADERA(n.y.)
Operation&Maintenance
•Maintenanceshouldbedonebyprofessionals.
•Manholes are installed wherever there is a change of gradient or
alignmentandareusedforregular inspection andcleaning.
•Itmust besystematicallyplannedandcarefullyimplemented.
•Overflowsarerequiredto avoidhydraulic surchargeoftreatmentplants
duringheavyrainevents.
3.ConventionalSewers
Seweraccessmanhole.
Source:USAID(1982)
•Maintenanceshouldbedonebyprofessionals.
•Manholes are installed wherever there is a change of gradient or
alignmentandareusedforregular inspection andcleaning.
•Itmust besystematicallyplannedandcarefullyimplemented.
•Overflowsarerequiredto avoidhydraulic surchargeoftreatmentplants
duringheavyrainevents.
3.ConventionalSewers
Seweraccessmanhole.
Source:USAID(1982)
Applicability
•Suitablefor urbanareasthat havetheresources suchasystem.
•They only make sense if a centralised treatment system exists which is
ableto handle bigloadsofwaste-andstormwater.
•Sufficientwateras atransportmediumneedstobeavailable.
•Aprofessionalmanagementsystemmust bein place.
•Theyprovide ahigh level ofhygieneandcomfort fortheuser.
3.ConventionalSewers
•Suitablefor urbanareasthat havetheresources suchasystem.
•They only make sense if a centralised treatment system exists which is
ableto handle bigloadsofwaste-andstormwater.
•Sufficientwateras atransportmediumneedstobeavailable.
•Aprofessionalmanagementsystemmust bein place.
•Theyprovide ahigh level ofhygieneandcomfort fortheuser.
3.ConventionalSewers
3.ConventionalSewers
•Advantages:
–Convenience (minimal
interventionbyusers)
–Lowhealthrisk
–No nuisance from smells,
mosquitoesorflies
–Stormwater and greywater can
bemanagedatthesametime
–Noproblemsrelatedto
discharging industrial
wastewater
–Moderateoperationand
maintenancecosts
Disadvantages:
•Highcapitalcosts
•Needa reliablesupplyofpipedwater
•Difficulttoconstructinhigh-density
areas,difficultandcostly tomaintain
•Recyclingofnutrientsandenergy
becomes difficult
•Unsuitabilityforself-help,requiresskilled
engineersandoperators
•Problems associatedwithblockagesand
breakdownofpumpingequipment
•Adequate treatment and/or disposal
required
•Advantages:
–Convenience (minimal
interventionbyusers)
–Lowhealthrisk
–No nuisance from smells,
mosquitoesorflies
–Stormwater and greywater can
bemanagedatthesametime
–Noproblemsrelatedto
discharging industrial
wastewater
–Moderateoperationand
maintenancecosts
Disadvantages:
•Highcapitalcosts
•Needa reliablesupplyofpipedwater
•Difficulttoconstructinhigh-density
areas,difficultandcostly tomaintain
•Recyclingofnutrientsandenergy
becomes difficult
•Unsuitabilityforself-help,requiresskilled
engineersandoperators
•Problems associatedwithblockagesand
breakdownofpumpingequipment
•Adequate treatment and/or disposal
required
DesignPrinciple
4.SeparateSewers
Source:
LADEN
(2010)
•Incontrasttoconventionalsewer systems,wastewater(e.g.fromhouseholds
orindustries)andstormwateraretransportedseparately.
➢During heavyrains,overflowcontainsnoharmfulblackwater.
➢Stormwateringeneralis lesscontaminated.Source:
4.SeparateSewers
Source:
LADEN
(2010)
•Incontrasttoconventionalsewer systems,wastewater(e.g.fromhouseholds
orindustries)andstormwateraretransportedseparately.
➢During heavyrains,overflowcontainsnoharmfulblackwater.
➢Stormwateringeneralis lesscontaminated.Source:
Costs
4.SeparateSewers
•Constructioncostsmight be higher thanforthecombinedsewer system
becausetwoseparatednetworks arenecessary.
•Theymust alsobemaintainedandoperated separately.
•Areplacementofa combinedsystembya separatedsystemisverycostly.
Operation&Maintenance
•Sameasconventionalsystems
HealthAspect
•Moresecurethanaconventionalsystem,becauseblackwateris
transportedinaclosednetwork.
4.SeparateSewers
•Constructioncostsmight be higher thanforthecombinedsewer system
becausetwoseparatednetworks arenecessary.
•Theymust alsobemaintainedandoperated separately.
•Areplacementofa combinedsystembya separatedsystemisverycostly.
Operation&Maintenance
•Sameasconventionalsystems
HealthAspect
•Moresecurethanaconventionalsystem,becauseblackwateris
transportedinaclosednetwork.
Applicability
4.SeparateSewers
Newconstructionofaseparated
sewersysteminGermany.Source:
VILLINGEN-SCHWENNINGEN (2010)
•Suitablefor urban areasthathavetheresources toimplement,operate
and maintain such systems plus provide adequate treatment to avoid
pollutionat thedischargeend. UNEP(2002)
•Enoughwaterfortransportationmustbe available.
•Especially suitable during
monsoon–>largeamounts
of storm water can be
treatedseparately.
4.SeparateSewers
Newconstructionofaseparated
sewersysteminGermany.Source:
VILLINGEN-SCHWENNINGEN (2010)
•Suitablefor urban areasthathavetheresources toimplement,operate
and maintain such systems plus provide adequate treatment to avoid
pollutionat thedischargeend. UNEP(2002)
•Enoughwaterfortransportationmustbe available.
•Especially suitable during
monsoon–>largeamounts
of storm water can be
treatedseparately.
4.SeparateSewers
•Advantages:
–Surface run-off, grey water
and black water can be
managedseparately
–Limitedofsewageoverflow
–Lowhealthrisk
–No nuisance from smells,
mosquitoesorflies
–Noproblemsrelatedto
discharging industrial
wastewater
–Moderateoperationcosts
–Surface run-off and rainwater
canbereused
Disadvantages:
•Supplyofpiped water
•Difficult to construct in high-density
areas, difficultandcostlytomaintain
•Highcapitalcosts
•Requiresskilledengineersand
operators
•Problemsassociatedwithblockages
andbreakdownofpumping
equipment
•Adequate treatment and/or disposal
required
•Higher risk of waterpollutionby
accidents
•Advantages:
–Surface run-off, grey water
and black water can be
managedseparately
–Limitedofsewageoverflow
–Lowhealthrisk
–No nuisance from smells,
mosquitoesorflies
–Noproblemsrelatedto
discharging industrial
wastewater
–Moderateoperationcosts
–Surface run-off and rainwater
canbereused
Disadvantages:
•Supplyofpiped water
•Difficult to construct in high-density
areas, difficultandcostlytomaintain
•Highcapitalcosts
•Requiresskilledengineersand
operators
•Problemsassociatedwithblockages
andbreakdownofpumping
equipment
•Adequate treatment and/or disposal
required
•Higher risk of waterpollutionby
accidents
•It is a simplified sewerage, which is technically and institutionally feasible,
economicallyappropriateandfinancially affordable sanitationoption.
5.SimplifiedandCondominalSewers
Source:
STAUFFER
(2012),
adapted
from
TILLEY
et
al.
(2008)
DesignPrinciple
economicallyappropriateandfinancially affordable sanitationoption.
5.SimplifiedandCondominalSewers
Source:
STAUFFER
(2012),
adapted
from
TILLEY
et
al.
(2008)
DesignPrinciple
•Itconsistsof:
•Small-diameterpipes(e.g.100mm).
•Inspectionschambers(for maintenance).
•Everyhouseholdshouldhaveagrease trapor anotherappropriatepre-
treatmentfacility.
•Semi-centralisedtreatmentfacility ortransfer/discharge station.
5.SimplifiedandCondominalSewers
DesignPrinciple
•Small-diameterpipes(e.g.100mm).
•Inspectionschambers(for maintenance).
•Everyhouseholdshouldhaveagrease trapor anotherappropriatepre-
treatmentfacility.
•Semi-centralisedtreatmentfacility ortransfer/discharge station.
5.SimplifiedandCondominalSewers
DesignPrinciple
•Sewersarelaidonusers property:
•Higherconnectionrates can be achieved.
•Fewerand shorter pipescanbeused.
•Lessexcavationisrequired (reducedtrafficload).
• This requires careful negotiation between stakeholders (see
stakeholder analysis), since design and maintenance must be jointly
coordinated.
5.SimplifiedandCondominalSewers
A simplified sewer (condominal
sewer) network. Sewers are laid
withinpropertyboundariesrather
than beneath central roads. Source:
EAWAGandSANDEC(2008)
DesignPrinciple
•Higherconnectionrates can be achieved.
•Fewerand shorter pipescanbeused.
•Lessexcavationisrequired (reducedtrafficload).
• This requires careful negotiation between stakeholders (see
stakeholder analysis), since design and maintenance must be jointly
coordinated.
5.SimplifiedandCondominalSewers
A simplified sewer (condominal
sewer) network. Sewers are laid
withinpropertyboundariesrather
than beneath central roads. Source:
EAWAGandSANDEC(2008)
DesignPrinciple
•Costs are low (50 to 80 % less expensive than conventional sewerage)
because:
•Flattergradients
•Shallowexcavation depths
•Smalldiameterpipe
•Simpleinspectionunits
• The costs for emptying interceptors and pre-settling units must be
considered!
5.SimplifiedandCondominalSewers
Costs
because:
•Flattergradients
•Shallowexcavation depths
•Smalldiameterpipe
•Simpleinspectionunits
• The costs for emptying interceptors and pre-settling units must be
considered!
5.SimplifiedandCondominalSewers
Costs
Operation&Maintenance
•Allgreywatershouldbeconnectedto ensure adequate hydraulicloading.
•Nosolidsshouldenter the system.
•Thesystemneedstobeflushedregularly.
•Interceptor tanksandpre-settlementunits mustbeemptiedperiodically
5.SimplifiedandCondominalSewers
A typical cleanout, also called
flushingpoint(right)andajunction
without a cleanout (left). Source: MARA
(2001)
•Allgreywatershouldbeconnectedto ensure adequate hydraulicloading.
•Nosolidsshouldenter the system.
•Thesystemneedstobeflushedregularly.
•Interceptor tanksandpre-settlementunits mustbeemptiedperiodically
5.SimplifiedandCondominalSewers
A typical cleanout, also called
flushingpoint(right)andajunction
without a cleanout (left). Source: MARA
(2001)
Applicability
•Appropriatefordense,urban
settlements
•If ground is rocky or the
groundwatertableishigh
•Can be an alternative in areas with
individualsoakaways
5.SimplifiedandCondominalSewers
Junction chamber for
simplified sewerage using
larger diameter concrete
pipes,usedinGuatamala.
Source:MARAandSLEIGH(2001)
•Appropriatefordense,urban
settlements
•If ground is rocky or the
groundwatertableishigh
•Can be an alternative in areas with
individualsoakaways
5.SimplifiedandCondominalSewers
Junction chamber for
simplified sewerage using
larger diameter concrete
pipes,usedinGuatamala.
Source:MARAandSLEIGH(2001)
217
5.SimplifiedandCondominalSewers
•Advantages:
–Canbebuiltand repaired with
locallyavailablematerials
employmenttolocallabourers
% less than conventional gravity
sewers
–Operatingcostsarelow
–Canbeextendedasacommunity
changesandgrows
Disadvantages:
•Requires waterforflushing
•Requiresexpertdesign
–Constructioncanprovideshort-term•Requiresrepairsandremovalsofblockages
morefrequentlythana conventionalsewer
–Capitalcostsarebetween50 and80•Effluent andsludgerequiressecondary
treatment
•Overflowifnotmaintainedproperly
•Blockagebecauseofillegalconnections
•Onlysuitablewherethereareinterceptor
tanks,septictanksorotherpre-treatment
systems
•Requirestheinvolvementofawell-organised
seweragedepartment
5.SimplifiedandCondominalSewers
•Advantages:
–Canbebuiltand repaired with
locallyavailablematerials
employmenttolocallabourers
% less than conventional gravity
sewers
–Operatingcostsarelow
–Canbeextendedasacommunity
changesandgrows
Disadvantages:
•Requires waterforflushing
•Requiresexpertdesign
–Constructioncanprovideshort-term•Requiresrepairsandremovalsofblockages
morefrequentlythana conventionalsewer
–Capitalcostsarebetween50 and80•Effluent andsludgerequiressecondary
treatment
•Overflowifnotmaintainedproperly
•Blockagebecauseofillegalconnections
•Onlysuitablewherethereareinterceptor
tanks,septictanksorotherpre-treatment
systems
•Requirestheinvolvementofawell-organised
seweragedepartment
DesignPrinciple
•Solids-free sewer systems are similar to conventional systems, but the
wastewateris pre-settledand solidsremovedbeforeenteringthesystem, e.g.:
•Septictanks
•Biogassettlers
•Anaerobicbaffledreactor
6.Solids-freeSewers
Source:TILLEYetal.(2008)
The recommended pipe
diameter is 75 to 100 mm
and an depth of at lest 300
mm. (OTIS and MARA
1985)
•Solids-free sewer systems are similar to conventional systems, but the
wastewateris pre-settledand solidsremovedbeforeenteringthesystem, e.g.:
•Septictanks
•Biogassettlers
•Anaerobicbaffledreactor
6.Solids-freeSewers
Source:TILLEYetal.(2008)
The recommended pipe
diameter is 75 to 100 mm
and an depth of at lest 300
mm. (OTIS and MARA
1985)
•Ifwellmaintained,thereislittleriskofclogging,thusthereisnoneed
ofself-cleansingvelocity,i.e.;
•Shallowdepths
•Smalloreveninflectivegradients
•Fewerinspectionpoints
•Canfollowtopographymoreclosely
• Thisresultsinsignificantlylowerinvestmentcostsduetothe
simplifieddesign!
6.Solids-freeSewers
DesignPrinciple
ofself-cleansingvelocity,i.e.;
•Shallowdepths
•Smalloreveninflectivegradients
•Fewerinspectionpoints
•Canfollowtopographymoreclosely
• Thisresultsinsignificantlylowerinvestmentcostsduetothe
simplifieddesign!
6.Solids-freeSewers
DesignPrinciple
•Solids-free sewers can be built for 20% to
50%lesscosts thanconventional
sewerage.
• s well as costs
tlingunitmust
Repairsandremoval ofa
foremptyingthepre-set
beconsidered.
220
6.Solids-freeSewers
Costs for emptying the pre-
treatment unit must be
considered (organisation and
costs):avacuumtruckempties
apitinBharakpurnearCalcutta.
Source:EAWAG/SANDEC (2008)
Costs
50%lesscosts thanconventional
sewerage.
• s well as costs
tlingunitmust
Repairsandremoval ofa
foremptyingthepre-set
beconsidered.
220
6.Solids-freeSewers
Costs for emptying the pre-
treatment unit must be
considered (organisation and
costs):avacuumtruckempties
apitinBharakpurnearCalcutta.
Source:EAWAG/SANDEC (2008)
Costs
Applicability
•Wellsuitedforareaswhereleachingfields/soakpitsareinappropriatedue
tosensitivegroundwaterorlackofspaceforon-siteinfiltrationingrowing
communities.
•Inareaswithahighwillingnesstopay(fortheoperationandmaintenance)
andwithlocallyavailableexpertiseandresources.
•Usersshouldreceivesomebasictraining.
6.Solids-freeSewers
Operation&Maintenance(TILLEYetal.2008)
•Pre-settlingunitmustbemaintainedandemptiedperiodically.
•Riskofpipe cloggingis relativelylow.
•Sewershouldbeflushedonceayear.
•Sewersrequireaconstantsupplyofwater,althoughlesswateris
neededcomparedtoconventionalsewers.
•Wellsuitedforareaswhereleachingfields/soakpitsareinappropriatedue
tosensitivegroundwaterorlackofspaceforon-siteinfiltrationingrowing
communities.
•Inareaswithahighwillingnesstopay(fortheoperationandmaintenance)
andwithlocallyavailableexpertiseandresources.
•Usersshouldreceivesomebasictraining.
6.Solids-freeSewers
Operation&Maintenance(TILLEYetal.2008)
•Pre-settlingunitmustbemaintainedandemptiedperiodically.
•Riskofpipe cloggingis relativelylow.
•Sewershouldbeflushedonceayear.
•Sewersrequireaconstantsupplyofwater,althoughlesswateris
neededcomparedtoconventionalsewers.
6.Solids-freeSewers
145
•Advantages:
–Canbebuiltandrepairedwith
locallyavailablematerials
–Capitalcostsare lessthan for
conventionalsewers
–Lowoperatingcostsifwell
maintained
–Canbeextendedasacommunity
changesandgrows
–Appropriate for densely populated
areas with sensitive groundwater or
no space for a soak pit or leaching
field
Disadvantages:
•Requiresrepairsandremovalsof
blockagesmorefrequentlythana
conventionalgravitysewer
•Requiresexpertdesignand
constructionsupervision
•Requires education and acceptance
tobeusedcorrectly
•Effluentandsludge(from
interceptors) requires secondary
treatmentand/orappropriate
discharge
145
•Advantages:
–Canbebuiltandrepairedwith
locallyavailablematerials
–Capitalcostsare lessthan for
conventionalsewers
–Lowoperatingcostsifwell
maintained
–Canbeextendedasacommunity
changesandgrows
–Appropriate for densely populated
areas with sensitive groundwater or
no space for a soak pit or leaching
field
Disadvantages:
•Requiresrepairsandremovalsof
blockagesmorefrequentlythana
conventionalgravitysewer
•Requiresexpertdesignand
constructionsupervision
•Requires education and acceptance
tobeusedcorrectly
•Effluentandsludge(from
interceptors) requires secondary
treatmentand/orappropriate
discharge
•This system is not dependent on gravity
tomove wastewater
•Shallowtrenchesandrelativelysmallpipe
nd
diameters
•Requirespermanent electricitya
grinderpumps
7.PressurisedSewers
Apressurisedsewer
system is
independent from
landtopographyand
does not need deep
excavationwork.
Source:ITT(n.y.)
146
DesignPrinciple
tomove wastewater
•Shallowtrenchesandrelativelysmallpipe
nd
diameters
•Requirespermanent electricitya
grinderpumps
7.PressurisedSewers
Apressurisedsewer
system is
independent from
landtopographyand
does not need deep
excavationwork.
Source:ITT(n.y.)
146
DesignPrinciple
•Wastewateriscollected bygravityin acollectiontank.
•Agrinderpumpmovesitto thesewer thistransfer ofwastewater
pressurisesthesewer.
•Variouspumpsalongthesewerlinemovethewastewater progressively.
7.PressurisedSewers
Source:(WERF2010)
DesignPrinciple
•Agrinderpumpmovesitto thesewer thistransfer ofwastewater
pressurisesthesewer.
•Variouspumpsalongthesewerlinemovethewastewater progressively.
7.PressurisedSewers
Source:(WERF2010)
DesignPrinciple
•Generallypre-fabricated products.
•Acollectiontankincludinggrinderandpump,non-returnvalve(prevents
backflowfromthepressuresewer).
•Thegrindingallowssmallpipediameters.
•Wiredtothehouseholdpowersupplyandregulatedbyacontrolpanel.
•Alternative to this unit: a septic tank situated outside in the ground or in
thebasement. Effluentflowsinto an undergroundholdingtankcontaining
a pump and control devices from where it is then pumped into the
pressurisedsewer.(U.S.EPA2002)
7.PressurisedSewers
DesignPrinciple–PressureSewerUnit
•Acollectiontankincludinggrinderandpump,non-returnvalve(prevents
backflowfromthepressuresewer).
•Thegrindingallowssmallpipediameters.
•Wiredtothehouseholdpowersupplyandregulatedbyacontrolpanel.
•Alternative to this unit: a septic tank situated outside in the ground or in
thebasement. Effluentflowsinto an undergroundholdingtankcontaining
a pump and control devices from where it is then pumped into the
pressurisedsewer.(U.S.EPA2002)
7.PressurisedSewers
DesignPrinciple–PressureSewerUnit
DesignPrinciple–PressureSewerUnit
7.PressurisedSewers
Aprefabricatedpressuresewerunitmadeoutofplasticforoutsideplacement.Source:SHOALHAVEN WATER(n.y.)
149
7.PressurisedSewers
Aprefabricatedpressuresewerunitmadeoutofplasticforoutsideplacement.Source:SHOALHAVEN WATER(n.y.)
149
•Costs can be devided in two major
components:
➢On-lot costs: pump, basin, controls,
buildingsewer,lateralpiping,electrical
service,installation
➢Collection network: includes all the
pipinginthe utilityeasementsthatdirects
the sewageto the treatmentfacility.
150
7.PressurisedSewers
Costs
components:
➢On-lot costs: pump, basin, controls,
buildingsewer,lateralpiping,electrical
service,installation
➢Collection network: includes all the
pipinginthe utilityeasementsthatdirects
the sewageto the treatmentfacility.
150
7.PressurisedSewers
Costs
Operation&Maintenance
•Regularserviceisimportant forallsystem components.
•Electricityneeds tobe availableallthetime.
•Pumpsshouldbe checked regularly.
•Pipeconnectionsshouldbe controlledforleakages.
7.PressurisedSewers
Three examples of damages on pressurised piping system. Therefore it is very important to inspect and
maintainthesewersystem.Thisavoidshighrepaircost,environmentaldamagesandpublichealthhazard.
Source:WSAA(2003)
•Regularserviceisimportant forallsystem components.
•Electricityneeds tobe availableallthetime.
•Pumpsshouldbe checked regularly.
•Pipeconnectionsshouldbe controlledforleakages.
7.PressurisedSewers
Three examples of damages on pressurised piping system. Therefore it is very important to inspect and
maintainthesewersystem.Thisavoidshighrepaircost,environmentaldamagesandpublichealthhazard.
Source:WSAA(2003)
Applicability
•Basically, pressurised sewer systems have the same advantages as vacuum
sewers.Thereforetheyare usedinsimilarsurroundings;
•Flat or hilly topography: gravity systems demand installation at great
depthstomaintainadequateflow orrequirespumpingandliftstations.
•Rocklayers,running sandorahigh groundwatertablemakedeep
excavationdifficult.
•Highgroundwatertable.
•Denselypopulatedareas.
7.PressurisedSewers
•Basically, pressurised sewer systems have the same advantages as vacuum
sewers.Thereforetheyare usedinsimilarsurroundings;
•Flat or hilly topography: gravity systems demand installation at great
depthstomaintainadequateflow orrequirespumpingandliftstations.
•Rocklayers,running sandorahigh groundwatertablemakedeep
excavationdifficult.
•Highgroundwatertable.
•Denselypopulatedareas.
7.PressurisedSewers
230
7.PressurisedSewers
•Advantages:
–Effectivewastewater
transportation at minimum depth,
minimising the excavation for the
pipingsystem
–Gravity free; independent from
landtopography
–Lower costs compared to a
conventional gravity sewer (pipe
size and depth requirements are
reduced and many small pumps are
cheaper than some large-capacity
liftstations)
–Requireslittle wateronlyfor
transportingtheexcreta
Disadvantages:
•Needsexpertdesign,highcapital costs
•Needsapermanentenergysource
•Aproperrecyclingofnutrientsandenergy
becomes difficult,becauseall kindsof
wastesaremixed
•Unsuitabilityforself-help,requiresskilled
engineers& operators
•Itisstillaflushingsystemwhichtransports
wastewateraway.Ifthereisnotreatment
plantand anunprofessionaldischargeit
cancontaminatetheenvironment
•Leakagesmaylead tocontaminations
7.PressurisedSewers
•Advantages:
–Effectivewastewater
transportation at minimum depth,
minimising the excavation for the
pipingsystem
–Gravity free; independent from
landtopography
–Lower costs compared to a
conventional gravity sewer (pipe
size and depth requirements are
reduced and many small pumps are
cheaper than some large-capacity
liftstations)
–Requireslittle wateronlyfor
transportingtheexcreta
Disadvantages:
•Needsexpertdesign,highcapital costs
•Needsapermanentenergysource
•Aproperrecyclingofnutrientsandenergy
becomes difficult,becauseall kindsof
wastesaremixed
•Unsuitabilityforself-help,requiresskilled
engineers& operators
•Itisstillaflushingsystemwhichtransports
wastewateraway.Ifthereisnotreatment
plantand anunprofessionaldischargeit
cancontaminatetheenvironment
•Leakagesmaylead tocontaminations
•A central vacuum source conveys sewage from individual households to a
centralcollectionstation.(UNEP2002)
8.VacuumSewers
DesignPrinciple
centralcollectionstation.(UNEP2002)
8.VacuumSewers
DesignPrinciple
8.VacuumSewers
•Useofdifferentialairpressure(“negativepressure”or“vacuum”)tomove
thesewage.
•Acentralsourceofpowertooperatevacuumpumpsis requiredto
maintainvacuum.
Source:ROEDIGER(2007)
DesignPrinciple
•Useofdifferentialairpressure(“negativepressure”or“vacuum”)tomove
thesewage.
•Acentralsourceofpowertooperatevacuumpumpsis requiredto
maintainvacuum.
Source:ROEDIGER(2007)
DesignPrinciple
8.VacuumSewers
•Useofdifferential air pressure (“negativepressure”or “vacuum”)to move
thesewage.
•Acentralsourceofpowertooperatevacuumpumpsisrequiredto maintain
vacuum.
•Ateachentrypoint(collectionchamber),aninterfacevalveisrequiredto
seal thelinessothatvacuumcanbemaintained.
DesignPrinciple
•Useofdifferential air pressure (“negativepressure”or “vacuum”)to move
thesewage.
•Acentralsourceofpowertooperatevacuumpumpsisrequiredto maintain
vacuum.
•Ateachentrypoint(collectionchamber),aninterfacevalveisrequiredto
seal thelinessothatvacuumcanbemaintained.
DesignPrinciple
Design Principle–Transportof Wastewater
1.Gravitylinecarrieswastewaterfromthesource tothecollection
chamber.
2.Whenadefinedheight isreached,thevacuuminterfacevalvesopens
andsucksthewastewater into thevacuumsewermain.
3.Attheend ofthis mainitiscollectedinabigtank.
4.Afterthistankisfilledtoapredeterminedlevel,thewastewateris
transferredtoatreatmentplantviaaconventional/separatesewer
system.
8.VacuumSewers
1.Gravitylinecarrieswastewaterfromthesource tothecollection
chamber.
2.Whenadefinedheight isreached,thevacuuminterfacevalvesopens
andsucksthewastewater into thevacuumsewermain.
3.Attheend ofthis mainitiscollectedinabigtank.
4.Afterthistankisfilledtoapredeterminedlevel,thewastewateris
transferredtoatreatmentplantviaaconventional/separatesewer
system.
8.VacuumSewers
DesignPrinciple-Piping
•Narrowandshallowtrenches(1.0to 1.2 m)
•Inspectionpointsfor pressuretesting
•Smallpipediameter(80to250mm)
•If a pipe is damaged, risk of leaking is low because of the negative
pressure.
8.VacuumSewers
Local workers at
constructionofashallow
vacuumsewersystem.
Source:ROEDIGER(2007)
•Narrowandshallowtrenches(1.0to 1.2 m)
•Inspectionpointsfor pressuretesting
•Smallpipediameter(80to250mm)
•If a pipe is damaged, risk of leaking is low because of the negative
pressure.
8.VacuumSewers
Local workers at
constructionofashallow
vacuumsewersystem.
Source:ROEDIGER(2007)
It is a high-tech system, thus it is costly. But in comparison with a
conventionalsewersystem,it ischeaper:
•SmallPipes(lessmaterial)
•Shallowtrenches(noheavy machinery)
•Independentfromtopography
•Large amounts offlushing watercan besaved(economicalandecological
reasonable)
Permanentsourceofelectricalpowercanincrease thecosts!
8.VacuumSewers
Costs
conventionalsewersystem,it ischeaper:
•SmallPipes(lessmaterial)
•Shallowtrenches(noheavy machinery)
•Independentfromtopography
•Large amounts offlushing watercan besaved(economicalandecological
reasonable)
Permanentsourceofelectricalpowercanincrease thecosts!
8.VacuumSewers
Costs
Operation&Maintenance
•Riskofcloggingislow; almostno cleaning/emptying
•Periodicallypressuretesting
•Complex and/or technical problems are in the responsibility of the
manufacturer.
8.VacuumSewers
Constructionofa
sewer at the left
side and
pressure testing
ettherightside.
Source:ROEDIGER(2007)
•Riskofcloggingislow; almostno cleaning/emptying
•Periodicallypressuretesting
•Complex and/or technical problems are in the responsibility of the
manufacturer.
8.VacuumSewers
Constructionofa
sewer at the left
side and
pressure testing
ettherightside.
Source:ROEDIGER(2007)
Applicability
•Flattopography: gravitysystemsdemandinstallation at greatdepthsto
maintainadequateflow(pumpstations, liftstations).
•Rock layers, running sand or a high groundwater table make deep
excavation difficult.
•Areasshort ofwatersupplyorpoor communitiesthatmustpayforwater,
but cannot afford great amounts of water necessary for operation of
gravitysystems.
•Areasthat areecologicallysensitive.
•Areaswherefloodingcanoccur.
•Areaswithobstaclestoagravitysewerroute.
•Installation of a new fresh water network, allowing sewerage pipe
installationin thesametrench.
8.VacuumSewers
•Flattopography: gravitysystemsdemandinstallation at greatdepthsto
maintainadequateflow(pumpstations, liftstations).
•Rock layers, running sand or a high groundwater table make deep
excavation difficult.
•Areasshort ofwatersupplyorpoor communitiesthatmustpayforwater,
but cannot afford great amounts of water necessary for operation of
gravitysystems.
•Areasthat areecologicallysensitive.
•Areaswherefloodingcanoccur.
•Areaswithobstaclestoagravitysewerroute.
•Installation of a new fresh water network, allowing sewerage pipe
installationin thesametrench.
8.VacuumSewers
239
8.VacuumSewers
•Advantages:
–Requireslessflushingwater
–Considerablesavingsin
constructioncosts
–Shallowandnarrowtrenches,
small diameterpipelines,
flexiblepipelineconstruction
–Sewers and water mains can
be laidinacommontrench
–Closed systems with no
leakage or smell
–Nomanholesalongthe
vacuum sewers
–One central vacuum station
can replaceseveralpumping
stations
Disadvantages:
•Needsexpertdesign
•Needsenergytocreatethe
permanentvacuum
•Relatively high capital costs
•Recyclingofnutrientsand
energy becomes difficult
•Unsuitabilityforself-help,
requires
skilledengineersoperators
•Itisstillaflushingsystem.Ifthere
is notreatmentplantandan
unprofessionaldischargeit can
contaminatetheenvironment
8.VacuumSewers
•Advantages:
–Requireslessflushingwater
–Considerablesavingsin
constructioncosts
–Shallowandnarrowtrenches,
small diameterpipelines,
flexiblepipelineconstruction
–Sewers and water mains can
be laidinacommontrench
–Closed systems with no
leakage or smell
–Nomanholesalongthe
vacuum sewers
–One central vacuum station
can replaceseveralpumping
stations
Disadvantages:
•Needsexpertdesign
•Needsenergytocreatethe
permanentvacuum
•Relatively high capital costs
•Recyclingofnutrientsand
energy becomes difficult
•Unsuitabilityforself-help,
requires
skilledengineersoperators
•Itisstillaflushingsystem.Ifthere
is notreatmentplantandan
unprofessionaldischargeit can
contaminatetheenvironment
•Separatelycollectedstormwaterhashigh potentialforincreasing agricultural
productioninruralareas. The most basic way to drain off rain and storm
waterisviaopen channels.
•It consists of a secondary drainage system, with a network of small drains
attached(micro-drainage).
•Each serves a small catchment area that ranges from a single property to
severalblocksofhouses.
•The smalldrainsbringthewatertoa primarydrainage system,composedof
maindrains(alsocalledinterceptordrains),whichservelarge areasofthe city.
•The main drains are generally connected with natural drainage channels such
asriversorstreams.
9.OpenChannelsandDrains
DesignPrinciple
productioninruralareas. The most basic way to drain off rain and storm
waterisviaopen channels.
•It consists of a secondary drainage system, with a network of small drains
attached(micro-drainage).
•Each serves a small catchment area that ranges from a single property to
severalblocksofhouses.
•The smalldrainsbringthewatertoa primarydrainage system,composedof
maindrains(alsocalledinterceptordrains),whichservelarge areasofthe city.
•The main drains are generally connected with natural drainage channels such
asriversorstreams.
9.OpenChannelsandDrains
DesignPrinciple
DesignPrincipleCase
•‘El Gran Canal’ in Mexico City used as primary drainage system. The water in
thiscanal,whichalsotransportsrainandstormwater,isheavilypollutedwith
litteranduntreatedwastewater.
9.OpenChannelsandDrains
Source:
WALDWIND
(n.y.)
164
•‘El Gran Canal’ in Mexico City used as primary drainage system. The water in
thiscanal,whichalsotransportsrainandstormwater,isheavilypollutedwith
litteranduntreatedwastewater.
9.OpenChannelsandDrains
Source:
WALDWIND
(n.y.)
164
DesignPrinciple –SteepTerrain
165
•Areturnperiodof5-yearsiswidelyusedto
designprimarydrainagesystemsintropical
cities,formicro-drainage3-yearorless.
•On steep terrain, uncontrolled velocities can
lead to erosion, therefore several designs
exist:
a.Baffles
b.Steps
c.Checkwalls
•They are all built into the drain to slow down
the waterflowfor unlined drains. The water
deposits silt behind each checkwall, gradually
building up a stepped drain. The checkwalls
shouldbeburiedwellintotheground.
9.OpenChannelsandDrains
Source:
WHO
(1991)
§
165
•Areturnperiodof5-yearsiswidelyusedto
designprimarydrainagesystemsintropical
cities,formicro-drainage3-yearorless.
•On steep terrain, uncontrolled velocities can
lead to erosion, therefore several designs
exist:
a.Baffles
b.Steps
c.Checkwalls
•They are all built into the drain to slow down
the waterflowfor unlined drains. The water
deposits silt behind each checkwall, gradually
building up a stepped drain. The checkwalls
shouldbeburiedwellintotheground.
9.OpenChannelsandDrains
Source:
WHO
(1991)
§
DesignPrinciple–FlatTerrain
•The centralchannelor“cunette”withanarrowbottomcarriestheflowin dry
weatherandmoderate rain.
•The outerchannelfacilitatesfor theoccasionalheavyfloodflow. Theouter
channel floorshouldpreferablyslopegently down tothecentralchannel.
•Ifnotproperly designorclogged riskof puddlingand mosquitobreeding
9.OpenChannelsandDrains
•The centralchannelor“cunette”withanarrowbottomcarriestheflowin dry
weatherandmoderate rain.
•The outerchannelfacilitatesfor theoccasionalheavyfloodflow. Theouter
channel floorshouldpreferablyslopegently down tothecentralchannel.
•Ifnotproperly designorclogged riskof puddlingand mosquitobreeding
9.OpenChannelsandDrains
Design Principle–Transportof Wastewater
•Couldbeatemporarysolution–butisNOTasatisfactorytechnology:
•Peoplecaneasilycomeinto contactwith thewastewater,with itspotentially
highpathogencontent.
•If there is a storm event, flooding and spreading of pathogens and other
pollutantscan occur.(WORLDBANK2011)
•Veryoftenopendrains/channelsaremisusedfordepositinglitterandexcrete.
(CORCORANet al.2010)
•Householdsewerlinesare sometimesillegallyconnectedtoopendrainage
systems.(CORCORANetal.2010)
9.OpenChannelsandDrains
•Couldbeatemporarysolution–butisNOTasatisfactorytechnology:
•Peoplecaneasilycomeinto contactwith thewastewater,with itspotentially
highpathogencontent.
•If there is a storm event, flooding and spreading of pathogens and other
pollutantscan occur.(WORLDBANK2011)
•Veryoftenopendrains/channelsaremisusedfordepositinglitterandexcrete.
(CORCORANet al.2010)
•Householdsewerlinesare sometimesillegallyconnectedtoopendrainage
systems.(CORCORANetal.2010)
9.OpenChannelsandDrains
•Comparedtoundergroundsewersystems.
•Pricedependson:
oSteepterrain(extraconstructionto slowdownvelocity)
oFlatterrain(deeporwideexcavation)
oCostsformaterial
•Consideration of community participation could have a positive offset on
theoverallcosts(O&M).
•A typical value for the annual cost of maintenance would be about 8% of
theconstructioncostof thesystem.
9.OpenChannelsandDrains
Costs
•Pricedependson:
oSteepterrain(extraconstructionto slowdownvelocity)
oFlatterrain(deeporwideexcavation)
oCostsformaterial
•Consideration of community participation could have a positive offset on
theoverallcosts(O&M).
•A typical value for the annual cost of maintenance would be about 8% of
theconstructioncostof thesystem.
9.OpenChannelsandDrains
Costs
Operation&Maintenance(WHO1991)
•Themaindutiesand responsibilitiesforO&Mare:
•Routinedrain cleaning andrepairs
•Semiannualinspection,reportingofdefects andblockages
•Paymentformaintenance
•Passingofby-lawsregardingtheuseofdrains
•Enforcementofby-laws.
9.OpenChannelsandDrains
Cleaningoutopendrainsisdifficult
toorganisebututterlynecessary.
Blockagescancausespill-overand
causeflooding.Asolutioncouldbe
tocoveritwithconcreteslabs.Source:
SANIMAS(2005)
•Themaindutiesand responsibilitiesforO&Mare:
•Routinedrain cleaning andrepairs
•Semiannualinspection,reportingofdefects andblockages
•Paymentformaintenance
•Passingofby-lawsregardingtheuseofdrains
•Enforcementofby-laws.
9.OpenChannelsandDrains
Cleaningoutopendrainsisdifficult
toorganisebututterlynecessary.
Blockagescancausespill-overand
causeflooding.Asolutioncouldbe
tocoveritwithconcreteslabs.Source:
SANIMAS(2005)
9.OpenChannelsandDrains
Opendrainsbeara highhealthrisk,becausewaterinopenchannels
cancontainall sortsofcontaminantsandpathogens
•Pondingenforcesmosquitobreeding
•Illegaldisposalofsolid wasteleadstoclogging
•Defecationintothesechannelsis notanunusualhabit
Childrentendtoplayin suchchannels
HealthAspect
Grey water from laundry (left) and
solidgarbagewhichisdisposedin
open drains (right) pollute water
andcausehealthhazards.
Bangalore,Nepal.Source: BARRETO(2009)
Opendrainsbeara highhealthrisk,becausewaterinopenchannels
cancontainall sortsofcontaminantsandpathogens
•Pondingenforcesmosquitobreeding
•Illegaldisposalofsolid wasteleadstoclogging
•Defecationintothesechannelsis notanunusualhabit
Childrentendtoplayin suchchannels
HealthAspect
Grey water from laundry (left) and
solidgarbagewhichisdisposedin
open drains (right) pollute water
andcausehealthhazards.
Bangalore,Nepal.Source: BARRETO(2009)
Applicability
•Itcan be constructedinalmostalltypesofsettlements(urbanor rural),
butenoughlandareaisrequiredto builda reasonableconstruction.
•Scheduledmaintenanceisnecessary topreventclogging
•Ingeneral, theybearmanyriskfor publichealth
•If possible, they should be applied only where an adequate wastewater
treatment and collection systems for sewage sludge as well as a solid
wastemanagementareprovided.
9.OpenChannelsandDrains
•Itcan be constructedinalmostalltypesofsettlements(urbanor rural),
butenoughlandareaisrequiredto builda reasonableconstruction.
•Scheduledmaintenanceisnecessary topreventclogging
•Ingeneral, theybearmanyriskfor publichealth
•If possible, they should be applied only where an adequate wastewater
treatment and collection systems for sewage sludge as well as a solid
wastemanagementareprovided.
9.OpenChannelsandDrains
9.OpenChannelsandDrains
•Advantages:
–Low-cost drain-off solution if drains
alreadyexist
–Simpletoconstruct
–Construction materials are often
locallyavailable
–Creates employment (construction
andmaintenance)
Disadvantages:
•High health risk due to risk illegal
discharge of wastewaters and solid
waste
•Blockagescan causespill-overand
flooding
•Foulodoursource establishment
•Breeding ground for insects and
pests
•Regularcleaningservicerequiredto
removesolids
•Advantages:
–Low-cost drain-off solution if drains
alreadyexist
–Simpletoconstruct
–Construction materials are often
locallyavailable
–Creates employment (construction
andmaintenance)
Disadvantages:
•High health risk due to risk illegal
discharge of wastewaters and solid
waste
•Blockagescan causespill-overand
flooding
•Foulodoursource establishment
•Breeding ground for insects and
pests
•Regularcleaningservicerequiredto
removesolids
•Theyare usedtomovewastewater to higher elevations.Ingeneral, the need
forsewerpumpingstations ariseswhen:
•The existing topography and required minimum sewer grades create deep
sewers that have high construction costs. The sewage is raised and then
conveyed bygravity.
•Basementsaretoolowtodischargesewagetothemain sewer.
•Sewagemustbeconveyedoveraridge.
•The sewagemust beraisedtogetheadforgravityflow throughatreatment
plant.
•Dischargeoutlets arebelowthe level ofthereceiving bodyofwater.
•An existinggravitysystemisnotyetavailable.Apumpingstationwillenable
developmentand growth inaccordance withtheapplicablecommunityplan.
10.SewerPumpingStations
DesignPrinciple
forsewerpumpingstations ariseswhen:
•The existing topography and required minimum sewer grades create deep
sewers that have high construction costs. The sewage is raised and then
conveyed bygravity.
•Basementsaretoolowtodischargesewagetothemain sewer.
•Sewagemustbeconveyedoveraridge.
•The sewagemust beraisedtogetheadforgravityflow throughatreatment
plant.
•Dischargeoutlets arebelowthe level ofthereceiving bodyofwater.
•An existinggravitysystemisnotyetavailable.Apumpingstationwillenable
developmentand growth inaccordance withtheapplicablecommunityplan.
10.SewerPumpingStations
DesignPrinciple
1.Sewageisfedintoandstoredinan undergroundpit(wetwell).
2.When the level rises to a predetermined point, a pump will be started to
lift the sewage upward through a pressurised pipe system (sewer force
mainor risingmain).
3.Fromthereitisdischargedinto agravity manholeagain.
10.SewerPumpingStations
Asewerpumpingstation
in Germany with the
pump shaft and the
electricity/controlunit.
Source:MAW(2010)
DesignPrinciple
2.When the level rises to a predetermined point, a pump will be started to
lift the sewage upward through a pressurised pipe system (sewer force
mainor risingmain).
3.Fromthereitisdischargedinto agravity manholeagain.
10.SewerPumpingStations
Asewerpumpingstation
in Germany with the
pump shaft and the
electricity/controlunit.
Source:MAW(2010)
DesignPrinciple
A pumping station is always in
combination with a (on-site or semi-
centralised) treatment plant and/or a
sewersystem.
•High costs for construction material,
electricity, maintenanceandof
courseexpert design.
•Construction and installation costs
arehigh.
10.SewerPumpingStations
A fibreglass tank for single households with an
integratedsewagepumpThesewageispumped
uptocouncilseweroronsitetreatmentplant.
Source:FTM(2010)
Costs
combination with a (on-site or semi-
centralised) treatment plant and/or a
sewersystem.
•High costs for construction material,
electricity, maintenanceandof
courseexpert design.
•Construction and installation costs
arehigh.
10.SewerPumpingStations
A fibreglass tank for single households with an
integratedsewagepumpThesewageispumped
uptocouncilseweroronsitetreatmentplant.
Source:FTM(2010)
Costs
Operation&Maintenance
•Thesystemismostly computer-orelectronicallymonitored.
•Sensors check the sewage level of the wet wells and start/stop the
pumps.
•The pumps and its monitoring unit should be maintained periodically by
thesupplier.
•Overflows of wet wells should be avoided and it is important that there is
atreatmentplantattheendofeverysewersystem.
10.SewerPumpingStations
•Thesystemismostly computer-orelectronicallymonitored.
•Sensors check the sewage level of the wet wells and start/stop the
pumps.
•The pumps and its monitoring unit should be maintained periodically by
thesupplier.
•Overflows of wet wells should be avoided and it is important that there is
atreatmentplantattheendofeverysewersystem.
10.SewerPumpingStations
Applicability
•Pumping stations become necessary as soon as sewage has to be lifted from a
lowerparttoahigherpart.
➢Awellconstructedpipingsystem (e.g.conventionalsewersystem)anda
treatmentplantisnecessary.
➢Constructionmaterial andsparepartsisexpensiveandmightbe difficultto
acquirelocally.
10.SewerPumpingStations
•Advantages:
–Sewagecanbepumped
automaticallytohigher
elevations
–No contact with
wastewaterisnecessary
Disadvantages:
•Verycostly
•Local availability of
constructionmaterialand
spareparts
•Needsexpertdesign
•Pumping stations become necessary as soon as sewage has to be lifted from a
lowerparttoahigherpart.
➢Awellconstructedpipingsystem (e.g.conventionalsewersystem)anda
treatmentplantisnecessary.
➢Constructionmaterial andsparepartsisexpensiveandmightbe difficultto
acquirelocally.
10.SewerPumpingStations
•Advantages:
–Sewagecanbepumped
automaticallytohigher
elevations
–No contact with
wastewaterisnecessary
Disadvantages:
•Verycostly
•Local availability of
constructionmaterialand
spareparts
•Needsexpertdesign
•Transferstations actasintermediatedumpingpointsforfaecal sludge/black
waterwhenitcannotbeeasilytransportedtoatreatmentfacility.It is
emptiedbyavacuumtruck.
•Asewerdischargestationisdirectly connectedtothesewersystem.
11.TransferandSewerDischargeStations
DesignPrinciple
waterwhenitcannotbeeasilytransportedtoatreatmentfacility.It is
emptiedbyavacuumtruck.
•Asewerdischargestationisdirectly connectedtothesewersystem.
11.TransferandSewerDischargeStations
DesignPrinciple
•The dumping point at the transfer station should be built low enough to
minimisespillswhen labourersaremanually emptying theirsludgecarts.
•Itshouldincludea vent,atrashscreentoremovelargedebris(garbage)and
awashingfacilityforvehicles.
•It should be well protected and maintained to prevent random dumping into
thesewerandtoensurethesafetyoftheusers.
11.TransferandSewerDischargeStations
DesignPrinciple
•The moderate capital costs may be offset with access permits and the
construction andmaintenancecancreatelocalincome.
•The systemforissuingpermitsorchargingaccessfeesmustbecarefully
designed so that those who most need the service are not excluded because
ofhigh costs.
•Costs for maintenance, observation and operation of the facility must be
considered.
Costs
minimisespillswhen labourersaremanually emptying theirsludgecarts.
•Itshouldincludea vent,atrashscreentoremovelargedebris(garbage)and
awashingfacilityforvehicles.
•It should be well protected and maintained to prevent random dumping into
thesewerandtoensurethesafetyoftheusers.
11.TransferandSewerDischargeStations
DesignPrinciple
•The moderate capital costs may be offset with access permits and the
construction andmaintenancecancreatelocalincome.
•The systemforissuingpermitsorchargingaccessfeesmustbecarefully
designed so that those who most need the service are not excluded because
ofhigh costs.
•Costs for maintenance, observation and operation of the facility must be
considered.
Costs
Operation & Maintenance(TILEYetal.2008)
•Racks(screens)mustbecleaned frequently.
•Sandandgritmustbe periodicallyremoved.
•The padandloadingareashouldbecleanedregularlytominimiseodours.
•Sludge from transfer or sewer discharge stations is treated in an appropriate
secondarytreatmentfacility andnot beillegallydumped.
11.TransferandSewerDischargeStations
Ifthereisnoopportunitytodisposesludge,
disposal sites which are unhygienic and
hazardous for local residents are often the
onlysolution.Source:SuSanAonFlickr(2011)
•Racks(screens)mustbecleaned frequently.
•Sandandgritmustbe periodicallyremoved.
•The padandloadingareashouldbecleanedregularlytominimiseodours.
•Sludge from transfer or sewer discharge stations is treated in an appropriate
secondarytreatmentfacility andnot beillegallydumped.
11.TransferandSewerDischargeStations
Ifthereisnoopportunitytodisposesludge,
disposal sites which are unhygienic and
hazardous for local residents are often the
onlysolution.Source:SuSanAonFlickr(2011)
Applicability(TILLEYetal.2008)
•Especiallyappropriatefordense,urbanareaswherethereisno
alternativedischarge point.
•For a sewer discharge station, a connection to a sewer main must be
possible.
•The site for the transfer station should be easily accessible, conveniently
located,andeasyto use.
•Aproperlegalandinstitutional frameworkisrequired aswell.
11.TransferandSewerDischargeStations
•Especiallyappropriatefordense,urbanareaswherethereisno
alternativedischarge point.
•For a sewer discharge station, a connection to a sewer main must be
possible.
•The site for the transfer station should be easily accessible, conveniently
located,andeasyto use.
•Aproperlegalandinstitutional frameworkisrequired aswell.
11.TransferandSewerDischargeStations
11.TransferandSewerDischargeStations
•Advantages:
–Mayreduceillegaldumpingof
faecalsludge
–Moderate capital and operation
costs
–Potential for local job creation and
incomegeneration
–Reduces transport distance and
may encourage more community-
levelemptyingsolutions
Disadvantages:
•Requiresexpertdesignandconstruction
supervision
•May cause blockages and disrupt sewer
flow(sewerdischargestation)
•Sludgerequiressecondary treatment
and/or appropriatedischarge
•Requiresaninstitutionalframework
taking careofaccessfees,connection
tosewersor regularemptyingand
maintenance
•Requiresexpertdesignandconstruction
supervision
•Advantages:
–Mayreduceillegaldumpingof
faecalsludge
–Moderate capital and operation
costs
–Potential for local job creation and
incomegeneration
–Reduces transport distance and
may encourage more community-
levelemptyingsolutions
Disadvantages:
•Requiresexpertdesignandconstruction
supervision
•May cause blockages and disrupt sewer
flow(sewerdischargestation)
•Sludgerequiressecondary treatment
and/or appropriatedischarge
•Requiresaninstitutionalframework
taking careofaccessfees,connection
tosewersor regularemptyingand
maintenance
•Requiresexpertdesignandconstruction
supervision
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