Wastewater Class B Texas QUESTIONS WITH 100% CORRECT ANSWERS, Exams of Nursing

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Wastewater Class B Texas QUESTIONS

WITH 100% CORRECT ANSWERS

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 Most important to providing adequate sewage treatment in a stabilization pond -

CORRECT ANSWER-sunlight, algae, bacteria and time

Offensive and objectionable odors which sometimes occur in trickling filters usually

indicate - CORRECT ANSWER-septic conditions are present

Dissolved Oxygen (DO) in aeration tank of an activated sludge plant should be

maintained at or about - CORRECT ANSWER-2 to 4 mg/L

Contributes to the infiltration in a collection system - CORRECT ANSWER-

breaks in the main lines, high ground water levels, heavy rains, hydro jet cleaning plugged mains

When a centrifuge pump loses prime the - CORRECT ANSWER-pump is no

longer moving liquid

A Rotating Biological Contactor (RBC) is - CORRECT ANSWER-fixed firm

biological treatment process

Needs to be checked regularly to properly operate an activated sludge treatment plant -

CORRECT ANSWER-aeration equipment and mixed liquor solids

Point source discharges are - CORRECT ANSWER-discharges that come from

pipes or ditches that are monitored, controlled and inspected

Non-point discharges are - CORRECT ANSWER-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 - CORRECT ANSWER-setting stream standards, issues permits for

discharges, identifies non-point source controls, and establishes water reuse.

The wastewater plant operator is primarily responsible for - CORRECT

ANSWER-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 - CORRECT ANSWER-Chapter 26

and Texas Commission of Environmental Quality The Texas Commission on Environmental Quality can revoke an operator's license if

the operator - CORRECT ANSWER-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 - CORRECT

ANSWER-

Aerobic Bacteria require_____ in the water for their metabolism - CORRECT

ANSWER-oxygen

Anaerobic Bacteria _____ live with O2 present in the water for their metabolism -

CORRECT ANSWER-cannot

Facultative Bacteria require__________in the water for their metabolism -

CORRECT ANSWER-either aerobic or anaerobic conditions

Chemical characteristics of sewage include - CORRECT ANSWER-solids,

greases, dissolved oxygen, O2 Demand, pH, and gasses

_________removes Total Suspended Solids (TSS) - CORRECT ANSWER-

filtration

Inorganic solids include - CORRECT ANSWER-sand, grit and minerals

Organic solids include - CORRECT ANSWER-organic materials from plants,

animals or humans

A good plant influent pH is about - CORRECT ANSWER-7.

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.

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, acrylontrile 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, heaver 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 anareobic 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-

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 Effluent dosage of chlorine in the contact chamber must produce a total combined

residual of - CORRECT ANSWER-1.0 mg/L after 20 minutes

Besides disinfection, chlorine has other uses at the wastewater treatment plant such as

• CORRECT ANSWER-Reduces BOD, Odor, Algae growth, Helps with Grease

TCEQ allows the reuse of wastewater, some of these include - CORRECT

ANSWER-Irrigation, aquifer recharge, cooling towers and fire protection

All reclaimed water piping must be _______in color - CORRECT ANSWER-

purple

Before entering a manhole the operator should test for ________and oxygen levels and

________the manhole before entering. - CORRECT ANSWER-all hazardous

gasses and ventilate When a municipal wastewater effluent has a high nitrate level and low ammonia level

this most likely means - CORRECT ANSWER-the effluent has received a high

degree of aerobic treatment

Total solids in wastewater are the sum of - CORRECT ANSWER-Settleable and

volatile solids This treatment device is commonly used to separate and remove large solids from raw

wastewater - CORRECT ANSWER-A Mechanically raked bar screen

___________would have an adverse effect on the proper settling of solids in a clarifier.

• CORRECT ANSWER-A short circuiting flow pattern This test would give the best information on how efficiently a trickling filter was operating
• CORRECT ANSWER-Percent BOD Removal This trickling filter problem could be reduced by increasing the recirculation ratio -

CORRECT ANSWER-Filter files

What gases are produced by the controlled anaerobic digestion of wastewater sludge's -

CORRECT ANSWER-Methane & Carbon Dioxide

These diseases are caused by pathogenic organisms that may be present in raw

wastewater - CORRECT ANSWER-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 -

CORRECT ANSWER-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 - CORRECT ANSWER-Wear protective clothing and

avoid direct contact with waste water

_________will increase the chances that sewage will turn septic - CORRECT

ANSWER-Stoppages in the main line

Extensive use of garbage disposals (grinders) in a community would likely have the

following effect on the collection system - CORRECT ANSWER-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 - CORRECT ANSWER-6 inch and a grade of 0.50 percent

The most accurate way to find the average wastewater flow rate in an existing 10-inch

sewer main is - CORRECT ANSWER-Obtaining actual flow data & verifying with

field data 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 /

The typical pH of an influent entering the plant will vary from - CORRECT

ANSWER-6.5 to 8.

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

Zoogleal Mass refers to - CORRECT ANSWER-A thick layer of jelly like slime

where organisms bacteria, fungi, protozoa and ciliates thrive.

The efficiency of a trickling filter is measured in - CORRECT ANSWER-Percent

BOD Removed

Common operating problems with a trickling filter include - CORRECT

ANSWER-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 - CORRECT ANSWER-35 lbs

BOD/Acre/Day with a minimum of 30 days detention time Wastewater Stabilization Ponds work through a complex process which includes -

CORRECT ANSWER-Sunlight, Oxygen, Nutrients, Algae, and Bacteria

Facultative Lagoons have two zones of treatment - CORRECT ANSWER-an

aerobic surface layer and an anaerobic bottom layer Typically one could expect ____ % BOD removal in a Facultative Lagoon -

CORRECT ANSWER-

Aerated Lagoons rely on ______ to provide ____and _____ - CORRECT

ANSWER-Mechanical aeration/ Aeration & mixing

The most common method of dewatering and drying sludge is - CORRECT

ANSWER-drying bed

Digester gas typically contains about ________%_______ - CORRECT

ANSWER-65-75% methane

The depth of sludge drawn to a drying bed should be - CORRECT ANSWER-

Approximately 9 inches

Newly hired personnel have _________to become licensed. - CORRECT

ANSWER-1 year

Force Mains and fittings must have a pressure rating of at least - CORRECT

ANSWER-150 psi

Most pumping stations and electrical equipment used today in wastewater collection or

treatment is ________ and typically either _______ or _________ volts - CORRECT

ANSWER-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 - CORRECT ANSWER-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 _________. -

CORRECT ANSWER-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 - CORRECT ANSWER-90 to

99%

The Activated Sludge plant has five (5) Critical Components. They are - CORRECT

ANSWER-Oxygen supply, Aeration tanks, Clarifiers, Return & Waste

The Activated Sludge process is an ________process. - CORRECT ANSWER-

Aerobic 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-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 - 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 In the activated sludge plants, the operator will experience problems. Some common

Environmental problems include. - CORRECT ANSWER-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 - CORRECT ANSWER-Return activated sludge rate, Sludge

blanket thickness, & the Solids concentration of the return flow

The typical sludge age for extended aeration plants is - CORRECT ANSWER-

to 40 days In the activated sludge plant, good quality sludge will settle _________& _______ over

_________ minute period. - CORRECT ANSWER-Gently & Uniformly over 15 to

20 minutes In the activated sludge plant, old sludge quality will settle ________& _________ over

________ minute period. - CORRECT ANSWER-Rapidly and ragged over 5

minutes. In the activated sludge plant, there are (5) important nitroen transformation processes

that occur by microorganisms. They are- - CORRECT ANSWER-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 - CORRECT

ANSWER-Nitrogen

Denitrification occurs in an activated sludge system when there is __________ to

maintain the aerobic metabolism of the carbon stabilizing bacteria. - CORRECT

ANSWER-Insufficient Dissolved Oxygen

The lack of _________ triggers the facuitative bacteria to change from aerobic and

anaerobic - CORRECT ANSWER-Dissolved Oxygen

In the activated sludge system, "Hydraulic Wash Out" is - CORRECT ANSWER-

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 -

CORRECT ANSWER-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- - CORRECT ANSWER-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 - CORRECT

ANSWER-Plugged diffusers

In the activated sludge system, if the operator observes white thick billowing sudsy foam

on the aeration tank, the operator would suspect - CORRECT ANSWER-

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 -

CORRECT ANSWER-Leaks in the system piping, Plugged air diffusers & High

organic loading

The maximum safe withdrawal rate for a 150 lb chlorine cylinder is - CORRECT

ANSWER-40 lbs

To determine the approximate number of gallons per day being discharged to the

collection system, multiply the population by ____ gallons/person/day. - CORRECT

ANSWER-