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Client:First&ForemostHotels&Resort-Maldives
Technology–“GreenSTPAD+”
ZeroDischargeSewageTreatmentPlant
ReuseoftreatedwaterforLandscape&Irrigation
Date:08thApril2017–Mumbai[INDIA]
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Preamble
The environment of Maldives comprises of a delicate and complex series of ecosystemswhich isuniquetothetropicalworldandmanyhavefounditapleasuretogazeupon.Currentissuesincludedbeacherosion,coralmining,freshwaterresources,wastedisposalandsewagedisposal.
Oneof themajor threats toenvironment isdisposalof sewage. Sewageposesa seriesofpotentialproblems depending on the mode of disposal, discharges of raw and untreated sewage into themarine environment which tends to cause nutrient enrichment algal blooms, sea-grass, de-oxygenation. Such conditions adversely affect coral growth. Sewage related problems are amajorconcernaroundthedenselypopulatedislandsandsometouristresorts.
Waste water (domestic sewage water) reuse is emerging as an alternative resource. It allowsincrease in the supplyofwater resourcesand reducespollutionproblemsbecause itprevents thedischarge of waste water into the environment. Feasibility of Water Reuse project is currentlysubjectedtoeconomicassessment.
Maldivesislandsdoesnothavenaturalsourceofwater,soallpotablewaterdemandiscateredbyseawater,usingdesalinationplant.Also,tooperatedesalinationplantelectricityisproducedfromdieselgenerators. The “GREEN STP AD+” converts domestic sewage water into nutrient rich irrigationwater.So,using this treatedwater the fresh (desalination)waterdemandsignificantlygoesdown,savingcapital&operatingcostofthedesalination.
Considering the remote location of the site, we have proposed self-sustained, scientificallydeveloped,naturalrecyclingtreatmentplant,withleastoperation&maintenancecomparedtoanytechnologyintheworld.
Copyright:
“All contents copyright by Chemtronics Technologies (I) Pvt. Ltd. – India & Autark Engineering – Switzerland. All rights reserved. No part of this document or the related files may be reproduced or transmitted in any form, by any means (electronic, photocopying, recording, or otherwise) without the prior written permission of the publisher.
Please note that much of this publication is based on personal experience and anecdotal evidence. Although the author and publisher have made every reasonable attempt to achieve complete accuracy of the content in this Guide, they assume no responsibility for errors or omissions. Also, you should use this information as you see fit, and at your own risk. Your particular situation may not be exactly suited to the examples illustrated here; in fact, it's likely that they won't be the same, and you should adjust your use of the information and recommendations accordingly.
Any trademarks, service marks, product names or named features are assumed to be the property of their respective owners, and are used only for reference. There is no implied endorsement if we use one of these terms.”
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INDEX
1. Preamble .......................................................... Page2
2. ProjectProponent ....... ............................................ Page4
3. Objective ........................................................... Page4
4. WaterBalance/Budget ............................................ Page5
4.1 ClientsData................................................... Page5
4.2 DesignConsideration&Estimation ........................ Page5
4.3 WaterQuality–Raw&Treated............................... Page5
5. TreatmentTechnology ............................................ Page6
5.1 Concept ............................................ Page6
5.2 Coretreatment ............................................ Page6
5.3 SalientFeatures ............................................ Page7
5.4 Advantages ............................................ Page8
6. ProcessDescription ............................................ Page9
6.1 PrimaryTreatment .................................... Page9
6.2 SecondaryTreatment ..................................... Page9
6.3 TertiaryTreatment........................................... Page10
7. ProcessFlowDiagram ............................................ Page11
8. TechnicalSpecification ............................................ Page13
8.1 ADTankOption1[Civil]...................................... Page14
8.2 AdTankOption2 [Pre-fabricated]............................ Page15
8.3 FootPrint–Equipment....................................... Page17
8.4 PowerRating ..................................... Page17
8.5 ReclaimEfficiency ..................................... Page17
8.6 LifeSpan .............................................. Page17
9. Operation&Maintenance ............................................ Page18
10. Consumables ............................................ Page18
10.1 Chemical ............................................ Page18
10.2 ManPower ............................................ Page18
10.3 Electricity ............................................ Page18
10.4 Spares ............................................ Page18
11. AnnualMaintenanceContract......................................... Page19
12. CapitalCost ......................................................... Page19
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ProjectProponent
Nameoftheproject : First&ForemostHotels&ResortatMaldives
Requirement : SewageTreatmentPlant
Typeofproject : ResortVillas&Staffquarters
ApplicationofTreatedWater : Landirrigation,WCflushinginstaffquarters&anyother
non-potableapplications
Locationoftheproject : Maldives.
Objective
ü NaturalSelf-Sustaineddesign
ü LeastpossibleOperation&Maintenance
ü MostEnergyefficienttechnology
ü Maximumrecoveryofwater
ü LowerFootprint
ü EnvironmentalFriendly
ü Nofoulodor
ü Longlifespan
ü Economical–CapitalCost
ü Simpletooperate
ü MeetsInternationalPollutionStandards
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WaterBalance/Budget
Theplantisdesignedtotreatsewagegeneratedofhavingfollowingdetails.
ClientData
SourceofWasteWater : DomesticWasteWatergeneratedfromResort,Kitchen,Laundry,SwimmingPoolBackwashWater,Bathroom,StaffQuarters,WC,Washbasin,etc.
NumberofGuestRooms : 76nos.
NumberofStaff : __________nos.
ApplicationofTreatedWater : Landirrigation&Gardening
DesignConsideration&Estimation
Waterrequireperperson : __________litersperday
TotalSewageWaterCapacity : 90KLD(asperclient90KLDisproducedperday)
PlantOperatingHrs : 22–24HRs
PlantFlowRate : 4.5m3/hr
Treatment : AnaerobicDigestion[AD]+Polishing+Ozonation
GreenSTP/AD+ModelNo. : AD+/STP-90
WaterQuality–RawSewage&Treated/Recycled
Parameters RawSewageWaterQuality
TreatedWaterQualityForReuse
Color Slightlybrownish Clear
Odor Characteristic Unobjectionable
pH 5.0–8.0 5.5–8.0
TSS 100–150ppm ≤1ppm
BOD(3days28⁰C) 150–200ppm ≤10ppm
COD 300–450ppm ≤100ppm
Oil&Grease 20–25ppm ≤10ppm
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TreatmentTechnology
Concept-GreenSTPAD+
Green STPAD+ combines state of the artHighRateAnaerobicReactor (HRAR) technologywith aselection of adequate tertiary treatment methods of filtration & disinfection. This full-blowndecentralizedwastewatertreatmentandreusesystemsisalignedwiththeprojectspecificconditionsand requirements. We provide our clients custom and tailored wastewater solutions withoutstandingeconomicandecologicperformanceswhilemakingmaximalbenefitoutofon-sitereuseof products out ofwastewater treatment. Our STPs are engineered to complywith the respectiveregulationsandnorms.
AD+[AnaerobicDigestion+]isawastewatertreatment,particularlysuitedtoorganicmaterial&iscommonlyusedforeffluent,sewage&greywatertreatment.Anaerobicwastewatertreatmentisabiologicaltreatmentwithouttheuseofairorelementaloxygen.Manygroupsofanaerobicbacteriawork together inabsenceofoxygentodegradecomplexorganicpollutants intomethane/biogasandcarbondioxide.Inanaerobicdigestionthemicro-organismsresponsiblefortheconversionoftheorganicmatterortheotherconstituentsinthewastewatertogases&celltissuesaremaintainedin-suspensionwithin the liquid. Anaerobic digestion is a simple process that can greatly reduce theorganicmatterwithoutusinganyotherresource&anyformofenergy.
CoreTreatment-HighRateAnaerobicReactorTechnology
HighRateAnaerobicReactors(HRAR)refers tobioreactorswhichcanretainactivebiomass in thereactorindependentlyoftheincomingwastewater(HydraulicResidenceTimeHRT).Slowgrowinganaerobescanbemaintainedinthereactorsathighconcentrations,enablinghighreactionrateperunit reactorvolumeandhighresistanceoforganicorhydraulic shock loads.HRARcanbeused totreat wastewater from various sources and strengths like waste water from domestic sources,hospitalsandindustrieslikedistilleriesorfood-processing.TheHRARweusearecascadedinseriestomulti-stepanaerobicsystems,enablingseparationoftheanaerobic treatment steps (Hydrolysis/Acidogenesis/Acetogenesis/Methanogenesis) withoutdifficult process controlling. With respect to sustainability and cost- effectiveness, anaerobictreatmenthas the coreadvantageof avoiding the lossof energy fordestructionoforganicmatter,whileenergyisreclaimedfromtheorganicwasteconstituentsintheformofmethaneinbiogas.
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SalientFeatures:
* OverallOrganic&Inorganiccontentreduction(BOD,COD&TSS)withcolor&odor.
* TreatedSewageWaterQuality -MostsuitedforIrrigation&Landscape.
* EnergyEfficiency -Highest–50–90%lessconsumption
* Sustainability -SelfSustained[Autark]
* ReusableOutput -Highest–morethan99%
* Operation&Maintenance -Least–Operatornotrequired
* SludgeManagement -Least–OnceinaYear
* Consumables -Minimum
* LifeSpan -VeryHigh–100Years[CoreTechnology]
* FootPrint -Minimum60–80%less
* Nutrients -Rich
* Process&Technology/R&D -GREENSTPAD+fromSwitzerland
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Advantages–HRAR[AD]:
* LowProcessControl
* LowProcessEnergy
* NoChemicals
* LowSludgeProduction
* MLSSandSVImonitoringnotrequired
* EnergyGenerationintheformofBiogas
* MinimumMechanical&ElectricalParts
* UnderGroundStructure(Canbeaboveground)
* HighShockLoadResistance[Organic&Hydraulic]
* HighTreatmentPerformanceInTermsOfCOD,BOD&TSS
* Self-Sustained
* ReclaimedWatermorethan99.0%
* Innovativestillnaturaltreatmentprocess
* Energyefficient.60–90%lesserpower
* Extremelystabletohydraulicshockloads
* Hightreatmentperformance
* Lowoperatingcost
* Lowspacerequired–beingsubsoil
* Nofoulodour
* Longlife–atleast50years
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ProcessDescription
PrimaryTreatment
Screening: - This is the first unit of the Green STP AD+. Sewage water from sewage collectionchamberiscollectedintoanADtankthroughabarscreenbygravity.Barscreenisprovidedtotrapfloatingmaterialslikeleaf,flowers,cottons,plastic,halfeatenfood,papers,etc.Oil&GreaseChamber: - Sewagewater from the kitchenwhich contains free oil, if not removedcreates scum accumulation and affects the functioning ofmicrobes. To avoid this, oil & grease, achamberisprovidedafterthebarscreenwherefreefloatingmaterialoilisarrestedpriortoentryintheADTank.Accumulatedoilwillberemovedperiodicallyanddisposedofproperly.
SecondaryTreatment
BiologicalTreatment:-
SewagefromOil&GreasechamberwillpassthroughtheADTank.TheADTankisacascadeofthreemajor treatments steps i.e. Settler,HighRateAnaerobicReactor [HRAR]/AnaerobicBaffleReactor[ABR]andupflowAnaerobicFilterwhichisconstructedbelowgroundlevel.Thesethreedifferentphases are built together in a single AD Tank with interconnecting compartments. The AD Tankperformsthecoretreatmentofthesewagewateroxidization&decompositionoforganicpollutantwith the help of anaerobicmicroorganism to provide higher surface area formicro – organisms,floating random media is provided, on which micro- organisms growth takes place. Generallyactivation of AD tank with full sewage load can take 40 to 50 days and come to its optimumefficiency.
1. Settler
The first compartment ofADTank is a settler. The settler has two treatment processes. First is asedimentationinwhichtheliquidpartisseparatedfromthesolidmatterandsecondisstabilization,whichsettlesoutmostofthesolidsinthewastewater.
2. HighRateAnaerobicReactor/AnaerobicBaffleReactor(HRAR/ABR)
In this treatment phase, biological and natural chemical processes are used to digest and removemostoftheorganicmatter.Inthishighrateanaerobicreactor,withoutoxygenmechanicalmixingisapplied.Treatmentisachievedbyanaerobicdigestionbynaturallyselectedanaerobicmicrobial.Thisgivesgoodretentiontimetowastewateranddevelopmentofathicksludgeblanketinthebottomofcompartment.
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Fig.1,AnaerobicDigester[AD]Tank–CivilOnSiteConstruction
3. UpflowAnaerobicFilter
After the HRAR/ABR Treatment sewage water is transferred into up flow Anaerobic Filtercompartment inorder to improve further treatmentefficiency, a filtermediaallowingwidespreadcontactwiththewastewaterstreamisusedwhichisveryefficientinretaininganddigestingtheleftoverpollutants.Theprocessworkswithfixedplasticbiomedia.Thewastewaterpassingoutoftheanaerobicfiltershas90%oftheoriginalpollutionloadremoval.
PolishingTertiaryTreatment
Secondary (biological) treated water from AD Tank will be collected in a equalization tank. Thistreatedwaterisozonatedforpathogendisinfection.Ozonationalsoreducesfoulodor&tintofcolor,if present in treatedwater. PostOzonationwater is filtered by “ChargedActivatedMedia Filter[CAMF]” through a filter feed pump to trap tiny suspended particles from water. Ozonation oftreatedsewagewaterreducetinyorganicandinorganicimpuritiesfromwater.FrombackwashcumTreatedWaterTankwater isused forbackwashingof filters. From this tankwaterwillbefurthercollectedinmaintreatedwatertank.
Equalization
HRAR
BarScreen
UFAF
Settler
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Fig.2,TertiaryTreatment:ChargedActivatedPressureFiltration+OnlineOzonation
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ProcessFlowDiagram
Fig.3,ProcessFlowDiagramof“GreenSTPAD+”
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TechnicalSpecification
Therearefouroptionsforanaerobictankconstruction:
Option1[A]–CivilTankConstructionUnderGround
Option1[B]–CivilTankConstructionAboveGround
Option2[A]–Pre-FabricatedHDPETanksUnderGround
Option2[B]–Pre-FabricatedHDPETanksAboveGround
Inoption1[A]or1[B],theconstructionofthesewagecollectioncumtreatmenttank&treatedwatertanksaretobeconstructedonsitebyyourcivilcontractor&wewillgiveyouthedimensionaldrawings.Thebio-media&pipegridwillbeinstalledbyourteam,afterthetankisconstructed&beforetheconstructionoftopslab.Also,thetertiarytreatmentplantwillbesupplied&installedbyourteam.
Inoption2[A]or2[B],thesewagecollectioncumtreatmenttank&treatedwatertankwillbepre-fabricatedinourfactory&alongwithtertiarytreatmentplantwillbedeliveredtoyoursite.
Inanyoftheoptedoption,oncethetanksareready,theywillbeinoculatedforanaerobicbacteriaatthesite.
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Option1–CivilConstruction
FootPrint–ADTank
Fig.4,ADTank,OxidationTank&FinalTreatedWaterTankcanbelocatedbelowlandscape
Fig.5,ADTank,OxidationTank&FinalTreatedWaterTankcanbelocatedbelowcarpark.
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Fig.6,ADTank,OxidationTank,FinalTreatedWaterTank&PlantRoom.
ADTank : UnderGround/AboveGround :250m2[Area]X3.0m[Depth]
OxidationTank : UnderGround/AboveGround :10m2[Area]X3.0m[Depth]
TreatedWaterTank: UnderGround/AboveGround :10m2[Area]X3.0m[Depth]
PlantRoom : AboveGround :15m2[Area]X3.0m[Depth]
TotalAreaRequired: UnderGround/AboveGround :285m2[Area]x3.0m[Depth]
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Option2–Pre-fabricatedConstruction
Fig.7,Pre-fabricatedADTank,OxidationTank,FinalTreatedWaterTank&PlantRoom.
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FootPrint–Equipment
ADTank : AboveorBelowGround : 285–300m2x3.0m[Ht/depth]
PlantRoom : AboveGround : 15–18m2x3.0m[Height]
PowerRating
ABR+AF : 0.0Kw
TertiaryTreatment : 1.0Kw
Ozonation : 1.6Kw
TotalPowerRating : 2.6Kw
ReclaimEfficiency
TreatedWaterQuantity : 90KLD : 95–97%Recovery
BiogasProduction : 5.0m3/day : Electricityof10kw/day*
*at50%efficiency.
Lifespane
ADTank–CoreTreatment : 50Years
TertiaryTreatment : 50Years
OzonationPlant : 20Years
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Operation&Maintenance
In AD tank waste water flows naturally by gravity. Tertiary treatment & disinfection process isautomaticanddoesnotrequireanyoperator.Onlyaparttimenon-technicaloperatorisrequiredforgeneral supervision & log keeping. Sludge management is also minimal & does not demand forfrequentsludgehandling.
Maintenance&ReplacementFrequency
SludgeMonitoring : Oncein6Months
Sludgeinspection : Oncein6Months
SludgeMaintenance : Settler : OnceinaYear
ABR/AF : Oncein3-4Years
Consumables
Chemicals
NoConsumablechemicalsarerequired.
ManPower
Non-technicaloperatorisrequiredforparttime. : 1hr/day
Electricity
BasicSewagetreatmentplant :24units/day :0.27Kw/m3
Ozonation :38units/day :0.42Kw/m3
Total :62units/day :0.69Kw/m3
Spares
ABR&AF : Nospares
TertiaryTreatment : FilteringMedia : 50Years
OzoneGenerator : OzoneCell : 2Years
OxygenGenerator : MolecularSelves : 2Years
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AnnualMaintenanceContract
Annualmaintenancecontractisavailableposthandoverduringwarrantyperiod&postwarranty,forrestofplantlife.
CapitalCost
Option1–CivicConstruction
CivilTankConstruction : ClientsScope–Chemtronicswillprovidedimensionaldrawing
EquipmentSupply : USD30,000
Installation&Commissioning : USD500perdayperperson+To&froAirfare+LocalConveyance+Food+Accommodation
EstimatedtimeforI&C : AdTank -2persons-10days Equipment -2persons-6days
Inoculation –2persons-6daysTotal -2persons–22–25days
Equipmentdelivery : 8–10weeks
Option2–Pre-fabricatedConstruction
Prefabricatedtanks&EquipmentSupply : USD150,000
Installation&Commissioning : USD500perdayperperson+To&froAirfare+LocalConveyance+Food+Accommodation
EstimatedtimeforI&C : -2persons-10-15daysTanks&Equipmentdelivery : 10–12weeks