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Wastewater Operations Level 1 Review
Major Points to Review
61
Environmental Studies
02/28/2013

Additional Environmental Studies Flashcards

 


 

Cards

Term
What are the three parts of a wastewater system?
Definition
  1. Collections: force mains, lift stations, and pumps
  2. Treatment Facilities: The actual plant where the processing of waste takes place.
  3. Discharge or Disposal: the pumps and infrastructure required to dispose of the treated water.
Term

What are the three types of wastewater collection systems?

 

Definition
  1. Storm Sewer : Carrying water from storm drains, run offs, roof drains, and drainage systems.
  2. Sanitary Sewer : carrying sewage from households, businesses, and  industries.
  3. Combines Sewer : Carrying both sanitary sewage and storm water.
Term
Ground Water that gets into a sewer system through cracks and bad joints is called :
Definition
INFLITRATION
Term
Water that leaks out of a sewer through cracks and bad joints is called :
Definition
EXFILTRATION
Term
Unwanted Water that is piped into a sewer system from roof drains and pool drains is called :
Definition
INFLOW
Term
The combination of  unwanted water getting into a sewer system through direct piping or bad joints and cracks is called :
Definition
I and I , Inflow and Infiltration
Term
The minimum flow through a gravity sewer system, when flowing full,   in ft. / sec.  is :
Definition
 2 ft. / sec., 2 fps
Term
How far apart are Manholes usually  spaced ?
Definition
300 to 500 feet
Term
What are the four types of pollution found in wastewater?
Definition
  1. Organic : waste matter, vegetable scraps, fats oils grease, leaves.
  2. Inorganic : sand , grit , plastics.
  3. Thermal : cold water from chillers and hot water from boilers drains and steam plants.
  4. Radioactive : waste from medical facilities, x ray dyes.
Term
Why treat wastewater?
Definition
Wastewater is treated to remove organic and inorganic wastes and to protect receiving waters from oxygen depletion and pathogenic organisms.
Term
What is a Pathogenic organism ?
Definition
A disease causing organism.
Term
  1. Cholera
  2. Typhoid
  3. Hepatitis
  4. Dysentery
  5. Cryptosporidium
  6. Giardia

The above are examples of :

 

 

Definition
Pathogenic Organisms
Term
Preliminary treatment includes :
Definition
Bar screens, racks and grit removal systems.
Term
What is a Parshall flume ?
Definition
A device for measuring flow through an open channel.
Term
Flow measurement should be done _________ to properly determine the quantity of waste being treated and adjustments can be made.
Definition
at the Influent of the plant
Term
Primary treatment is also referred to as :
Definition
Sedimentation
Term

Trickling filters, RBC's, and Aerated activated sludge are examples of :

 

Definition
Secondary Treatment
Term
Secondary treatment processes that require oxygen to operate properly are referred to as _______ processes.
Definition
Aerobic
Term

Air is supplied to the Mixed liquor in the activated sludge process for Two reasons :

 

Definition
  1. To supply oxygen to the microorganisms
  2. To bring the microorganisms into contact with the incoming food.
Term
With the exception of the Complete Mix process, all Activated Sludge processes are _____flow designs.
Definition

With the exception of the Complete Mix process, all Activated Sludge processes are _Plug_flow designs.

 

This means the flow runs from one end to the other as in a pipe. Complete mix systems in corporate flow and aeration to cause mixing through turbulance.

Term
Name the Two way air is supplied in the activated sludge process.
Definition

1)      Air is supplied in two ways:

a)      Mechanical aeration: using propellers or rotors to agitate the surface of the water to mix the air into the water.

b)      Diffused air: The use of blowers (either centrifugal or positive displacement) to supply the air through a series of air pipes (Headers) and perforated devices called diffusers.

Term
Name the three classifications of air diffusers.
Definition

1)      Diffusers can be classified by their bubble size;

a)      Fine bubble diffusers: Plate and tube or dome diffusers.

b)      Medium bubble diffusers: Porous nylon or Dacron socks or saran fiber glass wrapped tubes.

c)      Coarse bubble diffusers: are generally plastic tubes with holes in them or large bore duck bills. 

Term
How many pounds of DO is required to convert one pound of CBOD into CO2 and Water.
Definition

It takes about 1.5 lbs. of DO to convert 1 lb. of CBOD to CO2 and Water.

 

Term
How many pounds (lbs.) of DO does it take to convert one pound (lb.) of ammonia to nitrate?
Definition

      It takes approximately 4-5 pounds of D.O. to convert one pound  of ammonia to  nitrate.

Term
List Five test that can be used  as process control tests to control the activated sludge process.
Definition
  1.     MCRT= Mean Cell Residency Time, (SRT Sludge Retention Time), the average time a microorganism will spend in the activated sludge process, controlled by wasting.
  2.       F/M Ratio = Food to Microorganism ratio, measure the amount of food (CBOD) compared to the amount of microorganisms there is to consume it.
  3.       Sludge age (GSA Gould Sludge Age) = Measure of how old your sludge is. Controlled by wasting.
  4.       MLSS target mg/L = Keeping you MLSS mg/L at a specific range through wasting.
  5.       Settleometer ml/L= a measure of how well your sludge is settling. Controlled by D.O. and RAS and WAS flow control.
Term
Which is considered more accurate the MCRT calculation or the Sludge age calculation?
Definition

      Of the two, Sludge age and MCRT, MCRT is considered the most accurate.

Term
What is criteria is used to classify wastewater ponds?
Definition

    Ponds are classified by the type of treatment the water receives coming to the pond.

Term
Ponds receiving raw waste are called ____________.
Definition

    Ponds receiving raw waste are called Stabilization ponds.

Term
Ponds receiving water after primary treatment are called _____________.
Definition

     Ponds receiving water after primary treatment are called Oxidation ponds.

Term
Ponds receiving water after secondary treatment are called ____________________.
Definition

   Ponds receiving water after secondary treatment are called Tertiary treatment ponds.

Term
Wastewater Ponds can be categorized as one of these three types.
Definition

The three types of ponds are Aerobic, Anaerobic, and Facultative.

 

Term
What is an Aerobic pond?
Definition

   Aerobic Ponds = Having D.O. distributed throughout the pond.

     Air can be supplied by algae during the day or mechanical aeration.

Term
What is an Anaerobic pond?
Definition

    Anaerobic = Having no D.O. or oxygen present other than in chemical form, such as NO2 nitrite or NO3 nitrate.

   

Term
What is a Facultative pond?
Definition

      Facultative = Ponds that have a lower anaerobic zone and an upper aerobic zone.

Term
How many pounds of oxygen can a pound of algae produce on a good summers day?
Definition
One pound of algae can supply 1.6 pounds of Oxygen to a pond on good summer’s day.
Term
Define Disinfection?
Definition

     Disinfection is the process of killing or inactivating most microorganisms in water or wastewater.

Term
What is the difference between Disinfection and Sterilization?
Definition
Disinfection targets pathogenic microorganisms, while Sterilization kills all microorganisms.
Term
The three types of Disinfection commonly used in Wastewater Treatment are ?
Definition
  1.       Chlorination = the use of chlorine is the most widely used method of disinfection in water and wastewater.
  2.       UV ultraviolet light = the use of UV rays to damage the genetic material of microorganisms to make the unable to reproduce.
  3.       Ozonation = the use of O3 or Ozone, to disinfect water or wastewater.

 

Term
The main objective of disinfection is :
Definition

1)     Prevent the spread of Pathogenic Microorganisms and disease to:

a)      Public water supplies

b)      Receiving waters used for public recreation.

c)       Water used for shell fisheries.

Term
Chlorine comes in three forms, these are :
Definition

a)      Gas = 100 percent chlorine , a greenish yellow gas, highly toxic, it comes in 100 or 150 pound cylinders, one ton cylinders, and Rail Tankers to 90 tons.

b)      Calcium Hypochlorite = Granular and tablet form 65 to 75 percent chlorine.

c)      Sodium Hypochlorite = Bleach, industrial strength varies by manufacturer, usually 10-12 percent chlorine.

Term
How many parts per million of chlorine gas are detectable in the air?
Definition

    It is detectable at .08 ppm in the air.

Term
Chlorine gas in dangerous for long term exposure at what part per million in air?
Definition

     It is dangerous for long term exposure a 5 ppm in air.

Term
Chlorine gas is lethal at what part per million in the air?
Definition

    It is lethal at 1000 ppm in air.

Term
When changing a chlorine gas cylinder always use ______ and never ______.
Definition

      When changing a gas cylinder for chlorine it is important to use proper safety equipment and to never work alone.

Term
When you change a chlorine gas cylinder never reuse the _________.
Definition
When you change a chlorine gas cylinder never reuse the lead gasket. Always use a new gasket each time the valve yoke is loosened.
Term
List the three classifications of chlorine repair kits and the type cylinder they are used for.
Definition

1)      Repair kits are available for chlorine cylinders:

a)      “A” kit for 100 and 150 pound cylinders

b)      “B” kit for one ton cylinders

c)      “C” kit is for rail cars.

Term
True or False, Chlorine cylinders contain only gas.
Definition
False, chlorine cylinders contain liquid chlorine as well as gas.
Term
There are two valves on a one ton cylinder, they sholud be aligned ________ to the ground.
Definition

There are two valves on a one ton cylinder, they sholud be aligned perpendicular  to the ground.

 

↑      top valve

↓ bottom vlave

↔          ground

Term
The top valve on a ton cylinder dispenses ____ while the valve on the bottom dipenses _____.
Definition
The top valve on a ton cylinder dispenses GAS while the valve on the bottom dipenses LIQUID.
Term
Chlorine is a ________colored gas.
Definition
Chlorine is a  greenish yellow colored gas.
Term
Chlorine is ____ times _____ than air.
Definition
Chlorine is 2.5 times heavier than air.
Term
Chlorine liquid will expand into a gas at a rate of :
Definition

Chlorine liduid will expand at a rate of 460 to 1.

 

This means that 1 cc of liquid will expand to 460 cc of gas.

Term

Chlorine cylinders are equipped with fusible plugs to keep the cylinder from rupturing if exposed to  high heat.

At what temperature will the plugs melt?

Definition

   

       All cylinders are equipped with fusible plugs that will melt at 158oF to 165oF  to  

   prevent the tank from rupturing.

Term
What chemical vapor is used to check for chlorine leaks?
Definition

      To check for chlorine leaks ammonia is used, a small amount of ammonia vapor is squeezed near the valve and fittings, if a white cloud appears then there is a chlorine leak.

Term
What are the two types of sludge digestion?
Definition

     Sludge digestion can take place either anaerobically or aerobically.

Term
Anaerobic digesters can have either a ______ or _______ lid.
Definition
Anaerobic digesters can have either a fixed or floating lid.
Term
The most important process control for anaerobic digestinon is ?
Definition

Volatile Acid to Alkalinity ratio is the most imprtant tool used as a process control.

The pH is improtant for Methane Fermenter health, but by the time the pH has risen or dropped the process is already in upset.

Term

Methane fermenters require a very specific pH range to operate properly.

That range is ?

Definition

    Methane fermenters are very particular about their pH requirements the range they function best at is between       6.8 -7.2.

Term

There are three types of bacteria that require specific temperature ranges to function.

What are they and at what temperature ranges do they function?

Definition

1)      These bacteria  also need specific temperature ranges.

a)  Psychrophilic bacteria = like cold temperature to 68oF

b)  Mesophilic bacteria = like temperatures between 68oF and 112oF, But prefer 85oF to 100oF, with the best temperature at 95oF. Most Anaerobic digesters operate in this area.

c) Thermophilic bacteria = like very high temperatures in the 120oF to 135oF range.

        

Term
The flame on the after burner of an anaerobic digester will burn what color if the process is working properly?
Definition

      The flame on the afterburner should be Blue to indicate good Methane production, Orange flame is indication of excess CO2.

Term
What are the two main disadvatages of an anaerobic digestion system?
Definition
High energy and safety cost are the main disadvantages of anaerobic digestion.