The primary, secondary, and tertiary wastewater treatment stages are the three main phases of the wastewater treatment process. More sophisticated treatment, or quaternary water treatment, is necessary in particular applications.
These steps deal with pollution at the part per million to part per billion levels, and frequently use oxidation or fine filtering techniques. As the water progresses through these stages, it becomes cleaner and each stage targets a new pollutant.
Let’s look at the various differences between the primary, secondary and tertiary treatment of wastewater.
What is the importance of treating wastewater on a primary, secondary, and tertiary level?
One of the crucial steps in removing BOD, phosphorus, nitrogen, sediments, and germs from wastewater is by treating it.
Wastewater has a complicated composition that varies based on the sources, the type of treatment, or lack thereof. Wastewater treatment plants are designed to speed up the natural cleaning of water. The number of people on the planet and the amount of wastewater they produce are too much for the natural processes. The volume would cause mayhem without wastewater treatment.
More than 80% of the wastewater that is released globally is untreated. The nations that do have wastewater treatment plants, employ a range of procedures to treat the water, with one common goal in mind: to purify the water as much as is humanly possible before releasing it back into the environment to preserve human and environmental safety.
· Wastewater treatment safeguards the environment and people
1: Elements in wastewater are hazardous to both people and the environment. These treatment facilities aid in the water purification and thus, help to prevent problems.
2: Unclean water provides serious health concerns and is responsible for 1.7 million annual deaths, more than 90% of which occur in developing nations.
3: In many developing nations, where only a very tiny portion (in some cases less than 5 percent) of domestic and urban wastewater is treated, before being released into the environment, some water-related diseases, such as cholera and schistosomiasis, continue to be common.
4: The ecology is also protected by wastewater treatment. Fresh and clean water is necessary for the fish and the aquatic life. They are unable to survive when the water they live in is polluted. Excessive levels of chemicals, such as nitrogen and phosphates, can cause excessive plant growth and the discharge of toxins into water in streams, rivers, and other large bodies of water. Dead zones, where fish and other aquatic life can no longer exist, are the result of oxygen deprivation.
· The process of naturally treating water is overworked/overloaded
The amount of effluent is too much for Mother Nature to handle, despite her best efforts. The wastewater is increasing due to size and the growth of the population. Natural wastewater processing cannot keep up with the enormous amounts present.
· Reintroduces cleaned water to the ecosystem
Wastewater treatment facilities reintroduce water into the environment after cleaning it in a manner similar to nature.
What is the difference between primary, secondary and tertiary treatment of wastewater?
There are various techniques for treating wastewater:
· Preliminary wastewater treatment
Many solids that can't be removed by the wastewater treatment process are present in the wastewater, when it reaches the treatment facility. Rags, paper, wood, food scraps, eggshells, plastic, toys, and even money might fall into this category.
The wastewater enters a structure known as the Headworks and travels through huge screen filters to remove these solids. After that, a dumpster is used to transport the solids to the landfill.
· Primary treatment of wastewater
During primary treatment, wastewater is momentarily held in a settling tank where heavier solids sink to the bottom, and lighter solids float to the top. As soon as the materials have settled, they are held back while the liquid is drained or continues to a second, more rigorous stage of wastewater treatment.
The sludge that has accumulated at the bottom of these gigantic tanks is continuously moved, by motorised scrapers into a hopper before being pumped to sludge treatment facilities.
Use of Primarily clarifiers in primary wastewater treatment
The wastewater from the Headworks enters two enormous circular tanks known as Primary Clarifiers. Each of these tanks has a capacity of around 600,000 gallons. Here, the wastewater slows down and spends roughly two hours in the tanks. As a result, any substance suspended in the effluent can either float to the top or sink to the bottom.
These materials are taken out of the wastewater by large paddles that slowly revolve over the Primary Clarifier's surface and floor. Clarifiers are covered to cut down on smells.
· Secondary or biological treatment of wastewater
Basins for aeration
A biological procedure known as the "activated sludge ?process" is used to cleanse the wastewater, after it exits the primary clarifiers into big, rectangular tanks called aeration basins. Large amounts of air bubble up through the water as the wastewater slowly moves through a succession of chambers. There is so much extra air that it gives the impression that the water is boiling. The wastewater is combined with "activated sludge," or hundreds of millions of single-celled microorganisms (mainly bacteria and protozoa), which are actively developing, in these basins.
The creatures depend on the air to survive and grow. The wastewater gets cleaned while the microorganisms eat it. After eight hours, when all of the food (waste) has been consumed, the wastewater exits the aeration basins.
Use of secondary clarifiers in secondary treatment of wastewater
To keep the process moving, some of the microorganisms are returned to the Aeration Basin. Some organisms proceed to the Secondary Clarifiers, the next stage of the treatment process, along with the wastewater. The Aeration Basins have a capacity of 1.1 million gallons.
Thus, the wastewater still has a lot of microorganisms from the aeration basins when it enters the two secondary clarifiers, and is brown and murky in appearance. Materials in the wastewater sink and float, and spinning arms remove this material from the wastewater in the Secondary Clarifiers, which function just like the Primary Clarifiers.
Tertiary wastewater treatment
Physical and chemical wastewater from the secondary clarifiers after tertiary treatment, such as the use of advanced oxidation, RO Plants, UV water purification systems is as clean as drinking water! This water can travel directly to the disinfection process to create recycled water, depending on the circumstances.
Also, a number of sand filters can filter gallons of water per hour. Prior to disinfection, the filters remove very small particulates also known as "suspended solids" from the wastewater. At this stage, polymers are added to make the suspended solids cluster together and make them easier to filter out.
Conclusion
We all need access to clean water in order to live normal lives. Without it, there would be a lot of risky and dangerous lifestyle choices. Hence, protecting people and the environment from the hazardous and destructive substances, contained in wastewater is the primary objective of wastewater treatment facilities. Because, the natural process of purifying water is overburdened, wastewater treatment facilities are created to accelerate the natural process. These wastewater treatment plants are used to cleanse wastewater in a variety of ways.
Netsol Water specialises in industrial wastewater treatment plants in order to ensure that criteria for safe water discharge or reuse are followed. Our specialised solution targets the impurities that are most difficult to treat.
Therefore, we are delighted to offer field services and assistance with the choice of treatment products, in addition to providing comprehensive system design and engineering. To find out more, get in touch with us at +91 9650608473 or enquiry@netsolwater.com
