Industrial wastes should be treated prior to disposal. Processing is intended to reduce their volume and weight and to ensure their hygienic safety by reducing BOD toxicity and poisonous quality of the effluent/emission to the required standard.
After processing, the wastes may b discharged into receiving waters, more rarely onto receiving soils, or reclaimed for industrial water supply.
Zoning and Phasing
It is desirable that industrial estates be zoned according to a broad categorisation of industrial units. One useful categorisation is as follows:
Iron and Steel
Electrical & light engineering
Less polluting processes and small industries
Less mechanical processes.
Such categorisation allows rational zoning, reflecting the varied traffic generation and pollution caused by different types of industries. Heavy traffic generators should be placed near the main entrance/exit, while heavy polluters leewards. Less mechanised processes can conveniently adjust to rolling topography.
However, zoning will almost inevitably clash with the objective of compact development at every phase of growth. Compact development at each phase minimizes the lengths of idle services.
The planner should recognise this dilemma and attempt design solutions such that every phase of growth is relatively compact, while maintaining zoning to an acceptable degree.