The modern technology solution to treat sewage and make it reusable for further use is what we call a sewage treatment plant (STP). In other words, a type of wastewater treatment system it is!
Perhaps, it is one of the salient mechanisms to conserve the finite water resource on earth, and simultaneously conduct other activities that require water, such as gardening, irrigation, construction, etc.
Well, it is an indication that we lack awareness about STP. It is a sign that we are yet to utilize this modern technology in every industry, educational and healthcare institution, hotel, commercial building, and housing society across the country.
How about you fill your knowledge gap by exploring all about STP this time? If so, do not hesitate to read below!
What is the main objective of a sewage treatment plant?
The wastewater that gets released from household, commercial, or industrial sources every day contains harmful substances, such as suspended solids, biodegradable organic, refractory organics, pathogens, etc. So, if this water is left untreated, it can cause –
- Biological degradation,
- Deposition of sludge in the aquatic environment, creating an anaerobic condition, and
- Eutrophication, where excessive nutrients in the water body stimulate a dense growth of plants and algae.
In fact, even when you intend to reuse this water for several commercial, domestic, and industrial purposes, untreated wastewater can affect public health and safety. It opens up the path for harmful pathogens to breed and spread diseases.
Hence, a sewage treatment plant takes the stage with the aim to remove contaminants from the wastewater and ensure that the reusable water is much cleaner and environmentally-friendly. It eliminates all the above possibilities, and makes this world a better place to live in!
What are the main components of a sewage treatment plant?
A sewage treatment plant typically holds four componential systems –
- The mechanical processing system,
- The physical therapy system,
- The chemical treatment system, and
- The biological treatment system.
While the mechanical processing system includes filtration, homogenous baths, and oil separation equipment, the physical therapy system involves sedimentation and flotation apparatus.
And,
While the chemical treatment system entails instruments for undertaking oxidation and chlorination, the biological treatment system constitutes mechanisms to activate sludge and perform secondary aeration.
Note that each componential system, and each part has a specific function in the process of wastewater treatment.
What are the operational stages of a sewage treatment plant?
A sewage treatment plant operates in three main stages: the primary treatment stage, secondary treatments stage, and tertiary treatment stage.
1) Primary Treatment: The Stage of Contaminant Separation!
It is the stage where the STP seeks to separate inorganic solids and other toxic substances from the wastewater, and reduce the impact of pollutants from it. The primary treatment stage also works to homogenize the sewage, especially during a shared sewage network or extensive pouring of industrial wastewater into this chamber.
- The filter placed at the beginning of the chamber, functions to seize the large solid materials from the sewage. It may be a fine or coarse filter, depending on the type of sewage treatment plant you install.
- Then comes the shredding devices! They break the solid materials such as stones present in the wastewater.
- Next are the sand precipitators that seize fine gravel materials and sand. They reduce the volume of sediments existing in the sedimentation basins.
- Furthermore, the adjustment basins adjust the intensity of sewage water that arrives in the STP.
- On the same note, the flotation ponds begin their action to remove grease and oil from the sewage water.
- Last but not the least, the sedimentation basins intend to completely remove the fine solids that act as a burden to the biological treatment chambers. Such equipment can be rectangular or circular.
2) Secondary Treatment: The Stage of Biological Treatment!
It is the second stage of the functioning of a sewage treatment plant, where the oxidization process of various organic materials in the sewage water takes place. As a result, these substances turn into biomass and stable compounds, and the sewage water gets free from organic pollutants.
- Here, different aeration tanks, such as conventional, extended aeration, split feeding, contact stabilization, and full mixing tanks, operate together to activate sludge.
- Then appears the ventilated ponds, which provide oxygen, and keep the aerobic organisms suspended, so they can effectively decompose the organic materials in the sewage.
- Next comes the biological filters! These are where the bacterial colonies break down the nutrients in the sewage, such asnitrogen or phosphorous-containing compounds.
- Further, lay a rotating biological disk that rotates to accelerate the oxidization process.
- And the stabilization ponds act to stabilize the organic materials in the sewage via natural processes, including sunlight, atmospheric oxygen, nutrients, and so forth.
3) Tertiary Treatment: The Stage to Make Water Ready for Reuse and Its Discharge!
It is the final stage of this multi-stage wastewater treatment in a sewage treatment plant. During this stage, the final filtration process takes place. In case any contaminant remains in the treated water, despite the active operations of the primary and secondary treatment stages, the tertiary treatment runs a check and removes them. Multiple methods are used in this, from disinfection to dichlorination, and vary from one STP type to another.
- The tertiary filtration technology wipes out particulate particles through a porous medium.
- The membrane technology eliminates a wide range of wastes before the delivery of effluent water.
- The advanced oxidization system adds ozone to the water to kill bacteria and decompose organic pollutants.
What are the benefits of a sewage treatment plant?
Modern technology such as the STP, undoubtedly, provides multiple benefits to people’s lives and our ecosystem. Now, you must be wondering what those benefits are! So, here they go.
1) An STP is a high-performing wastewater treatment system.
If you are looking forward to having a proven technology that offers reliable wastewater management and treatment systems, it is none other than a sewage treatment plant.
It is because if you use such a technology, it is unlikely for you to encounter any issue. In fact, an STP works much better than others, such as a septic tank, an ascendant flow, electro-oxidation, a reed bed, and more.
Indeed, a high-performing STP can empower homes, businesses, and communities to enjoy improved safety and derive abundant reusable water for domestic, industrial, or commercial endeavors.
2) STPs are easy to install and maintain.
Sometimes, installing and maintaining heavy and complex wastewater treatment systems become challenging, specifically on compact sites. And sometimes, such installation or maintenance requires too much cost and labor. Not anymore if you opt for a sewage treatment plant!
Such technology is simple and easy to install and maintain. Of course, you would require professionals for that. But you won’t need to involve many of them!
You can position an STP in various places, be it above the ground or below! Additionally, the installation process is quick too!
3) Advanced urban STP consumes lower energy.
It is true that most STPs require a constant supply of electricity, and that too in extensive amounts. But not when you use the advanced urban STPs! That’s right! This particular STP type uses much lower energy to conduct wastewater treatment.
They lay designed in a way that fits urban sites and demands. They lay designed with environmental sustainability in mind!
So, today, where energy consumption has grown into a crucial concern, getting to treat wastewater at a nominal energy extraction yet not deteriorating the output efficiency is a rare boon.
4) STPs are cost-effective compared to other wastewater treatment technologies.
While STPs hold a long-life span, even up to around 35 years or more, they are certainly cost-effective.
Moreover, in using a sewage treatment plant, all you need to pay for are – the installation, energy, and annual maintenance. However, as the installation and maintenance processes are simple and require lesser effort, the expenses are less! There is no additional operational cost, in some cases.
On top of that, the lower energy usage, in the case of some advanced urban STP, makes it easier for you to secure a cost cut!
And over time, such benefits get reflected clearly.
5) STPs comply with the governmental standard set for the emission of pollutants.
When it comes to compliance factors, sewage treatment plants adhere to the latest standard set in terms of the emission of pollutants. The governmental bodies that set these specifications are CPCB (Central Pollution Control Board) and MoEF&CC (Ministry of Environment, Forest, and Climate Change of India).
So, you can get relief concerning the delivery of safer water from this wastewater treatment system.
If you desire a better pedigree, you can even check whether the STP you install is accredited or certified by ISO. When it is so, you can stay assured that the recycled water you receive is devoid of pollutants and pathogens.
6) Many STPs are modular and scalable.
Another significant benefit of a sewage treatment plant is, no wonder, its modular and scalable design. It is a modern and advanced version of STP that encompasses a higher concentration of bacteria for wastewater treatment.
On top of that, such state-of-the-art technology comes with custom designs! Thus, you can ask the STP provider to increase the size of this plant, making it accommodative for more wastewater treatment. These STPs have a higher effluent loading rate that can enhance the overall system footprint.
You can get various types of STPs, from an AC-SED system to an NBF system and so on!
How can you use the recycled water generated by a sewage treatment plant?
You can use the treated water from an STP for multiple purposes, some of them are:
- Use the recycled water from an STP for washing your cars and toilet flushing.
- Water the plants and gardens with the treated water.
- Use the water for construction activities, building roads and houses, the STP-treated water can serve your business activities.
- STP-treated water often comes to serve in fire protection and street washing.
- Use the water for recreational purposes too, in artificial fountains and water toys.
- Utilize this water for irrigation and agricultural purposes.
- Above all, this STP-treated water can be treated to such a level, that it becomes fit for drinking as well!
Where can you install an STP, and where can’t you, as per CPCB guidelines?
According to CPCB guidelines, you can install a sewage treatment plant –
- 250 meters away from a water body,
- Underneath any driveway,
- Beneath play areas,
- Beneath clubhouse, or
- A little far from the residence.
CPCB recommends not installing an STP in any building’s basement because that may cause complications during rain flooding or create too much noise.
Final Thoughts:
Hey, are you still here, learning all about STPs?
Well, this is a wrap-up for the time, and we shall come back soon with other wastewater management solutions. We hope the article served your purpose.
You can now grow awareness among your fellow mates regarding this modern wastewater treatment technology and encourage residential neighborhoods, institutions, commercial entities, and others to install it.
Always remember that the more sewage and wastewater gets treated, the more you get to conserve this natural resource, and similarly use it to the fullest! So, are you not up for it?
