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Question
What are the different types of inorganic and organic impurities generally present in sewage?
Solution
Wastewater is generated in homes, industries, hospitals, hotels, offices and other places. Domestic wastewater contains urine,’ faeces, detergent and dirt released after washing clothes and utensils, and food wastes. Industrial wastewater contains poisonous chemicals. Wastewater from hospitals may contain several types of disease-causing germs, and dangerous radioactive materials (material that emits harmful rays). Rainwater that has run down the land also forms wastewater as it contains fertilisers and pesticides from agricultural fields. All this wastewater forms sewage. Sewage contains dissolved and suspended impurities known as contaminants. Various inorganic and organic impurities present in sewage are as follows:
- Inorganic impurities – nitrates, phosphates and metals
- Organic impurities – fruit and vegetable wastes, oil, urea, human faeces, animal waste, pesticides and herbicides.
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