Chapter 6 Manufacturing Industries Solutions
Question - 11 : - How do industries pollute the environment?
Answer - 11 : -
Industries are responsible for four types of pollution:
1. Air
2. Water
3. Land
4. Noise
Air pollution is caused by the presence of a high proportion of undesirable gases, such as sulphur dioxide and carbon monoxide and airborne particulate matter.
Water pollution is caused by organic and inorganic industrial wastes, and effluents discharged into water bodies. Paper, refineries and tanneries are the main culprits.
Soil and water pollution are closely related. Dumping of waste makes the soil useless for agricultural activities. The pollutants then reach the groundwater through the soil and contaminate it.
Noise pollution is caused by industrial machinery and construction activities.
Question - 12 : - Discuss the steps to be taken to minimise environmental degradation by industry.
Answer - 12 : -
The steps that can be taken to minimise environmental degradation by industries are:
1. Adopting the latest techniques and upgrading existing equipment to improve energy efficiency.
2. Providing green belts for nurturing ecological balance.
3. Particulate matter in the air can be reduced by fitting smokestacks to factories with electrostatic precipitators, fabric filters, scrubbers and inertial separators.
4. Using silencers for noise generating equipment.
5. Minimising water usage by reusing and recycling it in two or more successive stages.
6. Harvesting of rainwater to meet water requirements
7. Treating hot water and effluents before releasing them in rivers and ponds. Treatment of industrial effluents can be done in three phases:
a. Primary treatment by mechanical means. This involves screening, grinding, flocculation and sedimentation.
b. Secondary treatment by biological process
c. Tertiary treatment by biological, chemical and physical processes. This involves the recycling of wastewater.