Distributed Sources Source (or sink) that is spread out along the - - PDF document

CEE 577 Lecture #11 10/23/2017 1

Lecture #11a (Distributed Sytems)

Chapra, L9 (cont.)

David A. Reckhow CEE 577 #11 1

Updated: 23 October 2017

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Distributed Sources

 Source (or sink) that is spread out along the

stream length

 classical non‐point sources

 agricultural, urban runoff

 Sediment processes

 sediment oxygen demand

 Atmospheric deposition

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H B Jin Jout SD

CEE 577 Lecture #11 10/23/2017 2

Distributed source in PFR @SS

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H B Jin Jout SD 0     U dc dx kc SD

   

c c e S k e

• k xu

D k x u

        

 

1

0.5 1 1.5 2 2.5 3 2 4 6 8 10

Distance (miles) Concentration (mg/L) David A. Reckhow CEE 577 #11 4

Increasing SD 0.9 mg/L/d 0.6 mg/L/d 0.344 mg/L/d K=0.344/d

CEE 577 Lecture #11 10/23/2017 3

0.5 1 1.5 2 2.5 3 3.5 4 2 4 6 8 10

Distance (miles) Concentration (mg/L) David A. Reckhow CEE 577 #11 5

Decreasing k 0.23/d 0.344/d 0.58/d 0.88/d SD = 0.9 mg/L/d

Variable Channel Geometry

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H B Jin Jout SD

V c t J A J A rV

in c

• ut

c

    

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Lecture #11b (Waste Load Allocations)

Chapra, here and there

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Updated: 23 October 2017

Graphical Representation

 See also: Fig 1.2 from Thomann & Mueller

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Miles Downstream

• 2

2 4 6 8 10 12 14 16

Dissolved Oxygen (mg/L)

1 2 3 4 5 6 7 8 9 10 11

Loading

10 20 30 40 50 60 70 80

Fishing Boating Fishing

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WLA: Step by Step

 Designate a specific water use

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Adopt a Water Quality Criterion Determine action necessary

formulate several alternatives evaluate the alternatives

Is cost OK? No Yes

WLA: breakdown of steps

 Designate a specific water use

 recreation: swimming, boating, aesthetics  water supply: municipal, industrial  agriculture  fisheries: commercial or sport  ecological balance

 Adopt a Water Quality Criterion

 must support the above use  EPA “red book”

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CEE 577 Lecture #11 10/23/2017 6

WLA: breakdown of steps

 Determine the action necessary to meet criterion: usually a

discharge or effluent Water Quality Standard (enforceable)  Formulation of several engineering alternatives to meet

the WQC

 choose model  collect data  calibrate model  verify model  sensitivity analysis  model run under design conditions  alter waste loads and re‐run model

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 To next lecture

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