Sewage treatment plant (STP) is the process of purifying sewage water and reusing it for gardening, agriculture, and other general purposes.
Purification and upkeep standards for treated sewage water are set by the Pollution Control Board. In the majority of industries, housing colonies, and flats, STP are required. STP is outfitted with highly precise components and cutting-edge technology.
STP & ETP are often confused. In contrast, an effluent treatment plant (ETP) is a device or method used to clean wastewater before it is released into the environment or used again. The process of cleaning sewage runoffs (effluents), including industrial and domestic sewage, is known as sewage treatment plant (STP).
Sewage treatment plant works by moving air to promote the development of bacteria that decompose waste. Delivering significantly cleaner, more environmentally friendly wastewater is the aim. There are some significant differences, but the process is comparable to that of a typical septic tank. Depending on its size, sewage treatment plants can handle the waste from a single business property or a large number of residential area.
City Water Purifier is one of the best sewage treatment plant service providers in Bangladesh. We are also collaborating successfully with other organizations to improve the quality of wastewater for recycling. Sewage treatment plants use primary, secondary, biological, and tertiary treatment processes.
What Are The Sewage Treatment Plant Stages?
A sewage treatment plant and a septic tank are both generally built in very similar ways. Sewage enters the first chamber of the sewage treatment plant from the property being served, much like a septic tank. Here, the water rests until sediments have accumulated on the tank’s bottom and grease, oil, and scum have floated to the top.
Sewage treatment plants and septic tanks differ in that the liquid moves into a second chamber when the separation process is complete. An air pump is installed in this chamber to move air around the space and promote the development of aerobic bacteria. By assisting in the breakdown of the water’s pollutants, this bacteria successfully cleans the water.
A final settlement tank serves as the sewage treatment plant’s ultimate stage. Before the wastewater is released into a soakaway or watercourse, this final tank enables any remaining solids to fall to the bottom of the tank.
Wastewater can be released into the environment when the treatment procedure is finished and it has been treated as fully as possible. Sewage treatment plants differ from wastewater treatment facilities in one important regard. While you need an Environment Agency Consent to Release to discharge effluent from a septic tank into a soakaway for additional treatment in the ground, you can discharge your wastewater directly from your treatment plant into nearby water sources. This is a result of the treatment procedure’ significantly improved effluent quality.
Technology Used
- ASP: Activated Sludge Process
- MBBR: Moving Bed Bioreactor
- SAFF: Submerged Aerated Fixed Film
- SBR: Sequential Bioreactor
- MBR: Membrane Bio-Reactor
- SBR: Sequential Bioreactor
Process of a Sewage Treatment Plant
Sewage can be treated by constructing a sewage treatment plant (STP) with three stages: primary, secondary, and tertiary.
Primary Treatment
Sewage water is first permitted to travel through screens or a grit chamber in a sewage treatment facility, where big solids are removed. The suspended solids settle down after aeration/mixing in a tank and then primary sedimentation. The inclusion of a coagulant as a primary treatment tries to remove grits, coarse solids, oil, and grease, if any are present.
Biological or Secondary Treatment
Through biological processes, this stage transforms organic waste in sewage into stable forms, resulting in secondary sedimentation. Trickling filters and the activated sludge technique are two common approaches.
An enclosed tank with a bed of bricks and a layer of microorganisms makes up trickling filters. The effluent is pumped into the tank through an intake and then sprinkled over the bed layer. Microbial activities oxidize the organic matter in the effluent, resulting in fine solids removal, sludge formation, and effluent with fewer organic solids.
Tertiary Treatment
The wastewater is subsequently treated with UV radiation or chlorination for tertiary treatment/disinfection. Other technologies for this step of treatment, such as sand filters and reverse osmosis, may be used instead, depending on the type of sewage and the effluent from secondary treatment.
In some countries, the word “sewage treatment plant” (or “sewage treatment works”) has been superseded by the term “wastewater treatment plant.”
Sewage can be treated near to the source of the sewage, which is known as a “decentralized” or “on-site” system (in septic tanks, biofilters, or aerobic treatment systems). Alternatively, sewage can be collected and delivered to a municipal treatment facility via a network of pipes and pump stations. A “centralized” system is what this is referred to as (see also sewerage and pipes and infrastructure).
Types of Sewage Treatment Plants (STP)
Here are a few STP systems and processes that are widely utilize
- Activated Sludge Process
- Moving Bio Bed Reactor (MBBR)
- Membrane Bio Reactor (MBR)
- Electro Coagulation System
- Sequential Bio Reactor (SBR)
- Rotating Bio Reactor (RBC)
Out all the systems mentioned above, the following are the ones that are currently most widely used:
SBR-Sequencing Batch Reactor
A waste-water treatment method that uses activated sludge is the sequencing batch reactor. The mixture of wastewater and activated sludge is bubbled with oxygen to break down the organic materials.
MBR-Membrane Bio Reactor
The membrane process and a biological waste-water treatment process are combined in the MBR-Membrane Bio Reactor. One of the most popular processes is it.
MBBR-Moving Bed Biofilm Reactor
Moving Bed MBBR Activated sludge systems require more area than a biofilm reactor, which uses less. The late 1980s saw the invention of this method.
Manufacturers of Sewage Treatment Plants (STP)
Waste from residential, institutional, commercial, and industrial organizations is referred to as sewage. The sewage is treated at the STP facility to make it safe for disposal, agricultural use, or home usage in toilets, among other things. Organic and inorganic pollutants are typically found in large quantities in sewage. Before sewage may enter any water body, it must be treated. If sewage is allowed to enter water sources without being treated, it will contaminate them; therefore, it is critical to properly treat sewage before releasing it into rivers or other water sources.
Primary Treatment Areas in an STP Plant
Wastewater is run through a screen in primary treatment to remove any big objects suspended in the water. The water then passes through a grit chamber, where the grit is removed. Sand, gravel, eggshells, bone pieces, seeds, and other items make up grit. To decrease heavy deposits in aeration tanks, digesters, channels, and conduits, grit treatment is required. The principal settling tanks are the next step. Solids sink down due to gravity and are collected as sludge from the bottom of these tanks, which are usually huge in size. In the meantime, the oil floats to the top and is skimmed off. It is estimated that 50-60% of the suspended solids will be eliminated, and the five-day biological oxygen consumption would be reduced by 30-40%.
Subsequent Treatment
The second stage of wastewater treatment is secondary treatment. Suspended solids, colloidal particles, oil, and grease are removed during the initial treatment. The wastewater is then subjected to a second biological treatment to eliminate any remaining organic debris.
Biodegradable soluble pollutants like sugar, fat, detergent and food waste are consumed by indigenous and aquatic microorganisms such as bacteria and protozoa. These processes are temperature sensitive, and the rate of biological reactions increases as the temperature rises.
Secondary treatment is separated into two types of procedures:
1. Aerobic Treatment – Aerobic wastewater treatment is a biological treatment that breaks down organic materials and removes other contaminants such as nitrogen and phosphorus using oxygen. In most cases, aerobic treatment is used in sewage treatment.
2. Anaerobic Treatment — Anaerobic treatment is a procedure in which microorganisms break down wastewater or materials without the use of dissolved oxygen. Anaerobic bacteria, on the other hand, can and will use oxygen from the oxides put into the system or from organic material in the effluent.
Treatment in the Final Stage
Tertiary treatment, often known as an advanced treatment, is the third step of wastewater treatment. The burden of nitrogen and phosphorus in the water is removed during tertiary treatment. Filtration, ion exchange, activated carbon adsorption, electrodialysis, nitrification, and denitrification are some of the processes involved.
The properties of effluent after secondary treatment and the type of water required at the end of the treatment determine the treatment options in tertiary treatment. If we need potable water, for example, filtration and disinfection are used to handle wastewater.
Applications
Sewage Treatment and Reuse Plants for
- Hotels
- Hospitals
- Residential
- Commercial Complexes
- Shopping Centers
- Institutions of Higher Learning
- Units of production
Learn More: Package Sewage Treatment Plant
Why Are Sewage Treatment Plants (STP) Necessary in Bangladesh?
Getting linked to the main sewage system should be the first consideration for anyone organizing a new development. They are often the most affordable and dependable way to handle your wastewater. It’s not always possible to get a mains sewer connection, though. In some cases, it may not be possible to have your property serviced by a mains sewer due to the distance from the closest sewer or the nature of the land. Sewage treatment plants and other options can help with that. A sewage treatment plant may be put practically anywhere as long as there is an electrical connection, thanks to the way they work.
FAQs about Sewage Water Treatment Plant
What is Sewage?
Sewage is made up of the waste water produced by hotels, homes, and sometimes even industries.
What is Sewage Treatment Plant?
The basic idea of a sewage treatment plant (STP) is to remove contaminants and poisons from wastewater by treating it using a number of physical, biological, and chemical processes. The main idea is to purify water by reproducing and enhancing natural processes that take place in the environment.
What is the Sewage Treatment Plant Purposes?
Sewage treatment plants provide a service that is vital to the environment and public health by collecting, treating, and discharging wastewater. Sewage will leak into the environment and contaminate ecosystems if it is not properly treated.
What are sewage treatment’s five stages?
- Initial Treatment: Grit chambers and screens filter out large particles and solid materials from wastewater.
- Primary Treatment: To remove solid particles from wastewater, sedimentation is used to create primary sludge.
- Secondary Treatment: Microorganisms in aeration tanks decompose organic contaminants in biological procedures.
- Tertiary Treatment: In this stage, bacteria and nutrients are eliminated using advanced methods like oxidation, disinfection, and filtration.
- Sludge Treatment and Disposal: Before being disposed of or put to good use, sludge produced throughout the process is stabilized and treated using techniques such as anaerobic digestion, dewatering, and drying.
How does an STP plant work?
The basic function of a sewage treatment plant (STP) is to remove harmful substances from wastewater by treating it through several physical, biological, and chemical processes. The main idea behind water filtration is to mimic and strengthen natural processes found in the environment.
This is accomplished by encouraging the growth of beneficial bacteria that decompose organic materials, filtering out particles, and disinfecting the water to guarantee that it satisfies quality requirements before it is released into the environment or used again.
How is the wastewater treatment process referred to?
Sewage or wastewater treatment refers to the process of treating wastewater.