What are the steps in the water treatment process?
The Basics of Wastewater Treatment. Wastewater treatment of plating and metal finishing process is a complicated process with multiple steps. This article briefly discusses some of the main points and products involved. Plating wastewater has several issues to overcome. You have solutions that can include acids, caustics, solvents, water, and usually metal particulate.
How to reduce chemical oxygen demand (COD) in wastewater?
Wastewater Treatment Basics. Wastewater is generated after human and commercial consumption of water. The domestic use produces wastewater, also called sewage, from showers, sinks, various household cleaning appliances and flush toilets. Industrial and agriculture wastewater comes from water usage for various processes and washing and …
How do you treat waste water?
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 is MBBR wastewater treatment?
The Basic Processes of Wastewater Treatment. Wastewater treatment is a complex topic that involves numerous processes, components and equipment that all have the singular goal to turn any liquid into water that can either be reused or returned to the water cycle. There are even a lot of wastewater treatment systems that everyone from households to industries use to meet …
What are the 7 steps of wastewater treatment?
- Step 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 principles for water treatment?
- Coagulation and Flocculation. ...
- Sedimentation. ...
- Filtration. ...
- Disinfection.
What are the 3 steps to wastewater treatment?
- Primary Treatment. Before wastewater even gets to primary treatment, it is funneled through collection systems and treated with odor-neutralizing chemicals. ...
- Secondary Treatment. In secondary treatment, the goal is to break down wastewater even further. ...
- Tertiary Treatment.
What are the 4 stages of wastewater treatment?
What are the 5 steps of water treatment?
- Coagulation. 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 is Formula A in wastewater treatment?
Why is wastewater treated with chlorine or UV light?
What is the most common stage of wastewater treatment?
What are the three major components of a wastewater system?
Which microbes are used in sewage treatment?
- 2.1. Bacteria. ...
- 2.2. Protozoa. ...
- 2.3. Metazoa. ...
- 2.4. Filamentous bacteria. ...
- 2.5. Algae. ...
- 2.6. Fungi.
Which bacteria is used in aeration tank?
What are the major drivers for wastewater treatment?
What are the constituents of wastewater?
Basic Constituents of Wastewater. Biochemical oxygen demand. One of the most commonly measured constituents of wastewater is the biochemical oxygen demand, or BOD. Wastewater is composed of a variety of inorganic and organic substances.
Why is a sewage treatment plant called a bod?
This is because sewage high in BOD can deplete oxygen in receiving waters , causing fish kills and ecosystem changes.
What is the most common form of nitrogen in a septic system?
Nitrogen is present in many forms in the septic system. Most nitrogen excreted by humans is in the form of organic nitrogen (dead cell material, proteins, amino acids) and urea. After entering the septic tank, this organic nitrogen is broken down fairly rapidly and completely to ammonia, NH 3, by microorganisms in the septic tank. Ammonia is the primary form of nitrogen leaving the septic tank. In the presence of oxygen, bacteria will break ammonia down to nitrate, NO 3. In a conventional septic system with a well aerated leaching facility, it is likely that most ammonia is broken down to nitrate beneath the leaching field.
What is the BOD removal?
BOD removal can be especially important where sewage effluent flows to a leaching field in tight soils. Tight soils are usually composed of silts and clays (particle size < 0.05 millimeter). These small soil particles are tightly packed and the pore space between them is small.
How is BOD removed from a septic tank?
Some BOD is removed in the septic tank by anaerobic digestion and by solids which settle to the bottom of the septic tank, but much of the BOD present in sewage (especially detergents and oils) flows to the leaching field.
What does it mean to reduce BOD?
Reducing BOD means that the sewage will support the growth of less bacteria and therefore the effluent will be better able to infiltrate tight soils. Many enhanced treatment technologies that remove BOD were designed specifically to enhance disposal of effluent in tight silt or clay soils.
Why is anaerobic environment necessary for denitrification?
As discussed above, an anaerobic environment is also necessary for denitrification, as the bacteria which carry out this process require anaerobic conditions to reduce nitrate to nitrogen gas. Many nitrogen-removal technologies are designed to provide an anaerobic treatment chamber as part of the treatment process.
What is the process of wastewater treatment?
Wastewater treatment is a complex topic that involves numerous processes, components and equipment that all have the singular goal to turn any liquid into water that can either be reused or returned to the water cycle.
Why is wastewater treated in a tertiary stage?
After the primary and secondary treatment stages, wastewater needs to undergo the tertiary treatment process to ensure that it is free of suspended and dissolved substances. Even though the effluent from the secondary stage is somewhat safe for release into the environment, undergoing the tertiary stage is necessary for the following reasons: (1) it has the ability to remove up to 99% of the wastewater’s impurities; (2) it produces effluent water that is close to drinking water quality; (3) to meet standard requirements in developed countries; (4) for the removal of hazardous nitrogen and phosphorus compounds.
How does wastewater get into a plant?
It is usually done by pouring the wastewater into big sedimentation tanks (can either be square, circular or rectangular) for the macrobiotic solid matter to settle at the bottom or at the surface of tanks. Once the solid matter settles, it turns into sludge that is removed using large scrappers and is moved to the center of the cylindrical tanks. After that, the sludge is pumped out of the tanks for further treatment (it can be used as a fertilizer), with the remaining water also being pumped out for secondary treatment.
Why is chlorine used in wastewater treatment?
In some cases, chlorine is used to disinfect the effluent in order to complete the secondary treatment process .
What is the secondary process of treatment?
The secondary process of treatment is where the removal of fine and dissolved colloidal organic matter occurs, with the help of microorganisms (algae, fungi, and bacteria) that help decompose the organic matter to stable organic forms . When the effluent leaves the sedimentation tank in the primary stage, it is typically transferred to a facility that uses this treatment, and different processes (activated sludge process, aerobic digestion, anaerobic ponds, etc.) are used by different plants when removing organic matter. By the end of this treatment process, the remaining organic matter turns into large particles that settle down at the bottom of huge tanks, which makes them easy to separate from the remaining wastewater. In some cases, chlorine is used to disinfect the effluent in order to complete the secondary treatment process.
What happens when sedimentation leaves the sedimentation tank?
When the effluent leaves the sedimentation tank in the primary stage, it is typically transferred to a facility that uses this treatment, and different processes (activated sludge process, aerobic digestion, anaerobic ponds, etc.) are used by different plants when removing organic matter.
What is primary treatment of wastewater?
Primary treatment of wastewater refers to mechanical and biological processes that remove solids, settleable materials, and other impurities from wastewater contaminants that can’t be broken down into smaller components.
How many stages of wastewater treatment?
Since this is a massive task, treatment of wastewater is done in three stages; primary, secondary, and tertiary; each of which deals with a different aspect of cleansing.
What is the process of adding sodium bisulfite to water?
Dichlorination: Dichlorination is completed by adding sodium bisulfite, which removes the chlorine added to the water in the disinfection stage. This is an important step in wastewater treatment as chlorine isn’t safe for aquatic life and can degrade the quality of water.
Why is wastewater treatment important?
Been in use for decades now, wastewater treatment helps remove or destroy pollutants in wastewater to achieve water quality standards. From an environmental point of view, conservative wastewater treatment methods have proven their worth by making sure that harmful chemicals within the water are safely eliminated.
What is the purpose of the sludge stage?
The purpose of this stage is to remove suspended solids, settleable particles, dissolved chemicals, and other pollutants from anaerobically digested primary sludge.
What is biofiltration in water?
Biofiltration uses porous materials biofilters such as sand filters or trickling filters, to remove any residual sediment from the wastewater. With biofiltration, the organic matter in the waste can be broken down into carbon dioxide and water.
What is tertiary wastewater treatment?
Tertiary wastewater treatment is the process that follows primary and secondary wastewater treatment. While the primary and secondary treatments target the physical and inorganic removal of large solids, tertiary focuses on making the water safe for drinking.
What is wastewater treatment?
The basic concept of wastewater treatment is to use different methods to separate and remove any solid material from wastewater and disinfect the remaining liquid before releasing it back into our environment.
What is the purpose of the Basics of Wastewater?
Wastewater: The Basics is written to help educate residents and other stakeholders about the complex process of transporting and treating wastewater, and about the different technologies proposed in the Clean Water Program. If something isnt clear, tell us! Chances are someone else has the same question.
What is a sewer main?
Sewer Mains are sewer lines which convey wastewater from private sewer laterals to larger sewer trunks. Sewer Trunks are larger sewer lines which convey wastewater from sewer mains to the wastewater treatment plant.
What is the Clean Water Program?
The Clean Water Program is a comprehensive, 10-year plan to upgrade San Mateos sanitary sewer collection system and the San Mateo Wastewater Treatment Plant. Public outreach and transparency are key components of the Clean Water Program.
Why is wastewater treated at the wastewater treatment plant?
Thankfully, wastewater must first travel through a sewer collection system and be treated and disinfected at the wastewater treatment plant in order to remove contaminants and harmful bacteria and make sure we are minimizing our impact on our environment.
Why is wastewater removed from WWTP?
Once wastewater is pumped into the WWTP, it contains a variety of solid materials that need to be removed in order to protect the equipment used in the later stages of treatment.
What does a water line do?
Water lines bring in clean water for your sinks, toilets, irrigation, etc.
Introduction
Definition
- One of the most commonly measured constituents of wastewater is the biochemical oxygen demand, or BOD. Wastewater is composed of a variety of inorganic and organic substances. Organic substances refer to molecules that are based on carbon and include fecal matter as well as detergents, soaps, fats, greases and food particles (especially where garbage grinders are us…
Health
- However, BOD content of sewage is also important for septic systems. Sewage treatment in the septic tank is an anaerobic (without oxygen) process; in fact, it is anaerobic because sewage entering the tank is so high in BOD that any oxygen present in the sewage is rapidly consumed. Some BOD is removed in the septic tank by anaerobic digestion and by solids which settle to th…
Purpose
- Many of the enhanced treatment technologies discussed later in this document were designed specifically to reduce BOD in treated sewage. BOD removal can be especially important where sewage effluent flows to a leaching field in tight soils. Tight soils are usually composed of silts and clays (particle size < 0.05 millimeter). These small soil particles are tightly packed and the p…
Benefits
- BOD is fairly easy to remove from sewage by providing a supply of oxygen during the treatment process; the oxygen supports bacterial growth which breaks down the organic BOD. Most enhanced treatment units described incorporate some type of unit which actively oxygenates the sewage to reduce BOD. This unit is often located between the septic tank and the leach field. Or…
Formation
- Nitrogen is present in many forms in the septic system. Most nitrogen excreted by humans is in the form of organic nitrogen (dead cell material, proteins, amino acids) and urea. After entering the septic tank, this organic nitrogen is broken down fairly rapidly and completely to ammonia, NH3, by microorganisms in the septic tank. Ammonia is the primary form of nitrogen leaving th…
Environment
- Nitrate can have serious health effects when it enters drinking water wells and is consumed. Nitrate and other forms of nitrogen can also have deleterious effects on the environment, especially in coastal areas where excess nitrogen stimulates the process known as eutrophication. For this reason, many alternative technologies have been designed to remove tot…
Analysis
- The first step in the process, conversion of ammonia to nitrite and then to nitrate, is called nitrification (NH3 NO2 + NO3). The process is summarized in the following equations:
Significance
- It is important to note that this process requires and consumes oxygen. This contributes to the BOD or biochemical oxygen demand of the sewage. The process is mediated by the bacteria Nitrosomonas and Nitrobacter which require an aerobic (presence of oxygen) environment for growth and metabolism of nitrogen. Thus, the nitrification process must proceed under aerobic …
Properties
- Phosphorus is a constituent of human wastewater, averaging around 10 mg/liter in most cases. The principal forms are organically bound phosphorus, polyphosphates, and orthophosphates. Organically bound phosphorus originates from body and food waste and, upon biological decomposition of these solids, is converted to orthophosphates. Polyphosphates are used in sy…
Mechanism
- It is unknown how much phosphorus is removed in a conventional septic system. Some phosphorus may be taken up by the microorganisms in the septic system and converted to biomass (of course, when these microorganisms die the phosphorus is re-released, so there really is no net loss of phosphorus by this mechanism). Any phosphorus which is removed in the septi…
Reactions
- At slightly acidic pH (as is found in the soils of Cape Cod and most of New England), orthophosphates combine with tri-valent iron or aluminum cations to form the insoluble precipitates FePO4 and AlPO4.
Composition
- Domestic wastewater usually contains only trace amounts of iron and aluminum. However, the sandy soil of Cape Cod frequently contains significant amounts of iron bound to the surface of sand particles. It is likely that this iron binds with phosphorus and causes some removal of total phosphorus below the leaching facility.
Management
- The treatment of sewage is largely a biochemical operation, where chemical transformations of the sewage are carried out by living microorganisms. Different environments favor the growth of different populations of microorganisms and this in turn affects the efficiency, end products, and completeness of treatment of the sewage. Sewage treatment systems, whether they are standar…
Types
- Three basic types of biochemical transformations occur as sewage is treated. The first is the removal of soluble organic matter. This is composed of dissolved carbon compounds such as detergents, greases, and body wastes, which make up much of the BOD content of the sewage. The second is the digestion and stabilization of insoluble organic matter. These are the sewage …
Other uses
- Other aerobic systems utilize suspended culture of microorganisms to aerobically treat the sewage. This type of treatment assumes that a resident population of bacteria are present in the solids and sludge in the treatment unit; vigorous mixing of the sewage in the treatment compartment causes these bacteria to stay in suspension where they can aerobically digest the …
Operation
- The activated sludge process is similar to suspended culture in that it also utilizes the resident population of bacteria in the solids and sludge in the treatment unit, again, usually by mixing of the sewage so that the bacteria are kept in suspension. In the activated sludge process, however, there are usually periods where mixing ceases, and the solids are allowed to settle. It is then ass…
Resources
- Grady, C.P. Leslie and Henry C. Lim, 1980. Biological Wastewater Treatment. Marcel Decker, Inc., N.Y Peavey, Howard S., Donald R. Rowe, and George Tchobanoglous, 1985. Environmental Engineering, McGraw Hill Inc., N.Y.