Operation Of Wastewater Treatment Plants

Front 1

Wastewater should be sterilized because it is necessary and practical.

Back 1

False

Front 2

The reaction of chlorine gas in waste water tends to decrease the pH, while the reaction of hypochlorite in waste water increases the pH.

Back 2

True

Front 3

Free available chlorine has the highest disinfecting action of any form of chlorine.

Back 3

True

Front 4

The rise in pH caused by hypochlorination will decrease the disinfection effectiveness of the hypochlorite, thereby requiring a higher dosage.

Back 4

True

Front 5

Mixing of the chlorine solution with waste water as well as the speed of mixing are extremely important ahead of a chlorine contact tank or a residual sampling point.

Back 5

True

Front 6

When something abnormal is observed in a chlorination system, corrective action must be taken.

Back 6

True

Front 7

There must be funding to purchase safety equipment and to enforce safety regulations required by OSHA and industrial safety programs.

Back 7

True

Front 8

Chlorine ton tanks may be stacked for storage.

Back 8

False

Front 9

In case of a liquid chlorine leak, the container should be rotated so leaking chlorine escapes as a liquid rather than as a gas.

Back 9

False

Front 10

Before any new chlorine system is put into service, it should be cleaned, dried, and tested for leaks.

Back 10

True

Front 11

Hypochlorination systems consist of a water meter and a diaphragm metering pump.

Back 11

True

Front 12

Sodium chlorite is usually supplied to plants as a salt and is very combustible around organic compounds.

Back 12

True

Front 13

Chlorination is the physical or chemical removal of all traces of residual chlorine remaining after the disinfection process.

Back 13

False

Front 14

Always wash your hands thououghly after handling sulfur dioxide.

Back 14

True

Front 15

The sulfonator vacuum is regulated by an orifice opening and the water flowing through the throat of the aspirator.

Back 15

True

Front 16

Chlorinators used as sulfonators can deliver the full rated capacity of sulfur dioxide.

Back 16

False

Front 17

As flow increases or transmission reduces, the ultraviolet (UV) dose will be reduced.

Back 17

True

Front 18

What is the purpose of disinfection?

Back 18

To destroy pathogenic micro organisms and thus prevent the spread of waterborne diseases.

Front 19

What is chlorine demand?

Back 19

Difference between the amount of chlorine added to wastewater and the amount of residual chlorine remaining after a given contact time.

Front 20

Where is the most effective place for chlorine application for disinfection?

Back 20

After treatment and on a well-clarified effluent.

Front 21

What happens if moisture in the air enters a chlorination system?

Back 21

The moisture readily mixes with chlorine and forms bydrochloric acid, which will corrode the pipes, valves, joints and fittings.

Front 22

What is break point chlorination?

Back 22

The amount of chlorine that is needed for a particular purpose.

Front 23

What is combined available chlorine?

Back 23

The total chlorine, present as chloramine or other derivatives, that is present in a water and is still available for disinfection and for oxidation of organic matter.

Front 24

What could happen if chlorine comes in contact with the seat on your body?

Back 24

The chlorine could form hydrochloric acid.

Front 25

Why should water never by put on a chlorine leak?

Back 25

A mixture of water and chlorine will increase the rate of corrosion of the container and make the leak larger.

Front 26

How can an operator repair pinhole leaks in the walls of a chlorine cylinder?

Back 26

By using a clamping pressure saddle with a turnbuckle available in repair kits.

Front 27

What should an operator do if a chlorine container is delivered to the plant showing evidence of leaking, stripped threads, or abuse of any kind?

Back 27

Refuse delivery.

Front 28

What is the purpose of a chlorinator injector water supply?

Back 28

To provide a source of water for the chlorine solution.

Front 29

What are hypochlorinators?

Back 29

Chlorine pumps or devices used to feed chlorine solutions made from hypochlorites on site.

Front 30

When chlorination is practiced for disinfection, why must the chlorine facilities provide continuity of chlorination?

Back 30

For the protection of downstream water users.

Front 31

Why are treatment plant effluents dechlorinated?

Back 31

To protect receiving waters from toxic substances.

Front 32

Why should soapy water never be used to look for a sulfur dioxide leak?

Back 32

The soapy water combines with sulfur dioxide to form sulfuric acid, which is very corrosive and will make any leak worse.

Front 33

Why must the residual sulfur dioxide in plant effluent be measured?

Back 33

To be sure the sulfonator is not overdosing and wasting sulfur dioxide.

Front 34

What happens when ultraviolet (UV) radiation is absorbed by the cells of micro organisms?

Back 34

The UV radiation damages the genetic material in such a way that the organisms are no longer able to grow or reproduce.

Front 35

The ultra violet (UV) light intensity that reaches the pathogens in the water being disinfected is affected by which factors?

Back 35

The condition of the UV lamps and the quality of the waste water.

Front 36

Why must the flow velocity past the ultraviolet (UV) lights be controlled?

Back 36

So that the waste water is exposed to UV radiation long enough for the desired level of disinfection to occur.

Front 37

Which types of illnesses may be transmitted by waste water to operators during on the job activities?

Back 37

Cryptosporidiosis

Giardiasis

Infectious hepatitis

Front 38

Since chlorine is very reactive, it is often used up before disinfection takes place by side reactions with which types of substances?

Back 38

Ferrous iron

Hydrogen sulfide

Front 39

What are the possible benefits of upsewer chlorination?

Back 39

BOD reduction to decrease the load on waste water treatment processes.

Odor control

Septicity control

To prevent the deterioration of structures

Front 40

Why might pre-chlorination be applied at a waste water treatment plant?

Back 40

For corrosion control

For grease removal

For odor control

To aid sedimentation

To reduce plant BOD load

Front 41

Which factors make hypochlorite use cost effective in smaller plants?

Back 41

Application equipment costs are lower.

Safety costs are lower

Storage costs are lower

Training costs for hypochlorite usage are lower.

Useful chlorine concentration in hypochlorite compounds is lower.

Front 42

Before starting any chlorination system, operators should perform which tasks?

Back 42

Determine what equipment, pipelines, pumps, tanks, and valves are to be placed into service or are in service. Read the manufacturers literature to become familiar with the equipment. Read the plants operation and maintenance (O & M) manual. Review the plans or drawings of the facility.

Front 43

Which tasks should be performed daily on chlorinators, including injectors?

Back 43

check the chlorinator vacuum, Check the injector water supply pressure, inspect the system for chlorine leaks, measure the chlorine residual at eh application point and read the chlorinator feed rate on the rotameter tube.

Front 44

Which items are abnormal chlorinator conditions?

Back 44

Chlorne gas pressure is too low,

Chlorine leak in the chlorinator.

Chlorine residual is low

Chlorine usage is high

Injector vacuum is too low.

Front 45

When trouble shooting a chlorination system, what could be a probable cause of a breadout (breakaway) of chlorine?

Back 45

Excess mixing

Inadequate diffuser submergence

Inadequate mixing

Insufficient injector water flow

overfeeding chlorine

Front 46

Periodic hands on training on the use and maintenance of safety equipment should include what equipment?

Back 46

Atmospheric monitoring devices

Leak detection equipment

Leak repair equipment

Respiratory protective equipment

Front 47

Which items should be examined when reviewing plans and specifications for chlorine facilities?

Back 47

Ample working space around the equipment and storage space for spare parts should be provided.

Chlorinators should be located as near the point of application as possible.

The building should be adequately heated.

There should be a separate room for chlorinators and chlorine container storage (above ground) to prevent chlorine gas leaks from damaging equipment and harming personnel.

Front 48

Chlorine valves consist of which types of valves?

Back 48

Auxiliary tank valves for use at the container.

Header valves for use on or in conjunction with manifolds.

Line valves for insertion in liquid and gas lines for shut off purposes.

Pressure reducing valves to reduce the pressure in gas lines where necessary.

Front 49

Which items are problems of hydrogen sulfide?

Back 49

Breathing hydrogen sulfide can impair your ability to smell and too much will paralyze your respiratory center.

Causes corrosion of metals and concrete.

Explosion hazard when mixed with air in certain concentrations.

Odor nuisance.

Front 50

Which items could cause a sulfur dioxide leak?

Back 50

Broken lines

Broken sight glass

Leaking joints

Front 51

If sulfur dioxide or solium sulfite gets on the skin, which items are recommended first-aid responses?

Back 51

If a burn has occurred, transport the injured person to a doctor for treatment and care.

Remove any clothing that has been contaminated.

Wash off immediately with large amounts of water.

Front 52

Which precautions must be exercised when handling and storing sodium sulfite tablets used for dechlorination?

Back 52

Flood with water in case of fire.

Flush away small spills of dust or powder with water.

Keep tablets dry in a tightly closed container when not in use.

Shovel up spilled material for disposal in accordance with directions on the Material Safety Data sheet (MSDS)

Store tablets in a cool, dry place, away from acids or oxidizers.

Front 53

Which items are possible symptoms of trouble in the operation of a gas sulfonator system?

Back 53

Freezing of the rotameter.

Leaking joints.

Low injector vacuum reading

Sulfonator not feeding.

Sulfonator not reaching maximum output.

Front 54

Maintenance of sulfur dioxide systems involves maintenance in which areas?

Back 54

Evaporator, Piping, Sulfonator and Supply area.

Front 55

Maintenance in the supply area of a sulfur dioxide system includes which tasks?

Back 55

A record of all maintenance and repairs.

All lifting devices such as hand trucks and hoists should be properly maintained.

The area should be kept clean and free of unused objects.

The ventilation system should be periodically inspected for proper operation.

Front 56

The ultraviolet (UV) channel water level control device must be regulated by the operator to achieve which objectives?

Back 56

Keep the UV lamps submerged at all times.

Maintain the channel's water level at a defined level.

Minimize variation of the channel's water level.

Prevent excessive water layer thickness above the top lamp row.

Front 57

Which items are preliminary steps for shutdown or startup of the ultrviolet (UV) disinfection process units and equipment?

Back 57

Check Switches,

Clean Units,

Plan ahead,

Prepare equipment

Set controls