What is bod in wastewater treatment?
Wastewater is water that has been contaminated from human activity, environmental, or industrial processes and must be treated for reuse or safe disposal. Usually determined alongside chemical oxygen demand (COD) in wastewater treatment, BOD is an important index that every industrial and municipal authority in the country should be aware of.
What is soluble BOD and how can it be treated?
Others opt to install waste treatment and filtration technology at their plant. For Soluble BOD, an industrial user needs to remove the suspended solids, oil and grease and metals prior to discharge. Discharging BOD typically results in a user fee or surcharge.
What is a BOD test for water pollution?
A BOD test is typically carried out over a standard 5-day incubation period at 20°C (68°F) for the most accurate results. Generally, a higher BOD value indicates a higher level of water pollution, while a lower BOD value indicates less polluted, or cleaner water.
What is the treatment and disposal of sewage sludge?
Treatment and disposal of sewage sludge are major factors in the design and operation of all wastewater treatment plants. Two basic goals of treating sludge before final disposal are to reduce its volume and to stabilize the organic materials.
What is STP and CETP?
Some of the major important types of wastewater treatment process are as follows: 1. Effluent Treatment Plants (ETP) 2. Sewage Treatment Plants (STP) 3. Common and Combined Effluent Treatment Plants (CETP). It is estimated that every year 1.8 million people die due to suffering from waterborne diseases.
What is STP and WWTP?
Basically, there are three types of treatment plants for water – water treatment plant (WTP), effluent treatment plant (ETP), and sewage treatment plant (STP). All of them have the sole purpose of treating wastewater.
What is the meaning of CETP?
Common effluent treatment plant (CETP) not only helps the industries in easier control of pollution, but also act as a step towards cleaner environment and service to the society at large.
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.
Is STP and ETP same?
1- ETP may be a system that removes toxic and non-toxic material from water and making it usable for various purposes. STP unit removes contaminants from municipal wastewater or household sewage. 2- ETP is employed in industrial areas whereas STP cleanses household water.
What is ETP sludge?
SLUDGE. • ETP (Effluent Treatment Plant) is a process design for treating the. industrial waste water for its reuse or safe disposal to the environment. • Influent: Untreated industrial waste water.
Why CETP is required?
They serve to reduce effluent treatment cost, provide better collective treatment, and reduce land cost for small-scale industrial facilities that cannot afford individual treatment plants. Optimum working conditions for treatment of effluent to be at par with discharge standards is a major mandate for any CETP.
Which chemical is used in STP?
Sodium Sulphate : Sodium sulfate, also known as sulfate of soda, is the inorganic compound with formula Na₂SO₄ as well as several related hydrates. All forms are white solids that are highly soluble in water.
How many types of WTP are there?
Typically, there are 5 types of WTP processes.
What are the 3 types of wastewater treatment?
There are three main stages of the wastewater treatment process, aptly known as primary, secondary and tertiary water treatment. In some applications, more advanced treatment is required, known as quaternary water treatment.
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 is called sludge?
The residue that accumulates in sewage treatment plants is called sludge (or biosolids). Sewage sludge is the solid, semisolid, or slurry residual material that is produced as a by-product of wastewater treatment processes. This residue is commonly classified as primary and secondary sludge.
Wastewater BOD And Pollution
BOD is considered to be one of the most important measurements to be taken in wastewater treatment and is a key indicator of water health and safety.
The Role BOD Plays In Water
Dissolved oxygen plays a big role in natural water sources. Without the right concentration of dissolved oxygen, aquatic life and water quality start to deteriorate.
BOD In Wastewater Treatment Plants
As mentioned, BOD is a key indicator of organic pollution in wastewater. This means that the industrial sector is tasked with discharging their final water product only if it meets the right level of BOD.
The In-Pipe Difference
Wastewater treatment is a careful biological process. The microorganisms already naturally present in the wastewater do the majority of the work when it comes to reducing harmful nutrients and push clean water back into the waterways.
In-Pipe And FOG
In-Pipe is also effective when it comes to dealing with FOG. Food-related industries are some of the most notorious sources of FOG in sewer collection systems, and the build-up can cause serious issues. These blockages require regular, labor-intensive cleaning which can be costly to do on a consistent basis.
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.
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 BOD in wastewater?
Industries that discharge wastewater into municipal sanitary sewers or waterways are facing strict regulations on levels of biological or biochemical oxygen demand (BOD). Solid materials in wastewater can consist of organic and/or inorganic materials and organisms.
What is the purpose of a biological oxygen demand test?
Biological Oxygen Demand (BOD) is a chemical procedure for determining the amount of dissolved oxygen needed by aerobic biological organisms “bio-bugs” in a body of water to break down organic material present in a given water sample at a certain temperature over a specific time period. It is not a precise quantitative test, although it is widely used as an indication of the quality of water.
Does ALAR water treatment increase BOD?
ALAR Water Treatment provides these industries with cost effective wastewater equipment solutions in order to help achieve BOD discharge compliance.
An Overview of Caustic Soda
Caustic soda is an alkaline substance known by the chemical formula of NaOH. This product, which is also called caustic soda, some of the applications of caustic soda are water purification, food production, detergents, and …. One of the important features of this product is its corrosive properties in the presence of water.
Application of Caustic Soda in Water and Wastewater Treatment
Caustic soda is known as an alkaline substance and for this reason it is known as a neutralizer of acidic environments. Due to the low pH value, in addition to having an acidic environment, untreated water has a relatively high corrosive property, which leads to damage to the walls of pipes.
Case Study of the Effect of Caustic Soda on Water and Wastewater Treatment
Surveys of treated water from two treatment plants in Washington, D.C., and North Virginia in the United States have shown that the pH of water entering these treatment plants varies in different weather conditions.
What is wastewater treatment plant?
Wastewater treatment plant is the process of removing contaminants from wastewater and converting it into effluent that can be recycled into the water cycle. Once returned to the water cycle, the effluent has an acceptable environmental impact or is reused for a variety of purposes. A wastewater treatment plant is where the treatment ...
Where is sludge removed from sedimentation tanks?
The sludge is removed from the bottom of the first sedimentation tank and placed in a large, closed tank known as the digester tank. Many different types of anaerobic bacteria decompose the organic matter in sludge in the digester tank to produce biogas.
Why is activated sludge returned to the aeration tank?
Some of the activated sludge is returned to the aeration tank to boost the population of aerobic bacteria and accelerate the cleaning of watery waste. The digester tank receives the remaining activated sludge. The water in the second sedimentation tank contains very little organic material and suspended matter.
What is the difference between biogas and sludge?
As a result, wastewater treatment (or sewage treatment) yields two useful products: (i) biogas and (ii) sludge. Biogas is used as a fuel, and sludge is used as manure (or fertiliser).
What is the solid component of sewage?
The majority of the solid organic matter (faeces, for example) settles as sludge on the sloping bottom of the sedimentation tank. As a result, the solid component of sewage is known as sludge .
What is biogas used for?
Biogas is used as a fuel , and sludge is used as manure (or fertiliser). The use of dried sludge as manure restores the nutrients to the soil. b. The wastewater remaining in the first sedimentation tank contains some organic waste in the form of tiny suspended particles as well as soluble organic matter.
What is WWTP in water treatment?
WWTP is an abbreviation for Waste-Water Treatment Plant. A wastewater treatment plant is also referred to as a sewage treatment plant. A modern wastewater treatment plant treats wastewater or sewage through a series of physical, chemical, and biological processes until it becomes fit to be discharged into the environment.
What is sludge in sewage treatment?
The residue that accumulates in sewage treatment plants is called sludge (or biosolids). Sewage sludge is the solid, semisolid, or slurry residual material that is produced as a by-product of wastewater treatment processes . This residue is commonly classified as primary and secondary sludge. Primary sludge is generated from chemical precipitation, sedimentation, and other primary processes, whereas secondary sludge is the activated waste biomass resulting from biological treatments. Some sewage plants also receive septage or septic tank solids from household on-site wastewater treatment systems. Quite often the sludges are combined together for further treatment and disposal.
Why treat sludge before disposal?
Two basic goals of treating sludge before final disposal are to reduce its volume and to stabilize the organic materials. Stabilized sludge does not have an offensive odour and can be handled without causing a nuisance or health hazard. Smaller sludge volume reduces the costs of pumping and storage.
What is the process of sludge being passed through a dewatering step?
Digested sludge is passed through a dewatering step; the dried solids are disposed of, and the water is sent back to secondary treatment. Encyclopædia Britannica, Inc. Treatment and disposal of sewage sludge are major factors in the design and operation of all wastewater treatment plants.
How is hydrolyzed sludge passed through?
The hydrolyzed sludge is passed through a flash tank, where a sudden drop in pressure causes cells to burst, and then to anaerobic digestion, where bacteria convert dissolved organic matter to biogas (which can be used to fuel the treatment process). Digested sludge is passed through a dewatering step; the dried solids are disposed of, ...
What is the first step in sludge treatment?
Thickening. Thickening is usually the first step in sludge treatment because it is impractical to handle thin sludge, a slurry of solids suspended in water. Thickening is usually accomplished in a tank called a gravity thickener. A thickener can reduce the total volume of sludge to less than half the original volume.
What is sludge digestion?
Sludge digestion is a biological process in which organic solids are decomposed into stable substances. Digestion reduces the total mass of solids, destroys pathogens, and makes it easier to dewater or dry the sludge. Digested sludge is inoffensive, having the appearance and characteristics of a rich potting soil.
Why is sludge inoculated?
In some cases, the sludge is inoculated with extra hydrolytic enzymes at the beginning of the first digestion stage in order to supplement the action of the bacteria. It has been found that this enzymatic treatment can destroy more unwanted pathogens in the sludge and also can result in the generation of more biogas in the second stage of digestion.
