Which organism is used for municipal wastewater?
Biological treatments rely on bacteria, nematodes, or other small organisms to break down organic wastes using normal cellular processes. Wastewater typically contains a buffet of organic matter, such as garbage, wastes, and partially digested foods. It also may contain pathogenic organisms, heavy metals, and toxins.
Which bacteria is used for sewage treatment?
Furthermore, anaerobic bacteria are an important element in the wastewater treatment processes. They are responsible for methane fermentation of sewage sludge, facilitating decomposition of macromolecular organic matter into simpler compounds.
Which is the biological waste treatment?
In microbiological terms, biological waste-treatment processes are effectively large man-made microbial culture systems designed to transform large amounts of carbonaceous material into inoffensive products (including relatively innocuous microbial biomass).
What is sludge and how it is treated?
The residue that accumulates in sewage treatment plants is called sludge (or biosolids). Digested sludge is passed through a dewatering step; the dried solids are disposed of, and the water is sent back to secondary treatment.
What is required to keep the activated sludge suspended?
To maintain aerobic conditions and to keep the activated sludge suspended, a continuous and well-timed supply of oxygen is required. It consists of flocs of bacteria, which are suspended and mixed with wastewater in an aerated tank.
Why secondary treatment is called as biological treatment?
2. Secondary treatment of wastewater works on a deeper level than primary level. It is called as biological treatment because it is designed to substantially degrade the biological content of the waste through aerobic biological processes. This step removes the dissolved organic matter by the use of biological agents.
What is difference between primary and secondary sewage treatment?
The main difference is the way each respective treatment is processed. Primary treatment works on sedimentation, where solids separate from the water through several different tanks. In contrast, secondary treatment uses aeration, biofiltration and the interaction of waste throughout its process.
What do you mean by secondary treatment of sewage?
Secondary treatment is a treatment process for wastewater (or sewage) to achieve a certain degree of effluent quality by using a sewage treatment plant with physical phase separation to remove settleable solids and a biological process to remove dissolved and suspended organic compounds.
What is bod in zoology?
Biochemical oxygen demand (BOD), the amount of dissolved oxygen used by microorganisms in the biological process of metabolizing organic matter in water.
In which water bod is maximum?
Moderately polluted rivers may have a BOD value in the range of 2 to 8 mg/L. Rivers may be considered severely polluted when BOD values exceed 8 mg/L. Municipal sewage that is efficiently treated by a three-stage process would have a value of about 20 mg/L or less.
What does the high BOD indicates?
Higher BOD indicates more oxygen is required, which is less for oxygen-demanding species to feed on, and signifies lower water quality. Inversely, low BOD means less oxygen is being removed from water, so water is generally purer.
What is BOD Class 9?
BOD measures the amount of oxygen utilized by microorganisms for the process of decomposition of the organic matters in the water bodies. It symbolizes the amount of organic pollution present in an aquatic ecosystem. Used in the medicinal & pharmaceutical industries to test the oxygen consumption of cell cultures.
What is BOD very short answer?
Biochemical oxygen demand (BOD) represents the amount of oxygen consumed by bacteria and other microorganisms while they decompose organic matter under aerobic (oxygen is present) conditions at a specified temperature. The decay of organic matter in water is measured as biochemical or chemical oxygen demand.
What is BOD COD and do?
BOD is the amount of oxygen that will be consumed by bacteria or other aerobic microorganisms while decomposing organic matter under aerobic conditions. COD measures the amount of oxygen that will be consumed by the chemical breakdown, or oxidation (degeneration) of organic pollutants in water.
What is BOD of drinking water?
BOD is the biochemical oxygen demand of the water and it is related to the concentration of the bacterial facilitated decomposable organic material in the water. For freshwater the concentration should be less than 0.0004 mg/L.
What is COD in wastewater?
The chemical oxygen demand (COD) is a measure of water and wastewater quality. The COD test is often used to monitor water treatment plant efficiency. The COD is the amount of oxygen consumed to chemically oxidize organic water contaminants to inorganic end products.
How do you reduce COD in wastewater?
The most important way to get rid of the sludge is to use coagulants and flocculants. The principle is to bind the sludge to one another so that a larger clumps of sludge and then be deposited in a sedimentation tank. Some chemicals commonly used as a coagulant, among others; PAC, FeCl3 (Ferric Chloride) and Alum.
What causes COD in wastewater?
Chemical oxygen demand (COD) is often used to measure organic matter in wastewater, treated effluent, and receiving waters. Residual food waste from bottles and cans, antifreeze, emulsified oils are all high in COD and are common sources of COD for industrial stormwater.
Is high COD good or bad?
The higher the COD value, the more serious the pollution of organic matter by water. The most common application of COD is in quantifying the amount of oxidizable pollutants found in surface water (e.g., lakes and rivers) or wastewater (Davidson, 2001; Sara and Goncaloglu, 2008).
Why is cod bad for you?
Consuming cod in moderate amounts is safe and generally without adverse effects. Cod, like most types of fish, contains mercury. Excessive mercury consumption can be toxic and may cause neurological and behavioral disorders. It may be particularly problematic in children.
Is cod or salmon better for you?
However, it is important to note that cod and other lean fish are lower in omega-3 fatty acids than fatty fish like salmon ( 3 ). These fats are presumed responsible for many health benefits. Nonetheless, cod is nutrient-dense, meaning that it contains many beneficial nutrients in relatively few calories.