Chapter 13. Filters (41 pages)

1.Equipement granular media filters
1.1.Service conditions
1.1.1.Cycles
1.1.2.Service re-instatement
1.2.Media support structure
1.3.Filter washes
1.3.1.Washing fluid distribution
1.3.2.Backwash water consumption in relation to the volume filtered
1.4.Floors for concrete open gravity filters
2.Pressure filters
2.1.Filters backwashed with water only
2.2.Filters backwashed with air and water simultaneously
2.3.Filters suitable for successive water and air washes
3.Gravity filters
3.1.Aquazur sand filters
3.1.1.Aquazur V filters
3.1.2.High speed Aquazur filters
3.1.3.Aquazur T filters
3.2.Médiazur dual-media filters
3.3.Carbazur activated carbon filters
3.3.1.Carbazur G
3.3.2.Carbazur V and GH
3.3.3.Carbazur DF
4.Special filters
4.1.Filtrazur filters
4.1.1.Filtrazur filter washing
4.1.2.Advantages of the Filtrazur filter
4.1.3.Standard dimensions
4.2.Greenleaf filters
4.2.1.Filtration
4.2.2.Backwash
4.3.ABW filters (figure 19 and photo 9)
4.3.1.Filtration
4.3.2.Backwash
4.4.Self-washing valveless filter
4.5.Upflow oil-separation filters - Colexer (figure 20)
5.Filter monitoring and control
5.1.Constant rate, variable head filter
5.2.Constant rate compensated-clogging filter
5.2.1.Filter battery control
5.2.2.Filter rate controllers
5.3.Declining rate filters

Introduction

Chapter 3 § 5 discussed general laws and mechanisms applicable to filtration together with the problems encountered in connection with filter washing. In turn, this chapter is devoted to the technology applicable to the various Degrémont filters.
The widely differing conditions applicable to the use of granular filter media have led to the creation of an extensive range of filters that can be classified on the basis of their hydraulic operating conditions and of their washing conditions or even according to their operating modes (see § 5.):

constant rate, variable head filter;
constant rate compensated-clogging filter with partialised siphon or valve;
declining rate filter.