The effluent load of individual industrial sites depends upon their particular type of production. Whereas the continual production of paper, paints, food stuffs and mass chemicals (alcohols, carbonic acids, sugar, proteins, etc....) usually generates effluent with readily degradable contaminants, multistage manufacturing plants operating intermittently produce complex effluents, particularly if their products must be
- durable, i.e. light and washproof (dyes, optical brighteners, etc..) or biologically active (herbicides, pharmaceuticals etc..
which usually contain
- Several classes of substances of varying chemical structure, properties and degradability (usually poorly degradable), and
- high salinity, whereby their
- composition and concentration is subject to substantial fluctuations
Apart from the chemicals industry, such complex effluent is also produced in other industrial sectors, for example in the:
- Manufacture of chemicals, pulp and paper
- Textile finishing and tanneries
- Coal refining (coking plants),
- Disposal plants (landfills, fermentation and composting plants, the concentrate from emulsion separation plants, sludge treatment, etc.)
- Manufacture of petrochemical products
