Wastewater treatment works are often situated on relatively low-lying ground in order to encourage the flow of water to the plant through the sewers under gravity. There is therefore a risk of the enclosed plant becoming inundated with water in the event of high flood water levels.
Full Answer
How is wastewater treated in a wastewater treatment plant?
In this treatment plant, wastewater first undergoes primary and secondary treatment. For the tertiary treatment, the BNR process occurs in the bioreactors. The BNR process uses bacteria in different conditions in several tanks, to digest the contaminants in the water.
How does a water treatment facility work?
One of the first steps that a water treatment facility can do is to just shake up the sewage and expose it to air. This causes some of the dissolved gases (such as hydrogen sulfide, which smells like rotten eggs) that taste and smell bad to be released from the water. Wastewater enters a series of long, parallel concrete tanks.
Can industrial wastewater be treated on-site?
Some wastewater can be treated on-site and reused within the plant for various purposes. 2. There are some wastewater treatment plants that are designed to treat industrial wastewater.
How are insoluble contaminants removed from wastewater treatment?
Various physical methods may be used for the removal of wastewater contaminants that are insoluble in water, such as suspended solids, oil, and grease. Ordinarily, water-soluble contaminants are chemically converted to an insoluble form to allow removal by physical methods.
What are the three types of wastewater treatment facilities?
The 3 types of wastewater treatment processing facilities are sewage treatment plants, effluent treatment plants, and combined effluent treatment plants.Sewage Treatment Plants. ... Effluent Treatment Plants (ETP) ... Combined and Common Effluent Treatment Plants (CETP)
What are the 5 stages of wastewater 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 8: Oxygen Uptake. ... Sludge Treatment.
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 is the purpose of a wastewater treatment facility?
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.
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.
Where does wastewater go after treatment?
The treated wastewater is released into local waterways where it's used again for any number of purposes, such as supplying drinking water, irrigating crops, and sustaining aquatic life.
What are the types of wastewater?
There are three types of wastewater, or sewage: domestic sewage, industrial sewage, and storm sewage.
What materials Cannot be removed from wastewater?
When wastewater arrives at the treatment plant, it contains many solids that cannot be removed by the wastewater treatment process. This can include rags, paper, wood, food particles, egg shells, plastic, and even toys and money.
What are the methods of water treatment?
Top 7 Methods of Water TreatmentCoagulation / Flocculation. Coagulation is adding liquid aluminum sulfate or alum and/or polymer to raw or untreated water. ... Sedimentation. When water and flocs undergo the treatment process, they go into sedimentation basins. ... Filtration. ... Disinfection. ... Sludge Drying. ... Fluoridation. ... pH Correction.
What is the difference between water treatment and wastewater treatment?
Water Treatment Plants (WTP) generally are smaller operations than Wastewater Treatment Plants WWTP) because of the water quality coming in. WTPs pull water from a local river, lake or well. This water is generally clean (compared to sewage!) and just need a bit of cleaning and disinfection.
What is primary wastewater treatment?
Primary treatment removes material that will either float or readily settle out by gravity. It includes the physical processes of screening, comminution, grit removal, and sedimentation.
What are the two types of water treatment plant?
Types of Water Treatment PlantsWastewater Treatment Plant (WWTP) ... Sewage Treatment Plants (STPs) ... Effluent Treatment Plants (ETP's) ... Demineralization (DM) Treatment Plants. ... Reverse Osmosis (RO) Water Treatment.
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 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.
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 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.
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.
What is the Canadian Environmental Protection Act?
The Canadian Environmental Protection Act governs the release of toxic substances into the environment and allows the federal government to develop regulations for the use of toxic substances. Most provincial and territorial governments have legislation regarding wastewater treatment standards and requirements.
What is wastewater treatment?
Wastewater treatment refers to the physical, chemical, and biological processes used to remove pollutants from wastewater before discharging it into a waterbody. Facilities are designed to ensure effluent will not adversely affect the receiving waterbodies and meet the requirements of the National Pollution Discharge Elimination System (NPDES) ...
What is secondary treatment?
Secondary treatment uses biological processes to further reduce solids in the effluent. Bacteria feed on organic matter; the excess sludge is removed to be made into biosolids and the water goes through secondary clarification, followed by disinfection.
What is a membrane reactor?
Membrane Reactors. Membrane reactors use a permeable membrane combined with a chemical or biological process to perform a separation and reaction in the same vessel. In wastewater treatment, membrane bioreactors are common, combining a membrane like microfiltration or ultrafiltration with a biological wastewater treatment process like activated ...
What is the purpose of wastewater treatment plants?
Wastewater treatment plants are designed to convert liquid wastes into an acceptable final effluent and to dispose of solids removed or generated during the process. In most cases, treatment is required for both suspended and dissolved contaminants.
What is biological waste treatment?
Various physical methods may be used for the removal of wastewater contaminants that are insoluble in water, such as suspended solids, oil, and grease. Ordinarily, water-soluble contaminants are chemically converted to an insoluble form to allow removal by physical methods. Essentially, biological waste treatment is this conversion ...
How is sludge dewatered?
In this section, sludge is dewatered by the gravity drainage of free water. The gravity drainage zone should increase the solids concentration of the sludge by 5-10%. If the sludge does not drain well in this zone, the sludge can squeeze out from between the belts or the belt mesh can become blinded.
What is the natural buffering system of a water source?
The natural buffering system of a water source is exhausted by the discharge of acids and alkalies. Aquatic life is affected by the wide swings in pH as well as the destruction of bicarbonate alkalinity levels.
Can lagoons be used for biological treatment?
Where organic loads are low and sufficient land area is available, open lagoons may be used for biological treatment. Lagoons provide an ideal habitat for microorganisms. Natural infiltration of oxygen is sufficient for biological oxidation if the organic loading is not too high. However, mechanical aeration (Figure 37-6) is often used to increase the ability to handle a higher loading.
Does activated sludge have a low BOD?
The recirculated bacteria continue to oxidize wastewater contaminants, and if present in sufficient quantity , produce a relatively low BOD effluent water. Because the activated sludge process incorporates the return of concentrated microorganisms, it must include a process for microorganism concentration and removal.
What is wastewater treatment?
Wastewater treatment encompasses numerous treatment methods, each with its own procedures, advantages, equipment, and outcomes. Keeping track of the various techniques and using them in the appropriate applications is essential. It helps plants get the most productivity out of a treatment system, comply with regulatory standards, ...
Why is wastewater treatment important?
It helps plants get the most productivity out of a treatment system, comply with regulatory standards, and keep operating costs and time demands manageable. The guide below will discuss anoxic, anaerobic, and aerobic conditions in wastewater treatment, explain how they differ, and describe how plants can best put these processes to work.
What is activated sludge?
Activated sludge: The activated sludge process uses an aeration tank with aerators or diffusers. As the organic material in the waste breaks down, it forms large bacteria-containing chunks known as flocs. The flocs then settle to the bottom of the tank, where they are easy to remove.
What happens to anaerobic wastewater?
During anaerobic wastewater treatment processes, microorganisms break down waste matter in the absence of oxygen. These processes often occur in an airtight, enclosed bioreactor filled with sludge. The sludge contains anaerobic bacteria and other beneficial microbes. In the bioreactor, the microorganisms digest the organic matter in the wastewater.
How does wastewater settle in lagoons?
In the lagoons, wastewater settles into different layers, with liquid layered over the sludge to prevent oxygen from reach ing it during microbial digestion. Sludge blanket reactors: Anaerobic sludge blanket reactors send wastewater through a floating blanket-like layer of sludge.
Why do wastewater treatment plants use anaerobic treatment?
For this reason, treatment plants often use anaerobic treatment first to remove a significant part of the wastewater’s organic matter before sending it on for further aerobic treatment . The two methods are also useful independently.
What is anaerobic filter reactor?
Filter reactors: An anaerobic filter reactor uses a tank with an attached filter medium. Microorganisms affix themselves to the filter medium and form a biofilm. Once formed, the biofilm and its microbes are effective in breaking down organic matter in the wastewater.
How much energy does a wastewater treatment plant use?
Solids handling processes use over 20% of the energy at a wastewater treatment facility, and pumping and disposing of solids requires energy every step of the way. Options to save money and energy are abundant, from minimizing transported water and solids to utilizing biogas for producing electricity and heating water, also known as co-generation.
How to eliminate hazardous chemicals?
Eliminate costly and hazardous chemicals by replacing your chlorine disinfection with an ultraviolet (UV) light disinfection system. Chlorine and dechlorination chemicals are expensive and energy-intensive to manufacture and transport.
What is SCADA in a plant?
Supervisory Control and Data Acquisition (SCADA) can provide real-time data on the treatment processes in your plant. SCADA can automate the operation of your plant or allow the operator to control the plant remotely. The system can monitor equipment and alert the operator of emerging issues. When properly planned and integrated, the SCADA system can provide operators with the desired amount of hands-on versus hands-free control, freeing operators to perform other duties. Continuous monitoring and trending of various processes and equipment can reveal periods when energy usage can be reduced or peak energy loads can be shaved.
What is a submersible pump?
Submersible Pump (Wet Well) Submersible pumps, as the name suggests, are submerged in the wastewater they pump. It is mounted inside the wet well and uses a motor to pump the wastewater. This method is more modern due to the reduced health and safety concerns they offer. Lift Station Components.
How does a wet well work?
Once the wet well is full, a lift station pump will “lift” the sewage upwards using a pressurized sewer force main. A sewer force main is a system that consists of pumps and compressors.
What is sewer force main?
A sewer force main is a system that consists of pumps and compressors. Its purpose is to elevate the wastewater to a higher elevation so that it can continue its inevitable journey towards treatment and recirculation. Types of Lift Stations.
What is a dry well pump?
The submersible pump, which is more modern, and the dry well/wet well pump, which is more traditional. Dry Well. In dry-well lift stations, the system is housed in a separate location (usually underground or in a separate chamber).
Does wastewater have to be transported to a higher elevation?
In some situations, it’s necessary for wastewater to enter the pipe system from a lower elevation. In order for the raw sewage to continue the journey towards a wastewater treatment plant, it needs to be efficiently transported to a higher elevation.
Is a lift station a hazardous material?
Lift Station Maintenance. Sewage is a hazardous material and needs to be handled and treated as such. It is important that wastewater operators are keenly aware that lift stations require routine maintenance. Keeping a maintenance record is not only a best practice, but it’s also often a legal requirement.
What is the complete process of wastewater treatment?
The complete process includes preliminary treatment, primary treatment, secondary treatment and often tertiary treatment. The treatment processes of a wastewater plant have become more and more sophisticated and the performance of the headworks is more important than ever. The function of them is to remove inorganics such as sticks, stones, ...
What is headworks in wastewater treatment?
The " headworks " of a wastewater treatment plant is the initial stage of a complex process. This process reduces the level of pollutants in the incoming domestic and industrial wastewater to a level that will allow the treated wastewater or effluent to be discharged into a stream, river or lake. This treated effluent also may be sprayed onto dedicated land areas where it is used for the irrigation of crops and even golf courses. The complete process includes preliminary treatment, primary treatment, secondary treatment and often tertiary treatment.
What is an axial pump?
The impellers are designed to be rounded and free of sharp corners and projections that would be likely to catch and hold rags and other stringy type materials. Axial pumps, commonly used in wet well installations, move liquid by the propelling or lifting action of the impeller vanes.
What is centrifugal pump?
Centrifugal pumps are classified into radial flow, mixed flow and axial flow types, according to the direction of flow in reference to the axis of rotation. The rotation axis of the pump shaft determines whether the pump is a horizontal or vertical unit.
Is washing and dewatering of screenings critical?
Therefore, washing and dewatering of the screenings is critical to maintaining a good screening process. Screens can be classified as coarse, fine and micro. Increasingly, treatment plants use a combination of coarse screens and fine screens.
