ContractoriBase Year20082iiCurrent Total Population 1064695iiiAdopted Growth rate4%5ivDomestic Water Demand50Lpd5vOther Uses of Water:5aCommerce and Industry20%bInstitutions20%cFire Services5%dHorticulture5%Total Other Uses50%

viAllowance for:aBackwashing of Treatment FacilitiesbFlushing of Sludge in Sedimentation TankcLaboratory Works (Chemical Mixing etc)dStaff Quarters Use etc.Total Allowance = 10%

Adopted Operation Hour20hrs

viiPopulation EstimationYearPopulation Figure at 4% annual growth ratePer Capita Water Demand (Lpd)Domestic DemandOther Uses DemandTotal Water Demandm3/daymgdm3/daymgdm3/daymgda20081064695053231.1726620.5979851.76b20101151575057581.2728790.6386371.90c20151401065070051.5435030.77105082.31d20201704605085231.8742620.94127852.81e202520739150103702.2851851.14155543.42f203025232350126162.7863081.39189244.16viiiTotal Water Demand:a4.16mgdb0.42mgdTotal =4.58mgdixScheme Design:aIntake WorksRaw Water Draft1040.83m3/h0.289m3/s103.67L/sDetention Time in well = 0.15hStorage in Well156.12m3Adopted Height of Water in Well4.5mAre of Well34.69m2No of Chambers 4Area of each Chamber8.67m2Width of Chamber2mLength of Chamber4.34m

Chamber DimensionsLength4.5mBreath2mAssumed Freeboard0.5mAdopted Height5mRaw Water Mains:Capacity0.104m3/sDiameter of Mains500mm0.5mArea of Mains0.20m2Length of Mains1840mVelocity of Flow0.53m/sHazen Williams Constant140Note: Decrease in the Constant will increase the Head Loss in mainsHead Loss (Hi)0.4970m/Km

Total Head Loss in mains line 0.91m

Raw Water PumpsNo of Pumps3Potential Head at Treatment Works96.55mNote: This is Determined From Spot heigths from Survey ReportPotential Head at Intake Works50.96mStatic Head Difference (SHD)45.59mFittings Losses 10% of SHD4.559mTotal D Head (TDH)51.06mPump Min. SpecificationNo of Duty3No of Standby1Capacity of Each346.94m3/h0.096m3/s96.37L/sMin. Allowable Head51.06mAssumed Pump Efficiency0.70(Adopt between 0.7 and 0.9)Acc. Due to Gravity (g)9.81m/s2Density of liquid ()1.00ton/m3Pump Power Consumption68.97KWConversion Factor to Horse Power (Divide by)745.7Pump Power Consumption92.49HPGenerator Power Rating0.80use 0.75 or 0.8 or 0.85Genset Power Rating344.8326875851KW

iiAeratorsType of AeratorSpray AeratorsNo. of Aerator2NosCapacity of each0.14m3/sAssumed Diameter of Riser Pipe350mm0.35mArea of Mains0.10m2Length of Mains5mVelocity of Flow1.50m/sHazen Williams Constant140Note: Decrease in the Constant will increase the Head Loss in mainsHead Loss (Hi)5.2278m/Km

Total Head Loss in mains line 0.03m

Header PipeNo of Header Pipe2.00Flow Through each0.07m3/sAssumed Diameter of Riser Pipe250mm0.25mArea of Mains0.05m2Length of Mains5mVelocity of Flow1.47m/sHazen Williams Constant140Note: Decrease in the Constant will increase the Head Loss in mainsHead Loss (Hi)7.4576m/Km

Total Head Loss in mains line 0.04m

LateralsNo of Laterals5.00Flow Through each0.01m3/sAssumed Diameter of Riser Pipe100mm0.1mArea of Mains0.01m2Length of Mains4mVelocity of Flow1.84m/sHazen Williams Constant140Note: Decrease in the Constant will increase the Head Loss in mainsHead Loss (Hi)32.8451m/Km

Total Head Loss in mains line 0.13m

NozzlesLateral Length4.00mSpacing of Laterals0.25mNo of Nozzles32.00Flow / Nozzle0.00m3/s1.63m3/hFlash Mixer DesignNo of Flash Mixer2Capacity of each Chamber520.4159478638m3/hAssumed Detention Time1mins30 - 60 secsVolume8.67m3Assumed Depth1.5mArea 5.7823994207m2Length4.7mWidth4.3mArea20.21m2Ok

FlocculatorsNumber of Flocculators2Assumed Detention Time15minsCapacity of each Chamber520.4159478638m3/hVolume130.10m3Assumed Tank Height4.5mArea 28.9119971035m2Length4.7mWidth4.7mArea22.09m2Error!!!: Redesign

Sedimentation Tank DesignNo of Sedimat4Capacity of Each Chamber260.2079739319m3/hAssumed Detention Time3Hrs3 - 4 hrsVolume780.62m3Assumed Depth of Tank3.3Note: Depth of Sedimat is 0.6 to 1.2m much than the depth of flocculatorSurface Area236.5527035744m2Length18.3mBreath6.5mArea118.95m2Error!!!: RedsignSurface Loading (overflow Rate)2.1875407645m/hrOk

Rapid Sand FilterNo of Beds2Assumed filtration rate9m3/m2/hOkArea of Filter115.6479884142Area of Each Bed57.8239942071Adopted Length9.1mOkAdopted Width7mArea of Bed63.7m2OkAssumed Depth of Sand80cm

Underdrainage System:Total Area of Holes =0.2 to 0.5% of Bed AreaAssumption0.25%Area of Lateral = 2 (Area of Holes of Lateral)Area of Manifold2 (Area of Laterals)So, area of Manifold = 4 (Area of Holes)Area of Holes = 0.15925m2Area of Manifold = 0.637m2Diameter of Manifold = 0.90m90.0cmAssume c/c of Lateral (Btw 15 and 30) = 30cmOkTotal Number (Length/c/c of Lateral) = 30.3333333333on either sideLength of lateral ((Width of Bed/no of beds) - (Diameter of Manifold/no of Beds) = 4.0997980251mCS area of Lateral (2 x area of perforation per Lateral)Take dia of holes12mmOk0.012m1.2cmTotal Area of Holes =0.15925m2Number of Holes1407.5126262626NumbersAdopt1410NumbersNumber of Holes/ Lateral17.625(Number of Holes /Depth of Sand BedArea of Perforations/lateral1994.1428571429mm2Spacing of Holes = (Length of Lateral/Number of Laterals)0.2326126539m23.2612653908cmCS area of Lateral 39.8828571429cm2Diamter of Lateral = 7.1246052522cmCheck: Length of Lateral < 60 d =427.4763151334cm4.2747631513mOkRising Washwater Velocity in Bed = 50cm/min0.5m/minWashwater discharge/bed=0.5308333333m3/sVelocity of Flow through Lateral1.6637265086m/sOkManifold Velocity = 1.3309812069m/sOk

WashWater GutterDischarge of Washwater/ bed0.5308333333m3/sSize of Bed:Length9.1mWidth7mAssume 3 troughs running lengthwise at =2.3333333333m c/cDischarge of each trough = (Q/3)0.1769444444m3/sQ = 1.71.b.h^(3/2)Assume b = 0.3mh = 0.6408330623mFree Board = 0.05mAdopted h = 0.69m

Clear Water Reservoir for BackwashingFor 4 Hour Filter Capacity,4Capacity of Tank = 4586.4m3Assume Depth = 4mSurface Area = 1146.6m2B = 23.9436839271mL = 47.8873678542mDiameter of Inlet Pipe coming from two filter150mmVelocity =< 0.6m/sDiameter of washwater pipe to overhead tank67.5cmAir Compressor unit1air/min/m2For 5minsAir required = 10.6166666667m3/ of air

Rapid Pressure Filter Design:Scheme Capacity = 2mgd9092m3/dayTotal Scheme Capacity = 9092m3/dayAt 22hrs operation, Scheme Capacity = 413.27m3/hrFlow Rate = 413.27m3/h114.80L/sAt 24hrs operation, Scheme Capacity = 378.83m3/hrFlow Rate = 378.83m3/h105.23L/s

Allow for 10% for other Uses = 909.2m3/dayTotal Scheme Capacity = 10001.2m3/dayAt 22hrs operation, Scheme Capacity = 454.6m3/hrFlow Rate = 454.60m3/h126.28L/sAt 24hrs operation, Scheme Capacity = 416.72m3/hrFlow Rate = 416.72m3/h115.75L/s

Filter Loading Rate = 10m3/m2/hOkWith Combined sand & anthracite media45.46m2No of Filters = 22 Sets in Parallel/ Sed TankArea of each Filter = 22.73m2Diameter of each filter = 5.38mAdopted Diameter = 5.00m

Transfer PumpsNo of Duty pumps = 2No of Standby = 1Pump Rate = 227.3m3/h63.14L/sAssumed Head = 10m

Backwashing:Backwashing Water rate = 37m3/m2/hOkFilter Surface Area =19.64m2Number of Filter(s) to be washed 2Quantity of Water needed for Backwashing1453.57m3/h403.77L/s Allowable Head10.00mPump Efficiency0.70(Adopt between 0.7 and 0.9)Motor Efficiency0.80Acc. Due to Gravity (g)9.81m/s2Density of liquid ()1.00Kg/m3Pump Power Consumption56.59KWConversion Factor to Horse Power (Divide by)745.7Pump Power Consumption75.88HPMotor Power Rating70.73KW

Backwash Tank:Backwash Duration10minsVolume of Wastewater242m3Assumed Height2.5mArea of Backwash Tank97m2

Contractor's SpecificationTank Dimension:Length5.7mBreath5.7mHeight2.5mVolume81.2m3Error!!!

Genset Power RatingClear Water Tank:Detention Time = 3HrsVolume = 3122.4956871827m3No of Tanks = 2Capacity of each = 1561.2478435913m3

for efficient treatment works, the clear water tank should have a minimum storage of 3 hrs. this will allow for a timely warning to the communities being served during any emergency situation at the plant.

Circular Ground Tank:Heigth of Tank = 9mSurface Area of Tank = 173.4719826213m2Diameter of Tank = 14.8587524152mAdopted Diameter = 15mFree Board = 0.6mTotal Height = 9.6mChemical Dosing:Chlorine Dosing = Normal Water = 4.5 - 5 mg/LHeavily Polluted Water = 10 mg/LAlum Dosing = 40 - 60 mg/LLime Dosing = 45 mg/L

Sheet3