WASTEWATER CLASS B TEXAS 2024/2025 QUESTIONS WITH 100% VERIFIED ANSWERS., Exams of Water and Wastewater Engineering

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The name of the State Agency responsible for enforcing pollution control laws in Texas -- Correct Answer ✔✔ Texas Commission of Environmental Quality The term pathogenic means -- Correct Answer ✔✔ Capable of causing disease The minimum separation between sewer lines and potable water lines is -- Correct Answer ✔✔ 9 feet A licensed wastewater operator is a professional -- Correct Answer ✔✔ consistently does best job possible, practices personal safety, strives to improve job knowledge, strives to keep the plant and collection system in the best appearance and working order An important step in testing a sample for Total Suspended Solids is -- Correct Answer ✔✔ Filtering a sample The Biochemical oxygen Demand (BOD) of a sample is based on -- Correct Answer ✔✔ Measuring the dissolved oxygen (DO) used The results of Biochemical Oxygen Demand (BOD) sample taken at a treatment plant tells the operator -- Correct Answer ✔✔ How the plant was operating 5 days ago Which of the following are dangerous gasses that are likely to be present in lift stations and manholes? -- Correct Answer ✔✔ Natural gas, gasoline fumes, hydrogen sulfide and carbon dioxide A preferred hydraulic method of cleaning sewer lines is -- Correct Answer ✔✔ Hydro Jet Cleaner Ways to reduce bad odors coming from a collection system -- Correct Answer ✔✔ routinely cleaning slow running or low flow lines, adding chlorine or hydrogen peroxide to the collection system Types of pipe that are commonly used in wastewater collection system -- Correct Answer ✔✔ ductile iron, Poly Vinyl Chloride (PVC) Before entering a confined space a worker should -- Correct Answer ✔✔ Use approved monitoring device and check for the presence of dangerous gasses, ventilate the space with a blower, wear a safety harness and attach a life line A properly designed and operated primary sedimentation tank should remove _____ percent of incoming BOD -- Correct Answer ✔✔ 30-40% Devices that may be used to determine the level of sewage in a lift station -- Correct Answer ✔✔ air bubbler, floats, electrodes, Acoustic (sonic) What is the most important role of aerobic bacteria in the treatment of wastewater? -- Correct Answer ✔✔ decompose organic matter The hydraulic loading of a trickling filter may be determined by -- Correct Answer ✔✔ flow rate and filter area These can be used to dewater sludge -- Correct Answer ✔✔ belt press, drying beds, solid bowl centrifuge, gravity thickener Dangerous gases are produced during bacterial decomposition of organics in wastewater. The main gasses are -- Correct Answer ✔✔ Hydrogen sulfide, carbon dioxide and methane The majority of Dissolved Oxygen in raw sewage comes from -- Correct Answer ✔✔ Potable Drinking Water Each person contributes approximately ______ lbs of BOD to the system daily. -- Correct Answer ✔✔ 0.17 Sources of waste water include -- Correct Answer ✔✔ domestic, storm water, commercial, food processing, agricultural and industrial A sewer manhole provides access into the system for cleaning or service. A manhole is located -- Correct Answer ✔✔ at changes in alignment, diameter, grade, direction and intersection New manholes must have an inside diameter of at least ______ feet and the entry access must be at least ____inches. -- Correct Answer ✔✔ 4 feet and 24 inches In the past ____ was used to construct manholes. This product is prohibited for construction or grading today -- Correct Answer ✔✔ brick and mortar Verified clay and Poly Vinyl Chloride (PVC) are the most common pipe materials used for sewer lines but other materials are available such as -- Correct Answer ✔✔ ductile iron, cast iron, acrylonitrile butadiene styrene (ABS) Concrete, polyethylene & asbestos concrete Whenever wastewater cannot flow to the treatment plant by _____ a _____ is typically used -- Correct Answer ✔✔ gravity/ lift station The primary cause of stoppage in a collection system is _____ and _____ -- Correct Answer ✔✔ grease/roots The _____pump is most commonly used in a lift station -- Correct Answer ✔✔ centrifugal A centrifugal pump must be ____ or it will not pump -- Correct Answer ✔✔ primed ______ gas is very toxic and deadens the sense of ______ -- Correct Answer ✔✔ Hydrogen Sulifide/smell ______ gas is colorless, odorless and heavier than air -- Correct Answer ✔✔ Methane ______ are the smallest , most numerous, and most important of the activated sludge microorganisms -- Correct Answer ✔✔ bacteria Organic loading refers to the pounds per day of ____ per acre feet or 1,000 cubic feet of filter media -- Correct Answer ✔✔ BOD Hydraulic loading refers to the volume of ____, including recirculation, applied to the filter -- Correct Answer ✔✔ water The most common type(s) of trickling filters are- -- Correct Answer ✔✔ Standard rate (1-4 mgd) and High Rate (10-40 mgd) Odors occur when treatment becomes -- Correct Answer ✔✔ anaerobic ____________gas is greenish-yellow, pungent, heavier than air and highly toxic -- Correct Answer ✔✔ chlorine One common type of weir design for measuring flow is -- Correct Answer ✔✔ V-Knotch Inflow and Infiltration (I&I) typically refers to -- Correct Answer ✔✔ unaccounted for water in the system after heavy rains If the ____ loading on the plant is high, the operator would need to ____Dissolved Oxygen (DO) levels. -- Correct Answer ✔✔ Organic/Increase A simple method for indicating when to waste sludge is -- Correct Answer ✔✔ 30 minute settling test Organic loading of a stabilization pond is about ____ pounds of BOD/acre/day with a detention time of at least ___ days. -- Correct Answer ✔✔ 35 BOD/ 30 Days Anaerobic digesters are covered to keep out ____, and to trap useful methane which can be used to keep the digester warm. -- Correct Answer ✔✔ free oxygen Unstable anaerobic sludge contains streaks of _________ or ________. -- Correct Answer ✔✔ gray/green Aerobic digestion is an ____process whereby the aerobic bacteria consume themselves -- Correct Answer ✔✔ Endogenous Approved disposal methods for digested, dewatered, sludge's are landfill, ____ and ____. -- Correct Answer ✔✔ Incineration & Land Application Landfill applied sludge must have a solids content of at least _________percent -- Correct Answer ✔✔ 20 Calcium Hypochlorite (HTH) is a strong _______ and reacts violently with _________. -- Correct Answer ✔✔ Oxidizer/Oil & Hydrocarbons When added to water chlorine forms _____&_______acid -- Correct Answer ✔✔ Hydrochlorous and Hydrochloric When ammonia is present in wastewater and reacts with chlorine_________are formed -- Correct Answer ✔✔ Chloramines What is the greatest advantage for using fiberglass manholes in areas with high groundwater? -- Correct Answer ✔✔ fiberglass is not subject to infiltration A __________ pump would most likely be used when discharging into a 10" diameter pressure sewer main. -- Correct Answer ✔✔ Centrifugal Excessive power consumption by a pump could be caused by -- Correct Answer ✔✔ Worn bearings and worn impeller Trench safety is a great concern in Texas. OSHA requires that anytime an excavation is greater than __ feet deep it must be protected by ______. -- Correct Answer ✔✔ 5 feet / An approved Trench Box, Shoring, or Sloping In an excavation if a ladder is used as a means of exit, it must extend ________feet above the ground and be secured and within ____ feet laterally of anyone in the excavation. -- Correct Answer ✔✔ 3 feet / 25 feet laterally A ____________ would be the best to determine if a storm drain is connected to a sanitary sewer line. -- Correct Answer ✔✔ Smoke Test _________ would most commonly be used to seal a number of joint leaks on a main with minimal interruption -- Correct Answer ✔✔ internal grouting Pre-treatment of wastewater would include: -- Correct Answer ✔✔ Coarse or fine screening, grinding and grit removal and grease removal and pre-aeration Primary treatment of wastewater would include -- Correct Answer ✔✔ settling tanks or basins, scum collection and removal, sludge collection and removal Secondary treatment typically used today would include -- Correct Answer ✔✔ Stabilization ponds, trickling filters, rotating biological contractors (RBC) & activated sludge Essential components of the wastewater collection system include -- Correct Answer ✔✔ Sewer mains & piping, Lift Stations, Pumps, Grease & Sand traps, & Manholes Grit removal would be considered -- Correct Answer ✔✔ A part of Primary Treatment The protozoa that causes dysentery would most likely be destroyed by -- Correct Answer ✔✔ Disinfection Using final plant effluent in cooling towers would be a -- Correct Answer ✔✔ Beneficial way to reuse treated effluent TCEQ may authorize discharge of untreated wastewater into or near a receiving stream in extreme cases. This is referred to as -- Correct Answer ✔✔ Bypass Enforcement action from TCEQ may be taken if pollution or waste violates the Texas Water Code. Violations of Water Code may include -- Correct Answer ✔✔ Unauthorized discharge, accidental discharge & health hazard Solids in wastewater are classified as -- Correct Answer ✔✔ Total (TR), Suspended (TSS), Dissolved (TDS), Settleable (SS), Non-setteable, Floatable, Organic and Inorganic Total Suspended Solids (TSS) are those that -- Correct Answer ✔✔ Can be filtered out Total Dissolved Solids (TDS) are those that -- Correct Answer ✔✔ cannot be filtered out Settable Solids (SS) are those that -- Correct Answer ✔✔ Settle out when left standing for extended periods of time Non-settleable Solids are -- Correct Answer ✔✔ Small particles that do not settle Volatile Solids (VSS) are those that -- Correct Answer ✔✔ Are determined by burning the residue from the Total Solids determination Inorganic Solids (ash) are those that -- Correct Answer ✔✔ Consist of sand, grit, & minerals and can be suspended or dissolved Organic matter in wastewater can be ______or________and makes up approximately _______% of the total solids -- Correct Answer ✔✔ Dissolved or Suspended / 65 The typical pH of an influent entering the plant will vary from -- Correct Answer ✔✔ 6.5 to 8.0 Acute toxicity occurs when -- Correct Answer ✔✔ There is a rapid die off of treatment organisms Chronic toxicity occurs when -- Correct Answer ✔✔ Certain microorganisms become inactivated but others continue to work resulting in a sick biological process A mechanical device that screens & cuts large solids in small particles -- Correct Answer ✔✔ Cumminuter Detention time in wastewater typically refers to -- Correct Answer ✔✔ The time sewage is kept in a sedimentation basis There are five (5) major components to a trickling filter -- Correct Answer ✔✔ Filter floor, underdrain, walls, filter media, & distributer arms In the activated sludge process aeration tanks provide the space necessary to _______, ________, & _______ and return biological solids. -- Correct Answer ✔✔ Mix, aerate, & Hold Influent In the active sludge process, Utilization is the process where -- Correct Answer ✔✔ Food supply is changed into a liquid state for use In the activated sludge process, Stabilization is -- Correct Answer ✔✔ Wastes biologically converted to water, carbon dioxide, or new cells In the activated sludge process, the _______ is called the heart of the activated sludge process. -- Correct Answer ✔✔ Clarifier In the activated sludge process, factors that will influence the operation of the final clarifier are -- Correct Answer ✔✔ Loading, solids applied, settling, thickness of solids, rate of return & Wasting In the activated sludge process, the clarifier will concentrate return sludge and waste sludge about ___ to__ times the solids concentration of the mixed liquor -- Correct Answer ✔✔ two (2) to four (4) In the activated sludge process, for the clarifier to do its job, the ____ must be retained long enough to allow ______ to settle and liquid to rise. -- Correct Answer ✔✔ water/ solids In the activated sludge process, as more mixed liquor flows to the clarifier, the thickness of the sludge blanket will -- Correct Answer ✔✔ Increase as solids accumulate In the activated sludge process, biological solids from the bottom of the clarifier must be returned to the aeration basin for re-seed. This process is accomplished by -- Correct Answer ✔✔ Air lift pumps, centrifugal pumps, Diaphragm pumps, Screw pumps & Gravity Flow In the activated sludge process, no sludge process will work properly without -- Correct Answer ✔✔ Regular removal of excess solids In the activated sludge process, Mass Balance refers to -- Correct Answer ✔✔ Maintaining the balance between Return Sludge Flow, Return Sludge, Aeration tank volume, Mixed liquor suspended solids In the activated sludge process, the terms F/M ratio is important because this refers to -- Correct Answer ✔✔ Food to Microorganism Ratio In the activated sludge process, the F/M Ratio is calculated by ______ the pounds of _________ by the pounds of MLVSS in the ___________. -- Correct Answer ✔✔ Dividing/ Incoming BOD/ aeration tank In the activated sludge process, the term Gould Sludge Age refers to -- Correct Answer ✔✔ How long in days a pound of solids stays in the aerator In the activated sludge process, Gould Sludge Age (GSA) is calculated by -- Correct Answer ✔✔ Dividing the total pounds of TSS in the aerator by the pounds of TSS entering the aerator as raw In the activated sludge process, the term Mean Cell Residence Time (MCRT) refers to -- Correct Answer ✔✔ The amount of time the living cells are kept in the plant In the activated sludge process, daily observation of the aeration basin treatment processes are essential. The operator should pay close attention to -- Correct Answer ✔✔ Surface turbulence, Foam, Odors, & Color In the activated sludge process, daily observation of the final clarifier is also essential. The operator should pay close attention to -- Correct Answer ✔✔ Surface scum, Sludge blanket, Weir Flow, Rising solids, & Clarifier overflow In the activated sludge process, five (5) Important control parameters are -- Correct Answer ✔✔ Dissolved Oxygen level, Aerator solids level, Solids quality, Rate of returned sludge, & Wasting rate In the activated sludge process, Dissolved Oxygen levels throughout the aeration basins are measured using a portable DO meter. The operator should keep DO levels between ______ and _______. -- Correct Answer ✔✔ 2 mg/L and 4.0 mg/L In the activated sludge process, "Classic Bulking" is a common problem typically caused by -- Correct Answer ✔✔ Low density sludge In the activated sludge process, Sludge Rising differs from "Sludge Bulking" and "Sludge Rising" is typically associated -- Correct Answer ✔✔ Nitrification - De-nitrification process In the activated sludge process, techniques used to reduce "Frothing & Foaming" typically include -- Correct Answer ✔✔ Adjusting sludge age, Reducing the amount of air, Spraying the frothing area with water, Applying de-foaming agents In the activated sludge process, floc is very important to the settling process. Floc is composed primarily of -- Correct Answer ✔✔ Bacteria, Protozoa, Microscopic Animals, & Fungi In the activated sludge plants, the operator will experience problems. Some of the common Treatment plant problems include -- Correct Answer ✔✔ Insufficient capacity, Equipment failures, Design inadequacies, Poor maintenance, & Inflow rates exceed plant capacities. In the activated sludge plants the operator will experience problems. Some of the common Influent problems include -- Correct Answer ✔✔ Septic inflow, Organic overloading, and under loading, Hydraulic overloading, Solids washout during storm inflow, Toxic substances, Shock loads, & Nutrient deficiencies In the activated sludge plants, the operator will experience problems. Some common Operational problems include -- Correct Answer ✔✔ Sludge quality, foaming, improper operating techniques