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SCREENING

Coarse Screens 6 to

150 mmMicroscreens < 50 m Fine Screens < 6 mm

Hand CleanedMechanically

CleanedStepDrum

Chain Driven Reciprocating Rake Catenary Continuous Belt

Static Wedgewire

Figure by MIT OCW. Adapted from Metcalf & Eddy Inc., G. Tchobanoglous, F. L. Burton, and H.D. Stensel, 2003. Wastewater Engineering: Treatment and Reuse, Fourth Edition. McGraw-Hill,New York.

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Simple Manually Raked Screen (flow is from left to right)

Figure by MIT OCW.

apted from: Mara, D. Domestic Wastewater Treatment in Developing Countries. London, UK:

arthscan, 2005, p. 79.

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h1

Area

Opening

WS

x

Y

Plate

3 inch(75 mm)

Min

3 inch(75 mm)

Min

Channel wall

Rejected

Area = Total rejected area

WIDTH

THE PROPORTIONAL WEIR

Figure by MIT OCW.

Adapted from: Reynolds, T. D., and P. A. Richards. Unit Operations and Processes in Environmental

Engineering. 2nd ed. Boston, MA: PWS Publishing Company,1996, p. 142.

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Q

Q

Q

Q

Proportional weir

Stop gate

WS WS WS

WSh

A

A

Proportionalweir

plat

A

B

PLAN

Grit storage

Grit storage

We

Weir opening

Section A-A

PROFILE & CHANNEL CROSS SECTION

A Horizontal-Velocity Grit Settling Chamber with a Proportional Weir Control Section

Figure by MIT OCW.

Adapted from: Reynolds, T. D., and P. A. Richards. Unit Operations and Processes in Environmental

Engineering. 2nd ed. Boston, MA: PWS Publishing Company,1996, p. 141.

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Figure by MIT OCW.

Adapted from: Viessman, W., Jr., and M. J. Hammer. Water Supply and Pollution Control. 7th ed.

Upper Saddle River, NJ: Pearson Education, Inc., 2005, p. 353.

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WSWS WS WS

W

Stop gate

hQ

Q Q

Q

PlanA

B

A

A

Grit storage

Parshall flume

Profile & channel cross section

A horizontal-velocity grit settling chamber with a Parshall flume control section.

Grit storage

Section A-

Figure by MIT OCW.

Adapted from: Reynolds, T. D., and P. A. Richards. Unit Operations and Processes in Environmental

Engineering. 2nd ed. Boston, MA: PWS Publishing Company,1996, p. 140.

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WS

Ideal parabolic cross section and design cross section for chamber with a Parshall flume.

Parabolic section

Design section

Space for mechanicalconveyor equipment

Figure by MIT OCW.

Adapted from: Reynolds, T. D., and P. A. Richards. Unit Operations and Processes in Environmental

Engineering. 2nd ed. Boston, MA: PWS Publishing Company,1996, p. 143.

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Figure by MIT OCW.

(A

)

IN

-LIN

E

(B)

SID

E-LIN

E

Raw

Preliminary

Treatment

PreliminaryTreatment

Overflow

Structure

Equalization

Basin

Controlled Flow

Pumps

Controlled Flow

Pumps

Sludge Processing Supernatant

Sludge Processing Supernatant

Flow Meter

& Controls

Flow Meter & Controls

EQUALIZATION BASINS

Final Effluen

Final Effluent

Primary

Treatment

Primary

Treatment

Secondary

Treatment

Secondary

Treatment

Waste

Raw

Waste

Equalization

Basin

Adapted from: Reynolds, T. D., and P. A. Richards. Unit Operations and Processes InEnvironmental Engineering.

2nd ed. Boston, MA: PWS Publishing Company, 1996.

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12

0 0

Qavg

126 A.M.

FLUCTUATING VOLUME DETERMINED BY HYDROGRAPH

Time

Q

gpm l

Q

pm

12 6 P.M.

Required Volume

Figure by MIT OCW.

Adapted from: Reynolds, T. D., and P. A. Richards. Unit Operations and Processes InEnvironmental Engineering.2nd ed. Boston, MA: PWS Publishing Company, 1996.