Wastewater Class B Texas questions with correct answers, Exams of Water and Wastewater Engineering

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Wastewater Class B Texas questions with

correct answers

The name of the State Agency responsible for enforcing pollution control laws in Texas - ** VERIFIED ANSWERS ** ✔✔ Texas Commission of Environmental Quality The term pathogenic means - ** VERIFIED ANSWERS ** ✔✔ Capable of causing disease The minimum separation between sewer lines and potable water lines is - ** VERIFIED ANSWERS ** ✔✔ 9 feet A licensed wastewater operator is a professional - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ Filtering a sample The Biochemical oxygen Demand (BOD) of a sample is based on - ** VERIFIED ANSWERS ** ✔✔ Measuring the dissolved oxygen (DO) used The results of Biochemical Oxygen Demand (BOD) sample taken at a treatment plant tells the operator - ** VERIFIED ANSWERS ** ✔✔ 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? - ** VERIFIED ANSWERS ** ✔✔ Natural gas, gasoline fumes, hydrogen sulfide and carbon dioxide A preferred hydraulic method of cleaning sewer lines is - ** VERIFIED ANSWERS ** ✔✔ Hydro Jet Cleaner Ways to reduce bad odors coming from a collection system - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ ductile iron, Poly Vinyl Chloride (PVC) Before entering a confined space a worker should - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ 30- 40% Devices that may be used to determine the level of sewage in a lift station - ** VERIFIED ANSWERS ** ✔✔ air bubbler, floats, electrodes, Acoustic (sonic) What is the most important role of aerobic bacteria in the treatment of wastewater? - ** VERIFIED ANSWERS ** ✔✔ decompose organic matter The hydraulic loading of a trickling filter may be determined by - ** VERIFIED ANSWERS ** ✔✔ flow rate and filter area

These can be used to dewater sludge - ** VERIFIED ANSWERS ** ✔✔ belt press, drying beds, solid bowl centrifuge, gravity thickener Most important to providing adequate sewage treatment in a stabilization pond - ** VERIFIED ANSWERS ** ✔✔ sunlight, algae, bacteria and time Offensive and objectionable odors which sometimes occur in trickling filters usually indicate - ** VERIFIED ANSWERS ** ✔✔ septic conditions are present Dissolved Oxygen (DO) in aeration tank of an activated sludge plant should be maintained at or about - ** VERIFIED ANSWERS ** ✔✔ 2 to 4 mg/L Contributes to the infiltration in a collection system - ** VERIFIED ANSWERS ** ✔✔ breaks in the main lines, high ground water levels, heavy rains, hydro jet cleaning plugged mains When a centrifuge pump loses prime the - ** VERIFIED ANSWERS ** ✔✔ pump is no longer moving liquid A Rotating Biological Contactor (RBC) is - ** VERIFIED ANSWERS ** ✔✔ fixed firm biological treatment process Needs to be checked regularly to properly operate an activated sludge treatment plant - ** VERIFIED ANSWERS ** ✔✔ aeration equipment and mixed liquor solids Point source discharges are - ** VERIFIED ANSWERS ** ✔✔ discharges that come from pipes or ditches that are monitored, controlled and inspected

Non-point discharges are - ** VERIFIED ANSWERS ** ✔✔ discharges that have intermittent, dispersed flows having little or no control The Texas Water Code establishes the protection of water quality and quantity of the state by - ** VERIFIED ANSWERS ** ✔✔ setting stream standards, issues permits for discharges, identifies non-point source controls, and establishes water reuse. The wastewater plant operator is primarily responsible for - ** VERIFIED ANSWERS ** ✔✔ treating wastewater discharged into the community Chapter ___ of the Texas Water Code is the state law controlling water pollution and ___ authority to control discharges in Texas - ** VERIFIED ANSWERS ** ✔✔ Chapter 26 and Texas Commission of Environmental Quality The Texas Commission on Environmental Quality can revoke an operator's license if the operator - ** VERIFIED ANSWERS ** ✔✔ causes permit violation, falsifies records or neglects their duty If accidental discharge, bypass, or spill (SSO) of wastewater occurs the responsible party MUST notify TCEQ regional offices within ____ hours - ** VERIFIED ANSWERS ** ✔✔ 24 Aerobic Bacteria require_____ in the water for their metabolism - ** VERIFIED ANSWERS ** ✔✔ oxygen Anaerobic Bacteria _____ live with O2 present in the water for their metabolism - ** VERIFIED ANSWERS ** ✔✔ cannot Facultative Bacteria require__________in the water for their metabolism - ** VERIFIED ANSWERS ** ✔✔ either aerobic or anaerobic conditions

Chemical characteristics of sewage include - ** VERIFIED ANSWERS ** ✔✔ solids, greases, dissolved oxygen, O2 Demand, pH, and gasses _________removes Total Suspended Solids (TSS) - ** VERIFIED ANSWERS ** ✔✔ filtration Inorganic solids include - ** VERIFIED ANSWERS ** ✔✔ sand, grit and minerals Organic solids include - ** VERIFIED ANSWERS ** ✔✔ organic materials from plants, animals or humans A good plant influent pH is about - ** VERIFIED ANSWERS ** ✔✔ 7. Dangerous gases are produced during bacterial decomposition of organics in wastewater. The main gasses are - ** VERIFIED ANSWERS ** ✔✔ Hydrogen sulfide, carbon dioxide and methane The majority of Dissolved Oxygen in raw sewage comes from - ** VERIFIED ANSWERS ** ✔✔ Potable Drinking Water Each person contributes approximately ______ lbs of BOD to the system daily. - ** VERIFIED ANSWERS ** ✔✔ 0. Sources of waste water include - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ 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. - ** VERIFIED ANSWERS ** ✔✔ 4 feet and 24 inches In the past ____ was used to construct manholes. This product is prohibited for construction or grading today - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ ductile iron, cast iron, acrylontrile butadiene styrene (ABS) Concrete, polyethylene & asbestos concrete Whenever wastewater cannot flow to the treatment plant by _____ a _____ is typically used - ** VERIFIED ANSWERS ** ✔✔ gravity/ lift station The primary cause of stoppage in a collection system is _____ and _____ - ** VERIFIED ANSWERS ** ✔✔ grease/roots The _____pump is most commonly used in a lift station - ** VERIFIED ANSWERS ** ✔✔ centrifugal A centrifugal pump must be ____ or it will not pump - ** VERIFIED ANSWERS ** ✔✔ primed ______ gas is very toxic and deadens the sense of ______ - ** VERIFIED ANSWERS ** ✔✔ Hydrogen Sulifide/smell ______ gas is colorless, odorless and heavier than air - ** VERIFIED ANSWERS ** ✔✔ Methane

______ are the smallest , most numerous, and most important of the activated sludge microorganisms - ** VERIFIED ANSWERS ** ✔✔ bacteria Organic loading refers to the pounds per day of ____ per acre feet or 1, cubic feet of filter media - ** VERIFIED ANSWERS ** ✔✔ BOD Hydraulic loading refers to the volume of ____, including recirculation, applied to the filter - ** VERIFIED ANSWERS ** ✔✔ water The most common type(s) of trickling filters are- - ** VERIFIED ANSWERS ** ✔✔ Standard rate (1-4 mgd) and High Rate (10-40 mgd) Odors occur when treatment becomes - ** VERIFIED ANSWERS ** ✔✔ anaerobic ____________gas is greenish-yellow, pungent, heaver than air and highly toxic

• ** VERIFIED ANSWERS ** ✔✔ chlorine One common type of weir design for measuring flow is - ** VERIFIED ANSWERS ** ✔✔ V-Knotch Inflow and Infiltration (I&I) typically refers to - ** VERIFIED ANSWERS ** ✔✔ 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. - ** VERIFIED ANSWERS ** ✔✔ Organic/Increase A simple method for indicating when to waste sludge is - ** VERIFIED ANSWERS ** ✔✔ 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. - ** VERIFIED ANSWERS ** ✔✔ 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. - ** VERIFIED ANSWERS ** ✔✔ free oxygen Unstable anareobic sludge contains streaks of _________ or ________. - ** VERIFIED ANSWERS ** ✔✔ gray/green Aerobic digestion is an ____process whereby the aerobic bacteria consume themselves - ** VERIFIED ANSWERS ** ✔✔ Endogenous Approved disposal methods for digested, dewatered, sludge's are landfill, ____ and ____. - ** VERIFIED ANSWERS ** ✔✔ Incineration & Land Application Landfill applied sludge must have a solids content of at least _________percent - ** VERIFIED ANSWERS ** ✔✔ 20 Calcium Hypochlorite (HTH) is a strong _______ and reacts violently with _________. - ** VERIFIED ANSWERS ** ✔✔ Oxidizer/Oil & Hydrocarbons When added to water chlorine forms _____&_______acid - ** VERIFIED ANSWERS ** ✔✔ Hydrochlorous and Hydrochloric When ammonia is present in wastewater and reacts with chlorine_________are formed - ** VERIFIED ANSWERS ** ✔✔ Chloramines

Effluent dosage of chlorine in the contact chamber must produce a total combined residual of - ** VERIFIED ANSWERS ** ✔✔ 1.0 mg/L after 20 minutes Besides disinfection, chlorine has other uses at the wastewater treatment plant such as - ** VERIFIED ANSWERS ** ✔✔ Reduces BOD, Odor, Algae growth, Helps with Grease TCEQ allows the reuse of wastewater, some of these include - ** VERIFIED ANSWERS ** ✔✔ Irrigation, aquifer recharge, cooling towers and fire protection All reclaimed water piping must be _______in color - ** VERIFIED ANSWERS ** ✔✔ purple Before entering a manhole the operator should test for ________and oxygen levels and ________the manhole before entering. - ** VERIFIED ANSWERS ** ✔✔ all hazardous gasses and ventilate When a municipal wastewater effluent has a high nitrate level and low ammonia level this most likely means - ** VERIFIED ANSWERS ** ✔✔ the effluent has received a high degree of aerobic treatment Total solids in wastewater are the sum of - ** VERIFIED ANSWERS ** ✔✔ Settleable and volatile solids This treatment device is commonly used to separate and remove large solids from raw wastewater - ** VERIFIED ANSWERS ** ✔✔ A Mechanically raked bar screen ___________would have an adverse effect on the proper settling of solids in a clarifier. - ** VERIFIED ANSWERS ** ✔✔ A short circuiting flow pattern

This test would give the best information on how efficiently a trickling filter was operating - ** VERIFIED ANSWERS ** ✔✔ Percent BOD Removal This trickling filter problem could be reduced by increasing the recirculation ratio - ** VERIFIED ANSWERS ** ✔✔ Filter files What gases are produced by the controlled anaerobic digestion of wastewater sludge's - ** VERIFIED ANSWERS ** ✔✔ Methane & Carbon Dioxide These diseases are caused by pathogenic organisms that may be present in raw wastewater - ** VERIFIED ANSWERS ** ✔✔ Hepatitis, typhoid, paratyphoid,dysentery, cholera, gastroenteritis, polio, hookworm and giardiasis During heavy rain it is possible that manholes and lift stations may overflow, discharge waste materials into roadways or ditches. This type of discharge (SSO) would be - ** VERIFIED ANSWERS ** ✔✔ considered an unavoidable discharge, a violation of the Texas Water Code, a bypass that must be reported within 24 hours and considered a health hazard An effective way for the collection system worker to prevent infection by waterborn pathogenic organism is to - ** VERIFIED ANSWERS ** ✔✔ Wear protective clothing and avoid direct contact with waste water _________will increase the chances that sewage will turn septic - ** VERIFIED ANSWERS ** ✔✔ Stoppages in the main line Extensive use of garbage disposals (grinders) in a community would likely have the following effect on the collection system - ** VERIFIED ANSWERS ** ✔✔ Increase the amount of flow, solids, and grease

The minimum size for a gravity flow sewer line on city right-of-way and the minimum grade is - ** VERIFIED ANSWERS ** ✔✔ 6 inch and a grade of 0. percent The most accurate way to find the average wastewater flow rate in an existing 10-inch sewer main is - ** VERIFIED ANSWERS ** ✔✔ Obtaining actual flow data & verifying with field data What is the greatest advantage for using fiberglass manholes in areas with high groundwater? - ** VERIFIED ANSWERS ** ✔✔ fiberglass is not subject to infiltration A __________ pump would most likely be used when discharging into a 10" diameter pressure sewer main. - ** VERIFIED ANSWERS ** ✔✔ Centrifugal Excessive power consumption by a pump could be caused by - ** VERIFIED ANSWERS ** ✔✔ 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 ______. - ** VERIFIED ANSWERS ** ✔✔ 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. - ** VERIFIED ANSWERS ** ✔✔ 3 feet / 25 feet laterally A ____________ would be the best to determine if a storm drain is connected to a sanitary sewer line. - ** VERIFIED ANSWERS ** ✔✔ Smoke Test

_________ would most commonly be used to seal a number of joint leaks on a main with minimal interruption - ** VERIFIED ANSWERS ** ✔✔ internal grouting Pre-treatment of wastewater would include: - ** VERIFIED ANSWERS ** ✔✔ Coarse or fine screening, grinding and grit removal and grease removal and pre-aeration Primary treatment of wastewater would include - ** VERIFIED ANSWERS ** ✔✔ settling tanks or basins, scum collection and removal, sludge collection and removal Secondary treatment typically used today would include - ** VERIFIED ANSWERS ** ✔✔ Stabilization ponds, trickling filters, rotating biological contractors (RBC) & activated sludge Essential components of the wastewater collection system include - ** VERIFIED ANSWERS ** ✔✔ Sewer mains & piping, Lift Stations, Pumps, Grease & Sand traps, & Manholes Grit removal would be considered - ** VERIFIED ANSWERS ** ✔✔ A part of Primary Treatment The protozoa that causes dysentery would most likely be destroyed by - ** VERIFIED ANSWERS ** ✔✔ Disinfection Using final plant effluent in cooling towers would be a - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ Bypass

Enforcement action from TCEQ may be taken if pollution or waste violates the Texas Water Code. Violations of Water Code may include - ** VERIFIED ANSWERS ** ✔✔ Unauthorized discharge, accidental discharge & health hazard Solids in wastewater are classified as - ** VERIFIED ANSWERS ** ✔✔ Total (TR), Suspended (TSS), Dissolved (TDS), Settleable (SS), Non-setteable, Floatable, Organic and Inorganic Total Suspended Solids (TSS) are those that - ** VERIFIED ANSWERS ** ✔✔ Can be filtered out Total Dissolved Solids (TDS) are those that - ** VERIFIED ANSWERS ** ✔✔ cannot be filtered out Settable Solids (SS) are those that - ** VERIFIED ANSWERS ** ✔✔ Settle out when left standing for extended periods of time Non-settleable Solids are - ** VERIFIED ANSWERS ** ✔✔ Small particles that do not settle Volatile Solids (VSS) are those that - ** VERIFIED ANSWERS ** ✔✔ Are determined by burning the residue from the Total Solids determination Inorganic Solids (ash) are those that - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ Dissolved or Suspended / 65

The typical pH of an influent entering the plant will vary from - ** VERIFIED ANSWERS ** ✔✔ 6.5 to 8. Acute toxicity occurs when - ** VERIFIED ANSWERS ** ✔✔ There is a rapid die off of treatment organisms Chronic toxicity occurs when - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ Cumminuter Detention time in wastewater typically refers to - ** VERIFIED ANSWERS ** ✔✔ The time sewage is kept in a sedimentation basis There are five (5) major components to a trickling filter - ** VERIFIED ANSWERS ** ✔✔ Filter floor, underdrain, walls, filter media, & distributer arms Zoogleal Mass refers to - ** VERIFIED ANSWERS ** ✔✔ A thick layer of jelly like slime where organisms bacteria, fungi, protozoa and ciliates thrive. The efficiency of a trickling filter is measured in - ** VERIFIED ANSWERS ** ✔✔ Percent BOD Removed Common operating problems with a trickling filter include - ** VERIFIED ANSWERS ** ✔✔ Ponding, Filter files, Odors, Clogging of Nozzles, & Snails Wastewater Stabilization Ponds are an approved process for wastewater treatment. Organic loading of Stabilization Ponds is typically - ** VERIFIED

ANSWERS ** ✔✔ 35 lbs BOD/Acre/Day with a minimum of 30 days detention time Wastewater Stabilization Ponds work through a complex process which includes - ** VERIFIED ANSWERS ** ✔✔ Sunlight, Oxygen, Nutrients, Algae, and Bacteria Facultative Lagoons have two zones of treatment - ** VERIFIED ANSWERS ** ✔✔ an aerobic surface layer and an anaerobic bottom layer Typically one could expect ____ % BOD removal in a Facultative Lagoon - ** VERIFIED ANSWERS ** ✔✔ 50 Aerated Lagoons rely on ______ to provide ____and _____ - ** VERIFIED ANSWERS ** ✔✔ Mechanical aeration/ Aeration & mixing The most common method of dewatering and drying sludge is - ** VERIFIED ANSWERS ** ✔✔ drying bed Digester gas typically contains about ________%_______ - ** VERIFIED ANSWERS ** ✔✔ 65-75% methane The depth of sludge drawn to a drying bed should be - ** VERIFIED ANSWERS ** ✔✔ Approximately 9 inches Newly hired personnel have _________to become licensed. - ** VERIFIED ANSWERS ** ✔✔ 1 year Force Mains and fittings must have a pressure rating of at least - ** VERIFIED ANSWERS ** ✔✔ 150 psi

Most pumping stations and electrical equipment used today in wastewater collection or treatment is ________ and typically either _______ or _________ volts - ** VERIFIED ANSWERS ** ✔✔ A.C. (Alternating Current) & 220 or 440 and in some cases A.C. (Alternating Current) & 100 or 208 To avoid electrical shock, the operator should ________ if they are experiencing equipment failures or power related issues - ** VERIFIED ANSWERS ** ✔✔ Refer the problem to a trained electrical repairperson and do not attempt to check fuses or open the disconnect box and Notify the power provider and let them send out a serviceman to assure the problem is not on the provider's side. When using Hydraulic Hydro Jetting sewer cleaning equipment the operator will want to go from a _______ manhole and clean toward the stoppage to avoid _________. - ** VERIFIED ANSWERS ** ✔✔ Clear or open / Forcing sewage into customer homes or businesses The Activated Sludge Process can produce a high degree of treatment. Typically one could expect a ______to_______% BOD removal - ** VERIFIED ANSWERS ** ✔✔ 90 to 99% The Activated Sludge plant has five (5) Critical Components. They are - ** VERIFIED ANSWERS ** ✔✔ Oxygen supply, Aeration tanks, Clarifiers, Return & Waste The Activated Sludge process is an ________process. - ** VERIFIED ANSWERS ** ✔✔ Aerobic In the activated sludge process aeration tanks provide the space necessary to _______, ________, & _______ and return biological solids. - ** VERIFIED ANSWERS ** ✔✔ Mix, aerate, & Hold Influent In the active sludge process, Utilization is the process where - ** VERIFIED ANSWERS ** ✔✔ Food supply is changed into a liquid state for use

In the activated sludge process, Stabilization is - ** VERIFIED ANSWERS ** ✔✔ 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. - ** VERIFIED ANSWERS ** ✔✔ Clarifier In the activated sludge process, factors that will influence the operation of the final clarifier are - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ 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. - ** VERIFIED ANSWERS ** ✔✔ water/ solids In the activated sludge process, as more mixed liquor flows to the clarifier, the thickness of the sludge blanket will - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ Air lift pumps, centrifugal pumps, Diaphragm pumps, Screw pumps & Gravity Flow In the activated sludge process, no sludge process will work properly without - ** VERIFIED ANSWERS ** ✔✔ Regular removal of excess solids

In the activated sludge process, Mass Balance refers to - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ 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 ___________. - ** VERIFIED ANSWERS ** ✔✔ Dividing/ Incoming BOD/ aeration tank In the activated sludge process, the term Gould Sludge Age refers to - ** VERIFIED ANSWERS ** ✔✔ How long in days a pound of solids stays in the aerator In the activated sludge process, Gould Sludge Age (GSA) is calculated by - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ Surface scum, Sludge blanket, Weir Flow, Rising solids, & Clarifier overflow

In the activated sludge process, five (5) Important control parameters are - ** VERIFIED ANSWERS ** ✔✔ 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 _______. - ** VERIFIED ANSWERS ** ✔✔ 2 mg/L and 4.0 mg/L In the activated sludge process, "Classic Bulking" is a common problem typically caused by - ** VERIFIED ANSWERS ** ✔✔ Low density sludge In the activated sludge process, Sludge Rising differs from "Sludge Bulking" and "Sludge Rising" is typically associated - ** VERIFIED ANSWERS ** ✔✔ Nitrification - De-nitrification process In the activated sludge process, techniques used to reduce "Frothing & Foaming" typically include - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ Bacteria, Protozoa, Microscopic Animals, & Fungi In the activated sludge plants, the operator will experience problems. Some of the common Treatment plant problems include - ** VERIFIED ANSWERS ** ✔✔ Insufficent 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 - ** VERIFIED ANSWERS ** ✔✔ 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 - ** VERIFIED ANSWERS ** ✔✔ Sludge quality, foaming, improper operating techniques In the activated sludge plants, the operator will experience problems. Some common Environmental problems include. - ** VERIFIED ANSWERS ** ✔✔ Low temperatures, System pH out of range, & Excessive algae growth In the activated sludge plants, to properly set the clarifier return rate the operator must know three things - ** VERIFIED ANSWERS ** ✔✔ Return activated sludge rate, Sludge blanket thickness, & the Solids concentration of the return flow The typical sludge age for extended aeration plants is - ** VERIFIED ANSWERS ** ✔✔ 20 to 40 days In the activated sludge plant, good quality sludge will settle _________& _______ over _________ minute period. - ** VERIFIED ANSWERS ** ✔✔ Gently & Uniformly over 15 to 20 minutes In the activated sludge plant, old sludge quality will settle ________& _________ over ________ minute period. - ** VERIFIED ANSWERS ** ✔✔ Rapidly and ragged over 5 minutes. In the activated sludge plant, there are (5) important nitroen transformation processes that occur by microorganisms. They are- - ** VERIFIED ANSWERS ** ✔✔ Assumilation, Ammonification, Nitrification, Denitrification, & Nitrogen fixation.

__________in the effluent from an activated sludge process is a pollutant and may create toxic conditions for aquatic life in the receiving stream - ** VERIFIED ANSWERS ** ✔✔ Nitrogen Denitrification occurs in an activated sludge system when there is __________ to maintain the aerobic metabolism of the carbon stabilizing bacteria. - ** VERIFIED ANSWERS ** ✔✔ Insufficient Dissolved Oxygen The lack of _________ triggers the facuitative bacteria to change from aerobic and anaerobic - ** VERIFIED ANSWERS ** ✔✔ Dissolved Oxygen In the activated sludge system, "Hydraulic Wash Out" is - ** VERIFIED ANSWERS ** ✔✔ When 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 - ** VERIFIED ANSWERS ** ✔✔ flow 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- - ** VERIFIED ANSWERS ** ✔✔ Over 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 observed uneven surface aeration, dead spots or inadequate mixing in some areas, the operator would suspect - ** VERIFIED ANSWERS ** ✔✔ Plugged diffusers In the activated sludge system, if the operator observes white thick billowing sudsy foam on the aeration tank, the operator would suspect - ** VERIFIED ANSWERS ** ✔✔ Overloaded aeration tank and or excessive sludge wasting

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 - ** VERIFIED ANSWERS ** ✔✔ Leaks in the system piping, Plugged air diffusers & High organic loading The maximum safe withdrawal rate for a 150 lb chlorine cylinder is - ** VERIFIED ANSWERS ** ✔✔ 40 lbs To determine the approximate number of gallons per day being discharged to the collection system, multiply the population by ____ gallons/person/day.

• ** VERIFIED ANSWERS ** ✔✔ 100