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TANKS
The choice of tank required for any
wastewater treatment process depends entirely on the nature of
the waste to be treated. Needless to say there are a great many
industrial waste products and each has its own particular method
of dealing with the waste. Tanks can be fabricated from
different materials such as welded steel tanks, steel and
concrete tanks, aluminium tanks, glass fused steel tanks, bolted
steel, galvanised steel or rubber/epoxy coated tanks.
 Many
oils can be recovered from open water surfaces by skimming
devices. Considered a dependable and cheap way to remove oil,
grease and other hydrocarbons from water, oil skimmers can
sometimes achieve the desired level of water purity. At other
times, skimming is also a cost-efficient method to remove most
of the oil before using membrane filters and chemical processes.
Skimmers will prevent filters from blinding prematurely and keep
chemical costs down because there is less oil to process.
 Parallel
plate separators are similar to API separators but they include
tilted parallel plate assemblies (also known as parallel packs).
The parallel plates provide more surface for suspended oil
droplets to coalesce into larger globules. Such separators still
depend upon the specific gravity between the suspended oil and
the water.
 Activated
sludge is a biochemical process for treating sewage and
industrial wastewater that uses air (or oxygen) and
microorganisms to biologically oxidize organic pollutants,
producing a waste sludge (or floc) containing the oxidised
material.
In general, an activated sludge process
includes an aeration tank and a settlement tank.
 A
trickling filter
consists of a bed of rocks, gravel, slag, peat moss, or plastic
media over which wastewater flows downward and contacts a layer
(or film) of microbial slime covering the bed media. Aerobic
conditions are maintained by forced air flowing through the bed
or by natural convection of air. The process involves adsorption
of organic compounds in the wastewater by the microbial slime
layer, diffusion of air into the slime layer to provide the
oxygen required for the biochemical oxidation of the organic
compounds. The end products include carbon dioxide gas, water
and other products of the oxidation. As the slime layer
thickens, it becomes difficult for the air to penetrate the
layer and an inner anaerobic layer is formed.
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