Wastewater means water that is contaminated, impure and is used water that is released from households (in form of human excreta, washing and various domestic usage), industries (from drainage, toxic waste) and from various sources.
Various effect of wastewater are:
- Destruction of natural habitats due to harmful chemicals.
- Waterborne diseases affect the health of people.
- Wastewater treatment is not always effective as sometimes water is not treated properly. So if this water is used in irrigation it affects crops as well as soil.
- If released in water bodies it affects aquatic animals and crops. It leads to eutrophication.
Removal of harmful chemicals and microorganisms from wastewater is called disinfection of wastewater.
Disinfectants are added to wastewater to kill disease-causing germs and microorganisms.
The first few methods for a disinfectant for wastewater are chlorination, ozone, UV light, potassium permanganate and chloramines.
Disinfectants for Waste Water Management are as follows:
Chlorine gas is often used as a disinfectant for wastewater Management, as it removes harmful microorganisms from water. It is a widely used method as it cost less than any other method.
Chlorination with sodium hypochlorite (NaOCl) solution contains chlorine but in less quantity is used as a Disinfectant for water purification and is easy to handle and store.
Chloramines used as a disinfectant are formed by the reaction of ammonia with free chorine and it is safer than chlorine gas as it produces fewer by-products.
Ozonation used as a disinfectant for wastewater that is ozone (O3) reacts in water and kills harmful germs in few seconds without causing the false odour, color change or change in taste.
There are various water treatment technologies that help in reusing of wastewater are:
- physical water treatment
- biological water treatment
- chemical treatment
- sludge treatment
Physicalwater treatment used for the treatment of wastewater without the use of chemicals. It consists of physical methods. The main techniques involved are sedimentation, aeration, filtration.
Biological water treatment used for the treatment of wastewater involves biological processes which consists of three process namely: Aerobic process, Anaerobic process and composting.
Chemical treatment involvesthe use of chemicals for wastewater treatment that we read about earlier like chlorination, use of ozone, etc.
Sludge treatment is a process in which the solid is separated from the liquid. The main method for this is a centrifuge.
It’s crucial to use disinfectant for wastewater as wastewater is harmful to all the biotic and abiotic components of the world. So to protect them from harmful impacts its necessary to take steps to prevent water pollution and less wastage of water.
Wastage of water leads not only add to wastewater but also reduces its availability for the future generation. So wastewater treatment is used to remove contamination and harmful microorganisms from the water.
There are three stages for waste water treatment these are primary, secondary and tertiary. At last stage, that is at the tertiary stage, water is fully capable to meet domestic and industrial requirements as it becomes safe for usage.
