waste water treatment how do we treat our water

Wastewater

treatment The major aim of wastewater treatment is to remove as much of the suspended solids as possible before the remaining water, called effluent, is discharged back to the environment. As solid material decays, it uses up oxygen, which is needed by the plants and animals living in the water.

Full Answer

What is waste water, and why treat it?

Wastewater treatment. The major aim of wastewater treatment is to remove as much of the suspended solids as possible before the remaining water, called effluent, is discharged back to the environment. As solid material decays, it uses up oxygen, which is needed by the plants and animals living in the water.

What are the stages of wastewater treatment?

What are the four stages of wastewater treatment?

1. Screening and Pumping.
2. Grit Removal.
3. Primary Settling.
4. Aeration / Activated Sludge.
5. Secondary Settling.
6. Filtration.
7. Disinfection.
8. Oxygen Uptake.

Why do we need to treat waste water?

• tainted drinking water
• water scarcity and water shortages
• foul lakes and rivers
• lower numbers of aquatic species
• dangers to livestock
• reduced waterfront property values

What are the steps in waste water treatment?

• Stage 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.

How do we treat our waste water?

Primary Treatment As sewage enters a plant for treatment, it flows through a screen, which removes large floating objects such as rags and sticks that might clog pipes or damage equipment. After sewage has been screened, it passes into a grit chamber, where cinders, sand, and small stones settle to the bottom.

What ways can water be treated?

4 Methods to Purify Your Water1 – Boiling. Boiling water is the cheapest and safest method of water purification. ... 2 – Filtration. Filtration is one of the effective ways of purifying water and when using the right multimedia filters it's effective in ridding water of the compounds. ... 3 – Distillation. ... 4 – Chlorination.

What are the 5 steps of water treatment?

THE 5 STAGES OF WATER TREATMENTScreening. As water enters a water treatment plant, either from lakes, rivers, or the ground, it passes through a screening. ... Coagulation. ... Sedimentation. ... Filtration. ... Disinfection.

Why do we treat water?

Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.

How is wastewater pumped?

Wastewater is pumped or carried by gravity along our sewer mains through to our wastewater treatment plants . Once it reaches the treatment plant, we begin our rigorous treatment processes. In this article we explain how we treat wastewater and where the water goes once it's treated.

Why is the end of a wastewater pipe important?

The end of the pipe contains small holes to ensure the wastewater is evenly dispersed into the sea. This is the most cost effective option as the process uses very little energy, instead relying on gravity to transport the water. Sunlight, oxygen and ocean currents combine to continue the wastewater treatment process.

What is the process of sludge being broken down into water and biosolids called?

The bacteria, in turn, breaks down the sludge into water and biosolids —this process is called anaerobic digestion. The biosolids are trucked off site to be made into fertilizer or used for agriculture. Methane gas is a primary by-product of the anaerobic digestion process.

Where does sludge go in a sedimentation tank?

Where does the sludge go? The sludge collected in the sedimentation tanks is pumped into huge tanks called ‘digesters’. These tanks are 8 meters high and go down another 8 meters into the ground. Each tank holds around 4 million litres of sludge. We heat the tanks to encourage the growth of bacteria.

What is the purpose of aeration in wastewater?

The microbes form ‘activated sludge’ flocks and feed on the organic matter remaining in the wastewater. The microbes remove contaminants and convert organic matter into carbon dioxide, nitrogen gas and more activated sludge. The aeration process is a natural alternative to chemical processing.

What is aeration process?

The aeration process is a natural alternative to chemical processing. If we relied on chemicals to treat wastewater, we'd also need a process to remove them before returning the water back to the environment. When the activated sludge flocks have done their job, the water flows through to secondary sedimentation tanks.

What is tertiary wastewater treatment?

Tertiary (or advanced) treatment removes dissolved substances, such as colour, metals, organic chemicals and nutrients like phosphorus and nitrogen.

What is the process of removing pollutants from water?

Another natural method is called rapid infiltration, which is a process where a basin is filled with wastewater, which has already gone through a pre-treatment. The ground acts as a filter and removes the pollutants from the water. This method is similar to what happens in a septic system.

How to reduce pressure on septic system?

Following some water conservation practices can greatly reduce pressure on your septic system. For more information about conserving water, see the fact sheet about Water Consumption. Here are a few things that you can do to care for your septic system: 1 Do not use your drain or toilet as a garbage disposal; avoid putting dental floss, diapers, coffee grounds and paper towel down the drain, as they can clog up your septic system. 2 Spread your loads of laundry out over the week. When too much water is added to the septic tank, it does not have time to treat wastes, and you could be flooding your drainfield with wastewater. 3 Plant grass on your drainfield, but keep trees and shrubs away from it, because roots can clog the system and cause damage. 4 Do not drive on your drainfield, because this can compact the soil and damage the septic system components.

Why is oxygen important in wastewater treatment?

The oxygen helps the bacteria to digest the pollutants faster. The water is then taken to settling tanks where the sludge again settles, leaving the water 90 to 95 percent free of pollutants. The picture below shows the settling tanks in the Winnipeg Wastewater Treatment Plant.

What are the different levels of wastewater treatment?

There are several levels of wastewater treatment; these are primary, secondary and tertiary levels of treatment. Most municipal wastewater treatment facilities use primary and secondary levels of treatment, and some also use tertiary treatments.

What is the process of tertiary treatment?

One of the biological treatment processes is called Biological Nutrient Removal (BNR). This diagram shows the treatment steps that Saskatoon wastewater goes through. Biological Nutrient Removal Process.

How much oxygen is removed from water?

The primary treatment generally removes up to 50 percent of the Biological Oxygen Demand (BOD; these are substances that use up the oxygen in the water), around 90 percent of suspended solids, and up to 55 percent of fecal coliforms.

What is homeland security water treatment?

Treatment of water related to the response to a homeland security incident can use some of the same technologies developed over the past 100 years for treatment in community water and wastewater system. Treatment for homeland security incidents differs, however, in the types of contaminants that can lead to a need to treat the water on-site. Such on-site treatment systems need to be compatible with potentially enormous volumes of contaminated water.

Why is drinking water contaminated?

Drinking water could become contaminated from breaks in pipes that allow contaminants to intrude, intentional tampering, or loss of electrical power and pressure resulting in water stagnation and bacterial growth. Contamination needs to be flushed from the drinking water distribution system and the resultant contaminated water treated. ...

How does disposing of waste affect response activities?

Disposal of wastes can impact response activities, especially for types or amounts of contaminants resulting from homeland security incidents. For contaminated water in an urban environment, it is likely that at some point some of this contaminated water enters the area’s storm/waste water collection system. As this could impact the wastewater ...

What happens to water after a hurricane?

Following a hurricane, flood, or tornado, stormwater and wastewater systems can become contaminated and require treatment, or enhanced treatment , to protect the environment.

What is the response to a wide area contamination incident?

Response to a wide-area contamination incident will likely require that external building surfaces, roadway, and vehicles be decontaminated. These decontamination operations can produce large amounts of water that must be treated before release to the environment or a wastewater treatment plant. In addition to managing the contaminated water, ...

Why is the EPA researching decision support tools?

Since response activities will be site specific, and because there are a multitude of contaminants and water systems, EPA is researching decision support tools to help decision makers balance the many factors that go into the design and implementation of a treatment system at their site.

Why is research needed to evaluate treatment technologies?

Thus, research is needed to evaluate treatment technologies for their ability both to reduce high levels of toxic chemicals and to produce treated water that is not toxic. Using a series of treatment technologies may further reduce toxicity of the most difficult to treat contaminants.

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.

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.

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.

Why is surface water more contaminated than ground water?

Typically, surface water requires more treatment and filtration than ground water because lakes, rivers, and streams contain more sediment and pollutants and are more likely to be contaminated than ground water. Some water supplies may also contain disinfections by-products, inorganic chemicals, organic chemicals, and radionuclides.

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.

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.

What is wastewater treatment?

Wastewater treatment is the process of converting wastewater into water that can be discharged back into the environment. According to the U.S. EPA, one of the most common forms of pollution control in the U.S. is wastewater treatment. The purpose of wastewater treatment is to speed up the natural processes by which water is purified.

What is the primary stage of wastewater treatment?

In the primary stage, solids are allowed to settle and be removed from wastewater. The secondary stage uses biological processes to further purify wastewater. Sometimes these stages are combined, and in some cases additional treatment such as tertiary treatment and advanced wastewater treatment are used.

What is activated sludge?

People tend to use the activated sludge process instead of trickling filters, since the activated sludge process speeds up the work of the bacteria. After the sewage leaves the settling tank in the primary stage, it is pumped into an aeration tank.

How is wastewater formed?

Wastewater is formed by a number of activities such as bathing, washing, using the toilet, and rainwater runoff. Wastewater is essentially used water that has been affected by domestic, industrial and commercial use. Some wastewaters are more difficult to treat than others, according to the Safe Drinking Water Foundation.

What is the process of removing chlorine from sedimentation tanks?

Many states now also require the removal of excess chlorine before discharge to surface waters by a process called dechlorination, according to the EPA.

What is primary treatment?

Primary Treatment. Primary treatment removes material that will either float or readily settle out by gravity. This treatment includes the physical processes of screening, comminution—the act of reducing a material to minute particles or fragments—grit removal and sedimentation. As wastewater enters a plant for treatment, it flows through a screen.

What happens if wastewater is not treated?

If wastewater is not properly treated, then the environment and human health can be negatively impacted, reported the United States Geological Survey (USGS). Among the impacts are harm to fish and wildlife populations, oxygen depletion, beach closures and other restrictions on recreational water use. Advertisement.

Organic matter

Organic matter in wastewater includes proteins, carbohydrates, fats, oils, greases, and synthetic compounds found in certain detergents.

Inorganic compounds

Inorganics in wastewater include compounds with copper, lead, magnesium, nickel, potassium, sodium, or zinc. In many cases, these harmful substances are the byproducts of commercial and industrial activities.

Nutrients

Nutrients in wastewater include nitrogen and phosphorus compounds. These often come from human waste and cleaning products like laundry detergent and dishwasher soap.

Microorganisms

Some microorganisms in wastewater are helpful because they break down organic matter that would otherwise pollute the environment.

How much of the toxins in GAC are removed?

In sum, the study found that GAC removed more than 85 percent of the toxins.

Can you drop off medicine you don't use?

Drop off medicine you don’t use, either prescribed or over the counter, a drug take back site, location, or program. If you can’t get to a take back location, don’t flush medicine down the toilet. Follow these instructions to discard the medicine in your trash at home.