How Does a Water Treatment Work
- Raw water. The first step is the input of raw water from private wells or municipal systems, such as city tap water.
- Pre-treatment. The next stage is filtering the water that is collected. ...
- Distillation. Steam distillation occurs next. ...
- Venting. ...
- Condensing. ...
- Post-treatment. ...
- Purification. ...
Full Answer
What are the 5 stages of water treatment?
Mar 17, 2021 · The process happens in a flocculation basin. The large particles then settle in a sedimentation basin allowing water to flow to the next stage. Although large particles are out of the water, small particles, germs, and chemicals are still present. Sedimentation. Sedimentation is the second phase of water treatment.
What are the steps of water 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- ment of wastes, primary and secondary, which are outlined here. In the primary stage, solids are allowed to settle and removed from wastewater.
How to make a water works at home?
Jun 30, 2016 · The first step of treatment is to remove the settleable and dissolved solids suspended in the water. In order to speed the settling and removal process up, chemicals called coagulants are added to...
How does wastewater treatment worksthe basics?
Once the filtration is over, the water is disinfected. There are three approaches that can be employed; chlorination, ozone treatment, and ultraviolet treatment. These approaches can be used either individually or in combination. Once all of these steps are completed, water is pumped out to be used by the population.
Why is drinking water not used in drinking water treatment plants?
The only drawback in this process is, once the water leaves the treatment plant to the households, bacteria in contact with the water will get ingested and cause diseases. There is no protection past the treatment plant. Maybe, that is why it is not commonly used in drinking water treatment plants.
What happens when you add chlorine to water?
Once chlorine is added to water, the remaining chlorine present in water is less concentrated. Chlorine acts as a barrier between germs and water. It also reacts to any organic agent available in the water.
What is the coolest thing about water treatment?
Advertisement. [Image Source: Wikimedia] One of the coolest things about the water treatment process is the freedom it gives the civil engineer behind the process. As long as the end result is clean water, cities and governing authorities tend to not care about the processes you are using to treat the water.
What are the two main types of water treatment plants?
There are two main types of treatment plants: drinking water and wastewater. Both serve the purpose of cleaning the water, but in general, the output of wastewater plants are streams or rivers, and the output of drinking water plants are your city's pipe network distribution system.
What is the process of a mixture of solids and water that sticks together called?
Now that the solids in the water can begin sticking together, the mixture is slowly mixed in a flocculation basin in order to continue to form what are called floc particles. These floc particles then settle out of the mixture in a sedimentation basin, and cleaner water flows overtop a weir.
Why do you add chlorine to water?
The reason you would add chlorine at the last step is that its reaction with organic matter can create disinfection byproducts, which can result in carcinogens or other harmful chemicals being present in the final water product. Chlorine is used mainly because of how it kills pathogens.
How to disinfect water?
There are two main ways to disinfect water, each with its pros and cons. In the US, the main method is by adding chloramines or chlorine-based compounds. When these chemicals are added, they kill microorganisms, but they also react with any organic material left in the water.
What is the clarity of water after sand filtering?
After passing through the sand filter, the water should have a clarity (turbidity) of around less than .3 Nephelometric Turbidity Units (NTU), or whatever the local code is for water clarity. The water is clear, but bacteria are still present. The final step in the process is disinfection.
What is the most common coagulant in water treatment plants?
The most common coagulant is aluminum sulfate, but this varies by the water treatment plant. Essentially this chemical has the opposite charge from the suspended solids, like clays or silts, which then neutralizes the charge and allows for the particles to stick together.
What is the process of removing particles from water?
The process is not simple and begins with coagulation and flocculation. This particular process is responsible for removing all of the natural particles that accompany water from the actual water source. Coagulants, when added to the water, can make the debris stick together. An example of a typical coagulant is aluminum sulfites ...
What are the resources used in water treatment?
The local water treatment plants usually rely on natural resources for procuring water, however; that is not always the case. The resources include river, dam, and well. The water that is obtained from these sources is treated thus making it safe for humans to consume at a mass level.
How are coagulants introduced into water?
These coagulants are introduced in the water when it enters the treatment plant. The water is then passed through flocculation basins where slow mixing takes place. This mixing makes sure that thorough coagulation takes place. Once coagulation is completed, the water is pumped into a sedimentation basin. Water is allowed to sit thus enabling the ...
How does water pass through a carbon filter?
Once the water reaches the filtration phase, it is made to pass through differing coarseness of sand. Particles keep on getting trapped as the coarseness of the sand filter decreases. In the end, the water is made to pass through an active carbon filter. Once the filtration is over, the water is disinfected. There are three approaches that can be ...
What are the three methods of disinfecting water?
Once the filtration is over, the water is disinfected. There are three approaches that can be employed; chlorination, ozone treatment, and ultraviolet treatment . These approaches can be used either individually or in combination. Once all of these steps are completed, water is pumped out to be used by the population.
Does filtration remove bacteria?
However, filtration helps remove the bacteria as well. Most of the water treatment plants make use of a sand filter. The sand filter is low-tech but is a very efficient way of carrying out water purification. Once the water reaches the filtration phase, it is made to pass through differing coarseness of sand.
3. Coagulation
Even if the water appears relatively clear and free from large pieces of organic material, looking at a drop under a microscope would probably reveal a world of floating particles and microorganisms. To remove the tiny floaters and swimmers, technicians add chemicals such as aluminum and iron compounds that make them coagulate into small clumps.
4. Flocculation
Flocculation is similar to coagulation but with more dramatic results. In this step, turbines or paddles stir the water for 20 to 30 minutes to increase the frequency with which the smaller pieces bump into each other. This slow agitation causes clumped particles to form larger pieces called flocs.
5. Sedimentation
The flocculated water then rests in a sedimentation basin for 2 to 4 hours. During this time, the flocs gradually sink to the bottom, leaving behind water free from particulate matter. To ensure the sedimentation process removed all impurities, the product flows through a deep layer of sand or anthracite on its way to the final step.
6. Disinfection
The deadliest pathogens in drinking water are invisible to the naked eye. For this reason, the final step is to kill any microorganisms remaining in the otherwise clean drinking water by the addition of disinfectant chemicals. Chlorine is a common substance many plants use, but some also use ozone, chlorine dioxide, or chloramines.
When to Employ Sedimentation
Please note that sedimentation is not and cannot be used for all water treatment applications. It’s essential to understand the characteristics of your wastewater to determine if it’s an effective treatment process. Plus, you need to define the goal of your water treatment.
Sedimentation Theory
When employing sedimentation as a water treatment process, it is essential to understand the sedimentation theory. Simply put, if you drop an object into a fluid and its density is greater than the fluid, the object sinks. This is why a colloid with low density will take a long time to settle vs. sand particles.
Chemicals Used in Sedimentation Clarification
Coagulants and polymer flocculants are two chemicals used to aid the sedimentation process.
Clarifiers & Tanks Used in Sedimentation Clarification
Clarifiers and tanks streamline the sedimentation water treatment process. They provide mechanisms to manage sludge created by sedimentation and transport clean water for discharge or reuse. These machines enhance the sedimentation process on their own and are often more efficient with the addition of coagulants and flocculants.
Community Water Treatment
Water Fluoridation
- Community water fluoridation prevents tooth decay safely and effectively. Water fluoridation has been named one of 10 great public health achievements of the 20th century 1. For more information on the fluoridation process and to find details on your water system’s fluoridation, visit CDC’s Community Water Fluoridationpage. Top of Page
Consumer Confidence Reports
- Every community water supplier must provide an annual report, sometimes called a Consumer Confidence Report, or “CCR,” to its customers. The report provides information on your local drinking water quality, including the water’s source, contaminants found in the water, and how consumers can get involved in protecting drinking water. 1. View the CDC’s guide to Understandi…