F
Ferric chloride or sulphate
Iron-containing substances used to coagulate and flocculate in effluent treatment processes
Filter press
A device that dewaters sludge by compressing it between membranes or cloth-lined plates to produce a cake
Fine bubble diffuser
An aeration device in which air is blown through a porous ceramic or synthetic membrane to create small bubbles in a liquid effluent
Flocculation
The agglomeration of coagulated particles to form a floc which can settle or float; may be assisted by biological, chemical or mechanical means
Fluidised bed
A body of solid particles through which gas or liquid is blown or pumped upwards causing separation and movement; a means of increasing reaction rates
Fluidised bed scrubber
A device that removes pollutant particles or trace gases from a gas stream, in which plastic spheres are wetted by a scrubbing liquor and fluidised by the contaminated gas stream
FOG (Fats Oils and Grease)
Wastewater components from food preparation, animal or vegetable processing; largely insoluble in water, high COD and likely to float
Fume
Solid particles smaller than 1µm in a gaseous emission
H
Halogenated hydrocarbons
organic compounds containing carbon, hydrogen and halogen atoms (fluorine, chlorine, bromine and iodine); implicated in stratospheric ozone loss
Hazardous waste
waste that originates from a specified waste stream or has hazardous properties or contains hazardous substances as defined in the Hazardous Waste Directive
Heavy metals
certain metals, used industrially and harmful to living organisms, for which discharge and emission standards are set; including cadmium, chromium, copper, lead, mercury, nickel, zinc
High performance filter
a device that separates particles 2-500 µm in size from relatively clean liquid streams
Hydrocyclone
a device that separates sand, silt and suspended solid particles from a liquid using centrifugal forces generated by the liquid flow
Hydrogen sulphide (H2S)
a foul smelling gas, a product of the reduction of organic sulphur by anaerobic organisms
I
Incineration
the controlled burning of municipal, clinical and chemical waste material and sewage sludge, commonly in two stages, to produce minimum amounts of gas and ash
Inorganic
substances such as sand, clay and metals whose molecular structures do not contain carbon-hydrogen (C-H) bonds except as carbonates and similar
Leachate
liquid that has percolated through a solid mass; soil leachate may be high in nitrate; landfill leachate may be high in BOD, ammonia, salinity and toxic substances
Legionella pneumophila
a water-borne pathogenic bacterium which causes Legionnaires' Disease; may be present in cooling systems and spread by droplets; controlled by chlorination, ozone, silver-copper, ultraviolet light
M
Media
Stones, pebbles or plastic that provides a substrate for the growth of a film of microorganisms in wastewater treatment; plastic, ceramic or metal shapes or surfaces that improve gas-liquid contact in gas scrubbing
Methane (CH4)
Highly calorific gas; 60 % of biogas; produced during anaerobic biological processes; may contribute to global warming
Microfiltration
The use of microporous filters operating under pressure to remove particles or microorganisms of 0·1-5·0 µm size from process and effluent liquids
Microorganisms
Microscopic living creatures; bacteria, protozoa, fungi and algae
Microwave disinfection unit
Equipment that shreds clinical waste and disinfects it with steam and microwave radiation
Mist eliminator
Unit that separates small droplets of liquid (mist) from gas streams by impingement on a mesh or plate surface; part of a wet scrubber
Mist
Very small droplets of liquid suspended in a gas
