Manikanth miw ppt

8/13/2019 Manikanth miw ppt

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UPFLOW SLUDGE BLANKETCLARIFIER

BY

N.MANIKANTH

(13MT03ENV008)


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INTRODUCTION

It incorporates the processes ofmixing, coagulation, flocculation and

filtration in a single unified vessel

It is a hopper bottom tank

Suitable for rural areas and small

towns


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SOLID CONTACT

CLARIFIER


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SLUDGE BLANKET CLARIFIER

PRINCIPLE


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PRINCIPLE

In a sludge blanket clarifier, the floc particlesare suspended in a condition of equilibrium

The larger particles will accumulate and form

a sludge blanket

When the water passes through this blanket,the flocs are entrapped

This entrapment gives this unit an edge overthe normal horizontal flow tanks


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IVES THEORY

ASSUMPTIONS:-

The velocity distribution of upflow over any

horizontal plane is uniform.

The diameter and the density of the individual

floc particle in the blanket is uniform at all

levels.

The free fall velocity of an individual floc

particle can be obtained by using Stokeslaw.VS=g ( S- )d2/ (18* )


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Blanket layers can be considered toremain in a state of equilibrium

momentarily when up flow velocity is

equal to settling velocity of flocs.


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BLANKET STABILITY

The sludge blanket is more or less a floc-filter which entraps turbidity from rawwater and allows only clear water to passthrough.

Efficiency of clarifier depends upon thestability of the blanket.

Under unstable blanket condition, theeffluent may have even higher turbiditythan the influent.


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FACTORS EFFECTING

BLANKET STABILITY

Blowing up of blanket by sudden

increase in up-flow velocity

Rupture/cracking of blanket


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ADVANTAGES

In a single unit, processes such ascoagulation, floculation and clarification orfiltration are carried out

Detention time of 1-2 hours may be sufficient

The unit can be so designed such that itmakes use of hydraulic energy only

It provides higher over floe rates thanconventional horizontal flow tanks


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As the previously formed sludge helpsin clarification, lesser chemical dosage

is required

Microbial removal is better than in

conventional horizontal flow tanks


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DISADVANTAGES

Requirement of skilled personnel

Low waste sludge solids content

Sludge blanket control

Surfacing of light flocs during low

turbidity flow


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APPLICATIONS

Potable WaterTreatment

Softening

Turbidity Removal

Iron and ManganeseRemoval

Color Removal

Wastewater Treatment Phosphorus Removal

Filter BackwashReclamation

Industrial Process &Waste Treatment

Suspended Solids

Removal

Metals Precipitation

Landfill Leachate

Boiler Blowdown

Cooling Tower

Makeup

Coal Pile Runoff Many Others


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DESIGN CONSIDERATIONS Kawamura

1 Flocculation Time = approximate = 20 min

2 Settling Time = 1 - 2 hr

3 Surface Loading = 2 - 3 m/hr

4 Weir Loading = 7.3 - 15 m3/hr

5 Upflow Velocity = < 10 mm/min

6 Slurry Circulation rate = up to 3 - 5 time the raw water inflow rate

7 G = 30 - 50 s-1

8 MAXIMUM MIXER TIP SPEE 0.9 m/s (Baffled Channel)

= 0.9 m/s (Horizontal Shaft with Paddles)

= 1.8 - 2.7 m/s (Vertical Shaft with Paddles)

Equation mixer tip speed = DN

9 Free Board is approxim = 0.6 m

10 Water Depth = 4 - 5 m.

11 Length and Width ratio = 6 : 1 (minimum 4 : 1) (Rectangular Basin)

12 Width and Water Depth = 3 : 1 (maximum 6 : 1) (Rectangular Basin)

13 Blade area/Rapid Mixing Tank area = 0.1 - 0.2 % (page 121)

14 Blade : Diameter Blade/Diameter Mixing Tank = 0.2 - 0.4 (page 121) 15 Shaft rpm = 8 - 12


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Cont..,

Q,Sim

1 Detention Time = 2 Hr

2 Surface Loading = 2 - 4 m/hr

3 Weir Loading = 7.1 m3/m.hr


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Cont.,

Sheet Master Degree of Environmental Engineering 1 Weir Loading = 7.1 m3/m.hr

2 Surface Koading

- Q < 0.35 m3/min = 0.5 - 1.0 m/hr

mixer tip speed = DN

8:16 AM/2/28/2007 1/2 Design Clarifier Tank(Skert)/DesignCriteria

- Q > 0.35 m3/min = 1.25 - 1.85 m/hr

3 Water Depth = 3 - 5 m.

4 Paddle radius = 65 - 75% of radius for Flocculator

5 Detention Time = 1 - 3 Hr 6 Diameter Tank < 45 m

7 Paddle at bottom tank high bottom =15 - 30 cm

8 Paddle Velocity = 2 - 3 rpm

9 Effective Paddle Area = 10 % Sweep area of the fllocculator


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Cont,

Water Work Engineering Book 1 Flocculation

1.1 Detention Time = 20 - 60 min

1.2 Velocity Gradie = 15 - 60 S-1

1.3 GT = 1x104 - 15x104

1.4 Periperal Velocity of Paddle =0.3 - 0.6 m/s

1.5 Shaft rotation speed = 1.5 - 5 rpm

2 Sedimetation (Coagulation)

2.1 Detention Time = 2 - 8 hr

2.2 Surface Loading = 20 - 40 m3/m2.day

2.3 Weir Loading = 200 - 300 m3/m.day

3 Sedimentation (Softening) 3.1 Detention Time = 1 - 6 Hr

3.2 Surface Loading = 40 - 60 m3/m2.day

3.3 Weir Loading = 250 - 350 m3/m.day


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CASE STUDIES


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CASE STUDY 1

LOCATION : Beaux Bridge, LA (1998)

AIM : Removal of hardness

RAW WATER CHARECTERISTICS :

o Source: well

o Total hardness: 380-400 mg/l as CaCO3

o Flow Rate: Design flows of 104 GPM min-1,042 GPM

maxCHEMICALS : Alum and Lime

RESULT: The effluent total hardness is about 100 mg/l

as CaCO3


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CASE STUDY 2

LOCATION: Trinity River Authority of Texas -Huntsville Water Treatment Plant (1999)

AIM: Turbidity removal

RAW WATER CHARECTERUSTICS:

o Source: Trinity River

o pH: 7 - 8

o Turbidity: 30 - 40 NTU

o

Total Alkalinity: 100 - 120 (as CaCO3)o Flow Rate: 390 GPM min - 3,680 GPM

max

The above analysis are normal values, but

during rainy season the turbidity is over 100NTU


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CHEMICALS:

Oxidant: Chlorine dioxide

Alkalinity Adjustment: Lime

Coagulant: Alum

Coagulant aid: Cationic Polymer

RESULT: Effluent is consistently less

than 1 NTU


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REFERENCES

C. Schlicht The MC CLARIFLOW The

Ultimate upflow solids contact

clarifier (1999)

Dr. S.M.Dhabadgaonkar, Study of

some aspect of sludge blanketclarification in WTP (1977)

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