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Topic II. 4. Dry Weather Design Flowrates

Basic Sewage Quantity Parameters

I. Domestic Sewage flowrates

Specific sewage flowrate - qs, l/d.ca

qs = 0,9.q0

Mean daily sewage flowrate - Qm.d, m3/d

Qm.d = qs.N/1000

Maximal daily sewage flowrate - Qmax.d, m3/d

Qmax.d = qs.N.Kh/1000

Kh - coefficient of hourly variability

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Basic Sewage Quantity Parameters

Maximal hourly sewage flowrate - Qmax.h, m3/h

Qmax.h = qs.N.K0/24.1000

where K0 = 1 + 2,5/ (Qm.d)0,22 ; Qm.d - in l/s

K0 - maximal coefficient of general variability

Sewage flowrate module - qm , l/s.ha

qm = (Qm.d - Qs,conc) / F.86400

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Basic Sewage Quantity Parameters

II. Industrial Sewage Flowrates

Mean daily sewage flowrate - Qm.d, m3/d

Qm.d = qind.Md/1000

Maximal hourly sewage flowrate - Qmax.d, m3/h

Qmax.h = qind.Mh.Kh/1000

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Sewage Design Flowrates

Separate Sewer System

(Dry Weather Flow)

Sewage design flowrate - Qd, l/s

Qd = 2Qmax,h = 2(qm.f.K0 + Qs,conc + Qmax.h)

where K0 = 1 + 2,5/(qm.f)0,22