NS EN 12255-13 : 1ED 2003

Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Requirements
  4.1 General
  4.2 Chemical background and process options
       4.2.1 Chemical process
       4.2.2 Precipitation processes
       4.2.3 Selection of precipitation chemicals
  4.3 Storage of chemicals
       4.3.1 General
       4.3.2 Aluminum salts
       4.3.3 Iron salts
       4.3.4 Calcium salts
  4.4 Dosing equipment
       4.4.1 General
       4.4.2 Aluminium salts
       4.4.3 Iron salts
       4.4.4 Calcium salts
  4.5 Silos and tanks
  4.6 Mixing systems
  4.7 Flocculators
  4.8 Sedimentation tanks
       4.8.1 General
       4.8.2 Design considerations
       4.8.3 Chemical sludge wasting
  4.9 Flotation
  4.10 Physical filtration
  4.11 Sludge
       4.11.1 Sludge production
       4.11.2 Sludge characteristics
Annex A (normative) Precipitation chemicals
        A.1 Aluminium salts
        A.2 Iron salts
             A.2.1 Ferrous salts
             A.2.2 Ferrous sulphate, monohydrate
             A.2.3 Ferrous sulphate, heptahydrate
             A.2.4 Ferric salts
        A.3 Calcium salts
             A.3.1 General
             A.3.2 Calcium oxide
             A.3.3 Calcium hydroxide
Bibliography

Provides the requirements for chemical treatment of wastewater by precipitation/flocculation for removal of phosphorus and suspended solids.