What is sewage?

Sewage is wastewater created by residential, industrial, educational and commercial establishments and also by hospitals. It includes household waste liquid from kitchens, toilets, baths, and liquid water from industries and hospitals that is disposed of via sewers.

Sewage may include stormwater runoff. Water that washes off roads and rooftops carries harmful substances with it. Sewage is liquid waste. Impurities present in the sewage are called pollutants.

What does sewage contain?

Organic impurities include- human feces, animal waste, oil, urea (urine), pesticides, herbicides, fruit and vegetable waste, etc.

Inorganic impurities such as nitrates, phosphates, and metals.
Nutrients such as phosphorus and nitrogen
Bacteria- such as which cause cholera and typhoid
Other microbes such as which cause dysentery.

Types of sewages

� Sullage water- wastewater released from the kitchens is called sullage water.
� Foul waste- wastewater released from toilets is termed foul waste. It is highly infectious.
� Trade waste- waste released from industries and commercial organizations is called trade waste. It contains acids and chemicals that are toxic in nature.

ALTERNATIVE ARRANGEMENT FOR SEWAGE DISPOSAL

To improve sanitation, low-cost onsite sewage disposal systems are being encouraged. Examples are septic tanks, chemical toilets, and composting pits.

Septic tanks are suitable for places where there is no sewerage system, for hospitals, isolated buildings, or a cluster of 4 to 5 houses.

Some organizations offer hygienic on-site human waste disposal technology. These toilets do not require scavenging. Excreta from the toilet seats flow through covered drains into a biogas plant. The biogas produced is used as a source of energy.

Read More:
Better Housekeeping Practices To Avoid Wastewater: Class 7 - Studynlearn