The overall aim of treating sewage is to produce an effluent that can be discharged to the environment while causing as little water pollution as possible, or to produce an effluent that can be reused in a useful manner. This is achieved by removing contaminants from the sewage. It is a form of waste management.
Full Answer
What is the process of sewage treatment?
Physical, chemical, and biological processes are used to remove contaminants and produce treated wastewater (or treated effluent) that is safe enough for release into the environment. A by-product of sewage treatment is a semi-solid waste or slurry, called sewage sludge.
What is a by-product of sewage treatment?
A by-product of sewage treatment is a semi-solid waste or slurry, called sewage sludge. The sludge has to undergo further treatment before being suitable for disposal or application to land.
What are the different types of sewage treatment systems?
There are a high number of sewage treatment processes to choose from. These can range from decentralized systems (including on-site treatment systems) to large centralized systems involving a network of pipes and pump stations (called sewerage) which convey the sewage to a treatment plant.
What is sewage and how is it made?
Sewage contains wastewater from households and businesses and possibly pre-treated industrial wastewater. Physical, chemical, and biological processes are used to remove contaminants and produce treated wastewater (or treated effluent) that is safe enough for release into the environment.
What does sewage treatment produce?
The resulting product is a methane-rich gas, or biogas, that can be used for on-site energy needs, or processed further and used in place of natural gas. In addition, the solid remnants of the waste create a nutrient-rich “digestate” that can be added to soil to boost plant growth.
What are two products of sewage treatment?
An STP separates the incoming sewage into two different products: sewage sludge, which is a semisolid mass consisting of organic and inorganic material from the primary sewage, and purified sewage water, which is cleaned from the major part of its organic and inorganic constituents.
What happens in each stage of sewage treatment?
There are two basic stages in the treat- ment of wastes, primary and secondary, which are outlined here. In the primary stage, solids are allowed to settle and removed from wastewater. The secondary stage uses biological processes to further purify wastewater. Sometimes, these stages are combined into one operation.
What are the three types of sewage treatment?
There are three main stages of the wastewater treatment process, aptly known as primary, secondary and tertiary water treatment. In some applications, more advanced treatment is required, known as quaternary water treatment.
How is wastewater produced?
Wastewater is the polluted form of water generated from rainwater runoff and human activities. It is also called sewage. It is typically categorized by the manner in which it is generated—specifically, as domestic sewage, industrial sewage, or storm sewage (stormwater).
What are the 4 stages of wastewater treatment?
4-Step Wastewater Sludge Treatment ProcessStep 1 – Sludge Thickening. The first step in the sewage sludge treatment plan is called thickening. ... Step 2 – Sludge Digestion. After amassing all the solids from the sewage sludge begins the sludge digestion process. ... Step 3 – Dewatering. ... Step 4 – Disposal.
What does primary treatment remove?
The purpose of primary treatment is to settle material by gravity, removing floatable objects,and reducing the pollution to ease secondary treatment. Primary Treatment aims to reduce the Biochemical Oxygen Demand (BOD) and Total Suspended Solids (TSS) in the wastewater.
What are the 3 stages of water purification?
Water treatment stepsCoagulation. Coagulation is often the first step in water treatment. ... Flocculation. Flocculation follows the coagulation step. ... Sedimentation. Sedimentation is one of the steps water treatment plants use to separate out solids from the water. ... Filtration. ... Disinfection.
What decomposes sludge?
Sludge is collected by a scrapper. It is transferred to a separate tank where it is decomposed by the anaerobic bacteria. The biogas produced in the process can be used as fuel.
What sewage water contains?
The term 'sewage' describes raw sewage, sewage sludge, or septic tank waste. Raw sewage is mainly water containing excrement, industrial release and debris such as sanitary towels, condoms and plastic. Excrement is the major source of harmful microorganisms, including bacteria, viruses and parasites.
What is primary secondary and tertiary treatment?
Wastewater is treated in 3 phases: primary (solid removal), secondary (bacterial decomposition), and tertiary (extra filtration). List the steps of wastewater/sewage treatment.
What are the three sources of wastewater?
There are three types of wastewater, or sewage: domestic sewage, industrial sewage, and storm sewage. Domestic sewage carries used water from houses and apartments; it is also called sanitary sewage. Industrial sewage is used water from manufacturing or chemical processes.
Do we drink poop water?
That separates water vapor from the solid waste, and then the two part ways. Water vapor travels up and through a cleaning system that uses a cyclo...
How long does it take for poop to decompose in toilet?
The number of visitors to national parks hit an all-time high of more than 330 million in 2016. The math pretty much stinks: Humans produce up to a...
Where does sewage go after treatment?
What happens to the treated water when it leaves the wastewater treatment plant? The treated wastewater is released into local waterways where it's...
What is sewage treatment?
wastewater treatment, also called sewage treatment, the removal of impurities from wastewater, or sewage, before it reaches aquifers or natural bod...
What do sewage plants do with poop?
The wastewater flows through bar screens to remove trash and debris, then slowly moves through a grit tank where sand and heavy particles settle an...
What are the 3 stages of sewage treatment?
There are three main stages of the wastewater treatment process, aptly known as primary, secondary and tertiary water treatment.Dec 6, 2018
What is sewage treatment plant and how it works?
Primary industrial wastewater treatment plant uses screens, grit chamber, and sedimentation tank to get quality water which is free from waste and...
What is the main purpose of sewage treatment?
The basic function of wastewater treatment is to speed up the natural processes by which water is purified. There are two basic stages in the treat...
Does shower water and toilet water go to the same place?
That separates water vapor from the solid waste, and then the two part ways. Water vapor travels up and through a cleaning system that uses a cyclo...
What happens when you flush the toilet while showering?
The shower and toilet are connected to the sanitary sewer system. The wastewater from both can be treated at the same facility. Gray water is waste...
What are the methods of sewage treatment?
The Toilet Flush When the toilet flushes while you're showering, the toilet demands a load of cold water, and because it shares a cold water line w...
What happens during the first stage of sewage treatment plant?
Majorly, four methods of sewage water treatment are followed – physical, biological, chemical, and sludge water treatment. By following these metho...
Where does poop go after the sewer?
Primary treatment in sewage treatment involves physical removal of particles (large and small) from the sewage through filtration and sedimentation...
What do sewage plants do with poop?
From the toilet, your poop flows through the city's sewage system along with all the water that drains from our sinks, showers and streets. From th...
What are the 5 stages of sewage treatment?
The wastewater flows through bar screens to remove trash and debris, then slowly moves through a grit tank where sand and heavy particles settle an...
What are the 3 stages of sewage treatment?
There are three main stages of the wastewater treatment process, aptly known as primary, secondary and tertiary water treatment.Dec 6, 2018
Stage 1: Primary Treatment (Solid Removal)
This stage essentially includes the process of sedimentation. The water is held in the large sedimentary or rainwater tanks where the settleable solids are removed. Since the sedimentation tanks work on the principle of gravity, the solids settle at the bottom, and the lighter solids float in the tanks.
Stage 2: Secondary Treatment (Bacterial Decomposition)
This stage involves the removal of soluble organic solid matter. It also deals with the treatment of smaller suspended particles. In this process, waste is broken down by aerobic bacteria and incorporated into the wastewater system. There are various methods under the secondary treatment. These are as follows:
Stage 3: Tertiary Treatment (Extra Filtration)
Tertiary treatment is also known as polishing and disinfecting the water with the highest standards. This stage is critical to producing the water to a particular specification such as technical water, mineral water etc. It is also used to treat the water in public systems.
Overview
Purposes and overview
The overall aim of treating sewage is to produce an effluent that can be discharged to the environment while causing as little water pollution as possible, or to produce an effluent that can be reused in a useful manner. This is achieved by removing contaminants from the sewage. It is a form of waste management.
With regards to biological treatment of sewage, the treatment objectives can include various de…
Terminology
The term "sewage treatment plant" (STP) (or "sewage treatment works" in some countries) is nowadays often replaced with the term wastewater treatment plant (WWTP). Strictly speaking, the latter is a broader term that can also refer to industrial wastewater.
The terms "water recycling center" or "water reclamation plants" are also in use.
Types of treatment processes
Sewage can be treated close to where the sewage is created, which may be called a "decentralized" system or even an "on-site" system (on-site sewage facility, septic tanks, etc.). Alternatively, sewage can be collected and transported by a network of pipes and pump stations to a municipal treatment plant. This is called a "centralized" system (see also sewerage and pipes and inf…
Design aspects
The "per person organic matter load" is a parameter used in the design of sewage treatment plants. This concept is known as population equivalent (PE). The base value used for PE can vary from one country to another. Commonly used definitions used worldwide are: 1 PE equates to 60 gram of BOD per person per day, and it also equals 200 liters of sewage per day. This concept is also used as a comparison parameter to express the strength of industrial wastewater compare…
Available process steps
Sewage treatment often involves two main stages, called primary and secondary treatment, while advanced treatment also incorporates a tertiary treatment stage with polishing processes. Different types of sewage treatment may utilize some or all of the process steps listed below.
Preliminary treatment (sometimes called pretreatment) removes coarse mater…
Environmental impacts
Sewage treatment plants can have significant effects on the biotic status of receiving waters and can cause some water pollution, especially if the treatment process used is only basic. For example, for sewage treatment plants without nutrient removal, eutrophication of receiving water bodies can be a problem.
Reuse
Increasingly, people use treated or even untreated sewage for irrigation to produce crops. Cities provide lucrative markets for fresh produce, so are attractive to farmers. Because agriculture has to compete for increasingly scarce water resources with industry and municipal users, there is often no alternative for farmers but to use water polluted with sewage directly to water …