PREMIER TECH Solido SMART - Inspection, maintenance and desludging; Evaluation of sludge level SSV90 norm and recommendation for desludging

6. Inspection, maintenance and desludging
Premier Tech 28 / 64 Solido SMART
DOKK5110E 15.04.2020
6.5 Evaluation of sludge level SSV90norm and recommendation for
desludging
For proper evaluation of SSV90
norm
sludge level calculate according to this formula:
SSV90
norm
= 0,95 x SSV30 x HR / HRmax
SSV90
norm
true sludge level in reactor after 90min of sedimentation
normalized / standardized to HRmax
0,95
factor for conversion of SSV30 to SSV90
(30 resp.90 min sedimentation
SSV30:
measurement of sludge level in reactor in 1+3 dilution after
30min sedimentation at current water level HR during service
HR:
current water level at service
HRmax:
max. reg. water level at full hydraulic load
(see table below)
Desludging is required when SSV90
norm
= 700 ml/l
EXAMPLE
• Type: EM2-35
• HR at service: 1,16 m
• HRmax according to table: 1,28 m
• level in cylinder (30min): 130 ml (1+3)
(250ml sample+750ml clearwater)
• SSV30 = 520 ml/l (4x130)
• SSV90
norm
= 0,95 x 520 x (1,16 / 1,28) ml/l
= 448 ml/l
➔ SSV90
norm
= 448 ml/l
➔ around 2/3 of total sludge storage volume capacity is currently filled