Hygiene MCQs Topic 9

Water supply and water supply networks are: A - a system of water canals with structures and devices on them for supplying water to the places of its consumption; B - complex construction, equipped with a pumping and power plant for lifting and supplying water to the water supply network; C - closed structures for storage of water after its cleaning; D - hydraulic engineering structure for abstraction of water from an open reservoir or from an underground source; E - a complex of buildings, structures and devices for water treatment in order to bring its quality indicators in line with the requirements of water users.

A - a system of water canals with structures and devices on them for supplying water to the places of its consumption

The disadvantage of the method of chlorination of water with preammonization is that: A - chloramines have weaker bactericidal properties than chlorine or chlorine lime; B - increases the consumption of chlorine; C - organoleptic properties of water deteriorate; D - it is necessary to dehydrate the water with sodium hyposulfite; E - long duration of chlorination (not less than 2 hours)

A - chloramines have weaker bactericidal properties than chlorine or chlorine lime

Methods of chlorination of water: A - double chlorination, perchlorination; B - triple chlorination, re-zoning; C - permanganation with preliminary chlorination; D - chlorination with preliminary ozonation; E - chlorination with pre -manganation.

A - double chlorination, perchlorination

Chlorination of water with preammonization is a method of water disinfection, in which: A - first, ammonia is introduced into the water, and after 0.5-2 minutes - chlorine; B - use of chloramines; C - chlorine is injected into the water, and after 0.5-2 min. - ammonia; D - the supply of chlorine into the water occurs before the settling tanks, and ammonia - after the filters; E - the supply of chlorine to water occurs before the filters and ammonia - after the filters.

A - first, ammonia is introduced into the water, and after 0.5-2 minutes - chlorine

Special methods for improving water quality include: A - fluorination, deferrization, desalination, decontamination; B - chlorination with preammonization, illumination; C - coagulation followed by filtration; D - double chlorination, ozonation, coagulation, filtration; E - perchlorination, dechlorination, disinfection.

A - fluorination, deferrization, desalination, decontamination

As a coagulant for clarification of water is used: A - iron vitriol, aluminum sulphate, ferric chloride; B - copper sulfate, hypochlorous acid, sodium tetraborate; C - silver sulphate, sodium chloride, calcium bisulfate; D - hypochlorous iron, copper vitriol, aluminum hydroxide; E - aluminum hydroxide, iron vitriol, copper sulfate.

A - iron vitriol, aluminum sulphate, ferric chloride

The methods of water clarification include: A - physical, chemical, combined; B - decolorization, decontamination, decontamination; C - hygienic, biochemical; D - sanitary, epidemiological; E - double chlorination, chlorination with preammonization

A - physical, chemical, combined

Water processing is: A - technological process, which is carried out to bring the safety and quality of drinking water indicators to the levels of hygienic standards; B - process of purification of waste water before discharge into an open reservoir; C - technological process of water treatment using the coagulation method; D - water treatment to bring its quality into compliance with the requirements for technical purposes; E - mechanical cleaning of undissolved contaminants (rubbish, sand, rust, scale, coarse and fine dispersions) with subsequent improvement of organoleptic properties.

A - technological process, which is carried out to bring the safety and quality of drinking water indicators to the levels of hygienic standards

In order for coagulation to take place the following conditions are necessary: A - the optimal dose of coagulant, equivalent to bicarbonate water hardness; B - maximum dose of coagulant with sufficient alkalinity of water; C - temperature of water not higher than 12 ° С and preliminary settling of water; D - preliminary sedimentation of water and minimum bicarbonate hardness of water; E - preliminary disinfection of water at a temperature not exceeding 15 ° С.

A - the optimal dose of coagulant, equivalent to bicarbonate water hardness

The advantage of the method of chlorination of water with preammonization is that: A - the resulting chloramines do not form chlorophenols with phenols; B - can be used to prevent the greenish color of water containing phenols; C - the technique of chlorination is simplified in comparison with usual chlorination; D - can be successfully used in the chlorination of water containing ammonia and its derivatives; E - it is possible to decontaminate turbid water.

A - the resulting chloramines do not form chlorophenols with phenols

The advantage of the water overchlorination method is that: A - the time is shortened and the chlorination technique is simplified; B - it is possible to disinfect salted water; C - it is necessary to dechlorinate water; D - chlororganic substances are not formed; E - transparency and color of water improves.

A - the time is shortened and the chlorination technique is simplified

The water supply system includes the following main elements: A - water abstraction, water processing station, reservoirs, water pumping station, water canals, water supply networks; B - water source, water abstraction, septic tanks, water supply station, water lines, water supply networks; C - water abstraction, water processing station, reservoirs, sewerage, water canals, water supply networks; D - water source, pumping station, water abstraction, reservoir, water supply networks, consumers; E - water abstraction, reagent, vertical septic tanks, reservoirs, water canals, water supply networks.

A - water abstraction, water processing station, reservoirs, water pumping station, water canals, water supply networks

Water processing station is: A - hydraulic structure for abstraction of water from an open reservoir or from an underground source; B - a complex of buildings, structures and devices for water treatment with the purpose of bringing the indicators of its quality in line with the requirements of water users; C - a structure equipped with a pumping-power plant for lifting and supplying water to the water supply network; D - closed structures for storage of water after its cleaning; E - a system of pipelines with structures and devices on them to supply water to places of consumption

B - a complex of buildings, structures and devices for water treatment with the purpose of bringing the indicators of its quality in line with the requirements of water users

Physical methods of water disinfection include: A - filtration, settling; B - boiling, microwave field; C - permanganation, ozonization; D - settling, ions of silver; E - ozonization, desalination.

B - boiling, microwave field

The alkalinity of water when calculating the optimal dose of coagulant (aluminum sulphate) is determined for: A - determination of the concentration of flocculant; B - calculation of bicarbonate hardness of water; C - the pH of the water; D - calculation of the dry residue of water; E - the establishment of the optimal type of coagulant

B - calculation of bicarbonate hardness of water

The advantage of the method of chlorination of water with preammonization is that: A - the resulting chlorophenols do not form chlororganic substances; B - can be used to prevent an unpleasant smell of water containing phenols; C - the technique of chlorination is simplified in comparison with usual chlorination; D - can be successfully used in the chlorination of water containing ammonia and its derivatives; E - it is possible to decontaminate turbid water.

B - can be used to prevent an unpleasant smell of water containing phenols

The methods of water disinfection include: A - bacteriological, biochemical; B - chemical, physical; C - coagulation, chlorination; D - filtration, sedimentation; E - physiological, epidemiological.

B - chemical, physical

Chemical methods of water disinfection include: A - UV rays, boiling, gamma radiation; B - chlorination, ozonation, permanganation; C - ozonation, X-rays; D - magnetic field, iodination, boiling; E - impulse electric charge, ultrasound.

B - chlorination, ozonation, permanganation

Substances used for the chlorination of water: A - hypochlorite of potassium, chlorine hydroxide, chlorophos; B - chlorine dioxide, chloramine, calcium hypochlorite; C - potassium hypochloride, aluminum hydroxide, iodine; D - calcium hydroxide, potassium permanganate, ozone; E - chloramine, ozone, iodonic potassium.

B - chlorine dioxide, chloramine, calcium hypochlorite

The principle of the method of quantitative determination of residual chlorine in water is based on: A - determination of bicarbonate water hardness; B - displacement of free iodine by active chlorine from potassium iodide in an equivalent amount and determination of its amount during titration with hyposulfite; C - colony count colostrum on a nutrient medium after 2 days of incubation in a thermostat at a temperature of 370 C; D - determination of the least pronounced aftertaste of water after its chlorination by different doses; E - testing of the effect of various amounts of 1% chloric lime solution on water and evaluating the results according to the taste of water.

B - displacement of free iodine by active chlorine from potassium iodide in an equivalent amount and determination of its amount during titration with hyposulfite

Physical methods of water clarification include: A - coagulation, freezing; B - filtration, settling; C - application of ultraviolet radiation, desalination; D - ozonization, oligodynamics; E - boiling, filtering

B - filtration, settling

The advantage of ozonization as a method of water disinfection is that: A - do not need to clarify the water beforehand; B - greater reliability in comparison with chlorination; C - increases the pH of the water; D - the disinfection technique is simplified; E is an economically more advantageous method.

B - greater reliability in comparison with chlorination

Free active chlorine in water, which has a bactericidal effect, is represented by the concentration: A - hydrochloric acid, aluminum sulfate and chlorine; B - hypochlorous acid, hypochlorite ions, atomic chlorine and oxygen; C - hyposulphate - ions, hypochlorous manganese; D - chloramines, iodobutyric acid and sodium hyposulphite; E - chlorophenols, ferric chloride and aluminum sulphate.

B - hypochlorous acid, hypochlorite ions, atomic chlorine and oxygen

Between the alkalinity of water and the speed of the coagulation process, there is a relationship, which is that: A - the higher the pH, the faster coagulation takes place; B - in water that does not contain alkaline reserves, coagulation will not occur; C - Coagulation requires no alkaline water reserves; D - for coagulation, sodium bicarbonate is necessary in water; E - the smaller the alkaline reserve, the faster coagulation will occur.

B - in water that does not contain alkaline reserves, coagulation will not occur

The essence of the coagulation process as a method of water purification: A - the formation of biologically active compounds, fatal to the microbial cell; B - interaction of the coagulant with alkaline water reserves (electrolytes) with the formation of hydroxides adsorbing suspended particles; C - the formation of molecules of hypochlorous acid, stopping the growth of microbial cells; D - formation of a set of gas bubbles formed when the coagulant is added to water and precipitating suspended particles; E - formation of complex compounds in the form of flakes that do not react with thiocyanates.

B - interaction of the coagulant with alkaline water reserves (electrolytes) with the formation of hydroxides adsorbing suspended particles

The advantage of the water overchlorination method is that: A - it is possible to disinfect salted water; B - it is possible to disinfect muddy and colored water; C - it is necessary to dechlorinate water; D - chlororganic substances are not formed; E - transparency and color of water improves.

B - it is possible to disinfect muddy and colored water

Re-chlorination of water is a method of water disinfection, in which: A - 3-5 mg / m3 of active chlorine is injected into the water; B - large doses of active chlorine (10-20 mg/dm3) are introduced into the water; C - first add ammonia, and then after 0.5-2 minutes - chlorine; D - water is chlorinated twice in usual doses; E - water is chlorinated twice: the first is gaseous chlorine, the second - BTSGK.

B - large doses of active chlorine (10-20 mg/dm3) are introduced into the water

The disadvantage of the method of chlorination of water with preammonization is that: A - chloramines do not possess bactericidal properties; B - long duration of chlorination (not less than 2 hours); C - the organoleptic properties of water deteriorate; D - it is necessary to dehydrate the water with hyposulfite; E - increases the consumption of chlorine.

B - long duration of chlorination (not less than 2 hours)

Disinfection of water is the process of exemption it from: A - poisonous impurities; B - pathogenic microbes and viruses; C - radioactive substances; D - suspended substances; E - products of mushroom activity.

B - pathogenic microbes and viruses

The principle of the method for determining the dose of bleach for water disinfection is based on: A - counting colonies of bacteria on a nutrient medium after 2 days of incubation in a thermostat at a temperature of 370 C; B - testing of the effect of various amounts of 1% chloric lime solution on water and evaluation of the results by the amount of residual chlorine; C - determination of the least pronounced aftertaste of water after its chlorination by various doses; D - measurement of bicarbonate water hardness; E - displacement of active iodine by active chlorine from potassium iodide in an equivalent amount and determination of its quantity during titration with hyposulfite.

B - testing of the effect of various amounts of 1% chloric lime solution on water and evaluation of the results by the amount of residual chlorine

Chlorine requirements of water is: A - the amount of active chlorine, which is expended on a direct bactericidal action; B - the amount of active chlorine in mg, necessary for disinfection of 1 liter of water; C - the amount of active chlorine that can be detected in water after its excessive chlorination; D - the amount of active chlorine that must remain in the drinking water after it has been chlorinated with usual doses; E - the amount of active chlorine that is absorbed by suspended substances during the chlorination of water.

B - the amount of active chlorine in mg, necessary for disinfection of 1 liter of water

The concept of water chlorine absorption: A is the amount of free chlorine, which after disinfection of water should be 0.3-0.5 mg/dm3; B - the amount of active chlorine, which interacts with easily oxidized and suspended substances in water; C - the amount of active chlorine in mg, necessary for disinfection of 1 dm3 of water; D - the amount of free chlorine, which after disinfection of water should be 0.6-1 mg/dm3; E - the amount of active chlorine in mg, which is necessary for disinfection of water that has not been purified.

B - the amount of active chlorine, which interacts with easily oxidized and suspended substances in water

The disadvantage of the double chlorination method of water is that: A - the smell of water deteriorates; B - the possibility of formation of organochlorine compounds increases; C - turbidity and color of water deteriorates; D - very weak bactericidal effect; E - it is necessary to dechlorinate the water with hyposulfite.

B - the possibility of formation of organochlorine compounds increases

Methods of chlorination of water: A - chlorination with double ozonation; B - usual doses of chlorine, chlorination with preammonization; C - triple chlorination; D - chlorination with permanganization and ammoniation; E - chlorination with preliminary iodination.

B - usual doses of chlorine, chlorination with preammonization

The disadvantage of the water chlorination method is that: A - a short disinfection time; B - water must be dechlorinated; C - the transparency decreases and the color of the water increases; D - a small bactericidal effect; E - it is necessary to desalinate the water.

B - water must be dechlorinated

When adding coagulant to soft water (not containing bicarbonates), coagulation: A - will not occur or will occur with the addition of calcium chloride; B - will not occur or will occur with the addition of lime milk; C - is significantly slowed down, which is due to its interaction with sodium chloride; D - will occur in part by the addition of inorganic chloramines; E - is significantly accelerated, which is due to the formation of ozonolysis products.

B - will not occur or will occur with the addition of lime milk

There is a relationship between the salt composition of water and the speed of the coagulation process, which is that: A - the more salts of manganese in water, the faster coagulation will occur; B - coagulation requires the presence of salts of heavy metals in water; C - coagulation requires the presence of bicarbonates in water; D - the more chlorine salts in the water, the more slowly coagulation takes place; E - requires the presence of salts of radioactive metals.

C - coagulation requires the presence of bicarbonates in water

Special methods for improving water quality include: A - double chlorination, ozonation, microwave treatment; B - coagulation, iodination, gamma-ray irradiation; C - deodorization, deferrization, desalination; D - disinfection, decontamination, ultrasound treatment; E - preammonization, re-chlorination, coagulation.

C - deodorization, deferrization, desalination

The advantage of ozonization as a method of water disinfection is: A - short disinfection time; B - increase of alkalinity of water; C - improving the organoleptic properties of water; D - simplification of the water disinfection technique; E - increase in the content of residual chlorine.

C - improving the organoleptic properties of water

By the ratio of ammonia-nitrite-nitrates in the water of reservoirs it is determined: A - fact of application of mineral fertilizers; B - water pollution by products of nitrogen fertilizers; C - prescription of organic contamination of protein nature; D - toxicological hazard of water; E - the water source class.

C - prescription of organic contamination of protein nature

The advantages of double chlorination of water is that the introduction of chlorine before the sedimentation tanks: A - increases the content of residual chlorine; B - leads to the possibility of formation of organochlorine compounds; C - suppresses the growth of microflora in sewage treatment plants; D - increases the oxygen content in water; E - prevents the appearance of an unpleasant odor.

C - suppresses the growth of microflora in sewage treatment plants

Substances used for the chlorination of water: A - chlorophos, potassium permanganate, silver salts; B - gaseous fluorine, ammonia, ozone; C - ozone, iodine, preparations of silver, nitrogen dioxide; D - bleach, gaseous chlorine, chlorine dioxide; E - chloroform, thiophos, chloramine, iodine preparations.

D - bleach, gaseous chlorine, chlorine dioxide

The advantage of the method of chlorination of water with preammonization is that: A - forming chlorophenols does not form chlororganic substances; B - can be used to prevent the greenish color of water containing phenols; C - the technique of chlorination is simplified in comparison with usual chlorination; D - can be successfully used in the chlorination of water containing phenol and its derivatives; E - it is possible to decontaminate turbid water.

D - can be successfully used in the chlorination of water containing phenol and its derivatives

Reservoirs are: A - a complex of structures and devices for water purification in order to bring its quality indicators in line with the requirements of water users; B - a structure equipped with a pumping and power plant for lifting and supplying water to the water supply network; C - hydraulic engineering structure for abstraction of water from an open reservoir or from an underground source; D - closed structures for storage of water after its cleaning; E - a system of pipelines with structures and devices on them to supply water to places of consumption.

D - closed structures for storage of water after its cleaning

Alkalinity of water when calculating the dose of coagulant - aluminum sulphate is determined for: A - calculation of the concentration of the flocculant; B - calculation of the approximate acidity of water; C - determination of the pH of water; D - definitions of approximate doses of coagulant used in experimental coagulation; E - the establishment of the optimal type of coagulant.

D - definitions of approximate doses of coagulant used in experimental coagulation

The dose of coagulant necessary for water purification depends on: A - the amount of potassium and manganese salts in water; B - bacterial contamination of water; C - the time that we have for water purification; D - degree of contamination and pH of water; E - content of radioactive substances in water.

D - degree of contamination and pH of water

Residual chlorine in water after its usual chlorination is necessary for: A - bactericidal action when storing water; B - improvement of the organoleptic properties of water; C - sporicidal effect in the chlorination of water; D - guarantees of complete disinfection; E - the presence of residual chlorine is not necessary.

D - guarantees of complete disinfection

Due to the coagulation process, water is clarified, because suspended particles: A - have opposite charges, as a result of which they are attracted and, forming large conglomerates, are deposited; B - have a positive charge, as a result of which they adsorb on the surface of negatively charged sedimented flakes of hydroxide; C - interact with organic compounds of water, forming undissociated complexes of organochlorine compounds; D - have a negative charge, as a result of which they are adsorbed on the surface of positively charged settling coagulant flakes; E - sorbed on the surface of ion-exchange filters that have a negative charge.

D - have a negative charge, as a result of which they are adsorbed on the surface of positively charged settling coagulant flakes

The predominantly double chlorination of water is that the introduction of chlorine before the sedimentation tanks: A - prevents the appearance of an unpleasant odor; B - leads to the possibility of formation of organochlorine compounds; C - increases the content of residual chlorine; D - increases the reliability of disinfection; E - increases the oxygen content in water.

D - increases the reliability of disinfection

The concept of residual free chlorine: A - the amount of active chlorine in mg, necessary for disinfection of 1 dm3 of water; B - the amount of active chlorine, which is expended on direct bactericidal action; C - is the amount of active chlorine that can be detected in the water after its excessive chlorination; D- is the amount of active chlorine that must remain in the drinking water after it has been chlorinated with usual doses; E - is the amount of active chlorine that is absorbed by suspended substances and microorganisms during the chlorination of water.

D - is the amount of active chlorine that must remain in the drinking water after it has been chlorinated with usual doses

The residual chlorine content in water is normalized: A - near the nearest water intake; B - on the backbone networks; C - in the water-side columns; D - output after pure water tanks; E - in all the above points.

D - output after pure water tanks

Physical methods of water disinfection include: A - defending, permanganization; B - filtration, ozonation; C - chlorination with preammonization; D - sonication, UV rays; E - iodination, chlorination.

D - sonication, UV rays

Between the dose of coagulant and the speed of the coagulation process, there is a relationship, which is that: A - the larger the dose of coagulant, the faster coagulation will occur; B - the smaller the dose of coagulant, the more optimal the coagulation process takes; C - the process of coagulation does not depend on the dose of the coagulant; D - the dose of coagulant should be optimal; E - the smaller the dose of coagulant, the lower the effect of coagulation.

D - the dose of coagulant should be optimal

Double chlorination of water is: A - the supply of chlorine in the water before the settling tanks and ammonia - after the filters; B - a method in which chloramines and ozone are used; C - with this method, ammonia is first introduced into the water, and after 0.5-2 minutes - chlorine; D - the supply of chlorine to the water for the first time before the settler, the second time after the filters; E - the supply of chlorine to water for the first time before the filters, the second time after the filters.

D - the supply of chlorine to the water for the first time before the settler, the second time after the filters

The amount of residual free chlorine in the prochlorinated tap water according to the norms, mg/l: A - 0.1-0.2; B - 0.2-0.3; C - 0.6-1.0; D - 1.0-2.0; E - 0.3-0.5.

E - 0.3-0.5

Between the dose of coagulant and the speed of the coagulation process, there is a relationship, which is that: A - the larger the dose of coagulant, the slower coagulation will occur; B - the dose of coagulant should be the average of 10 samples of experimental coagulation; C - the smaller the dose of coagulant, the more effective the process of coagulation; D - the more the dose of coagulant, the faster coagulation will occur; E - choose the minimum dose at which the best effect of coagulation is observed.

E - choose the minimum dose at which the best effect of coagulation is observed.

Purification of water (clarification) is a process: A - elimination of toxic substances; B - elimination of excess salts; C - elimination of pathogenic microorganisms; D - exemption from radioactive substances; E - exemption from suspended particles.

E - exemption from suspended particles.

Water abstraction is: A - a complex of buildings, structures and devices for water purification in order to bring its quality indicators in water canals to the requirements of water users; B - a system of pipelines with structures and devices on them to supply water to the places of its consumption; C - a structure equipped with a pumping-power plant for lifting and supplying water to the water supply network; D - closed structures for storage of water after its cleaning; E - hydraulic structure for the abstraction of water from an open reservoir or from an underground source.

E - hydraulic structure for the abstraction of water from an open reservoir or from an underground source.

The disadvantage of the water chlorination method is that: A - the transparency decreases and the color of the water increases; B - it is necessary to desalinate the water; С - a small bactericidal effect; D - short disinfection time; E - increases the consumption of chlorine.

E - increases the consumption of chlorine

Clarification of water is a process of elimination from water: A - odor, taste and improve the organoleptic properties; B - toxic substances and improvement of sanitary and toxicological properties; C - colour and improvement of physical and chemical properties; D - pathogenic microflora and improvement of epidemiological safety indicators; E - turbidity and improvement of organoleptic properties.

E - turbidity and improvement of organoleptic properties.