Community Water Treatment
- Coagulation and Flocculation Coagulation and flocculation are often the first steps in water treatment. Chemicals with a positive charge are added to the water. ...
- Sedimentation During sedimentation, floc settles to the bottom of the water supply, due to its weight. This settling process is called sedimentation.
- Filtration Once the floc has settled to the bottom of the water supply, the clear water on top will pass through filters of varying compositions (sand, gravel, and charcoal) and ...
- Disinfection After the water has been filtered, a disinfectant (for example, chlorine, chloramine) may be added in order to kill any remaining parasites, bacteria, and viruses, and to protect the ...
What are the steps in the water treatment process?
The water treatment process to deliver safe and wholesome water to customers includes many steps. Coagulation, flocculation, sedimentation, filtration, and disinfection are the water treatment processes that make up a conventional surface water treatment plant.
Do you know the 5 stages of water treatment?
So, knowing the 5 stages of water treatment is of the utmost importance. As water enters a water treatment plant, either from lakes, rivers, or the ground, it passes through a screening. This screening keeps large natural contaminants out of the water.
What is the community water treatment process?
Community Water Treatment. Sedimentation During sedimentation, floc settles to the bottom of the water supply, due to its weight. This settling process is called sedimentation. Filtration Once the floc has settled to the bottom of the water supply, the clear water on top will pass through filters of varying compositions (sand, gravel,...
How does the surface water treatment rule apply to your system?
In order to meet the requirements of the Surface Water Treatment Rule, a water system must both remove and inactivate the pathogens in the water. This process begins with coagulation, which destabilizes the particles in the water.
What is the most important step in drinking water treatment?
Filtration Filtration is necessary due to the small, dissolved particles that are still present in clear water, which include dust, parasites, chemicals, viruses, and bacteria.
What are the three main steps of water treatment?
There are three main stages of the wastewater treatment process, aptly known as primary, secondary and tertiary water treatment.
What are the 8 steps of water treatment?
Treatment StepsStep 1: Screening and Pumping. ... Step 2: Grit Removal. ... Step 3: Primary Settling. ... Step 4: Aeration / Activated Sludge. ... Step 5: Secondary Settling. ... Step 6: Filtration. ... Step 7: Disinfection. ... Step 8: Oxygen Uptake.
What are the four basic processes of water treatment system?
Chemical processes such as neutralisation, disinfection, flocculation and precipitation. Membrane processes such as filtration, osmosis and nanofiltration.
What is the fourth step of raw water treatment?
In the fourth step called ozonation, plant workers add a gas called ozone to destroy bacteria and other microorganisms as well as to improve taste. From there, the water is filtered using granular activated carbon to remove any fine particles.
What are the three stages in the treatment of water give the objectives of each stage?
The three stages of wastewater treatment are known as primary, secondary and tertiary. Each stage purifies water to a higher level. In some applications, only one or two stages are necessary. The level of treatment necessary depends on the water's intended use case, and what environment it will be discharged into.
What are the 6 steps of drinking water treatment?
They typically consist of several steps in the treatment process. These include: (1) Collection ; (2) Screening and Straining ; (3) Chemical Addition ; (4) Coagulation and Flocculation ; (5) Sedimentation and Clarification ; (6) Filtration ; (7) Disinfection ; (8) Storage ; (9) and finally Distribution.
What are the 7 steps in wastewater treatment?
The Wastewater Treatment ProcessStage One — Bar Screening. ... Stage Two — Screening. ... Stage Three — Primary Clarifier. ... Stage Four — Aeration. ... Stage Five — Secondary Clarifier. ... Stage Six — Chlorination (Disinfection) ... Stage Seven — Water Analysis & Testing. ... Stage Eight — Effluent Disposal.
What are the 7 steps to clean water?
The 7 Steps to Purify WaterScreening. ... Coagulation and Flocculation. ... Sedimentation. ... Filtration. ... Disinfection. ... Corrosion and Scale Control. ... Taste and Odor Control.
What is a water treatment system?
A wide variety of water treatment systems and devices exist that remove or reduce unwanted chemicals and/or microorganisms through disinfection, physical filtration, adsorptive filtration, oxidation/reduction and chemical exchange reactions in order to make water potable or improve the aesthetics of the water.
What are the steps of water treatment?
Today, the most common steps in water treatment used by community water systems (mainly surface water treatment) include: Coagulation and flocculation are often the first steps in water treatment. Chemicals with a positive charge are added to the water.
What is the most common type of water treatment system?
The most common types of household water treatment systems consist of: Filtration Systems. A water filter is a device which removes impurities from water by means of a physical barrier, chemical, and/or biological process. Water Softeners. A water softener is a device that reduces the hardness of the water.
How does a water treatment unit work?
Even though EPA regulates and sets standards for public drinking water, many Americans use a home water treatment unit to: 1 Remove specific contaminants 2 Take extra precautions because a household member has a compromised immune system 3 Improve the taste of drinking water
What is the process of boiled water?
Distillation is a process in which impure water is boiled and the steam is collected and condensed in a separate container, leaving many of the solid contaminants behind. Disinfection. Disinfection is a physical or chemical process in which pathogenic microorganisms are deactivated or killed.
What is a water softener?
Water Softeners. A water softener is a device that reduces the hardness of the water. A water softener typically uses sodium or potassium ions to replace calcium and magnesium ions, the ions that create “hardness.”. Distillation Systems.
Why is chlorine added to water?
After the water has been filtered, a disinfectant (for example, chlorine, chloramine) may be added in order to kill any remaining parasites, bacteria, and viruses, and to protect the water from germs when it is piped to homes and businesses.
Why do people use water treatment units?
Even though EPA regulates and sets standards for public drinking water, many Americans use a home water treatment unit to: Remove specific contaminants. Take extra precautions because a household member has a compromised immune system. Improve the taste of drinking water.
Why is it important to know the 5 stages of water treatment?
Meeting these standards is crucial to ensure water is properly purified and impacts the community positively . Safe drinking water is a key factor of the health and safety of a community. So, knowing the 5 stages of water treatment is of the utmost importance. As water enters a water treatment plant, either from lakes, rivers, or the ground, ...
Why do we need to go through a water screening?
As water enters a water treatment plant, either from lakes, rivers, or the ground, it passes through a screening. This screening keeps large natural contaminants out of the water. These can be anything from wood to fish. With ground water sources, it is not as necessary to go through screening, as its extraction from the ground acts, in itself, as a natural screening process.
How many people get their water from the water system?
According to the Environmental Protection Agency (EPA), 286 million people get their drinking water from a community water system. To make water safe for public consumption, it undergoes a series of treatments and tests on its journey from source to tap. Let’s explore some of the risks associated with drinking contaminated water, ...
What is the second stage of sedimentation?
2. Sedimentation. The second stage takes place when the suspended matter and pathogens settle at the bottom of a container. The longer the water sits undisturbed, the more solids will succumb to gravity and fall to the container floor.
Why is floc filtration necessary?
Filtration is necessary due to the small, dissolved particles that are still present in clear water, which include dust, parasites, chemicals, viruses, and bacteria.
Why is sedimentation more effective?
Coagulation makes the sedimentation process more effective because it makes the particles larger and heavier, causing them to sink more quickly . For a community water supply, the sedimentation process must happen continuously and in large sedimentation basins.
What is the charge of coagulation?
In coagulation, positively charged chemicals such as aluminum sulphate, polyaluminum chloride or ferric sulphate are introduced to the water to neutralize the negative charges held by solids, including dirt, clay, and dissolved organic particles.
What happens to the particles after coagulation?
After coagulation, a gentle mixing known as flocculation occurs, causing microflocs to collide with each other and bond together to form visible suspended particles.
What are the risks of drinking water?
Drinking water has the potential to be contaminated at its source as well as within the water distribution system. The EPA is responsible for regulating the quality of the drinking water in the U.S. and sets the maximum allowable levels for concentrations of various contaminants. Some of these are chemicals, organisms and pollutants that lead to dangerous health effects such as neurological disorders, gastrointestinal illness, reproductive issues, and increased risks for illness in people with compromised immune systems. The Centers for Disease Control and Prevention (CDC) ranked the top 10 contaminants in water systems that cause health issues: 1 Giardia 2 Legionella 3 Norovirus 4 Shigella 5 Compylobacter 6 Copper 7 Salmonella 8 Hepatitis A 9 Cryptosporidium 10 E.coli and excess fluoride (tied)
How many steps are involved in water treatment?
There are seven major steps involved in the large-scale water treatment for urban municipal water supply. Each of the steps are described in the article below,
What is water treatment?
Water treatment is the process of removing all those substances, whether biological, chemical, or physical, that are potentially harmful to the water supply for human and domestic use. This treatment helps to produce water that is safe, palatable, clear, colorless, and odorless. Water also needs to be non-corrosive, meaning it will not cause damage to pipework.
What is the process of separating solids from liquids?
Filtration is the process where solids are separated from a liquid. In water treatment, the solids that are not separated in the sedimentation tank are removed by passing the water through sand and gravel beds. With a flow rate of 4–8 cubic meters per square meter of filter surface per hour, rapid gravity filters are often used.
What are the two coagulants commonly used in the treatment of water?
Since their charges are now neutralized, the fine particles come together, forming soft, fluffy particles called 'flocs.' Two coagulants commonly used in the treatment of water are aluminum sulfate and ferric chloride.
How does aerated water work?
After screening, the water is aerated (supplied with air) by passing it over a series of steps to take in oxygen from the air. This process helps in expelling soluble gases such as carbon dioxide and hydrogen sulfide (both of which are acidic, so this process makes the water less corrosive) and expels any gas eous organic compounds an undesirable taste to the water. Aeration also removes iron or manganese by oxidation of these substances to their insoluble form. Iron and manganese can cause peculiar tastes and can stain clothing. Once in their insoluble forms, these substances can be removed by filtration.
What is the process of removing pathogenic organisms from water?
After sedimentation, the water is disinfected to eliminate any remaining pathogenic micro-organisms. The most commonly used disinfectant (the chemical used for disinfection) is chlorine, a liquid (such as sodium hypochlorite, NaOCl), or a gas. It is relatively cheap and simple to use. When chlorine is added to water, it reacts with any pollutants present, including micro-organisms, over a given period of time, referred to as the contact time. The amount of chlorine left after this is called residual chlorine. This stays in the water through the distribution system, protecting it from any micro-organisms that might enter it until the water reaches the consumers.
What materials are used in a treatment plant?
These materials include leaves, twigs, paper, rags, and other debris that could obstruct flow through the plant or damage equipment.
Coagulation
Flocculation
- Following the coagulant chemical addition and the rapid mix processes, the raw water will continue on to a flocculation basin. The goal of the flocculation treatment process is to increase the size of the flocs in order to increase their ability to settle out.
Sedimentation
- The water continues on to the sedimentationbasin, or clarifier, after the flocs have been formed. The goal of this stage of the treatment process is to reduce the amount of solids in the water before the water is filtered in the next treatment step. The large flocs will settle out of suspension via gravity. Clarifiers can remove a very large percentage of the suspended materials in water. I…
Disinfection
- As discussed previously, the surface water treatment rule requires both the filtration and disinfection of surface water sources. The water must be disinfected now that it has been filtered.
Chlorination Operations
- Chlorination was one of the first drinking water disinfection methods. It is still the most commonly used disinfection method used today. The filtered water is injected with either liquid sodium hypochlorite, gaseous chlorine, or solid calcium hypochlorite. Chlorine is a strong oxidant. It is used to both disinfect and also to remove color, taste and odor compounds, iron and manganes…
Conclusion
- In order to meet the requirements of the Surface Water Treatment Rule, a water system must both remove and inactivate the pathogens in the water. This process begins with coagulation, which destabilizes the particles in the water. Then, during flocculation, the destabilized particles bump into each other and form larger and larger flocs. These large flocs are given adequate time to se…
Screening
Aeration
Coagulation and Flocculation
Sedimentation
Filtration
Chlorination
Supplementary Treatment
- After screening, the water is aerated (supplied with air) by passing it over a series of steps to take in oxygen from the air. This process helps in expelling soluble gases such as carbon dioxide and hydrogen sulfide (both of which are acidic, so this process makes the water less corrosive) and expels any gaseous organic compounds an undesirable taste to the water. Aeration also remove…