MBR and Sludge glossary (F)

Fast pyrolysis
Non-oxidative thermochemical treatment employing rapid heating rates and high temperatures favouring bio-oil as the main product

FBDA
Fine bubble diffusion aeration

FC
Filter cartridge

Ferric
Iron (III) (iron having an oxidation state of +3)

Filamentous bacteria
Long, string-like bacteria such as nocardia or microthrix often associated with foam formation

Filter press FP
Sludge dewatering technology based on removing water under pressure by pressing sludge between a parallel series of porous plates

Filterability
Extent of filtration of water through sludge solids

Filtrate
Treated water exiting a filter

Flash dryer
Convective dryer operating with a very short residence time using a jet of fast-moving, upward-flowing air or steam

Floc water
Water held within flocs

Flocculant
Organic polyelectrolyte (polymer) used to carry out flocculation

Flocculation
Aggregation or agglomeration of suspended solids to form larger particles (aggregates or flocs) through destabilisation of the particles using organic polyelectrolytes

Flocs
Aggregates of solid particles formed in the activated sludge process

Flotation thickening FT
Sludge consolidation by encouraging particles to float and removing the clarified water

Flue gas
Mixture of waste gas products generated from incineration processes

Fluidised bed dryer
Type of convective dryer based on media (normally sand) fluidised by upward flowing hot air

Fluidised bed reactor FBR
Reactor configuration based on media fluidised by upward flowing gas or liquid

Fly ash
Particulate fraction of flue gas (the gaseous waste stream) from an incineration process

FO
Forward osmosis

FOG
Fats, oils and grease

Free water
Water fraction in sludge which is unassociated with the floc solids and can be largely removed by mechanical dewatering

Freeboard
Region above a reactor bed which allows for expansion of the bed when it is fluidised by a stream of upward flowing gas or liquid

Front end loader
Tractor with large, hinged bucket mounted on the front at the end of a pair of jointed arms

FS
Flat sheet (or plate-and-frame)