ABSTRACT
The main processes used to stabilise the sludge at small water treatment plants are tabulated in Table 9.1. Effective sludge stabilisation processes.
S. No.
Process
Process Description
1
Sludge Pasteurization
Minimum mean retention (MMR) of 30min at 70°C or 4h at 55°C followed by mesophilic anaerobic digestion.
2
Mesophilic anaerobic digestion
Minimum mean retention (MMR) of 12 d at temperature of 35 ± 3°C followed by MMR of 14 d secondary storage.
3
Thermophilic aerobic digestion
Minimum mean retention of 7 d with a minimum of 4h at 55°Cor higher.
4
Composting
Minimum mean retention (MMR) of 40°C for 5 d including 4 h at minimum of 55°C followed by minimum of 2 months maturation.
5
Lime stabilisation
pH not less than 12 for minimum of 2 h.
6
Lime conditioning dewatering and storage
Minimum storage period of 3 months
7
Dewatering storage
Minimum storage period of 6 months
8
Liquid storage
Minimum storage period of 3 months
