Waste Water D license Study Exam Questions and Complete Solutions.

Waste Water D license Study Exam Questions and Complete Solutions Water Resources in Texas includes lakes, rivers, bays, estuaries, wetlands, ground water, and storm (1-3) - Answer: False Water Polluntants include organic and inorganic material, heat, and radiation (1-4) - Answer: True In Texas, Clean water is needed to provide for human comsumption and recreation, Maintain aquatic habitats for wildlife, recharge ground water, and provide for industry. (1-4) - Answer: False Two sources of water contamination are discharges and non- point source discharges (1-4) - Answer: False Examples of point-source discharges are: - Answer: Municipal, industrial, and agricultural wastewater treatment facilities Protecting Texas water from contamination requires_______________ of wastewater - Answer: 1.Collection and transportation to treatment 2.Treatment that removes contaminates 3.Processing and disposal Benefits of treating point-source and non-point source wastes are prevention of ground and surface water pollution, and _________ - Answer: 1. Protection of human and animal health 2. Prevention of oxygen depletion in surface water The Texas Water Code establishes the following means of protecting state water: water quality standards for streams; discharge limitations for point sources; and __________ - Answer: Requiring disinfection of drinking water The states sets water quality standards, called ________________, for river and lakes. - Answer: Stream standards To meet stream standards the state issues _________________ for waste discharge - Answer: Permits A role of supervision and management is to set job assignments and secure permits and finances to do the job - Answer: True Responsibilities of the license operator include protecting the Public from waterborne disease, performing duties professionally, protecting state water from pollution, maintaining required license practicing safety and controlling Operation cost. - Answer: False The Federal Water Control. Act of 1972 (Clean Water Act) Has a goal of eliminating pollution of the nation's water - Answer: True Chapter 26 of the Texas Water Code is the law controlling water pollutions. - Answer: True TCEQ functions include setting water quality standards, monitoring discharges,m and enforcing the Clean Water Act - Answer: True To become a licensed operator it is necessary to (2-3) - Answer: Pass a test administered by TCEQ Paid by the permit holder - Answer: Personnel working at a domestic wastewater plant must be state licensed if they are (2-3) Local governments have authority to inspect facilities using the collection system, enforce local pollution control laws, set discharge rules, and collect _____________- - Answer: User charges The Local government may inspect and investigate water quality conditions within its jurisdiction to determine ___________________ (2-5) - Answer: 1. Standards are met 2. Discharges have permits 3. Permits are followed 4. All the above Local governments may make discharge rules to protect personnel, the wastewater system. - Answer: Treatment Facility A local government may bring suit to enforce it's - Answer: Rules Cities with more then ________________ population must have a water pollution control program - Answer: 10000 Goals of TCEQ include maintaining water quality for public health, commercial use, and - Answer: Wildlife Preservation TCEQ may revoke a license if the operator ____________ (2-6) - Answer: 1.Violate the permit 2.Falsifies records 3.Neglects their duty 4.All the above When a accidental discharge, bypass, or spill occurs, the discharger must notify TCEQ within _____________ hours - Answer: 24 An Administrative penalty can be up to ________________ per day - Answer: $10000 Penalty assessments is based upon physical effect, intentions, responsibility, and ________________(2-7) - Answer: Economics benefit accrued Penalties are levied for - Answer: 1,Failure to submits reports 2.Bypasses 3.No discharge permit 4. All the above In each permit, the TCEQ sets conditions including permit duration, strength of the discharge, monitoring requirements, point of discharge, and _________________ of the discharge. (2-7) - Answer: Quality State laws requires that self-reporting forms be complied and mailed each _________________ to TCEQ - Answer: Month The authorized agent or ______________ must sign the report (2-7) - Answer: ???????? Required records, such as flow and effluent quality must be kept at least ________________ years - Answer: 3 True - Answer: Because wastewater is mostly water, it weighs 8.34 Ibs./Gal. True - Answer: labs report many characteristics of wastewater as milliliters per liter (ml/L) False (#4 radiological) - Answer: wastewater characteristics are divided into 3 primary groups : Bacteriological, physical, and chemical. False ( Answer: Microscope) - Answer: bacteria are seen with a telescope and are present in soil, water, air, decaying organic matter, and the intestinal tract of humans and animals. True - Answer: Some bacteria cause disease and are called pathogens True - Answer: one way to classify bacteria is by Oxygen use : aerobic, facultative, and anaerobic False Answer Oxygen - Answer: Aerobic bacteria require dissolved, uncombined (free) Nitrogen Flase (Answer Dissolved) - Answer: Anaerobic bacteria cannot live when chemically combined Oxygen is present TRue - Answer: Facultative bacteria live with free oxygen or chemically combined Oxygen True - Answer: Fresh domestic wastewater contains dissolved Oxygen False (Answer Disagreeable/ Lacks) - Answer: Septic wastewater is dark, has agreeable odor, and contains dissolved Oxygen. False (Answer odorous) - Answer: Septic Wastewater contains Fragrant gases produced by bacteria TRue - Answer: Some chemical characteristics of wastewater include solid, grease, DO, pH and gases False (Answer doesn't include soft and hard solids - Answer: Solids include total, suspended, dissolved, settable, inorganic, organic, and soft and hard solids. TRUE - Answer: Suspended solids can be filtered out and dissolved solids pass through a filter True - Answer: Settleable solids are dissolved solids of sufficient weight to settle when left standing for a time. True - Answer: Inorganic material, suspended or dissolved, is sand, grit, and minerals True - Answer: Two other classifications of solids are inorganic (ash) and organic (volatile) True - Answer: The ash (fixed Solids) left after burning consists of inorganic solids True - Answer: Organic solids are volatile, combustible solids found by burning the residue from the total solid test or the filter from the TSS test FALSE (Iron is not included) - Answer: Examples of organic are sugar, butter, leather, paper, and iron The three primary organics are _______________, proteins, and grease - Answer: Carbohydrates ___________________ in raw wastewater comes from the water supply - Answer: Dissolved oxygen When dissolved oxygen is present, it indicates the wastewater is - Answer: Fresh As the water temperatures rises, the DO saturation level will - Answer: Decrease (inverse effect) The dissolved oxygen test must be performed as soon as a sample is taken because Oxygen levels can ______________ change - Answer: Quickly The ________________ test measures the oxygen depleting effect of the wastewater upon the receiving stream. - Answer: BOD The BOD test indicates wastwater - Answer: Strength The BOD test measures Oxygen consumed as organics are oxidized by biological and chemical action during incubation for __________________ days at ____________________ Celsius. - Answer: 5/20 Each person contributes about _______________________ Ibs of BOD daily - Answer: 0.17 The pH scale ranges from ________________ to ____________________ with 7 being neutral - Answer: 0/14 ___________________ water has a pH below 7.0 while ___________________ water has a pH above 7.0 - Answer: Acidic/ basic Dangerous gases produced during the breakdown of organics in wastewater are Hydrogen Sulfide, carbon dioxide, and ___________________. - Answer: Methane The __________________ Decomposition of organic matter produces methane which is colorless. - Answer: 1.Aerobic 2.Facultative 3.Anaerobic listed Hydrogen sulfide has a ___________________ odor, is a combustible in air, and is very toxic - Answer: Rotten egg _____________________ is odorless, colorless, heavier than air, and not combustible. - Answer: Carbon dioxide (suffocating) Grid sampling results depends on _________________ - Answer: 1. Ensuring the sample represents the waste stream 2. Using proper sampling technique 3. Preserving the sample until analyzed 4, all listed Select a point where ______________________ is thorough and the wastewater quality is uniform - Answer: Mixing A ______________________ sample is collected at any point, at any time - Answer: Grab When a sample of a plant unit influential is collected at any time and a sample if the effluent is collected corresponding to the units detention time, the sample is a - Answer: Timed grab Domestic waste uniform in content - Answer: False ( is not uniform in content) Some waste cannot be treated in a domestic wastewater treatment plant because the waste would harm the biological process or contaiminate the waste sludge - Answer: True (think of oil and gas) Sources of wastewater include domestic, I & I, food processing, agricultural operations, and industrial operations. - Answer: True By weight, domestic wastewater is about 99.9% water and 1% solids. - Answer: False ( answer 0.1%) Flows from domestic sources average about 100 gallons/day per person - Answer: True Inflow is stormwater that enters a collection system through openings such as house wastewater, line cleanouts or open manholes. - Answer: False ( Answer house wastewater is waste water) ( 2 reason has to be broken line cleanouts) Infiltration is stormwater that enters the collection system through broken pipe joints, manhole walls, and cracked pipes. - Answer: False ( Answer cracked pipes and brick manhole walls) I & I floods the collection system, creating flow 5-10 times higher than the daily average - Answer: True (I & I = inflow/infiltration) I & I results in bypassing, plant washout, poor treatment, and permit violations. - Answer: True I & I is easy and inexpensive to correct (True or False) - Answer: False ( cheaper to build a flow equalization basin) Food processing discharges large amounts of ________________ material into the waste water system - Answer: Organic ( think of using the restroom) Pesticides and herbicides used by the agricultural industry can be ________________________ to the treatment plant biological system. - Answer: Toxic ( pesticides and herbicides can kills plants) Some industries that may contribute a shock load to the treatment plant are refineries, paper mills, and ______________________. - Answer: Metal platers EPA requires some industries to pretreat waste before discharge to a ________________________ - Answer: POTW ( Publicly Owed Treatment Works) The most important problem prevented by monitoring or restricting industrial waste is ___________________. - Answer: Worker exposer ( Personal safety first) Federal regulations require cities to have an industrial waste control program when - Answer: Flow exceeds 5mgd and industrial waste is regulated by federal standards. (MGD= Millions Gallons per Day) ________________ results in the rapid die-off of treatment organisms - Answer: Acute toxicity (think of A Cut) While the TCEQ does not has specific pretreatment Standards, _____________________ provides specific pretreatment standards. - Answer: EPA (Environmental Protection Agency) Restricted discharges include those that ________________________. (4 things) - Answer: 1. Create a fire or explosion hazard 2. Create toxic conditions 3. Cause shock Loads 4. All the above. Some pretreatment processes include ________________. (4 things) - Answer: 1 Spill control 2 metal removal 3ph control 4 all the above The purpose of the collection system is to collect and transport waste to the point of treatment - Answer: True The most important benefit of a collection system is comfort and convenice - Answer: False (removal of potential hazards Parts of a collection system include wastewater lines, wastewater crossings, inverted siphons, clean outs, manholes, and lift staions - Answer: True If gasoline or solvent odors are detected in a manhole, the orperator should bolt and gasket the cover - Answer: False (Contact supervisor and emergency personal immediately) Safety rules for manholes include checking for gases and sufficient oxygen, wearing a lifeline, and having two workers assisting at the surface - Answer: True Clay and PVC are the most common pipe material. - Answer: True Pipe Materials used in collection system construction include polyvinyl chloride, clay, concrete, and iron - Answer: True Grade (or slope) and flow velocity are important to wastewater pipe installation - Answer: True For any gravity wastewater, the minimum velocity required to keep solids in suspension is 1 ft/sec - Answer: False (must be 2ft/sec) Pipe should be laid down so that the bell end is facing downstream or downhill - Answer: False (bell should be facing up stream or uphill Wastewater flowing into a collection system should come from - Answer: homes and businesses and industry Install waster water lines no closer to a water line then _________ ft. - Answer: 9 ft. OHSA sets standards for shoring, sloping, or trench boxes for trenches ___________________ feet or deeper - Answer: 6 ft. If the trench is _______________ feet or deeper, a means of exits is required. - Answer: 4ft. If a ladder is used, it must be portable and extend ______________ feet above the trench, in addition to being secured. - Answer: 3ft A ladder must be within ___________________ feet of anyone in the trench. - Answer: 25ft Excavation spoil must be at least ________________ feet from the edge of the trench - Answer: 2ft The primary cause of stoppages is roots or ______________ - Answer: Grease Wastewater cleaning can increase pipe capacity, prevent septic conditions, maintain flow velocity, and ___________ - Answer: Reduce stoppages Hydraulic cleaners (jetting units) use ______________ under pressure, which is forced through nozzles. - Answer: Water Maps should be as built, showing corrections made in the field during _________________ - Answer: Constructions When chemicals are used in the system, consider worker and public _______________. - Answer: Safety When wastewater cannot flow to treatment by ________________, a lift station is used. - Answer: Gravity. Lift station designs include _______________ - Answer: Wet well dry well pneumatic ejector Dry well stations have the ________________ and pumps in a dry well separated from the adjacent wet well - Answer: Motors The _____________ pump is most commonly used in a lift station - Answer: Centrifugal Foreign matter in the ________________ can cause noisy operation and should be investigated. - Answer: Impeller The centrifugal pump must be _______________ or it will not pump - Answer: Primed Discharge valves on a positive displacement pump must be ______________ - Answer: Open The ________________ valve, usually a swing type, prevents water on the discharge side of the pump from flowing backwards through the pump when it is off. - Answer: Check The best design of isolation valve is the _________________ valve because it leaves an unrestricted path when fully open. - Answer: Gate The ____________ valve is the most commonly used valve in the collection system. - Answer: Gate Motors used in wastewater are typically three-phase ______________ motors. - Answer: Induction The speed of an electric motor is measured in _______________. - Answer: Rpm To reduce gases, the TCEQ requires lift stations to have a ______________ system - Answer: Ventilation Hydrogen sulfide is very toxic and deadens the sense of ___________ - Answer: Smell If a pump loses prime, it will heat up and damage the _________________ - Answer: Seal Common methods to detect liquids depths and control pumps are _______________, pneumatic bubblers, electric probes, and ultrasonic sensors - Answer: Floats ______________ pump in dry wells collect packing seal leakage as well as cleanup water. - Answer: Sump A _______________ maintenance program keeps emergency repairs to a minimum. - Answer: Preventive __________________ are important to lift station and maintenance - Answer: Records Records include a ____________ checklist - Answer: Daily Preliminary treatment is usually the first step in the treatment process - Answer: True Before making screen repairs, the power should be turned off and the controls locked. - Answer: True Types of grinding units include comminutor and barminutor - Answer: True Grinding units return the debris to the wastewater stream for removal later - Answer: True Grit removal takes place in a grit chamber after primary treatment - Answer: False (before) Common designs of grit removal units are hand-cleaned chambers, mechanically cleaned chambers, aerated chambers, cyclone separators, and screw washers. - Answer: True Water velocity in a grit chamber is about 2 ft/sec - Answer: False (1ft/sec) A cyclone sepRATOR spins the wastewater in a spiral flow and throws the grit, by centrifugal force, to the wall of the unit, where it falls to the bottom - Answer: True The purpose of a grit washer is to remove _____________ material from the grit - Answer: Organic ___________________ interferes with the biological treatment process - Answer: Grease Diffused _____________________ causes lightweight grease particles to rise ti the surface - Answer: Air Chlorine helps__________ grease, making it easy to skim - Answer: Congeal Final disposal of grit, screenings, and grease is by burial in a _____________ - Answer: Landfill Pre-aeration is used to remove grit, reduce ___________________, add oxygen, and promote grease flotation. - Answer: Gases Use flow equalization to control variations in flow patterns or _____________ loads - Answer: Shock It is important to monitor the flow in order to calculate plant load, as well as to determine ______________ - Answer: Inflow/infiltration Flow is the water volume passing a given point, in a specified interval, in gallons per minute or cubic feet per _____________ - Answer: Second A weir is an obstruction placed in a channel, causing the water to ________________ - Answer: Back up The _________________ of the water flowing over the weir determines the flow rate. - Answer: Depth Common weir designs are rectangular, cipolletti, and __________________. - Answer: V-notch An ultrasonic flow monitoring device works on the principle of _______________ - Answer: Solar The magnetic meter works by the law of - Answer: Induction ___________________ calibrate flow measuring devices. - Answer: Annual Flow measuring devices must be +_____ % accurate - Answer: 10 Sedimentation is the process of separating a suspended solid from water by atmospheric pressure. - Answer: False (gravity) Common design features of a sedimentation tank include baffles, a skimmer, a grease ring, and a sledge rake. - Answer: True A primary clarifier settles biological sludge, and a secondary clarifier settles raw sludge. - Answer: False ( settles primary sludge/ secondary biological sludge) Factors affecting settling include solid weight, water temperature, detention time, velocity, surface loading, wastewater condition, and short-cutting. - Answer: False (short circuiting) The four settling zones in a sedimentation tank are the inlet zone, settling zone, sludge zone, and the outlet zone. - Answer: True Short-circuiting is the uneven flow of water through a tank. - Answer: True Primary clarifiers should remove 90-95% of the BOD and 35% of the settable solids. - Answer: False (percentages should be switched) Secondary sludge contains more water then primary sludge - Answer: True Maintenance of a clarifier includes ______________ inspection of the skimmer arm - Answer: Daily If the Skimmer fails, the sludge ______________ fails - Answer: Rake Floating sludge or excessive gas bubbles indicate a failure of the return sludge pump, sludge rake, or poor ______________ schedule. - Answer: Pumping Withdraw sludge slowly or water will break thought the sludge layer, _______________________ - Answer: Diluting Usual blanket depth in a secondary clarifier is no more then ______________ of the sidewall depth - Answer: 1/4 Imhoff tanks are ______ story high with ________ compartments - Answer: 2/3 The ______________ compartment of Imhoff tank is the settling tank, and the ________ compartment is the sludge digester - Answer: Upper/lower Gas vent alongside the settling tank are the ______________ compartment - Answer: 3rd The settling compartment provides aa dentention time of about ____________ hours - Answer: 2 A trapped slot in the bottom of the settling compartments permits _____________ solids to pass into the digester, but prevents septic solids from ______________ into the settling compartment - Answer: Settled/ rising The sloping bottom of the settling compartment __________ gas bubbles and grease, cause it them to _____________ into the gas vents - Answer: Deflect/ rise _______________ prevents septic solids from collecting and rising in the settling chamber - Answer: Chaining When sludge in an imhoff tank is near ___________ inches of the slot, withdraw sludge. - Answer: 18 Foaming can be caused by industrial waste, drawing too much sludge, low ph, and restricted - Answer: Gas vents Control foaming by controlling industrial waste, ____________________, and controlling pH with lime. - Answer: Wasting small amounts of sludge The five components of the activated sludge process are the oxygen supply system, aeration tank, clarifier, return sludge system, and the waste sludge system. True/false - Answer: True Mixed liquor is the mixture of raw wastewater and microorganisms. True/false - Answer: True In the clarifier, the biological solids separate by gravity settling. True/false - Answer: True Wasting removes excess solids, inert solids, and old or dead solids from the system. True/false - Answer: True The settled biological solids accumulate in the clarifier, then are always wasted from the process. True/ false - Answer: False( continuously returned to the aeration tank reseed it) The aeration tank should be observed weekly for a uniform aeration pattern, low amount of light colored foam, mild, earthy odor, and medium brown color. True/false - Answer: False daily The clarifier should have very little scrum, a sludge blanket in the bottom 1/4 of the clarifier, uniform weir flow, rising solids, and turbid supernatant. True/false - Answer: False few rising solids and clear supernatant Process control parameters include dissolved oxygen, quantity and quality of solids, return rate, and waste rate. - Answer: True Normally, DO should be kept between 20 and 40 mg/l - Answer: False between 2 and 4 mg/l At least 1 mg/l DO should be kept in the aeration basin to maintain the health of the anaerobic microorganisms. - Answer: False aerobic microorganisms The primary purpose of returning sludge is to have enough ______________ in the aerator to match the food supply. - Answer: Microorganisms If the _____________ loading on the plant is high, DO levels should be increased. - Answer: ORGANIC A simple method indicating when to waste is the _____________. - Answer: Sludge volume index _________________________ are the smallest, most numerous, and most important of the activated sludge microorganisms. - Answer: Bacteria ___________________ settles gently and uniformly, compacts slowly, and has sharp edges like a sponge. - Answer: Quality slidge The ____________________ modification of the activated sludge process has no primary clarifier, no digester, 24-hour aeration time, a low F/M ration, and complete nitrification. - Answer: Extended aeration The _____________________. Modification has no return sludge and the aeration tank is used as the clarifier. - Answer: Sequential batch reactor The microorganisms in fixed-film processes are attached to rocks or plastic media. True/ fasle - Answer: True The four basics parts of a trickling filter are the media, underdrain, tank walls/floor, and the distributor. True/false - Answer: True The media provides the surface area upon which a biological slime growth, called zoogleal mass, develops true/false - Answer: True Zoogleal mass consists of aerobic, anaerobic, and facultative organisms including bacteria, Protozoa, and fungi. True/false - Answer: True The media may be rock, steel, or molded plastic true/false - Answer: False (no steel) The underdrain system of a trickling filter, located above the media, collects the filter effluent. True/flase - Answer: False( under the media) The purpose of the distributor is to support the media. True/false - Answer: False( keep the media wet) The zoogleal mass must remain dry or it will die. True/false - Answer: False ( remain wet or it will die) The wastewater distributed on the media first passes through a final clarifier, but still contains about 65% of it s organic matter. True/fasle - Answer: False ( primary clarifier) When the zoogleal mass grows thick, some of it sloughs off or breaks off, then settles in a secondary clarifier. True/false - Answer: True Sloughed material settles in the final clarifier is called humorous sludge. - Answer: False (humus sludge) Fixed-film processes include trickling filters and _____________________. - Answer: RBC's Filter are classified according to ____________ and _____________ loading. - Answer: Hydraulic/ organic Hydraulic loading is volume of ______________, including recirculating, applied to the filter. - Answer: Water Organic loading is the pounds per day of ____________________ per acre-feet or 1,000 Cubic ft of media - Answer: BOD The ______________ test measures wastewater strength, filter efficiency, and effluent quality. - Answer: BOD Some problems associated with trickling filter operation are filter flies, odor, ponding, plugged nozzles, clogged underdrain, and ____________. - Answer: Snails Filter flies live in an environment that alternates between ________________ and ______________. - Answer: Wet/Dry Odor results when treatment becomes _________________. - Answer: Anaerobic Ponding is caused by _______________. - Answer: 1 Excessive zoogleal growth 2 poor primary treatment 3 Improper media 4 all of the above Rotating biological contractors have a rotating shaft surrounded by ___________ media - Answer: Plastic media Biological slime (microorganisms) grows on the surface of the ______________, consuming the organic matter (BOD) as the rotates in the wastewater. - Answer: Media In time, some of the biological growth sloughs from the media and settles in the ____________ clarifier. - Answer: Secondary The purpose of a wastewater pond is to treat wastewater by natural processes in a warm climate with ample sunshine and low rainfall. True/ false - Answer: True Ponds are classified as stabilization ponds (oxidation ponds), facultative ponds, or anaerobic ponds. True/ false - Answer: True The treatment of organic matter in a stabilization or facultative pond depends upon sunlight, algae, and bacteria. True/ flase - Answer: True In stabilization ponds, aerobic conditions exist throughout the pond length. True/ ffalse - Answer: False ( ponds depth) In stabilization and facultative ponds, aerobic bacteria consume organic material, produce Carbon dioxide, and, with sunlight, (algae) consume carbon dioxide and produce oxygen. True/false - Answer: True Anaerobic ponds require sunlight, algae, and dissolved oxygen to be present. True/false - Answer: False ( requires no sunlight / and Dissolved oxygen is absent) A pond should be lined and the soil compacted to prevent seepage into surface water true/ false - Answer: False (ground water) Levees must have a top width of at least 10 feet for fishing and picnic tables . True/false - Answer: False ( vehicles and mowing machines) Large vegetation should be removed within 2feet of the embankment and vegetation should be maintained at a mowing level. True/ false - Answer: False ( 20 feet) Ponds should be fitted with inlets having multiple outlets to control short-circuiting. - Answer: True Organic loading of a stabilization pond is about ___________________ pounds of BOD per acre per day with a detention time of at least ______________ days. - Answer: 35/30 Under idea conditions in a stabilization pond, BOD is reduced __________________ - Answer: 85-90% One surface acre furnishes treatment for about _______________ people. - Answer: 300 It is recommended that the following samples be taken daily: pH, temperature, and _________________ - Answer: DO (dissolved oxygen) The purposes of sludge digestion are to reduce the volume, to make it easier to dewater, to stabilize organic solids, and to change the color. True/false - Answer: false (dont change color) Four types of sludge are primary, humus, activated sludge, and digested sludge. True/false - Answer: True Primary sludge settles in the secondary clarifier. True/ false - Answer: False (settles in primary clarifier) Humus sludge sloughs off from the zoogleal mass in fixed-film processes. True/ false - Answer: True Activated sludge settles in the primary clarifier or wasted from an activated sludge process. True / false - Answer: False ( settles in final clarifier) Sludge is digested aerobically or anaerobically. True / false - Answer: True Aerobically digested sludge is brown in color, has very little odor, does not dewater readily. True/ false - Answer: True Anaerobically digested sludge is dark in color, has a tarry odor, a grainy texture, and does not dewater readily. True/ false - Answer: False ( fiber like texture/ dries readily) The two stages of anaerobic digestion are the acid stage and the methane fermentation stage. True/ false - Answer: True In the acid stage, facultative bacteria, called acid formers, convert organic material into volatile (organic) acids. True / false - Answer: True In the methane stage, aerobic bacteria, called methane formers, convert the organic acids in methane gas. True /false - Answer: False (anaerobic bacteria / volatile acid) In a well-operated anaerobic digester, the methane gas content is about _______________________. - Answer: 65-75 % Anaerobic digesters are covered to keep out ________________, to trap the useful methane, and to keep the digester warm. - Answer: Free oxygen Anaerobic digester mixing methods are gas, mechanical, or ______________________. - Answer: Pump Anaerobic sludge is heated by pumping it through pipes heated with _________________. - Answer: Hot water Overloading anaerobic digesters causes foaming, poor gas production, and _____________________. - Answer: Low ph Unstabilized anaerobic sludge contains streaks of __________________ or ________________. - Answer: Gray/ green Three layers found in anaerobic digesters are supernatant liquor, scum, and __________________. - Answer: Gas The useful ______________ can heat the digester or buildings, fuel engines, or produce steam. - Answer: Methane gas Anaerobic supernatant liquor is the ________________ that separates from the sludge. - Answer: Grey liquid Laboratory tests that should be done to operate an anaerobic digester are alkalinity, temperature, volatile acids, percent volatile solids, percent carbon dioxide, and ______________________. - Answer: pH Anaerobic digester trouble signs are low pH (add lime to near neutral), increased ____________________, decreased alkalinity, and increased volatile acids. - Answer: CO2 In an anaerobic digester, a _____________ change per day is best. - Answer: 1 degree Celsius Aerobic digestion is an____________ process whereby the aerobic bacteria consume themselves. - Answer: Endogenous Methods of removing water from sludge to reduce its bulk include drying beds, belt presses, gravity thickeners, and ________________. - Answer: Centrifuges Disposal methods for digested, dewatered sludge are ____________________, landfill, and incineration - Answer: Land application Land filled sludge must have a solids content of at least _______________. - Answer: 20% Disinfection prevents waterborne disease by protecting public water supplies, water for recreation, and shellfish growing areas. True/ false - Answer: TRue Water borne disease include typhoid, hepatitis A, cholera, dysentery, poliomyelitis, and measles. True/ false - Answer: False (no measles) Disinfection destroys disease-causing microorganisms called pathogens. True false - Answer: True Two methods often used to disinfect wastewater effluent are chlorination and ultra-purple radiation. True/ false - Answer: False (It's ultraviolet radiation) Chlorine is available in the pure gas and liquid state, granular or tablet form, and in water solutions. True/ false - Answer: False (chlorine solution) Liquid chlorine is bleach. True/ false - Answer: False (not bleach) Chlorine gas is greenish- yellow in color, 2 1/2 times havier than water, and has a strong pungent odor. True /false - Answer: False ( 2 1/2 times heavier then air) Chlorine does not burn, but is strong oxidizer and reacts violently with oil and other hydrocarbons. True/ false - Answer: True Calcium hypochlorite, known as HTH, contains 35% chlorine and 65% lime. True/ false - Answer: False (65% chlorine and 35% lime) Household bleach is 5.25% sodium hypochlorite dissolved in water. True/ false - Answer: True Dosage is amount of chlorine applied; demand is the amount of chlorine used up: and residual is the amount of chlorine left after demand. True/ false - Answer: True When chlorine and water mix, hypochlorous (HOCI) and hydrochloric (HCI) acid are formed. true/ false - Answer: True Hypochlorous acid (HOCI), a powerful disinfectant, is the combined residual. True/ false - Answer: False (free/uncombined) When chlorine reacts with lime, chloramines form. True / false - Answer: False ( chlorine reacts with ammonia) Chloramines are the combined residual. True/ false - Answer: True Strong concentrations of chlorine can cause - Answer: ing ing cation the above In case of exposure to chlorine, _____________________. - Answer: 1 wash under a safety shower or with a garden hose 2 flush eyes with cool water for 15 mins 3 get medical help 4 all of the above Milk, coffee, or _____________ candy relieves throat irritation. - Answer: Peppermint Operators must use ______________ as a chlorine indicator in the titrimetric or spectrophotomeric residual test methods. - Answer: DPD Factors influencing disinfection are pH, temperature, contact time, chlorine concentration, and ___________________. - Answer: Residual type Because HOCI is a _________________, it is more effective at low pH. - Answer: Acid The higher the water temperature, the ___________ this disinfection rate. - Answer: Faster The ____________ the dosage, the ____________ the contact time required. - Answer: Higher/ shorter The _________________ the dosage, the _________________ the disinfection process occurs. - Answer: Higher/ faster The _________________ residual is more powerful and faster acting than the _________________ residual. - Answer: Free/ combined In addition to disinfection, chlorine is used to _________________. - Answer: 1 reduce BOD 2 aid in grease removal 3 reduce odor 4 all of the above Gas chlorinators use _____________ to draw chlorine into a water stream. - Answer: Vacuum Gas chlorinator feed rates are indicated by the ________________ in pounds per day. - Answer: Rotameter Hypochlroinators pump solutions of calcium or ________________ hypochlorite into the effluent. - Answer: Sodium Effluent chlorine dosage must provide a total combined residual of at least ____________ mg/l for at least ______________ minutes at a peak flow. - Answer: 1.0/20 Chlorine container valve wrenchesmust be no longer than _________ inches. - Answer: 8 Chlorine leaks are detected with _____________ % ammonium hydroxide vapor. - Answer: 10 The addition of water to a chlorine leak _______________. - Answer: Makes the leak worse The TCEQ requires scales and a _______________ on-site at a chlorination facility. - Answer: SCBA (self contain breathing apparatus) To protect aquatic organisms from _________________ such as chlorine, the TCEQ requires dechlorination in some discharge permits. - Answer: Toxins Dechlorination may be achieved by long detention time, aeration, sunlight, activated carbon, or _____________________. - Answer: Chemicals. The TCEQ allows the reuse of treated wastewater for ____________________. - Answer: 1 golf course irrigation 2 aquifer recharge 3 Agricultural irrigation 4 All of the above Reclaimed water piping must be colored coded __________________. - Answer: Purple Reclaimed water provides must report monthly to the TCEQ the _______________ and _______________ of reclaimed water delivered to a user - Answer: Volume/ quality The federal law having the greatest impact on workplace safety is the Texas Hazard Communication Act. True/ False - Answer: False (OHSA) The Occupational Safety and Health Act (Right-to-know Act) requires employers to provide information about hazardous workplace chemicals. True/ False - Answer: True Elements of a safety program include a written policy, supportive administration, trained employees, safety inspections, accident review, and record keeping. True/ false - Answer: True General hazards around a collections system and wastewater treatment plant include disease, oxygen deficiency, gases, chemicals, fire, and electrical shock. True/ false - Answer: True Bodily injury is the most common result of an accident true/ false - Answer: TRue An atmosphere is oxygen deficient when oxygen content is less than 19.5% true/ false - Answer: True Carbon dioxide and methane are toxic; chlorine and hydrogen sulfide are suffocating. True/ false - Answer: False ( carbon and methane are suffocating/ chlorine and hydrogen sulfide and toxic) The atmosphere of underground structures should be ventilated and tested before entering true/ false - Answer: true Operators should be familiar with industrial waste entering the collection system true/ false - Answer: True Hot water or heat packs are first aid for burned skin true/ false - Answer: False (cool water/ ice packs) BEfore working on electrical equipment, breakers and switches should be locked out and tagged. True /false - Answer: True Operators should not use a ladder one-handed true /false - Answer: True In the collection system, traffic safety includes warning traffic with signs, cones, flagmen, and _________________. - Answer: Safety vest and warning lights. Traffic control devices must conform to standards set by the ___________________ Manual on Uniform Traffic Control Devices for Streets and Highway - Answer: Texas (TMUTCD) Before entering a manhole, test for gases and oxygen level and _____________________ the manhole before and during entry. - Answer: Ventilate Never enter a manhole alone; at least ______________________ people should stand by on the surface. - Answer: 2 Excavations __________________ feet or deeper should be shored, shielded, or sloped. - Answer: 5 Wear gloves, Such as ________________, because they are not easily cut. - Answer: Leather The most important aspect of plant safety is __________________. - Answer: Good housekeeping Do not smoke in a ___________________ atmosphere - Answer: Flammable Before using a chemical, read the _______________. - Answer: SDS Be sure ________________ lighting is available for night shifts. - Answer: Bright Storage should separate acids, akalies, flammables, oxidizer, and _________________. - Answer: Explosives Label and date _________________ - Answer: Chemicals Laboratories should have two _______________________, a safety shower, and an eye wash station. - Answer: Exits Never place a ________________ in a sample refrigerator - Answer: Lunch