How can the industrial pollution of fresh water be reduced?
Industrial pollution of fresh water can be reduced through several measures:
First, industries should minimise water usage for processing by reusing and recycling water in two or more successive stages. This reduces the overall volume of wastewater generated.
Second, harvesting rainwater can help meet water requirements, reducing dependence on freshwater sources.
Third, treating hot water and effluents before releasing them into rivers and ponds is essential. This treatment involves three phases: Primary treatment by mechanical means (screening, grinding, flocculation, sedimentation), Secondary treatment by biological process, and Tertiary treatment by biological, chemical and physical processes which involves recycling of wastewater.
Explanation
The textbook explicitly lists three main suggestions for reducing industrial pollution of fresh water: minimising water use through reuse and recycling, rainwater harvesting, and treating effluents before discharge. The three-phase treatment process (primary, secondary, tertiary) is also mentioned as a detailed method for effluent treatment. These points directly answer the 3-mark question comprehensively.