Water License Exam Quuestions and Complete Solutions

Water License Exam Quuestions and Complete Solutions What is the purpose of a water treatment plant? - Answer: To produce safe and pleasant drinking water What is the purpose of the clear well? - Answer: To provide chlorine contact time for disinfection and store water for high demand What is the purpose of coagulation-flocculation? - Answer: To gather together fine, light particles to form larger particles (floc) to aid the sedimentation and filtration processes What is the purpose of filtration? - Answer: To filter out suspended particles What is the main purpose of a water treatment plant's intake structure? - Answer: To draw in water while preventing leaves and other debris from clogging or damaging pumps What is corrosive water? - Answer: A water capable of deteriorating metal pipe Why should the water treatment plant operator be present during both the design and construction periods of a project to improve a water treatment plant? - Answer: To be completely familiar with the entire plant layout, including the piping, equipment,and machinery in their intended operation Why do operators take certification examination? - Answer: To obtain certificates that indicate a level of professional competence What are the expectations of safe and pleasant drinking water? - Answer: The water must be free of disease-causing organisms, toxic substances, and should not have a disagreeable appearance, odor, or taste Why are iron and manganese undesirable in water? - Answer: They can cause undesirable color in water, promote to growth of iron bacteria (can cause taste and odors), and can stain clothes and plumbing fixtures What tasks are performed by water treatment operators to keep the WTP producing safe, pleasant, and an adequate supply of water? - Answer: Adjust flows according to conditions of raw water, keep an eye on the water as it flows through all of the various treatment processes, maintain and repair the equipment and facilities as necessary to keep the water flowing What should you do when someone complains about their drinking water? - Answer: Have the complaint thoroughly investigated, notify person making complaint the results and what corrective action was/will be taken, record necessary information (name, date, location, problem, phone number) Which factors are contributing to an increase in the number of jobs in the water and wastewater treatment industries? - Answer: More sophisticated treatment, operator certification, population growth, regulatory requirements, retirement of many current operators Which problem has been caused by mineral residues from irrigation? - Answer: Once fertile soil is damaged Which problem is caused by acid rain? - Answer: Fish in mountain lakes are killed Why do water shortages directly influence energy consumption? - Answer: As groundwater levels fall, more energy is required to pump water from deeper levels in the basin If there is any question regarding the right to use of water, what should a property owner do? - Answer: Consult with the appropriate authority and clearly establish rights to its use What is an impermeable surface? - Answer: A surface that does not allow, or allows only with great difficulty, the movement or passage of water What is a lake or reservoir stratification? - Answer: The formation of separate layers (of temperature, plant, or animal life) in a lake or reservoir Why must recreation facilities be properly constructed and located away from water supply intake areas? - Answer: To protect the water supply from contamination With new water supply, when should the sanitary survey be made? - Answer: During the collection of initial engineering data covering the development of a five source and its capacity to meet existing and future needs What is a cross connection? - Answer: A connection between a drinking (potable) water system and an unapproved water supply Why is the coliform group of bacteria used to estimate the relative degree of bacterial contamination of water? - Answer: Coliforms are always present in fecal wastes and vastly outnumber specific disease-producing organisms Water rights may stem from or be acquired by which items? - Answer: A performance of a certain acts required by law, ownership of land by birding the source of water, ownership of the land overlying the source of water What can happen to precipitation? - Answer: Can be returned to the atmosphere by evaporation, can enter the ground through infiltration, can flow over the ground surface, can run off directly as surface water Which discharges could be sources of upstream pollution for a water treatment plant? - Answer: Agricultural drainage, industrial waste, and municipal wastewater The purpose of investigating or considering certain essential factors in a sanitary survey is to achieve which results? - Answer: To determine factors that affect water quality, to identify potential hazards, to select treatment requirements Once precipitations reaches the earth's surface, many opportunities are presented for the introduction of which forms of contamination? - Answer: Microorganisms, mineral substances, and organic substances Which items describe the physical characteristics of water? - Answer: Color, odor, taste, temperature, and turbidity Chemical analysis of a domestic water supply is broken down into which areas? - Answer: General mineral constituents, inorganic chemicals, organic chemicals The Safe Drinking Water Act gave the US EPA the authority to perform which tasks? - Answer: Establish uniform guidelines specifying the acceptable treatment technologies for cleansing drinking water of unsafe levels of pollutants, require public water systems to monitor and report their levels of identified contaminants, set national standards regulating the levels of contaminants in drinking water In the operation of WTPs, basic objectives include controlling which items? - Answer: Production of a safe drinking water, an aesthetically pleasuring drinking water, drinking water at a reasonable cost with respect to capital costs, and drinking water at a reasonable cost with respect to operation and maintenance costs Consumers show a preference for water supplies that have which characteristics? - Answer: Clear, colorless, does not leave scale deposits or spot glassware, free of objectionable tastes and odors, non corrosive to plumbing fixtures and piping, non staining (plumbing fixtures and washing clothes) What is a nutrient? - Answer: Any substance that is assimilated (taken in) by organisms and promotes growth What is a littoral zone? - Answer: That portion of the body of fresh water extending from the shoreline lake ward to the limit of occupancy of rooted plants What are the most notable impacts on water supply reservoirs as a result of increases in organic loading caused by algal blooms? - Answer: Increased color in the water supply and a major increase in Chlorine demand What causes high trihalomethane (THM) levels? - Answer: Organic loading resulting from algal blooms and free residual chlorination Why should dissolved oxygen depletion be controlled or eliminated within the metalimnion of water supply lakes and reservoirs? - Answer: To eliminate or control iron, manganese, and hydrogen sulfide problems What is the primary purpose of any watershed management program? - Answer: To control, minimize, or eliminate any practices within the watershed area that are harmful to water quality Why is copper sulfate effective as an algicide at low levels of alkalinity? - Answer: Because copper ions react with bicarbonate and carbonate ions to form insolvable complexes that precipitate from solution Why must the operator have a reservoir monitoring program in reservoirs where algae are a potential problem? - Answer: To anticipate a possible algal bloom Which chemical is being considered as an alternative algicide to copper sulfate? - Answer: Hydrogen-peroxide-based herbicides What is destratification? - Answer: The development of vertical mixing within a lake or reservoir to eliminate separate layers of temperature, plant, or animal life How is destratificafion accomplished? - Answer: By inducing vertical mixing within the reservoir Why should silt surveys of most reservoirs be conducted periodically? - Answer: To get an updated measure of silting as it affects available water storare What is the main safety hazard encountered during reservoir sampling? - Answer: Drowning Why is it important to keep a good record of when and under what conditions failures or malfunctions of intake facilities occur? - Answer: It may be possible to take preventive action Which items occurring within a reservoirs drainage area may lead to deterioration of water quality? - Answer: Agricultural runoff, drainage from mining areas, grazing of livestock, industrial discharges, and runoff from urban areas Which common water quality problems in domestic water supply reservoirs may be related to algal blooms? - Answer: Dissolved oxygen depletion, increased pH, organic loading, shortened filter runs of complete treatment plants, and taste and odor problems Reservoirs located in mountainous areas where snowmelt is the major source of runoff may experience increases in which water quality problems during snowmelt? - Answer: Nutrient loading, organic loading, turbidity Which factors are critical in order for a lake or reservoir water quality management program to be feasible? - Answer: Must be economically justifiable, prepared for each specific reservoir, and technically justifiable Which items are methods of reservoir management? - Answer: Algae control by chemical methods, direct in-line treatment of raw water, removal of trees and brush from areas to be flooded, and watershed management During the runoff period following a wildfire, what types of pollutants may enter the reservoir? - Answer: Large amounts of debris, nutrients and silt Which adverse impacts can occur if an algal bloom is allowed to become intense before chemicals are applied? - Answer: A large algae die-off may occur and cause an increase in tastes and odors, fish die-offs ?97@: result from dead algal bodies clogging fish fills or from low DO levels, rate of oxygen depletion in the deeper waters will probably be increased. Which factors influence the concentration of copper sulfate needed for effective control of any particular algal bloom? - Answer: Alkalinity of the water, amount of algae, pH of water, species of algae, and water temperature Why are full and accurate records an important part of any chemical algae control program? - Answer: For designing new or revising existing programs, for showing compliance with federal, state and local regulations, and to evaluate current and historical treatment programs If local authorities approve certain recreational activities on reservoir ice surfaces, operators should insist on provision of which safeguards against possible pollution? - Answer: Adequate toilet facilities and proper care of them, leakproof waste containers, proper and close supervision of activities on the ice, time limits on activities on the ice A reservoir maintenance program should consider which items? - Answer: Before draining for maintenance, determine when, where and how you will discharge the water, control shoreline vegetation, lower the water level slowly, and mechanical or manual techniques can be used to remove/control vegetation What types of laboratory analyses may best be performed for a small reservoir management agency by an outside or commercial laboratory? - Answer: Nutrients, pesticides, radioactivity, toxic minerals and heavy metals, and trihalomethanes If algal blooms are a problem in a particular reservoir, the laboratory should be able to develop what kind of information? - Answer: Extent and intensity of algal blooms, major species of algae involved, water quality problems that develop as a result of the bloom To be prepared for changing reservoir conditions, the WTP operator should take responsibility for which items? - Answer: Be alert for onshore winds, be prepared to make necessary changes in WTP operations to combat any sudden increases in taste and odor problems, maintain a lot of wind direction and velocity, maintain close surveillance of threshold odor test results, do everything possible to keep any water with a bad taste or odor from getting into distribution system The type of screen, trash rack, or log stop used in a given intake structure depends on which factors? - Answer: Depth or depths at which inlets are located, frequency and intensity of algal scum or algal mass accumulations, location of the intake structure in relation to where debris accumulates in the reservoir or stream, quantity and type of debris encountered, size, depth of distribution, and number of fish, crayfish and other forms of aquatic life What are polymers? - Answer: Long chain molecules formed by the union of many monomers What is the purpose of coagulation and flocculation? - Answer: To remove particulate impurities, especially nonsettleable solids, and color from the water being treated What is alkalinity? - Answer: The capacity of water to neutralize acids What is the purpose of the flocculation process? - Answer: To create a floc of a good size, density, and toughness for later removal in the sedimentation and filtration processes What is the most important consideration in coagulation-flocculation process control? - Answer: Selection of the proper type and amount of coagulant chemical(s) to be added to the water being treated Why is it a good practice to prepare jar test reagents using samples of chemicals actually used in the plant, rather than reagent grade chemicals? - Answer: Because sometimes, trace impurities in industrial chemicals have significant effects What are streaming current meters? - Answer: Devices used to optimize coagulant doses What is the usual culprit when there are suddenly increases in filtered water turbidity? - Answer: Poor coagulation-flocculation process performance What is the enhanced coagulation process designed to accomplish? - Answer: To remove natural organic matter (NOM) from water What is a representative sample? - Answer: A sample portion of material or water that is nearly identical in content and consistency as possible to that in the larger body of material or water being sampled How can an operator be sure all underground structures are feee of hazardous atmospheres? - Answer: By using gas detectors What does an efficient flocculation process involve? - Answer: A properly shaped basin for uniform mixing, mechanical equipment or other means of creating stirring action, the proper stirring intensity, the selection of the right stirring time (detention time) What are the most common laboratory tests for coagulation-flocculation process performance? - Answer: Alkalinity, color, pH, temperature and turbidity Which information is provided or described by the turbidity test? - Answer: Indirect measurement of suspended solids concentration The jar test attempts to duplicate in the lab what is occurring in the plant in the relation between which items? - Answer: Detention times, mixing conditions, and settling condition Which items are an essential part of good communication? - Answer: Advising other operators and support personnel of current process conditions, advising other operators and support personnel or unique or unusual events, clear and concise written or oral communications, good record keeping When troubleshooting the coagulation-flocculation process, changes in which items could indicate certain operator actions and possible process change? - Answer: Coagulation process effluent quality, flocculation basin flocculation quality, source water quality The enhanced coagulation process is designed to produce the greatest possible reduction of which water quality indicators? - Answer: Disinfection by-products (DBPs), dissolved or suspended organic carbon (color), total organic carbon (TOC), trihalomethanes (THMs) In the enhanced coagulation process, which effects take place at the lower (optimum) pH that enhance coagulation? - Answer: Flocculation is improved, sulfuric acid addition prior to coagulation feed preconditions the organic compounds, the coagulant demand decreases correspondingly to the degree of molecular dissociation, and the humid and fulvic molecules separate to a lesser degree Which items are potential hazards an operator may be exposed to when working around the coagulation-flocculation process? - Answer: Electric hazards, drowning, falls, rotating and mechanical equipment; and toxic and explosive gases or insufficient oxygen Which items are potential hazards an operator may be exposed to when working in a laboratory? - Answer: Acid or caustic solutions, dangerous chemicals, glassware, and reagents After start-up of a piece of equipment always check for which items? - Answer: Excessive noise, excessive vibration, leakage, and overheating What kinds of hazardous atmospheres may be encountered in underground structures? - Answer: Explosive gases, insufficient oxygen, and toxic gases What are the purposes of the sedimentation process? - Answer: To remove suspended solids (particles) that are denser than water and to reduce the load on the filters Currents in the sedimentation basin are beneficial to what extent? - Answer: That they promote flocculation Why were high-rate or tube settlers developed? - Answer: To increase the settling efficiency of conventional rectangular sedimentation basins What are the major means by which operators can control water treatment processes? - Answer: By adjusting chemicals and chemical feed rates Why should solids-contact units be drained periodically? - Answer: To inspect the sludge collectors for wear and corrosion Why must operators monitor the performance of the sedimentation process? - Answer: In order to anticipate quality or performance changes The actual frequency of monitoring the sedimentation process should be based on which factors? - Answer: Source of the water supply and variations in the supply What should the operator do when source water turbidity levels are increasing rapidly? - Answer: Verify the effectiveness of the coagulant chemicals and dosages being applied at the flash mixer What is required in order to prevent bad lab results? - Answer: What are the preventative maintenance programs designed to ensure? The continued satisfactory operation of treatment plant facilities by - Answer: Reducing the frequency of breakdown failures What types of presedimentation facilities are used to reduce the solids-removal load at the WTP? - Answer: Debris dams, grit basins and impoundments What types of currents are found in the typical sedimentation basin? - Answer: Density, Eddy, and Surface Density currents - Answer: Caused by differences in suspended solids concentrations and temperature differences Eddy Currents - Answer: Produced by the flow of the water coming into and leaving the basin Surface Currents - Answer: Caused by winds What are the advantages of an inlet baffle wall? - Answer: Minimize wind currents, density currents due to temperature differences, and the tendency of the water to flow at the inlet velocity straight through the basin