These chemicals perform 6 main roles in the treatment process, each providing a key function. These functions include: Removal of solid particles, pH Adjustment, Odor Control, Disinfection, Foam Prevention & Removal, and Sludge Removal.
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What is the role of chemicals in wastewater treatment?
Often, as a result of processing food, or in some other process at an industrial plant, the wastewater produces odors that are not only unpleasant but that can also be harmful. Odor Control is another key function for the use of chemicals in wastewater.
How does a wastewater treatment plant work?
First, the wastewater is directed to a screen or a sieve drum that filters out impurities that are relatively coarse, such as leaves, textiles, paper, or other large materials. A series of screens are used with various degrees of fineness from several centimeters down to a few millimeters to screen out coarse contaminants in the water.
What is the primary objective of wastewater treatment processes?
The primary objective of wastewater treatment processes is to purify the water and make certain that it is safe for subsequent use once it has been returned to the environment as part of the water cycle.
What are chemical unit processes in water treatment?
These chemical processes, which induce chemical reactions, are called chemical unit processes and are used alongside biological and physical cleaning processes to achieve various water standards. Specialized chemicals such as chlorine, hydrogen peroxide, sodium chlorite, and sodium hypochlorite (bleach)...
Why is surface chemistry important?
Surface chemistry is important in many critical chemical processes, such as enzymatic reactions at biological interfaces found in cell walls and membranes, in electronics at the surfaces and interfaces of microchips used in computers, and the heterogeneous catalysts found in the catalytic converter used for cleaning ...
Which chemical most commonly used in wastewater treatment?
Certain basic or alkaline chemicals used to raise wastewater pH are below: CaO (calcium oxide or lime), MgO (magnesium oxide), Ca (OH) (calcium hydroxide, a hydrated form of lime) or Mg (OH) (magnesium hydroxide) are the most commonly used chemicals because of availability, low cost, and high capacity.
What is the importance of chemistry in water treatment?
Chemical water treatment can be successfully used for the removal of both toxic organic and inorganic compounds, and physical–chemical methods are intended to remove a wide range on contaminants from water starting from organic and inorganic compounds and ending with biological pollution.
How is wastewater treated in chemistry?
2:053:43GCSE Science Revision Chemistry "Waste Water Treatment" - YouTubeYouTubeStart of suggested clipEnd of suggested clipWhen this water is treated any harmful chemicals first need to be removed. After this stage theMoreWhen this water is treated any harmful chemicals first need to be removed. After this stage the water can then safely entered general sewage treatment.
Which chemical is used to water treatment process?
The four main types of chemicals used in wastewater treatment are pH neutralisers, anti-foaming agents, coagulants and flocculants. The most straightforward class of chemicals is pH neutralisers, although why and how they are used varies depending on the process producing the wastewater.
What chemicals are utilized in the treatment of water and wastewater?
Water and wastewater treatment chemicalsDefoamers – organic matter in water decays to form surfactants. ... Biocides – anti-microbial biocides are used as anti-fouling agents to remove viruses or bacteria from wastewater.More items...
What is wastewater chemistry?
Wastewater is a complex matrix containing significant concentrations of solids (total solids 350–1200mg/l), dissolved and particulate matter (chemical oxygen demand 250–1000mg/l), microorganisms (up to 109 number/ml), nutrients, heavy metals and micro-pollutants.
What is sewage chemistry?
Sewage consists primarily of water and usually contains less than one part of solid matter per thousand parts of water. In other words, one can say that sewage is composed of around 99.9% pure water, and the remaining 0.1% are solids, which can be in the form of either dissolved solids or suspended solids.
What are the 3 stages of wastewater treatment?
There are three main stages of the wastewater treatment process, aptly known as primary, secondary and tertiary water treatment.
How does a surface aerator work?
Surface aerators push water from under the water’s surface up into the air, then the droplets fall back into the water, mixing in oxygen. The jets of water break the surface with varying degrees of force. There are many types of surface aeration devices, including floating aerators.
What is aeration used for?
It is also commonly used to treat agricultural wastes.
What is the process of aeration?
The process of aeration is used to mix, circulate, or dissolve air into a liquid or another substance. Mechanical aeration can reduce the amount of chemicals needed to treat a body of water by providing the oxygen that bacteria need to function properly. There are two common types of water aeration: subsurface and surface.
Why is surface aeration difficult?
Factors such as heat can prove challenging to surface aeration because of higher rates of evaporation, which can have an adverse effect on some applications.
Why is an aerator effective?
Because the equipment sits on the surface, this type of aerator is effective in introducing oxygen to the top foot or so of a body of water, depending on the type of nozzle used.
What are the two types of water aeration?
There are two common types of water aeration: subsurface and surface. Although subsurface aeration comes to mind first in discussions of wastewater treatment, surface aeration plays an equally important role in oxygenating liquids.
What are the functions of wastewater treatment?
These functions include: Removal of solid particles, pH Adjustment, Odor Control, Disinfection, Foam Prevention & Removal, and Sludge Removal .
What are the effects of wastewater?
Unpleasant odors produced by the wastewater can impact employee morale, invite complaints from neighbors including other businesses, and even be a health hazard. It is a major issue that must be solved. For most industrial plants something more must be done than just “covering up” the problem to contain the odors.
What is the purpose of anti foam?
To prevent foam from occurring , an Anti-foam chemical agent can be used. One other use of chemicals in wastewater treatment is for the purpose of Sludge Removal . The water must be removed from the sludge that is created in the wastewater treatment process. Often polymer chemicals are re-introduced into this stage of treatment to remove the water.
Why are coagulant and floculant polymers important?
These polymers help the tiny particles in the water to begin to combine with each other to form larger particles and chains of particles that settle out of the water and drop to the bottom. Basically, the polymers are used to change the “charge” of the particles ...
What is the most used acid in a plant?
Obviously either an acid or a base chemical will be used, depending on the pH level of the water. The most used acid is Sulfuric Acid.
What acid is used to adjust pH?
The most used acid is Sulfuric Acid. This is due to its cost, abundance, and effectiveness in adjusting the pH level. Other acids that are used include Hydrochloric Acid and Phosphoric Acid . As far as bases, some common chemicals that are effective are Sodium Hydroxide, Calcium Hydroxide (Lime), among others.
Can foam be in wastewater?
Often foam can develop in the wastewater treatment process, which can cause many problems. In fact, the foam can stand in the way of measuring instruments getting a true reading and can cause other difficulties. For more on how foam can develop in wastewater, see our article “What causes foam in wastewater treatment.”.
Why is wastewater treatment important?
Wastewater treatment has an important responsibility to react to changing consumer and industrial produced wastes that pose environmental challenges. Surfactants are one of these emerging contaminants. They are of interest because of their increasingly ubiquitous domestic and industrial use and the difficulty their presence causes traditional ...
What are the advantages of adsorption in wastewater treatment?
One advantage of the adsorption approach for wastewater treatment is material recycling that offsets the cost of wastewater treatment. This can be achieved from desorption processing downstream ( Shang et al., 2016 ). A key property of CNTs in this application is therefore desorption capacity. CNT desorption mechanisms have been studied in the literature although there appears to be a gap in the literature relating to surfactant desorption. Desorption for various molecules has been proven to be feasible for CNTs by parameter alterations such as pH change ( Engel and Chefetz, 2016 ), electric current ( Paul et al., 2015 ), temperature and shear ( Vo and Papavassiliou, 2017 ). These studies did not concern surfactant adsorption however. These studies do show that the desorption strategy is viable and that similar work to address surfactant would potentially yield promising results.
How can surfactants be useful?
Despite the many negative challenges their presence can cause in wastewater treatment, surfactants could prove useful in improving existing wastewater treatment processes. This field is gaining increasing attention in the literature. There is therefore a need to consider recent developments to provide a balanced overview. The aim is to provide the authors’ opinion on the progress of development by focussing on two key developments and their feasibility considering the potential risk of surfactant pollution. The first development to be investigated is the potential for improving the performance of zeolites, an increasingly important element of wastewater treatment.
What are the challenges of wastewater treatment?
This is because of the wide usage and range of surfactants and their negative impact both on the wastewater treatment process and more importantly on the environment.
What are the different types of surfactants?
Within the surfactant market, there are three main categories of surfactant: anionic, cationic and non-ionic.
What is a potential strategy for future surfactant removal?
A potential strategy for future surfactant removal could be to promote novel techniques more suited to dealing with surfactants. This section therefore reviews the cutting edge of surfactant removal techniques to provide an up to date position of these technologies.
What are CNTs used for?
In the wastewater treatment context, CNTs could be used as a nanomaterial for adsorption based treatment processes ( Burakov et al., 2018) as a replacement for traditional materials such as AC, zeolite and kaolin ( Gupta and Saleh, 2013; Bankole et al., 2017 ). As an example, the adsorption mechanism for anionic and cationic surfactants onto CNTs is shown in Fig. 3.
How does sewage affect the environment?
When the waste water is mixed with the waste materials such like garbage, household waste, toilets liquid and disposable things, the resulting product called sewage or waste water. This sewage water is normally will undergo a few process before it is release to the environment but there are still some impact on the environment. One of the impacts on the environment is agricultural impacts. The sewage water contains salts which is soluble that may accumulate in the root zone with possible harmful effect on soil health and crop yield. The physical and mechanical properties of the soil, such as dispersion of particle, stability of aggregates, soil structure and permeability are very sensitive to the types of exchangeable ions present in irrigation water. Thus, when effluent use is being planned, several factors related to the soil properties must be taken into consideration. On the other hand the effect of dissolved solids in the irrigation water on the growth of plants is also another aspect of agriculture which we have to concern. Dissolved salts increase the osmotic potential of soil water and increase the osmotic pressure of the soil solution which increases the growth and the yield of most plants decline progressively as osmotic pressure increases. In addition the one of the environment impact is ecological impact where the drainage water from waste water irrigation schemes drains particularly into small confined lakes and water bodies and surface water, and if phosphatesin the ortho phosphate form are present, the remains of nutrients may cause eutrophication. Here the overloading organic materials resulting in decrease in dissolved oxygen may lead to changes in the composition of a aquatic life such as fish deaths and reduced fishery. The eutrophication potential of waste water irrigation can be assessed using biological indices, which in turn can be qualified in monitory units using economic valuation techniques. The hidden impact on the environment is the increase on the production of green house emissions. The large agriculture reuse project might cause to the environmental externalities associated with pumping water uphill which emits greenhouse gas. Another impact is on the health. The sewage water contains pathogenic microorganisms like bacteria, viruses, protozoan’s and parasitic worms, the diseases and signs related with such infection are also diverse including typhoid,dysentry and cholera, diarrhea and vomiting. the concentration of he pathogens in waste water is dependent on the source population and the susceptibility to infection varies from one population to another. So basically he waste water is actually harm for the nature even though its treated and release to the environment so as a human being we should not dispose the waste into the water thus our water will be clean and the cost of the treatment can be reduced.
What is chemical engineering?
The Chemical Engineering is the profession that combines chemistry and engineering concepts that help to solve problems related to world hunger, pollution of our environment, creating new materials, or meeting demands for energy. Chemical engineers develop low cost processes for useful chemical products, which make it possible for both poor nations and the United States to manufacture important fertilizers.
What is the problem with water scarcity?
Although 2/3rd of the earths crust is made up of water but all this water is not available for drinking and for other human activities as either it is locked in the form of ice or present in the form of vast saline oceans and seas. It has been found out that 97% of the total water is salty that is of no use to human and animals (except marine animal) and the remaining three percent is available as freshwater. More than half of this three percent is locked in glacier and less than 0.01% is available as fresh water. So water resources are less as compare to human demand for water.
Why is wastewater treatment important?
Wastewater treatment protects humans and ecosystem. Wastewater contains elements toxic to humans and the ecosystem. Wastewater treatment facilities help to purify the water and eliminate situations like what is currently seen in developing countries .
What is the purpose of wastewater treatment facilities?
Summary. The main goal of wastewater treatment facilities is to protect humans and the ecosystem from harmful and toxic elements found in wastewater. Water treatment facilities were designed to speed up the natural process of purifying water because the natural process is overloaded.
Why is wastewater important for the ecosystem?
Wastewater treatment also protects the ecosystem. Fish and aquatic life require fresh water. When their water environment is laden with wastewater, they cannot survive. If chemicals, such as nitrogen and phosphates, enter streams, rivers or large bodies of water in excessive amounts, it causes excessive plant growth which release toxins into ...
What would happen if there was no wastewater treatment?
With billions of people and even more wastewater, the natural process is overloaded. Without wastewater treatment, the amount of wastewater would cause devastation, as it still does today in developing countries.
Why is natural water treatment overloaded?
While Mother Nature does her best to naturally process wastewater, there is too much for her to handle. Because the global population is so large and growing, so is wastewater. Nature can’t keep up with naturally processing the excessive amounts of wastewater.
How much of the world's wastewater is discharged without treatment?
Globally, over 80 percent of all wastewater is discharged without treatment. 1 In the countries that do have water treatment facilities, they use various methods to treat water with one common goal: purify water as much as possible and send it back into the environment to keep humans and the Earth safe and thriving.
Abstract
Water is a most crucial and limited resource on the Earth, which has contaminated due to the addition of heavy metals, pathogens, pesticides, and many organic and inorganic substances. Currently, the research has been focused on the sustainable remediation approach for waste reclamation.
About this chapter
Chaturvedi V.K., Kushwaha A., Maurya S., Tabassum N., Chaurasia H., Singh M.P. (2020) Wastewater Treatment Through Nanotechnology: Role and Prospects. In: Upadhyay A., Singh R., Singh D. (eds) Restoration of Wetland Ecosystem: A Trajectory Towards a Sustainable Environment. Springer, Singapore. https://doi.org/10.1007/978-981-13-7665-8_14
Mechanical Wastewater Treatment Processes
- The initial stage of wastewater treatment involves mechanical processes, which remove some 20-30% of solids in the water. First, the wastewater is directed to a screen or a sieve drum that filters out impurities that are relatively coarse, such as leaves, textiles, paper, or other large materials. A series of screens are used with various degrees of fineness from several centimeters down to a …
Biological Wastewater Treatment Processes
- Following the mechanical treatment stage, effluent is passed to a biological-based process for further purification. Aeration tanks are utilized to add oxygen to the water and to put the water into circulation through the use of propellers. The oxygen stimulates the growth of bacteria and microorganisms which feed off of any organic contaminants in the water and convert those into …
Chemical Wastewater Treatment Processes
- Chemicals are used during wastewater treatment in an array of processes to expedite disinfection. These chemical processes, which induce chemical reactions, are called chemical unit processes and are used alongside biological and physical cleaning processes to achieve various water standards. Specialized chemicals such as chlorine, hydrogen peroxid...
Summary
- Processing of wastewater for use, or recycling and reuse, represents a unification of several distinct technologies, including specialized chemicals, mechanical filtration products, purification systems, specially designed equipment, and wastewater treatment servicesto obtain satisfactory solutions to the challenges of water purification and remediation. This article provided a review …