NA-05 - Cleaning: Cleaning Strategy and Programme

Table of contents

Determination of cleaning intervals

System and Network data – Example invert gradient (2)

Example: Grouping of the sewer network sections based on invert gradient

 
Table: 
Characteristics of the three sewer network sections as per [ATV1994]
 
Section 1
Section 2
 Section 3
Sewer type
First sections
Branch sewers
Main collector
Nominal size
small
medium
large
Invert gradient
normally steep (1/DN), very variable, short flow times
normally constant, more even and lower than in section 1
normally lower than in sections 1 and 2, long flow times
ca. 3-10 %
ca. 2-3 %
ca. 1-2%
Discharge
discontinuous
continuous
continuous
Deposits
temporal and easily mobilisable
mineral and uniformly distributed across the sections
mineral and uniformly distributed across the sections
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