activated sludge process calculations - Sewage Treatment Plant Manufacturers

February 18, 2023

What is a Sewage Treatment Plant?

Sewage treatment plants are designed to treat and purify wastewater generated by households, industries, and commercial companies. The wastewater includes human and animal waste, food waste, cleaning products, and other contaminants.

The primary objective of a sewage treatment plant is to remove contaminants and pollutants from wastewater so that it can be safely disposed of or recycled for other uses. A sewage treatment plant typically consists of several stages, including primary, secondary, and tertiary treatment.

The primary treatment involves removing heavy solids and organic matter from the wastewater through a physical process such as sedimentation and screening. The secondary treatment is a biological process that includes removing the organic matter using microorganisms. The tertiary treatment, on the other hand, involves removing any remaining contaminants from the water through chemical or physical processes.

Sewage treatment plant manufacturers are essential to maintaining a clean and healthy environment. Untreated wastewater can have a significant impact on human health and the environment. It can lead to the spread of diseases, contaminate soil and water, and damage aquatic life.

Types of Sewage Treatment Plants

There are several types of sewage treatment plants, each with its own set of features and benefits. The most common types of sewage treatment plants include:

Activated Sludge Process (ASP)

The activated sludge process is the most commonly used sewage treatment plant. It involves introducing air into the wastewater to encourage the growth of microorganisms that break down organic matter. The process is effective in removing contaminants such as nitrogen and phosphorus.

The activated sludge process is widely used because it is effective in removing organic components and fertilizers from wastewater, and can be operated with a relatively small footprint. However, it can be energy-intensive due to the need for aeration and can also produce large amounts of excess sludge that require disposal or further treatment. As a result, modifications to the process, such as the use of advanced treatment technologies or the implementation of a sludge reduction program, may be necessary to optimize its performance and reduce its environmental impact.

Activated Sludge Process

Extended Aeration Process (EAP)

The extended aeration process is similar to the activated sludge process, but it involves a longer retention time. This allows the microorganisms to break down the organic matter more effectively, resulting in a higher quality of effluent.

The extended aeration process is known for its ability to produce high-quality effluent, even under variable or low wastewater flow conditions. It also typically requires less energy than other types of activated sludge processes, as the slower rate of microbial growth and longer aeration time results in less oxygen demand. However, the extended aeration process may require a larger footprint due to the larger aeration tank required and can produce more sludge than other processes, which may require additional handling and disposal.

Extended Aeration Process

Sequential Batch Reactor (SBR)

The sequential batch reactor is a batch process that involves alternating between anoxic and aerobic conditions. This process allows for the removal of nitrogen and phosphorus from the wastewater.

SBRs can operate using either aerobic or anaerobic conditions, depending on the specific treatment needs. In the aerobic SBR, air is provided to the tank during the reaction phase to provide oxygen for the microorganisms. In the anaerobic SBR, the treatment occurs in the absence of oxygen, allowing anaerobic microorganisms to break down organic matter.

Sequential Batch Reactor

Membrane Bioreactor (MBR)

The membrane bioreactor combines biological treatment with membrane filtration to produce high-quality effluent. The process is efficient in removing solids and contaminants from the wastewater.

MBRs can use either submerged or external membrane filtration. Submerged MBRs place the membrane directly into the aeration tank, while in external MBRs, the membrane is placed in a separate tank and the mixed liquor is pumped through the membrane.

Membrane Bioreactor

Moving Bed Biofilm Reactor (MBBR)

The moving bed biofilm reactor involves attaching biofilm to plastic carriers that move freely in the wastewater. The process is effective in removing organic matter and nitrogen from the wastewater.

In an MBBR, wastewater flows through a reactor tank containing the suspended biofilm carriers, which provide a surface for the growth of microorganisms. The aeration or mixing of the wastewater ensures that the biofilm carriers are constantly moving and in contact with the wastewater, which promotes the growth of the microorganisms on their surface.

As the wastewater flows through the reactor, the microorganisms on the biofilm carriers consume organic matter, converting it into biomass and other byproducts. The treated wastewater is then discharged, while the biofilm carriers are recycled back to the reactor tank.

Moving Bed Biofilm Reactor

Sewage Treatment Plant Manufacturers – Expert Solutions for Your Wastewater Treatment Needs

Choosing the right sewage treatment plant manufacturer is essential to ensure the quality and efficiency of the plant. Here are some of the top sewage treatment plant manufacturers:

Netsol Water

Netsol Water  Top Most leading Sewage Treatment Plant Manufacturer in India, starts manufacturing new wastewater machines –  Sewage Treatment Plant 5kld5kld packaged STP, Sewage Treatment Plants, and Zero Liquid Discharge Plants to safeguard “ Mother Earth Resources ”  – Save Water Now !!!
Netsol Water is always ready to solve problems and fulfill the expectations of our clients through the Netsol research wing. For this time we’re ready by Adopting and enhance the Best European Technology for “Compact STP”, And Launch a new Product Named- “Compact Sewage Treatment Plant“. This is for those Households, Hotel, Resorts, Farmhouses, and Schools who have low spaces or want a compact wastewater treatment plant at their place which take a low space and works efficiently & effectively.

Factors to consider when choosing a sewage treatment plant manufacturer

Urban STP plant

Urban STP Plant Top Most driving Conservative Sewage Treatment Plant Producer in India, begins fabricating other wastewater machines – Smaller Sewage Treatment Plant 5kld, 5kld bundled STP, Sewage Treatment Plants, and Zero Fluid Release Plants to shield ” Mother Earth Assets ” – Save Water Now.

Sewage Treatment Plants

We are the Sewage Treatment Plants (A Unit of Netsol Group & Research), having the best solution by STP Plant Manufacturer for waste and wastewater treatment. Since our establishment in the year 2012, we are one of the most trusted partners for waste management solutions. And integrated service providers of design, fabrication, installation, and maintenance services. With our years of expertise, we are the leading service provider for solutions, testing, monitoring, analysis, and recommended corrective actions in the field of waste and wastewater solutions.
We are the best solution provider for treating sludge and industrial effluent to save water as well as to save mother earth.

With our best innovation of Green Waste Converter Machine, we are daily converting thousands of kilo composite by treating Green and organic waste.

Factors to consider when choosing a sewage treatment plant manufacturer

Choosing a sewage treatment plant manufacturer is a decision that should be taken seriously. It is important to choose a manufacturer that provides quality products and services. Here are some factors to consider when choosing a sewage treatment plant manufacturer:

Experience: It is important to choose a manufacturer that has been in the industry for a significant amount of time. An experienced manufacturer is likely to provide better products and services.

Reputation: A good reputation is a clear indication of a manufacturer’s ability to deliver quality products and services. You can check the manufacturer’s website for customer reviews and testimonials.

Quality of products: The quality of products is a critical factor to consider. It is important to choose a manufacturer that provides high-quality products that meet your specific needs.

Customer service: Good customer service is important in any business. Choose a manufacturer that provides excellent customer service and is always available to answer your questions and address any concerns.

Price: The cost of the products and services is a significant factor to consider when choosing a manufacturer. It is important to choose a manufacturer that provides quality products and services at a reasonable price.

Why Choose Us?

We are one of the top manufacturers of sewage treatment plants in India, with years of experience and a track record of providing dependable and effective solutions to our customers. All sizes and capacities of sewage treatment plants can be designed, installed, and maintained by our team of professionals due to their technical skills and knowledge.

We offer a wide range of solutions, including:

  • Traditional sewage treatment plants
  • Packaged sewage treatment plants
  • Membrane bioreactor (MBR) plants
  • Sequential batch reactor (SBR) plants
  • Extended aeration (EA) plants
  • Moving bed biofilm reactor (MBBR) plants

All our solutions are designed to meet the highest quality standards and are backed by excellent after-sales service and technical support.

FAQs about sewage treatment plant manufacturers

What is a sewage treatment plant?

A sewage treatment plant is a facility that processes and treats wastewater to remove contaminants and produce clean water that can be safely discharged into the environment.

Why is it important to choose a reputable sewage treatment plant manufacturer?

Choosing a reputable sewage treatment plant manufacturer ensures that you receive high-quality products and services that meet your specific needs.

What are the different types of sewage treatment plants?

The different types of sewage treatment plants include conventional sewage treatment plants, package sewage treatment plants, and mobile sewage treatment plants.

How long do sewage treatment plants last?

Sewage treatment plants can last for up to 20-30 years, depending on the quality of the products and the maintenance practices.

What factors should I consider when choosing a sewage treatment plant?

The factors to consider when choosing a sewage treatment plant include the size and capacity of the plant, the quality of the products, the reputation of the manufacturer, and the cost of the products and services.

Sewage Treatment Plant Manufacturer in India
Sewage Treatment Plant Manufacturer in India


December 31, 2020

Biological treatment processes are a crucial component in many wastewater treatment systems. They’re one of the foremost efficient and effective ways of reducing organic material within the wastewater. There are quite a few of them that are researched and used over several decades. However, one among the foremost widely used conventional biological treatment processes is that the activated sludge process (ASP). Many sewage treatment plants use ASP within their secondary treatment steps thanks to the human and animal organic matter in the inlet waters of wastewater treatment plants.

The term “activated sludge” comes from the very fact that the sludge contains live bacteria and protozoa that actively digest and break down sewage. it’s different from the sludge solids removed following a settling process therein way, with the addition of being odorless.

The process itself involves pumping the effluent from the first treatment clarification step into an outsized tank that contains the activated sludge. The mixture is subjected to aeration, either from submerged or surface aerators. This provides oxygen to the effluent that the bacteria can then use to interrupt down the organic waste. After a sufficient amount of hydraulic retention time, the resulting slurry is pumped into a clarification system or tank to settle out the remaining solids. The treated water is pumped far away from the highest to any subsequent polishing filtration and disinfection while the sludge at rock bottom is re-circulated back to the ASP tank to reseed the leftover activated sludge.

We have included the most potential disadvantages of the activated sludge process to be discussed below.

Hydraulic Retention Time


Perhaps the foremost important aspect of any wastewater treatment process is time. Any treatment solution needs time to run its course and certain treatments take longer than others. ASP is one of those solutions. Thanks to the ratio of sewage to sludge and the way the method occurs, the hydraulic retention time of ASP can take most of each day (12-24 hrs.) or up to many days (3-5) to realize appropriate levels of treatment results.

Sludge Retention Time / Recycling

Time also applies to the medium of the reaction. In this case, the medium is that the activated sludge. With regards to the sludge itself, an ASP is an open system and there’s a special mass rate entering the system than there’s exiting the system.

Overtime (without a recirculation system) all of the activated sludge within the tank would get pumped out. the thought is to maximize the time the sludge spends within the system. this point is to make sure there’s enough biomass to interrupt down the incoming organic matter; hence the necessity for recirculation.

Therefore, as most suspended growth biological processes or fixed film processes including MBBR have higher sludge retention times, ASP tends to possess lower sludge retention times.


Due to both of the points stated above, reactor tanks for the activated sludge process (ASP) tend to be quite large so as to treat larger volumes of effluent. this needs large areas of land needed for his or her operation.

Changes in Volume or Character of Sewage

ASP can treat large quantities of varied organic materials, but the reaction depends on variables that make it quite vulnerable to an error in conditions outside of these it had been designed for.

In particular, changes in sewage volume and sewage characteristics may result in decreased treatment quality or treatment upsets. If a treatment plant decided it wanted to extend its treatment volume or began treating wastewater from a replacement and different source, the ASP reactors would typically be got to be completely redesigned accordingly.

Sludge Disposal

As are often expected from handling a treatment process that uses sludge to treat sewage, there are considerable volumes of sludge that require to be disposed of after this process. Larger sludge volumes mean higher associated disposal costs.

Operation / Supervision

Biology may be a complex subject; therefore, it stands to reason that a biological water treatment process would be complex in certain aspects. On a broad scale, the general process seems simple enough. However, the planning and operation of an Activated sludge reactor typically require experts in biological systems design to watch it. A system like this needs a touch more skilled supervision than simply watching out for mechanical failures and monitoring pH. There must be highly skilled operators and supervisors which will check for the viability and efficiency of the bacteria and protozoa within the sludge to stop system upsets.

Issues with Sludge Settling

Some of the most important issues with the activated sludge process reveal themselves in how everything settles call at the secondary clarification process. Sometimes, the solids don’t compact alright at rock bottom and therefore the sludge has high water content.

Sometimes, the supernatant (floating material) has higher turbidity than you would like which may affect the top effluent water quality. Other issues may result in decreased concentrations of return activated sludge.


For any queries and consultants regarding Sewage Treatment Plant and Effluent Treatment Plant or Commercial RO Plant, please call us on +91-9650608473 or you can write to us on

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