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Question 1
ప్రశ్న 1
What should primarily govern selection of the treatment flow sheet for a drinking-water treatment plant?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Water sources differ substantially in suspended, colloidal, dissolved and microbial contaminants. The required degree of treatment must therefore depend on the contaminants actually present and the quality required in the finished water. Current CPHEEO guidance explicitly links process selection to raw-water constituents and the desired drinking-water quality. A conventional surface-water train is common, but additional or fewer processes may be appropriate for particular sources. Therefore Option B is correct.
వివరణ:
Question 2
ప్రశ్న 2
Which classification correctly represents the broad physical forms in which impurities may occur in raw water?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Raw-water contaminants may occur as suspended solids, colloidal material or dissolved constituents. Suspended material may often be removed by settling or filtration depending on size and density. Colloids commonly require destabilization and floc formation before effective removal. Dissolved contaminants may require specific processes such as aeration, oxidation, softening, adsorption, ion exchange or membranes depending on their nature. Therefore Option A is correct.
వివరణ:
Question 3
ప్రశ్న 3
Which sequence best represents the core conventional treatment train for a typical turbid surface-water source after preliminary screening where required?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Coagulation first destabilizes fine suspended and colloidal particles. Flocculation then promotes collisions and growth of larger settleable flocs. Clarification removes a major fraction of these flocs before the water reaches the filters. Filtration removes remaining particulate matter, and final disinfection provides the microbiological barrier before supply. Therefore Option B gives the correct conventional sequence.
వివరణ:
Question 4
ప్రశ్న 4
Which statement correctly distinguishes coagulation from flocculation in an integrated water-treatment plant?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Many colloidal particles remain stable because surface charges prevent them from aggregating. Coagulant addition and rapid mixing destabilize these particles through chemical and physicochemical mechanisms. Flocculation follows with gentler mixing that allows destabilized particles to collide and form larger flocs. Successful coagulation and flocculation improve the performance of downstream sedimentation and filtration. Therefore Option A is correct.
వివరణ:
Question 5
ప్రశ్న 5
Why is clarification or sedimentation normally placed before rapid filtration in a conventional surface-water treatment plant?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Coagulation and flocculation convert fine impurities into larger particles that can be separated more readily. Clarification removes much of this particulate mass before filtration. Reducing the solids load increases filter-run length and reduces the frequency of backwashing. It also allows filtration to act as a polishing step rather than carrying the entire solids-removal burden. Therefore Option A is correct.
వివరణ:
Question 6
ప్రశ్న 6
Which statement best describes the integration of filtration and disinfection in conventional drinking-water treatment?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Filtration removes residual suspended solids and flocs that escape clarification. Lower turbidity reduces the possibility that microorganisms will be shielded within particles. Final disinfection then acts on comparatively well-clarified water under controlled concentration and contact-time conditions. Clear appearance alone is not evidence that all pathogenic microorganisms have been inactivated. Therefore Option A is correct.
వివరణ:
Question 7
ప్రశ్న 7
A groundwater source contains objectionable hydrogen sulphide, excess dissolved carbon dioxide and dissolved iron but has little suspended matter. Which treatment step is particularly appropriate near the beginning of the flow sheet?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Aeration promotes gas transfer between water and the atmosphere. It can expel hydrogen sulphide and carbon dioxide and can assist oxidation of dissolved iron. Once iron is oxidized to particulate forms, subsequent filtration or another solids-removal step is required. Aeration by itself does not constitute complete drinking-water treatment or final disinfection. Therefore Option A is correct.
వివరణ:
Question 8
ప్రశ్న 8
Which contaminant-control objective cannot normally be achieved reliably by aeration alone?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Aeration is principally a physical gas-transfer and oxidation-support process. It can remove volatile gases such as hydrogen sulphide and carbon dioxide. It can also introduce oxygen and assist precipitation of certain dissolved metals such as iron. Current CPHEEO guidance specifically notes that aeration is not an effective treatment for disease-causing bacteria and viruses. Therefore Option D is correct.
వివరణ:
Question 9
ప్రశ్న 9
A river source experiences extremely high coarse silt loads during the monsoon before the water reaches the conventional coagulation plant. Which additional preliminary treatment is most appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Very high settleable silt loads can impose an unnecessary solids burden on subsequent chemical treatment units. Pre-sedimentation can remove a substantial fraction of coarse settleable material before coagulation. This may reduce coagulant consumption and sludge loading in the main clarification system. The remaining colloidal and fine suspended material can then be handled by the conventional treatment train. Therefore Option A is correct.
వివరణ:
Question 10
ప్రశ్న 10
A clear groundwater has total hardness of 450 mg/L as CaCO3, negligible turbidity, no objectionable iron, manganese or dissolved gases, and otherwise acceptable chemical quality. Which process selection most directly addresses its principal stated problem before final disinfection?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The principal stated problem is excessive hardness rather than turbidity or colloidal solids. Softening processes such as lime-soda treatment or ion exchange can be selected according to hardness level, water quality and treatment objectives. Conventional coagulation and sedimentation are not inherently required solely because dissolved calcium and magnesium hardness is high. Final disinfection remains part of producing microbiologically safe drinking water. Therefore Option A is correct.
వివరణ:
Question 11
ప్రశ్న 11
Under the CPCB designated-best-use classification, what does Class A signify for a drinking-water source?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
CPCB Class A is designated as a drinking-water source without conventional treatment but after disinfection. The classification has specified source-water criteria including microbiological and physicochemical parameters. It should not be confused with the finished-water quality requirements applicable at the consumer end. A Class A designation therefore does not mean that disinfection can be omitted. Therefore Option A is correct.
వివరణ:
Question 12
ప్రశ్న 12
Under the CPCB designated-best-use classification, which statement correctly describes Class C water?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
CPCB Class C is designated as a drinking-water source requiring conventional treatment followed by disinfection. Its source-water criteria are less stringent than those of Class A for some key parameters. Consequently, the Class C designation explicitly assumes that an appropriate conventional treatment barrier will be provided. The classification concerns source-water designated use and is not itself a substitute for finished-water standards. Therefore Option A is correct.
వివరణ:
Question 13
ప్రశ్న 13
Which pair correctly illustrates the distinction between a primarily chemical unit process and a primarily physical unit operation in water treatment?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A unit operation is principally based on physical phenomena such as mixing, settling, filtration or gas transfer. A unit process involves a chemical or biochemical transformation. Coagulation depends strongly on chemical reactions and charge destabilization produced by added coagulants. Flocculation is principally a controlled physical mixing operation that promotes collisions among destabilized particles. Therefore Option A is correct.
వివరణ:
Question 14
ప్రశ్న 14
Which classification is most appropriate for chlorination and sedimentation respectively?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Chlorination involves chemical reactions of chlorine species with microorganisms and other constituents in the water. It is therefore appropriately treated as a chemical unit process in conventional engineering terminology. Sedimentation relies principally on gravitational separation of suspended particles from water. It is therefore a physical unit operation. Consequently Option A correctly distinguishes the two.
వివరణ:
Question 15
ప్రశ్న 15
A surface-water source develops a high natural-organic and wastewater-derived load that would require very high chlorine doses if the plant relied mainly on chlorination. What is the most appropriate integrated treatment principle?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
High organic loading can create substantial disinfectant demand. Applying increasingly large chlorine doses can also increase the potential for formation of disinfection by-products. CPHEEO therefore cautions against treating highly polluted water merely by excessive chlorination. Enhanced removal of organic matter or an alternative advanced treatment train may be necessary before final disinfection. Therefore Option A is correct.
వివరణ:
Question 16
ప్రశ్న 16
A treatment train has unit capacities in series of 60 MLD for coagulation-flocculation, 55 MLD for clarification, 50 MLD for filtration and 65 MLD for disinfection. Ignoring standby requirements and other constraints, what is the maximum hydraulic capacity of the complete train?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Water must pass through every required unit in a series treatment train. The capacity of the complete train therefore cannot exceed the capacity of its most restrictive required stage. Among the stated capacities, filtration is limited to 50 MLD. Increasing upstream capacity alone would not allow more than 50 MLD of completely treated water to pass through the full train. Therefore Option A is correct.
వివరణ:
Question 17
ప్రశ్న 17
A water-treatment plant receives 50 MLD of raw water and experiences total process-water losses equal to 5% of the raw-water inflow. What net finished-water production results, assuming no other losses?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A 5 percent process loss means that 95 percent of the raw-water inflow remains as finished-water production. The net quantity is therefore 50 × 0.95. This equals 47.5 MLD. Such losses can include filter washing, sludge handling and other treatment-plant uses depending on plant configuration. Therefore Option B is correct.
వివరణ:
Question 18
ప్రశ్న 18
A city requires 45 MLD of finished water from a treatment plant. If total treatment losses are expected to equal 4% of the raw-water inflow, what minimum raw-water treatment rate is required?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
If 4 percent of the incoming water is lost, the finished-water output equals 96 percent of raw inflow. Let the required raw-water rate be Q. Then 0.96Q = 45 MLD. Solving gives Q = 45/0.96 = 46.875 MLD, or approximately 46.9 MLD. Therefore Option C is correct.
వివరణ:
Question 19
ప్రశ్న 19
A rapid-filtration stage consists of four identical filters, each capable of treating 12 MLD at the specified operating condition. What is the firm filtration capacity if one filter must be assumed out of service?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Four filters provide a total installed capacity of 4 × 12 = 48 MLD when every unit is available. Firm capacity under the stated one-unit-out condition must be calculated using only three operating filters. Three filters at 12 MLD each provide 36 MLD. The distinction between installed and firm capacity is important when maintenance or backwashing removes a unit from service. Therefore Option C is correct.
వివరణ:
Question 20
ప్రశ్న 20
A plant has three clarifiers rated at 20 MLD each, eight filters rated at 8 MLD each and a disinfection system rated at 70 MLD. Ignoring standby criteria, what is the nominal maximum capacity of this integrated treatment train?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The three clarifiers together provide 3 × 20 = 60 MLD. The eight filters together provide 8 × 8 = 64 MLD. The disinfection system is rated at 70 MLD. Since all required treatment stages are in series, the smallest available process capacity controls the complete-train capacity. Therefore Option A, 60 MLD, is correct.
వివరణ:
Question 21
ప్రశ్న 21
A utility blends 32 MLD of surface water requiring the complete conventional treatment train with 18 MLD of chemically acceptable groundwater requiring only final disinfection. If the streams are kept separate until immediately before a common final disinfection stage, what minimum capacities are required for the conventional surface-water train and the common final-disinfection stage?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Only the 32 MLD surface-water stream passes through the stated conventional coagulation, clarification and filtration train. Those conventional units must therefore handle at least 32 MLD under the assumptions given. The final disinfection stage receives both the 32 MLD surface-water stream and the 18 MLD groundwater stream. Its required hydraulic capacity is therefore 32 + 18 = 50 MLD. Therefore Option A is correct.
వివరణ:
Question 22
ప్రశ్న 22
A water-treatment plant has a design capacity of 60 MLD and is currently processing 45 MLD. What is its hydraulic capacity utilization relative to design capacity?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Capacity utilization is the actual operating flow divided by the design capacity. The ratio is 45/60 = 0.75. Multiplying by 100 gives 75 percent. This figure describes hydraulic utilization and does not by itself prove that every process is operating optimally. Therefore Option B is correct.
వివరణ:
Question 23
ప్రశ్న 23
Filtered water appears visually clear, but microbiological safety has not yet been established and the water is intended for public distribution. What is the appropriate treatment interpretation?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Visual clarity primarily indicates low visible particulate matter and does not demonstrate absence of pathogenic microorganisms. Bacteria, viruses and protozoan stages may be present without making the water visibly turbid. Final disinfection therefore remains a critical barrier in conventional potable-water treatment. Residual disinfectant and microbiological monitoring provide additional evidence of treatment and distribution-system integrity. Therefore Option A is correct.
వివరణ:
Question 24
ప్రశ్న 24
A groundwater contains significant dissolved iron and also requires sodium-cycle ion-exchange softening because of high hardness. Which integrated sequence is generally more appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Dissolved iron can be oxidized to insoluble forms by suitable aeration or another oxidation process. The resulting solids should be removed before downstream processes. Iron deposits can foul or coat ion-exchange media and impair exchanger performance. After iron removal, ion exchange can address the dissolved calcium and magnesium hardness more effectively, followed by final disinfection as required. Therefore Option A is correct.
వివరణ:
Question 25
ప్రశ్న 25
Consider the following statements about integrated drinking-water treatment: I. Treatment selection should depend on raw-water quality and required finished-water quality. II. Coagulation and flocculation prepare fine particles for downstream clarification and filtration. III. Aeration can assist removal of gases and oxidation of iron but does not replace final disinfection. IV. The hydraulic capacity of a series treatment train is limited by its required bottleneck process. Which option is correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Statement I reflects the fundamental CPHEEO principle that the treatment flow sheet must respond to source-water characteristics and finished-water objectives. Statement II correctly describes the integrated role of coagulation and flocculation before clarification and filtration. Statement III is correct because aeration has gas-transfer and oxidation functions but is not a reliable pathogen-disinfection barrier. Statement IV follows from the fact that all required series units must carry the plant flow, so the lowest required process capacity constrains the complete train. Therefore all four statements are correct and Option D is the valid answer.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: B. The raw-water characteristics together with the required finished-water quality సమాధానం: B.
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Question 2 ప్రశ్న 2Answer: A. Suspended, colloidal and dissolved impurities సమాధానం: A.
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Question 3 ప్రశ్న 3Answer: B. Coagulation → flocculation → clarification or sedimentation → filtration → disinfection సమాధానం: B.
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Question 4 ప్రశ్న 4Answer: A. Coagulation destabilizes colloids chemically, while flocculation provides controlled mixing that promotes particle collisions and floc growth సమాధానం: A.
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Question 5 ప్రశ్న 5Answer: A. To remove a large portion of formed floc and thereby reduce solids loading on the filters సమాధానం: A.
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Question 6 ప్రశ్న 6Answer: A. Filtration removes remaining particulate matter before final disinfection, improving the reliability of microbial inactivation సమాధానం: A.
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Question 7 ప్రశ్న 7Answer: A. Aeration followed by suitable solids removal or filtration సమాధానం: A.
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Question 8 ప్రశ్న 8Answer: D. Reliable inactivation of pathogenic bacteria and viruses సమాధానం: D.
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Question 9 ప్రశ్న 9Answer: A. Pre-sedimentation or suitable preliminary solids removal before the main coagulation process సమాధానం: A.
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Question 10 ప్రశ్న 10Answer: A. Softening followed by final disinfection సమాధానం: A.
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Question 11 ప్రశ్న 11Answer: A. A drinking-water source usable without conventional treatment but after disinfection, subject to the Class A criteria సమాధానం: A.
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Question 12 ప్రశ్న 12Answer: A. It is a drinking-water source intended for use after conventional treatment and disinfection సమాధానం: A.
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Question 13 ప్రశ్న 13Answer: A. Coagulation as a chemical unit process and flocculation as a physical mixing operation సమాధానం: A.
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Question 14 ప్రశ్న 14Answer: A. Chlorination is primarily a chemical unit process, while sedimentation is a physical unit operation సమాధానం: A.
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Question 15 ప్రశ్న 15Answer: A. Improve removal of organic contaminants before final disinfection and evaluate enhanced or alternative treatment rather than merely increasing chlorine indefinitely సమాధానం: A.
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Question 16 ప్రశ్న 16Answer: A. 50 MLD సమాధానం: A.
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Question 17 ప్రశ్న 17Answer: B. 47.5 MLD సమాధానం: B.
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Question 18 ప్రశ్న 18Answer: C. Approximately 46.9 MLD సమాధానం: C.
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Question 19 ప్రశ్న 19Answer: C. 36 MLD సమాధానం: C.
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Question 20 ప్రశ్న 20Answer: A. 60 MLD సమాధానం: A.
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Question 21 ప్రశ్న 21Answer: A. 32 MLD and 50 MLD respectively సమాధానం: A.
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Question 22 ప్రశ్న 22Answer: B. 75% సమాధానం: B.
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Question 23 ప్రశ్న 23Answer: A. Maintain the required final disinfection and verify disinfectant residual and microbiological quality rather than relying on visual clarity సమాధానం: A.
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Question 24 ప్రశ్న 24Answer: A. Oxidize or aerate the iron, remove the resulting precipitate by filtration, then carry out ion-exchange softening and final disinfection సమాధానం: A.
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Question 25 ప్రశ్న 25Answer: D. I, II, III and IV సమాధానం: D.