Answer:
The goal of disinfection of public water supplies is the elimination of the pathogens that are responsible for waterborne diseases. The transmission of diseases such as typhoid and paratyphoid fevers, cholera, salmonellosis, and shigellosis can be controlled with treatments that substantially reduce the total number of viable microorganisms in the water.
While the concentration of organisms in drinking water after effective disinfection may be exceedingly small, sterilization (i.e., killing all the microbes present) is not attempted. Sterilization is not only impractical, it cannot be maintained in the distribution system. Assessment of the reduction in microbes that is sufficient to protect against the transmission of pathogens in water is discussed below.
Chlorination is the most widely used method for disinfecting water supplies in the United States. The near universal adoption of this method can be attributed to its convenience and to its highly satisfactory performance as a disinfectant, which has been established by decades of use. It has been so successful that freedom from epidemics of waterborne diseases is now virtually taken for granted. As stated in Drinking Water and Health (National Academy of Sciences, 1977), "chlorination is the standard of disinfection against which others are compared."
However, the discovery that chlorination can result in the formation of trihalomethanes (THM's) and other halogenated hydrocarbons has prompted the reexamination of available disinfection methodology to determine alternative agents or procedures (Morris, 1975).
The method of choice for disinfecting water for human consumption depends on a variety of factors (Symons et al., 1977). These include:
its efficacy against waterborne pathogens (bacteria, viruses, protozoa, and helminths);
the accuracy with which the process can be monitored and controlled;
its ability to produce a residual that provides an added measure of protection against possible posttreatment contamination resulting from faults in the distribution system;
the aesthetic quality of the treated water; and
the availability of the technology for the adoption of the method on the scale that is required for public water supplies.
Economic factors will also play a part in the final decision; however, this study is confined to a discussion of the five factors listed above as they apply to various disinfectants.
The propensity of various disinfection methods to produce by-products having effects on health (other than those relating to the control of infectious diseases) and the possibility of eliminating or avoiding these undesirable by-products are also important factors to be weighed when making the final decisions about overall suitability of methods to disinfect drinking water. The subcommittee has not attempted to deal with these problems since the chemistry of disinfectants in water and the toxicology of expected by-products have been studied by other subcommittees of the Safe Drinking Water Committee, whose reports appear in Chapter III of this volume (Chemistry) and Chapter IV (Toxicity) of Drinking Water and Health, Vol. 3.
Organization of the Study
The general considerations noted in the immediately following material should be borne in mind when considering each method of disinfection. Available information on the obvious major candidates for drinking water disinfection—chlorine, ozone, chlorine dioxide, iodine, and bromine—is then evaluated for each method individually in the following sections. Other less obvious possibilities are also examined to see if they have been overlooked unjustly in previous studies or if it might be profitable to conduct further experimentation on them. Disinfection by chloramines is dealt with in parallel with that effected by chlorine because of the close relationship the former has to chlorine disinfection under conditions that might normally be encountered in drinking water treatment.
steps of Biological method of study taking malaria as an examples
Explanation:
The different steps which are involved in biological method are the the invasion, the rapid division followed by the spread of infection. ... Malaria results in infection after the bite of the female anopheles mosquito. The parasites enter the bloodstream. as a result of this there is predominant infection.
What do nitrifying bacteria do?
Answer: Nitrifying bacteria such as Nitrosomonas play an important role in providing nitrogen to plants and limiting carbon dioxide fixation. They are found widely distributed in soil or water, where there are large amounts of ammonia, such as lakes or streams into which treated and untreated sewage is pumped.
Explanation:
Answer:
They change Nitrogen to Nitrite and ammonia. Which helps plants to use Nitrogen even though it's in another form.
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Why is environmental science important?
Explanation:
it is where we live and share resources with order species
I hope this was helpful
The image shows groundwater zones. Top to bottom: Porous rock or soil, Water, Impermeable rock. Zone 1 is at the top of porous rock. Zone 2 is between porous rock and water. Zone 3 is in the Water. Zone 4 is between the Water and Impermeable rock. Which is the saturated zone?
Answer:
zone 3
Explanation:
Answer:
C
Explanation:
name 3 physiological processes of cell membrane?{3mks} plz help me guys
Answer:
the cell membrane is an extremely pliable structure composed primarily of back -to- back phospholipids (a "bilayer")
Why was the Nationalist Party more popular in China’s cities than in the countryside? Wealthy people who supported the party were concentrated in cities. People in the countryside were less active in politics than people in the city. Poor city dwellers hoped the Nationalist Party would bring economic change. The Nationalist Party threatened to end crop trade with Western nations.
Answer:
Wealthy people who supported the party were concentrated in cities.
Explanation:
Answer:
The answer is A on edgeExplanation:
which best describes bacterium?
Answer:
Bacteria (singular: bacterium) are classified as prokaryotes, which are single-celled organisms with a simple internal structure that lacks a nucleus, and contains DNA that either floats freely in a twisted, thread-like mass called the nucleoid, or in separate, circular pieces called plasmids. Hope this helps :))
Explanation:
Answer:
Bacteria are classified as prokaryotes, which are single-celled organisms with a simple internal structure that lacks a nucleus, and contains DNA that either floats freely in a twisted, thread-like mass called the nucleoid, or in separate, circular pieces called plasmids.
Explanation:
Arrange the sentences in order to describe how oxygen from air is transported to the cells in the kidneys.
Answer:
The pulmonary veins carry oxygenated blood to the heart. Air enters the bronchioles in the lungs and reaches the alveoli. The capillaries join together to reach the arteries, transferring the oxygen. The oxygen-rich blood moves from the aorta and reaches the kidneys through a series of blood vessels.
what are the major groups of animals and how to they differ
Which element is being cycled through Earth's system in the image shown
below?
Fossil fuels
Cellular
respiration
Photosynthesis
Animals
Plants
Industry and Home
Death and
decay
A. Oxygen
B. Nitrogen
c. Hydrogen
O D. Carbon
2. How are each of the following groups likely to feel about the reintroduction of wolves in Yellowstone National Park? (write 2-3 sentences for each)
a. Tourists who visit the park
b. Environmentalists (people who want to protect the nature of Yellowstone)
c. People who live near the park
Answer:
a) Good
b) Good
c) Bad
Explanation:
Tourists who visit the park feels good about the reintroduction of wolves in the park because it is a new animal they are seeing in the park. Environmentalists also feels good because this action is a step towards the protection of organisms present in the nature. People who live near the park does not feel good because wolf is a dangerous animal and if he escaped from the park, the lives of the people will be in danger.
13. List 4 safety symbols that would be seen if you are working with a material that is biohazard, such as bacteria.
Answer:
1. Skull and crossbones
2. A triangle (commonly painted colour red or yellow) with an exclamation sign inside.
3. biohazard symbol
4. A radiation sign in the form of a triangle, having other little image descriptions inside.
Explanation:
Note that a biohazard material refers to dangerous substances of biological (living) nature that can pose a threat to humans. Thus, safety symbols try as much as to draw attention to the descriptions used.
For example, skull and crossbones and biohazard symbols are used to indicate that a material that is biohazard, such as bacteria could result in the death of a person.
who discovered micro organisms
Robert Hooke is the person that discovered Micro organism
Answer:
An English architect, "Robert Hooke" discovered micro organisms in 1665.
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Atmospheric nitrogen can be fixed by nitrogen-fixing bacteria. Arrange the following forms of nitrogen from the atmospheric N stage to the final form that enters the roots. 1. Ammonia 2. Nitrogen gas 3. Ammonium ion 4. Nitrite 5. Nitrate
Answer:the answer is ammonia
Explanation:the nitrogen fixing bacteria fix the nitrogen as ammonia
Proteins in the cell membrane have many functions. Which type of protein would be used for cell recognition and as a receptor? A. Pore proteins B. Endoplasmic proteins C. Glycoproteins D. Integral proteins
Answer:
C. glycoproteins
Explanation:
Glycoproteins are proteins containing glycans (oligosaccharide carbohydrates) attached to amino acid side chains. These oligosaccharides are attached to the amino acid chain by a posttranslational modification referred to as glycosylation, a modification generally found in extracellular regions. Glycosylation refers to the chemical reaction in which a glycosyl donor (i.e., the carbohydrate) is attached to a functional group in the protein. The glycosylation sites play distinct functional roles for both cell interactions and cell recognition. Moreover, glycosylation sites are also essential for substrate recognition by an enzyme. For example, secreted cytokines are glycosylated, which is required for their binding to receptors.
Which of the following is not a negative consequence of upward urban growth?
a pollution
b creation of a "heat island"
C. increased use of surrounding land
d. waste management issues
Please select the best answer from the choices provided
A
OOOO
Answer: I believe its C
Explanation:
Answer:
C. increased use of surrounding land
Explanation:
Edge2021
Only ------ percent of the food eaten is turned into its own body. *
20%
12%
10%
40%
Answer:
12% I think this is right answer v
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Answer:
the answer is 10%
Explanation:
the 10% rule states that only 10% of energy is passed from one trophic level to the other (organism to organism)
Which of the following is a distinct structure found specifically in the liver, spleen, and bone marrow?
Select one:
a. Sinusoidal capillaries
b. Fenestrated capillaries
c. Venous sinus
d. AV anastomoses
e. Continuous capillaries
Answer:
option A is correct
Explanation:
What results if a broken chromosomal fragment becomes reattached as an extra segment to a sister or non-sister chromatid? A Duplication B Inversion C Polyploidy D Nondisjunction
Answer:
The correct answer is option A "Duplication".
Explanation:
Chromosomal duplication is defined as a type of rearrangement of genetic material at which extra copies of a DNA fragment are created. In this case if a broken chromosomal fragment becomes reattached, this fragment will represent an extra copy, and therefore the resultant genetic material is considered a chromosomal duplication.
How are the hours of darkness linked to the flowering time in plants?
Answer:
Hope it helps
Explanation:
plants flower as days grow shorter (and nights grow longer) after 21 June in the northern hemisphere, which is during summer or fall. The length of the dark period required to induce flowering differs among species and varieties of a species.
Write TRUE or FALSE
(a)
A 'system' is the part of an organism that carries out a certain function.
Answer:
TRUE
Explanation:
The process whereby the earth’s life changes over time through changes in genes of populations of organisms in succeeding generations is called____.a. emigration.b. mutation.c. natural selection.d. evolution.e. genetic drift.
Answer:
The correct answer is option : d. evolution.
Explanation:
Change in the heritable traits or characteristics of population of a organism over time by the adaption or changes in genes of such population over successive generation is known as the evolution.
These changes that cause the evolution of the biological population is caused by the process of adaption through natural selection that is the ability of the passing beneficial genes from parent to offspring.
Thus, the correct answer is option D. evolution.
Ultra-high-temperature sterilization effectively reduces microbes that cause spoilage. removes only mesophilic microbes. reduces microbes that cause disease. removes all microbes that cause diseases or spoilage. reduces microbes that cause disease or spoilage.
Answer:
kills all microbes that cause disease or spoilage.
Explanation:
There are different methods of sterilization, such as ultraviolet radiation, autoclave mechanisms, etc.
The sterilization mechanisms eliminate the microorganisms completely, thus generating sterile surfaces.
These mechanisms are used with surgical instruments, the operating room environment.
The autoclave method is the most widely used today due to its economical price, its ease of use and its practicality.
Sterilization methods must be strictly controlled with pilot or test microbiological cultures to be able to corroborate that these mechanisms function correctly, since otherwise they could trigger strong pathologies due to cross contamination.
which type of cell(s) contain ribosomes?
Answer:
Ribosomes are found in prokaryotic and eukaryotic cells; in mitochondria, chloroplasts and bacteria. Those found in prokaryotes are generally smaller than those in eukaryotes. Ribosomes in mitochondria and chloroplasts are similar in size to those in bacteria. hope this is good enough to help you
Explanation:
A gamete is best described as what?
A. The protective outer layer of an egg cell.
B. An enzyme in a sperm used to digest the egg cell's membrane.
C. A haploid cell produced for reproduction.
D. A diploid cell produced for reproduction.
Answer:
C. A haploid cell produced for reproduction.
Explanation:
The term "gamete" refers to reproductive cells such as sperm and ova. Sperm and ova are both haploid cells that unite to form diploid cells.
Consider this animal cell. The organelles in an animal cell are labeled. Part E represents small dots on the nucleolus. What is the function of the small, dark organelles labeled E? They contain enzymes for the digestion of old cell parts. They regulate what enters and leaves the cell. They produce proteins for the cell. They store water and other materials.
The dark organelles labelled E is called the Ribosomes.
what type of cash crops have been genetically modified..... please help!!!!!
Answer:
Most food modifications have primarily focused on cash crops in high demand by farmers such as soybean, corn, canola, and cotton. Genetically modified crops have been engineered for resistance to pathogens and herbicides and for better nutrient profiles.
Explanation:
The image shows a food web in an Arctic ecosystem. Rising temperatures in the Arctic Ocean can lead to large die-offs of phytoplankton, which are autotrophs. What would most likely happen in an Arctic ecosystem if the phytoplankton population decreased?
Answer:
as the population of phytoplankton decreases, the amount of food for zooplancktons decreases
While performing an experiment, it is important to:
a. change the control setup
b. test many different variables at the same time
c. reach a conclusion
d. record observations and measurements
Answer:
D
Explanation:
While performing an experiment, it is important to record observations and measurements, as in Option d. Option d is correct regarding the facts of the experiments, while the others are wrong.
What is an experiment?The experiment is carried out to observe the hypothesis, and in this process, a control set-up is taken whose value or result is already known, and the variables are taken and compared with the control. The controls set should never change in the experiment because the variables are tested with reference to them, and the measurements and observations of the experiment should be taken into consideration to prove the hypothesis. All the variables should not be tested at once because if this is done, it would introduce error into the experiment, and not all the experiments are done to get the conclusion.
Hence, while performing an experiment, it is important to record observations and measurements, as in Option d.
Learn more about the experiment here.
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a pupil performed an experiment in a school lab to show the action of a digestive enzyme on a food substance
a) Name and enzyme suitable for such an experiment
b) Name a food substance on which the enzyme that you have named will act
c) Describe any preparation of the food required before the experiment is performed. If no preparation is required state why?
d) give the temperature at which the enzyme-food mix should be maintained for the experiment to work
e) how much time is needed for digestion of food in this experiment?
f) describe a test to confirm that digestion has occurred
