Texas Wastewater Class A (Test 3) 2024-2025: Questions and Correct Answers, Exams of Water and Wastewater Engineering

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Texas Wastewater Class A (Test 3) 2024-

2025. Questions and Correct Answers.

Graded A

___ and below is an oxygen deficient atmosphere. - ANS19.5% A good plant influent pH is about - ANS7. A good Primary Clarifier removes __ to __% of settable solids. - ANS90 to 95% A mechanical device that screens & cuts large solids in small particles - ANSComminutors A simple method for indicating when to waste sludge is - ANS30 minute settling test A Sludge Volume Index (SVI) number of ___ is an indication of sludge bulking. - ANS180 mL/g According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure mains shall have a minimum psi pressure rating of ________. - ANS Activated Carbon Beds remove what? - ANSdissolved organics

Activated Sludge - Extended Aeration has 3 major phases: - ANSlogarithmic growth phase, declining growth phase, and the endogenous phase Acute toxicity occurs when - ANSThere is a rapid die off of treatment organisms Advantage of wastewater stabilization ponds - ANSlow-cost technology, requires low maintenance, is highly efficient, mostly natural and sustainable. All reclaimed water piping must be the color - ANSpurple Allowable leakage in a new collection system can be tested by ___, ___, and ___. - ANSlow pressure air, exfiltration test, infiltration test. As the population of a collection system increases, the ratio of peak flow to average daily flow will - ANSdecrease Besides disinfection, chlorine has other uses at the wastewater treatment plant such as - ANSReduces BOD, Odor, Algae growth, Helps with Grease Calcium Hypochlorite or HTH, is a - ANSstrong Oxidizer and reacts violently with oil and hydro carbons. Carbon dioxide does not harm - ANSmucous membranes or your lungs

Carbon monoxide (CO) poisoning symptoms are ________. - ANS Chronic toxicity occurs when - ANSCertain microorganisms become inactivated but others continue to work resulting in a sick biological process CO2 does NOT irritate the ____ _____. - ANSmucous membranes Common operating problems with a trickling filter include - ANSPonding, Filter files, Odors, Clogging of Nozzles, and Snails Digesters show improvement by an increase in - ANSmethane, and a decrease CO Essay: Explain the 5 major mechanical components of an activated sludge system?

• ANS Essay: Explain the advantages and disadvantages (or differences) between an oxidation ditch and activated sludge system? - ANS Essay: List and explain the functionality/role of each float for a lift station that has 2 pumps and 4 floats installed? - ANS

Essay: What are the 6 major components of a Sewer System Evaluation Survey (SSES)? - ANS Excessive "Hum" in a motor indicates what? - ANSSingle Phase Excessive power consumption by a pump could be caused by - ANSWorn bearings and worn impeller Extended aeration is a _____ process that requires little operator interaction. - ANSsimple Facultative Lagoons have two zones of treatment - ANSan aerobic surface layer and an anaerobic bottom layer Frequency of TCLP monitoring, for dry metric tons of sludge disposed of - ANS0 to 290, once per year, 290 to 1,500, once per quarter, 1,500 to 15,000, once per 60 days. 15,000 monthly. Good Sludge has Lots of __ & ___ ___, a Few ___ and __. - ANSciliates & free swimmers, a few rotifers, and flagellates. Grit is washed in a snail to - ANSwash off organics.

How often should maintenance be scheduled? - ANSDaily If an employee, is guilty of misconduct, as defined by the utilities personnel policies, the supervisor should? - ANSAttempt to modify, the employee's behavior , through training ,and other forms of assistance, ,and inform the employee , of the consequences. If an existing centrifugal pump motor is replaced with a motor with 25 percent more speed, the motor horsepower required will increase by ________. - ANS In a Facultative Lagoon, typically one could expect - ANS50% B O D removal, In a normally operating trickling filter, the temperature difference between the atmosphere and the influent wastewater will - ANScause air to flow through the media and across the zoogleal mass In a stability pond, what is density stratification? - ANSWarm water being lighter the cool water remains near the surface, thus producing a layered effect. In a trickling filter, solids removal is affected by the ___ ___. - ANSreturn rate. In an excavation, if a ladder is used as a means of exit, it must extend how far above ground, and how far apart

laterally - ANS3 feet / 25 feet laterally In the activated sludge plant, good quality sludge will settle - ANSGently and Uniformly in 15 to 20 minutes In the activated sludge plant, old sludge quality will settle - ANSRapidly, and ragged in 5 minute period. In the activated sludge plant, there are 5 important nitrogen transformation processes that occur by microorganisms. They are - ANSAssimilation, Ammonification, Nitrification, Denitrification, and Nitrogen fixation. In the activated sludge plants, the operator will experience problems. Some common Environmental problems include. - ANSLow temperatures, System pH out of range, & Excessive algae growth In the activated sludge plants, the operator will experience problems. Some common Operational problems include - ANSSludge quality, foaming, improper operating techniques In the activated sludge plants, the operator will experience problems. Some of the common Treatment plant problems include - ANSInsufficent capacity, Equipment failures, Design inadequacies, Poor maintenance, & Inflow rates exceed plant capacities.

In the activated sludge plants, to properly set the clarifier return rate the operator must know three things - ANSReturn activated sludge rate, Sludge blanket thickness, & the Solids concentration of the return flow In the activated sludge process, as more mixed liquor flows to the classifier, the thickness of the sludge blanket will - ANSIncrease 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 - ANSAir lift pumps, centrifugal pumps, Diaphragm pumps, Screw pumps & Gravity Flow In the activated sludge process, daily observation of the aeration basin treatment processes are essential. The operator should pay close attention to - ANSSurface 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 - ANSSurface scum, Sludge blanket, Weir Flow, Rising solids, & Clarifier overflow In the activated sludge process, factors that will influence the operation of the final clarifier are - ANSLoading, solids applied, settling, thickness of solids, rate of return & Wasting In the activated sludge process, five (5) Important control parameters are - ANSDissolved Oxygen level, Aerator solids level,

Solids quality, Rate of returned sludge, & Wasting rate In the activated sludge process, floc is very important to the settling process. Floc is composed primarily of - ANSBacteria, Protozoa, Microscopic Animals, & Fungi In the activated sludge process, Gould Sludge Age (GSA) is calculated by - ANSDividing the total pounds of TSS in the aerator by the pounds of TSS entering the aerator as raw In the activated sludge process, Mass Balance refers to - ANSMaintaining the balance between Return Sludge Flow, Return Sludge, Aeration tank volume, Mixed liquor suspended solids In the activated sludge process, no sludge process will work properly without - ANSRegular removal of excess solids In the activated sludge process, Sludge Rising differs from "Sludge Bulking" and "Sludge Rising" is typically associated - ANSNitrification - De-nitrification process In the activated sludge process, Stabilization is - ANSWastes biologically converted to water, carbon dioxide, or new cells In the activated sludge process, techniques used to reduce "Frothing & Foaming" typically include - ANSAdjusting sludge age, Reducing the amount of air, Spraying the frothing area with water, Applying de-foaming agents

In the activated sludge process, the clarifier will concentrate return sludge - ANStwo (2) to four (4) In the activated sludge process, the F/M Ratio is calculated by ______ the pounds of _________ by the pounds of MLVSS in the ___________. - ANSDividing/ Incoming BOD/ aeration tank In the activated sludge process, the term Mean Cell Residence Time (MCRT) refers to - ANSThe amount of time the living cells are kept in the plant In the activated sludge process, the term Gould Sludge Age refers to - ANSHow long in days a pound of solids stays in the aerator In the activated sludge process, the terms F/M ratio is important because this refers to - ANSFood to Microorganism Ratio In the activated sludge system if the operator observed uneven surface aeration, dead spots or inadequate mixing in some areas, the operator would suspect - ANSPlugged diffusers In the activated sludge system, "Hydraulic Wash Out" is - ANSWhen the upward movement of the water in the clarifier exceeds the downward settling velocity

In the activated sludge system, Hydraulic Wash Out can be controlled by - ANSflow equalization, Additional clarifier capacity or inflow reduction In the activated sludge system, if the operator observed Boiling action, Violent turbulence throughout the aeration tank surface, Large air bubbles 1/2 inch or greater, the operator would suspect- - ANSOver aeration resulting in high DO, and or floc shearing, therefore the operator should reduce the, air SCFM to get DO into the proper range In the activated sludge system, if the operator observes excessive air being used with no apparent change in organic or hydraulic loading, the operator would suspect - ANSLeaks in the system piping, Plugged air diffusers & High organic loading In the activated sludge system, if the operator observes white thick billowing sudsy foam on the aeration tank, the operator would suspect - ANSOverloaded aeration tank and or excessive sludge wasting In the active sludge process, Utilization is the process where - ANSFood supply is changed into a liquid state for use Increasing the return rate of a conventional activated sludge plant has what effect on process control? - ANSDecrease detention time, in aeration basin, raise dissolved oxygen, lower sludge blanket.

Information on preventive maintenance procedures, materials, and frequencies for plant structures should be taken from? - ANSManufactures literature Inorganic Solids (ash) are those that - ANSConsist of sand, grit, & minerals and can be suspended or dissolved Inorganic solids include - ANSsand, grit and minerals Non-settleable Solids are - ANSSmall particles that do not settle On a water lubricated pump, what should the seal water pressure be? - ANS5 p s i over stuffing box pressure Organic matter, in wastewater, can be dissolved, or suspended ,and make up approximately - ANS65 % , of the total solids Organic solids include - ANSorganic materials from plants, animals or humans Pre- aeration of influent would aids in - ANSflotation of grease Pre-treatment of wastewater would include: - ANSCoarse or fine screening, grinding and grit removal and grease removal and pre-aeration

Primary treatment of wastewater would include - ANSsettling tanks or basins, scum collection and removal, sludge collection and removal Primary treatment uses - ANSgravity to treat Seeding of BOD samples is necessary when samples _______. - ANSto be tested contains materials not readily biodegradable, or if it contains toxic materials such as phenol, formaldehyde or similar microbic. Settable Solids - ANSSettle out when left standing for extended periods of time Solids in wastewater are classified as - ANSTotal: solids or residual (TR), Suspended (TSS), Dissolved (TDS), Settleable (SS), Non-setteable, Floatable, Organic and Inorganic TCEQ allows the reuse of wastewater, some of these include - ANSIrrigation, aquifer recharge, cooling towers and fire protection The Activated Sludge plant has five (5) Critical Components. They are - ANSOxygen supply, Aeration tanks, Clarifiers, Return & Waste

The Activated Sludge Process can produce a high degree of treatment. Typically one could expect a - ANS90 to 99%, B O D removal the best to determine if a storm drain is connected to a sanitary sewer line is a - ANSSmoke Test The depth of sludge drawn to a drying bed should be - ANSApproximately 9 to 12 inches The efficiency of a trickling filter is measured in - ANSPercent BOD Removed The maximum safe withdrawal rate for a 150 lb chlorine cylinder is - ANS40 lbs The minimum size for a gravity flow sewer line on city right-of-way and the minimum grade is - ANS6 inch and a grade of .50 percent The most accurate way to find the average wastewater flow rate in an existing 10-inch sewer main is - ANSObtaining actual flow data & verifying with field data The most common method of dewatering and drying sludge is - ANSdrying bed The sludge from a primary clarifier should contain what percent solids? - ANS4 to 6 %

The typical pH of an influent entering the plant will vary from - ANS6.5 to 8. The typical sludge age for extended aeration plants is - ANS20 to 40 days There are five (5) major components to a trickling filter - ANSFilter floor, underdrain, walls, filter media, & distributer arms This test would give the best information on how efficiently a trickling filter was operating - ANSPercent BOD Removal This treatment device is commonly used to separate, and remove large solids from raw wastewater - ANSA Mechanically raked bar screen This trickling filter problem could be reduced by increasing the re-circulation ratio - ANSFilter files To determine the approximate number of gallons per day being discharged to the collection system, multiply the population by ____ gallons/person/day. - ANS Total Dissolved Solids (TDS) are those that - ANScannot be filtered out Total Dynamic Head = - ANSStatic Head + Friction Loss

Total solids in wastewater are the sum of - ANSSettleable and volatile solids Total Suspended Solids (TSS) are those that - ANSCan be filtered out Volatile Solids (VSS) are those that - ANSAre determined by burning the residue from the Total Solids determination Wastewater Stabilization Ponds are an approved process for wastewater treatment. Organic loading of Stabilization Ponds is typically - ANS35 pounds of b. o .d. with a minimum, of 30 days detention time Wastewater Stabilization Ponds work through a complex process which includes - ANSSunlight, Oxygen, Nutrients, Algae, and Bacteria What are the limits of authority for a line manager position? - ANSSupervises their subordinates only What chapter of the Texas Water Code gives T C E Q authority to control discharges in Texas. - ANSChapter 26 What clarifiers have maximum surface loading at peak and design flow? - ANSPrimary and intermediate

What do you use to run a 30 minute settling test? - ANS1000 milliter graduated cylinder. What gives pistons longer wear? - ANSLonger stokes and slower RPM's. What is commonly used to seal joint leaks, on a main with minimal interruption - ANSinternal grouting What is the "Span of Supervision?" - ANSThe number of subordinates that you supervise. What is the assumed BOD removal rate used in plant design calculations for primary clarifiers? - ANS35% What is the expected organic loading of a stabilization pond and what is the detention time in days? - ANS35 pounds, of B O D, per acre, per day, and a detention time of 30 Days What is the greatest advantage for using fiberglass manholes in areas with high groundwater? - ANSfiberglass is not subject to infiltration What is the heart In the activated sludge process - ANSClarifier

What is the minimum surface loading rate on a trickling filter? - ANS MG/Acre/Day Standard Rate Filter What is the name of the algae that is abundant in stabilization ponds? - ANSPhytoplankton What is the purpose, of a sanitary sewer, evaluation survey - ANSA sewer system evaluation survey, is a systematic evaluation, used to investigate reports of excessive inflow , or infiltration sources, in a sewer system. The survey also assesses the flow rate, and the cost for rehabilitation, if said sources, are found to be excessive What meter measures resistance? - ANSOhm meter What process is used to re-seed Aeration Basins and remove solids from Secondary Claifires? - ANSReturn Activated Sludge (RAS) What regulates the RPM's on an air driven Rotating Biological Contactor (RBC)? - ANSAir volume What removes Total Suspended Solids from a sample (TSS) - ANSfiltration What type of process requires scum from the final clarifier to be place in the digester? - ANSTrickling filter and Rotating Biological Contactor (RBC)

What will not affect the vacuum filter system? - ANSDrum speed When a centrifugal blower is operating what happens to the oil level? - ANSIt drops When a municipal wastewater effluent has a high nitrate level, and low ammonia level, this most likely means - ANSa high degree of aerobic treatment When added to water what does chlorine form - ANSit forms Hypochlorite, and Hydrochloric acid When ammonia is present in wastewater and reacts with chlorine what is formed - ANSWhen ammonia is present in wastewater, and reacts with chlorine, Chloramines are formed. When Potable water is used for a hydraulic seal on a pump it should have - ANSan air gap. When setting work goals for an employee, the goals should be ________. - ANS When using Hydraulic Hydro Jetting sewer cleaning equipment, the

operator will want to go from a clear manhole, and - ANSclean toward the stoppage, to avoid forcing sewage into customer homes, or businesses. Which process is more like an oxidation pond? - ANSExtended aeration White foam on start-up of AB's is caused by - ANSLow MLSS Zoogleal Mass refers to - ANSA thick layer of jelly like slime where organisms bacteria, fungi, protozoa and ciliates thrive.