WASTEWATER TREATMENT TECHNOLOGIES WASTEWATER TREATMENT TECHNOLOGIES MEDAWARE Prof. George Ayoub Faculty of Engineering and Architecture American University.

WASTEWATER WASTEWATER TREATMENT TREATMENT

TECHNOLOGIESTECHNOLOGIES MEDAWARE

Prof. George AyoubProf. George Ayoub

Faculty of Engineering and ArchitectureFaculty of Engineering and Architecture

American University of BeirutAmerican University of Beirut

OUTLINEOUTLINE

Overview of the Conventional Overview of the Conventional Wastewater Treatment ProcessWastewater Treatment Process

Discussion of Existing Biological Discussion of Existing Biological Treatment TechnologiesTreatment Technologies

Examples from the Mediterranean Examples from the Mediterranean RegionRegion

Examples from the Lebanese ContextExamples from the Lebanese Context

Conventional Wastewater Treatment Conventional Wastewater Treatment ProcessProcess

Pretreatment involves:Screening Grit RemovalOil separationFlow equalization

Disinfection can use:Chlorine compoundsBromine ChlorideOzoneUV Radiation

Chemical Treatment is used in conjunction with the physical and chemical processes:Chemical precipitation Adsorption

Sludge Treatment and Disposal involves:grinding, degritting, blending, thickening, stabilization, conditioning, disinfection, dewatering, heat drying, thermal reduction, ultimate disposal

Biological TreatmentBiological Treatment In the case of domestic wastewater treatment, In the case of domestic wastewater treatment,

the objective of biological treatment is:the objective of biological treatment is:

• To stabilize the organic contentTo stabilize the organic content• To remove nutrients such as nitrogen and phosphorusTo remove nutrients such as nitrogen and phosphorus

Types:

Aerobic ProcessesAnoxic ProcessesAnaerobic ProcessesCombined Aerobic-Anoxic-Anaerobic Processes

Pond Processes

Attached GrowthSuspended Growth Combined Systems

Aerobic MaturationFacultativeAnaerobic

Major Aerobic Biological Major Aerobic Biological ProcessesProcesses

Type of Growth

Common Name Use

Suspended Suspended GrowthGrowth

Activated Sludge (AS)Activated Sludge (AS) Carbonaceous BOD removal Carbonaceous BOD removal (nitrification)(nitrification)

Aerated LagoonsAerated Lagoons Carbonaceous BOD removal Carbonaceous BOD removal (nitrification)(nitrification)

Attached Attached GrowthGrowth

Trickling FiltersTrickling Filters Carbonaceous BOD removal. Carbonaceous BOD removal. nitrificationnitrification

Roughing Filters Roughing Filters (trickling filters with (trickling filters with high hydraulic loading high hydraulic loading rates)rates)

Carbonaceous BOD removalCarbonaceous BOD removal

Rotating Biological Rotating Biological ContactorsContactors

Carbonaceous BOD removal Carbonaceous BOD removal (nitrification)(nitrification)

Packed-bed reactorsPacked-bed reactors Carbonaceous BOD removal Carbonaceous BOD removal (nitrification)(nitrification)

Combined Combined Suspended Suspended & Attached & Attached Growth Growth

Activated Biofilter Activated Biofilter ProcessProcessTrickling filter-solids Trickling filter-solids contact processcontact processBiofilter-AS processBiofilter-AS processSeries trickling filter-AS Series trickling filter-AS process process

Carbonaceous BOD removal Carbonaceous BOD removal (nitrification)(nitrification)

Activated Sludge ProcessActivated Sludge Process The aeration tank contains a suspension of the wastewater The aeration tank contains a suspension of the wastewater

and microorganisms, the mixed liquor. The liquor is mixed by and microorganisms, the mixed liquor. The liquor is mixed by aeration devices (supplying also oxygen)aeration devices (supplying also oxygen)

A portion of the biological sludge separated from the A portion of the biological sludge separated from the secondary effluent by sedimentation is recycled to the secondary effluent by sedimentation is recycled to the aeration tankaeration tank

Types of AS Systems: Conventional, Complete-Mix, Types of AS Systems: Conventional, Complete-Mix, Sequencing Batch Reactor, Extended Aeration, Deep Tank, Sequencing Batch Reactor, Extended Aeration, Deep Tank, Deep ShaftDeep Shaft

Advantages/DisadvantagesAdvantages/Disadvantages

AdvantagesAdvantages

Flexible, can adapt to Flexible, can adapt to minor pH, organic and minor pH, organic and temperature changestemperature changes

Small area requiredSmall area required Degree of nitrification Degree of nitrification

is controllableis controllable Relatively minor odor Relatively minor odor

problemsproblems

DisadvantagesDisadvantages

High operating costs High operating costs (skilled labor, electricity, (skilled labor, electricity, etc.)etc.)

Generates solids Generates solids requiring sludge disposalrequiring sludge disposal

Some process Some process alternatives are alternatives are sensitive to shock loads sensitive to shock loads and metallic or other and metallic or other poisonspoisons

Requires continuous air Requires continuous air supply supply

Trickling FiltersTrickling Filters The trickling filter or biofilter consists of a bed of The trickling filter or biofilter consists of a bed of

permeable medium of either rock or plastic permeable medium of either rock or plastic Microorganisms become attached to the media and Microorganisms become attached to the media and

form a biological layer or fixed film. Organic matter in form a biological layer or fixed film. Organic matter in the wastewater diffuses into the film, where it is the wastewater diffuses into the film, where it is metabolized. Periodically, portions of the film slough metabolized. Periodically, portions of the film slough off the mediaoff the media

Advantages/Disadvantages Advantages/Disadvantages


Good quality (80-90% Good quality (80-90% BODBOD55 removal) for 2- removal) for 2-stage efficiency could stage efficiency could reach 95% reach 95%

Moderate operating Moderate operating costs (lower than costs (lower than activated sludge)activated sludge)

Withstands shock Withstands shock loads better than other loads better than other biological processesbiological processes


High capital costs High capital costs Clogging of Clogging of

distributors or bedsdistributors or beds Snail, mosquito and Snail, mosquito and

insect problemsinsect problems

Rotating Biological Rotating Biological ContactorsContactors

It consists of a series of circular disks of polystyrene or It consists of a series of circular disks of polystyrene or polyvinyl chloride that are submerged in wastewater polyvinyl chloride that are submerged in wastewater and rotated slowly through itand rotated slowly through it

The disk rotation alternately contacts the biomass The disk rotation alternately contacts the biomass with the organic material and then with atmosphere with the organic material and then with atmosphere for adsorption of oxygenfor adsorption of oxygen

Excess solids are removed by shearing forces created Excess solids are removed by shearing forces created by the rotation mechanismby the rotation mechanism

Advantages/DisdvantagesAdvantages/Disdvantages

AdvantagesAdvantages Short contact periodsShort contact periods Handles a wide range Handles a wide range

of flowsof flows Easily separates Easily separates

biomass from waste biomass from waste streamstream

Low operating costs Low operating costs Short retention timeShort retention time Low sludge productionLow sludge production Excellent process Excellent process

controlcontrol

DisadvantagesDisadvantages Need for covering Need for covering

units installed in cold units installed in cold climate to protect climate to protect against freezingagainst freezing

Shaft bearings and Shaft bearings and mechanical drive units mechanical drive units require frequent require frequent maintenance maintenance

Major Anaerobic Biological Major Anaerobic Biological ProcessesProcesses

Type of Growth

Common Name Use

Suspended Suspended GrowthGrowth

Anaerobic Contact Anaerobic Contact ProcessProcess

Carbonaceous BOD Carbonaceous BOD removalremoval

Upflow Anaerobic Sludge-Upflow Anaerobic Sludge-Blanket (UASB)Blanket (UASB)



Anaerobic Filter ProcessAnaerobic Filter Process Carbonaceous BOD Carbonaceous BOD removal, waste removal, waste stabilization stabilization (denitrification)(denitrification)

Expanded BedExpanded Bed Carbonaceous BOD Carbonaceous BOD removal, waste removal, waste stabilizationstabilization

Anaerobic Contact ProcessAnaerobic Contact Process

Untreated wastewater is mixed with Untreated wastewater is mixed with recycled sludge solids and then recycled sludge solids and then digested in a sealed reactordigested in a sealed reactor

The mixture is separated in a clarifier The mixture is separated in a clarifier The supernatant is discharged as The supernatant is discharged as

effluent, and settled sludge is effluent, and settled sludge is recycledrecycled



Methane recoveryMethane recovery Small area Small area

requiredrequired Volatile solids Volatile solids

destructiondestruction


Heat requiredHeat required Effluent in reduced Effluent in reduced

chemical form chemical form requires further requires further treatmenttreatment

Requires skilled Requires skilled operationoperation

Sludge to be Sludge to be disposed off is disposed off is minimalminimal

Upflow Anaerobic Sludge Upflow Anaerobic Sludge BlanketBlanket

Wastewater flows Wastewater flows upward through a upward through a sludge blanket sludge blanket composed of biological composed of biological granules that granules that decompose organic decompose organic mattermatter

Some of the generated Some of the generated gas attaches to gas attaches to granules that rise and granules that rise and strike degassing baffles strike degassing baffles releasing the gasreleasing the gas

Free gas is collected by Free gas is collected by special domesspecial domes

The effluent passes into The effluent passes into a settling chambera settling chamber



Low energy demandLow energy demand Low land requirementLow land requirement Low sludge productionLow sludge production Less expensive than Less expensive than

other anaerobic other anaerobic processesprocesses

High organic removal High organic removal eficiencyeficiency


Long start-up periodLong start-up period Requires sufficient Requires sufficient

amount of granular amount of granular seed sludge for faster seed sludge for faster start-upstart-up

Significant wash out of Significant wash out of sludge during initial sludge during initial phase of processphase of process

Lower gas yield than Lower gas yield than other anaerobic other anaerobic processesprocesses

Major Anoxic and Combined Major Anoxic and Combined Biological ProcessesBiological Processes

Type of Process

Type of Growth

Common Name Use

AnoxicAnoxic SuspendeSuspended Growthd Growth

Suspended Growth Suspended Growth DenitrificationDenitrification

DenitrificationDenitrification

Attached Attached Growth Growth

Fixed-film Fixed-film DenitrificationDenitrification

DenitrificationDenitrification

Combined Combined Aerobic, Aerobic, Anoxic, Anoxic, and and anaerobic anaerobic ProcessesProcesses

SuspendeSuspended Growthd Growth

Single- or multi-stage Single- or multi-stage processes, various processes, various proprietary processesproprietary processes

Carbonaceous BOD Carbonaceous BOD removal, nitrification, removal, nitrification, denitrification, denitrification, phosphorus removalphosphorus removal


Single- or multi-stage Single- or multi-stage processesprocesses

Carbonaceous BOD Carbonaceous BOD removal, nitrification, removal, nitrification, denitrification, denitrification, phosphorus removalphosphorus removal

Pond Treatment ProcessesPond Treatment ProcessesCommon Name

Comments Use

Aerobic Aerobic Stabilization Stabilization PondsPonds

Treatment with aerobic Treatment with aerobic bacteria; oxygen is supplied by bacteria; oxygen is supplied by algal photosynthesis and algal photosynthesis and natural surface reaeration; natural surface reaeration; depth of 0.15 to 1.5 mdepth of 0.15 to 1.5 m


Maturation Maturation (tertiary) (tertiary) PondsPonds

Use aerobic treatment; applied Use aerobic treatment; applied loadings are low to preserve loadings are low to preserve aerobic conditionsaerobic conditions

Secondary effluent Secondary effluent polishing and polishing and seasonal nitrificationseasonal nitrification

Facultative Facultative PondsPonds

Treatment with aerobic, Treatment with aerobic, anaerobic and facultative anaerobic and facultative bacteria; the pond has 3 zones: bacteria; the pond has 3 zones: a surface aerobic zone, a a surface aerobic zone, a bottom anaerobic zone, and an bottom anaerobic zone, and an intermediate zone partly intermediate zone partly aerobic-anaerobicaerobic-anaerobic


Anaerobic Anaerobic PondsPonds

Treatment with anaerobic Treatment with anaerobic bacteria; depths of up to 9.1 m bacteria; depths of up to 9.1 m to conserve anaerobic to conserve anaerobic conditions conditions

Carbonaceous BOD Carbonaceous BOD removal (waste removal (waste stabilization)stabilization)

Examples from the Mediterranean Examples from the Mediterranean Region (1)Region (1)

Country Name of the Plant

Capacity m3/day

Treatment Technology

Reuse Application

SpainSpain VitoriaVitoria 55,00055,000 Secondary treatment Secondary treatment (screening, (screening, sedimentation, sedimentation, nitrification-nitrification-denitrification) + tertiary denitrification) + tertiary treatment (coagulation-treatment (coagulation-flocculation, sand filters, flocculation, sand filters, chlorine disinfection)chlorine disinfection)

Irrigation of orchardsIrrigation of orchards

SpainSpain TenerifeTenerife 90,00090,000 Secondary treatment Secondary treatment (activated sludge), (activated sludge), tertiary treatmenttertiary treatment

Irrigation of banana, Irrigation of banana, potatoes, and tomatoespotatoes, and tomatoes

GreeceGreece ChalkisChalkis 9,0009,000 Pretreatment, Pretreatment, clarification, aeration clarification, aeration tanks, final clarifiers, tanks, final clarifiers, advanced treatmentadvanced treatment

Irrigation of trees and Irrigation of trees and bushesbushes



Capacity m3/day


Reuse Application

PalestinePalestine Dan Dan Region Region ProjectProject

330,000330,000 Secondary treatment Secondary treatment (activated sludge, or (activated sludge, or stabilization lagoons), stabilization lagoons), soil aquifer treatmentsoil aquifer treatment

Irrigation of field crops, Irrigation of field crops, fruit plantations, fruit plantations, vegetables, flowersvegetables, flowers

ItalyItaly GrammichGrammich-elle-elle

1,5001,500 Activated Activated sludge, sludge, chlorine contact tank, chlorine contact tank, tank storagetank storage

Irrigation of Irrigation of orange, olive orange, olive trees, crops for caning trees, crops for caning industry, and vegetables industry, and vegetables to be eaten cookedto be eaten cooked

ItalyItaly ClatagironClatagiron-e-e

5,2005,200 Activated Activated sludge, sand sludge, sand filtration, reservoir filtration, reservoir storagestorage

Irrigation of Irrigation of orange, olive orange, olive trees, crops for caning trees, crops for caning industry, and vegetables industry, and vegetables to be eaten cookedto be eaten cooked

CyprusCyprus Larnaca Larnaca 8,5008,500 Oxidation ditches, sand Oxidation ditches, sand filtration, chlorinationfiltration, chlorination

Irrigation of corn, alfalfa, Irrigation of corn, alfalfa, in addition to gardens, in addition to gardens, parks and fieldsparks and fields



Capacity m3/day


Reuse Application

JordanJordan Al SamraAl Samra 150,000150,000 3 trains of ponds: 3 trains of ponds: 2 2 anaerobic, 4 anaerobic, 4 facultative, 4 facultative, 4 maturationmaturation

Irrigation of olive trees, Irrigation of olive trees, forest area, fodder crops forest area, fodder crops and non-restricted and non-restricted vegetables for experimentsvegetables for experiments

MoroccoMorocco City of City of DrarguaDrargua

600600 Primary treatment Primary treatment (anaerobic basins), (anaerobic basins), secondary secondary treatment (sand treatment (sand filters), tertiary filters), tertiary treatmenttreatment

Irrigation of alfalfa, Irrigation of alfalfa, tomatoes, zucchini, corn tomatoes, zucchini, corn and grassand grass

TurkeyTurkey GaziantepGaziantep 200,000200,000 Primary treatment, Primary treatment, secondary secondary treatment treatment (Activated Sludge)(Activated Sludge)

Irrigation of edible crops, Irrigation of edible crops, vegetables and nearby vegetables and nearby fieldsfields

Examples from LebanonExamples from Lebanon Lebanon has been rebuilding its water and Lebanon has been rebuilding its water and

wastewater infrastructure since 1992; in this wastewater infrastructure since 1992; in this context, the Government initiated the context, the Government initiated the cconstruction of large-scale WWTPs employing AS onstruction of large-scale WWTPs employing AS and Biofilter treatment systems mainlyand Biofilter treatment systems mainly

Except for the Ghadir pre-treatment station, no Except for the Ghadir pre-treatment station, no single large-scale plant achieving secondary single large-scale plant achieving secondary treatment has started to operatetreatment has started to operate

Some community-based plants funded by NGOs Some community-based plants funded by NGOs are achieving secondary treatment; however, are achieving secondary treatment; however, these are small-scale plants and rarely function these are small-scale plants and rarely function properlyproperly

Coarse Screening

Fine Screening

Grit and Grease Removal Tank

Pumping

Primary Settling TankPumpingAeration Tank

or Biofilter

Degassing Tank

Distribution Structure

Secondary Settling Tank

Venturi Flume Treated Water Pumping Station

Technology to be used inside WWTPs proposed by the Government

Ghadir Preliminary Treatment Ghadir Preliminary Treatment StationStation

Serves the Greater Beirut Serves the Greater Beirut Southern Wastewater Southern Wastewater Collection Basin (population of Collection Basin (population of 977,000)977,000)

Maximum instantaneous flow: Maximum instantaneous flow: 2.6 m2.6 m33/s; average: 1.6 m/s; average: 1.6 m33/s; /s; expected minimum: 1.1 mexpected minimum: 1.1 m33/s/s

Accepts also septic tank Accepts also septic tank septage and leachate from the septage and leachate from the Naameh landfillNaameh landfill

Effluent is discharged into the Effluent is discharged into the sea at a distance of 2.6 km sea at a distance of 2.6 km away from the shore and at a away from the shore and at a depth of 60 mdepth of 60 m

In periods of overflow, the In periods of overflow, the plant partially or completely plant partially or completely shuts down, and the effluent is shuts down, and the effluent is discharged into the sea at a discharged into the sea at a distance of 500 m from the distance of 500 m from the shore shore

GHADIR STATION

Treatment Steps At GhadirTreatment Steps At Ghadir

SCREENINGLIFTING

DEGRITTING

Baalbeck WWTPBaalbeck WWTP Completed in summer Completed in summer

20002000 Not yet functional Not yet functional

because the collection because the collection network is not yet network is not yet finishedfinished

Serves a population of Serves a population of 130,600, and has a 130,600, and has a daily capacity of daily capacity of 19,600 m19,600 m33/day/day

Will achieve Will achieve secondary treatment secondary treatment

Treatment Technologies in Treatment Technologies in Community-based WWTPsCommunity-based WWTPs

There are 42 plants as shown by the tableThere are 42 plants as shown by the table

ProcessProcess NGONGO

CHFCHF CAICAI MCIMCI YMCYMCAA

PMPM

Extended AerationExtended Aeration 11 22 77

Activated SludgeActivated Sludge 55 66 11

Anaerobic Anaerobic DigestionDigestion

1717

Aerobic DigestionAerobic Digestion 11 11

Mixed TreatmentMixed Treatment 11 11

TotalTotal 11 55 1818 1010 88

EXTENDED AERATION

ACTIVATED SLUDGE

ANAEROBIC DIGESTION

AEROBIC DIGESTION

MIXED TREATMENT

EXTENDED AERATIONKAWS AKKAR

YMCA

ACTIVATED SLUDGEKFEIRYMCA

ANAEROBIC DIGESTIONHASBAYA

MCI

AEROBIC DIGESTIONMARJ EL ZOUHOUR

YMCA

MIXED TREATMENTADVANCED INTEGRATED

WASTEWATER PONDS SYSTEMAIN HARSHA

YMCA

THANK YOUTHANK YOU

WASTEWATER TREATMENT TECHNOLOGIES WASTEWATER TREATMENT TECHNOLOGIES MEDAWARE Prof. George Ayoub Faculty of Engineering and Architecture American University.

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