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Sewage Exam 4
| Question | Answer |
|---|---|
| List five contaminants that are removed from sewage in wastewater treatment? | Solids; BOD; nutrients (nitrogen and phosphorus); pathogenic microorganisms; and harmful chemicals |
| This part of the process is necessary to ensure that large objects or grit do not damage piping or equipment in the treatment facility? | Preliminary treatment |
| It is the part of the process where sewage entering a WWTP initially passes through a series of devices designed to remove or reduce in size the large solids, greases, scum and grit present in the water? | Preliminary treatment |
| This part of the process uses coarse screens (bar screen), or uses chopping or shredding devices in a process commonly known as comminution? | Preliminary treatment |
| This part of the process removes grit such as sand, eggshells, stones and gravel in grit channels or chambers? | Preliminary treatment |
| The purpose of this stage in the process is to remove large settleable and floatable materials? | Primary treatment |
| In this part of the process, sewage flows to settling basins (primary clarifier) where the flow velocity is slowed so that solids settle or float to the surface? | Primary treatment |
| This part of the sewage treatment process removes dissolved or un-settleable impurities, such as BOD and suspended solids? | Secondary treatment |
| This part of the sewage treatment process includes the activated sludge process, Sequencing Batch Reactor (SBR), Trickling Filters, Rotating Biological Contactors (RBC), Moving Bed Biological Reactor (MBBR), or aerated lagoons? | Secondary treatment |
| Regardless of the methods used in this stage of the sewage treatment process, it is a method that depends upon the action of aerobic bacteria to breakdown the solids and BOD? | Secondary treatment |
| This part of the sewage treatment process utilizes both physical and biological processes, regardless of method used to process waste? | Secondary treatment |
| It is the part of the treatment process which is utilized to further treat the wastewater following secondary treatment? | Tertiary treatment |
| It is the part of the treatment process that mostly involves physical and chemical processes to remove specific types of waste? | Tertiary treatment |
| It is the part of the treatment process that uses chemical precipitation, reverse osmosis, carbon adsorption, filtration, and membrane filtration in order to treat sewage effluent? | Tertiary treatment |
| Describe at least two key variables that are being manipulated in wastewater treatment processes? | Oxygen and bacteria |
| The prime objective of this treatment stage is to “stabilize” the sludge so that there is a low oxygen demand? | Sludge treatment |
| The two most common methods used for sludge treatment are? | Aerobic and anaerobic digestion |
| This type of digester breaks down the solids in the sludge which produces methane gas, carbon dioxide and inert solids? | Anaerobic digester |
| As the “food” runs out in this type of digester, the microorganisms will use their own stored body mass for energy, resulting in a stable final product? | Aerobic digesters |
| Which is the most common secondary treatment process used in Ontario? | Activated sludge |
| Describe one key way that a Sequencing Batch Reactor (SBR) is operated differently than a conventional activated sludge system? | SBR’s are time-oriented batch systems rather than continuous flow through tanks |
| The microorganisms responsible for treatment of wastewater are attached to some inert material (instead of being held in suspension). This is known as? | The “attached-growth” principle |
| Trickling Filters; Rotating Biological Contractor (RBC); Moving Bed Biological Reactor (MBBR); and Membrane Biological Reactor (MBR) are specifically based on this? | The “attached-growth” principle |
| This process is used to remove water from sludge? | Dewatering |
| Chemicals are often added to the sludge in order to assist with this specific treatment process? | Sludge dewatering |
| Vacuum filtering, centrifuging, pressing, or drying beds are common methods of? | Dewatering sludge |
| These are used in many smaller communities within Ontario that do not use a conventional activated sludge process? | Lagoons |
| This uses physical and biological processes which occur naturally in ponds to treat wastewater? | Lagoons |
| Solids settle to the bottom while algae and bacteria process dissolved organic particles. This describes? | A lagoon |
| This combines the features of aerobic and anaerobic lagoons, which is a relatively deep pond in which the upper layer of water is aerobic in the lower layer is anaerobic? | Facultative lagoon |
| What are the three ways in which wastewater is disinfected before being released into the environment? | Chlorination in a contact chamber, ozone and UV |
| These transport potentially hazardous materials in a safe manner through sanitary sewers for treatment and disposal? | Wastewater collection systems |
| This occurs when a sewer is hydraulically overloaded (i.e. too much wastewater is trying to flow through a sewer) resulting in sewage backing up the collection system? | Sewer surcharge |
| This can result in the flooding of basements or the release of sewage through maintenance access points onto roads? | Sewer surcharge |
| This is caused by the inflow of surface water into sewers and the infiltration of groundwater through cracks in the sewer wall? | Sewer surcharge |
| This is a serious problem resulting in the collection and treatment of much larger volumes of water (sewer surcharge) than is necessary? | Infiltration of groundwater |
| The buildup of organic materials in the sewers may result in the production of? | Hydrogen sulfide and other potentially dangerous gases |
| Unpleasant odours or the cause of corrosion of sewer lines is caused by? | Hydrogen sulfide and other potentially dangerous gases |
| In this wastewater collection system, sewage flows by gravity and is well suited for areas of low to moderate relief? | Septic tank effluent gravity system |
| This wastewater collection system is a pressurized system using pumps to pump effluent? | Septic tank effluent pump system |
| This wastewater collection system collects sewage that is ground by grinder pump and then discharged to a low pressure sewer system? | Grinder pump system |
| This wastewater collection system uses the suction of a vacuum to draw and transport wastewater? | Vacuum sewer system |
| The settled and floating material skimmed from the surface of the primary settling basins (primary clarifier) is collected and pumped to where? | Sludge handling facilities |
| This process is a physical process since it relies on gravity to separate settleable materials from the liquid, in addition to skimming floating material from the surface? | Primary treatment |
| When the wastewater reaches this stage of the treatment process, it still contains a large amount of dissolved or un-settleable impurities? | Secondary treatment |
| In this stage of the treatment process, partially treated effluent is routed to aeration tanks where it is mixed with bacterial mass known as activated sludge in order to further achieve a higher quality of effluent? | Secondary treatment |
| It is bacteria mass that is also known as biomass? | Activated sludge |
| This stage of the treatment process utilizes aerobic microorganisms which require dissolved oxygen to survive, and consequently air must be added in the waste material? | Secondary treatment |
| In this stage of the treatment process, the dissolved oxygen level must be monitored carefully since the microorganisms are sensitive to drops in the dissolved oxygen? | Secondary treatment |
| It is a mixture of wastewater and microorganisms, and it is known as? | Mixed liquor |
| It is where the activated sludge and other suspended material settle out? | Secondary clarifiers |
| It is part of the settled material that is returned to the aeration basin to maintain the mass of activated sludge? | Return activated sludge (RAS) |
| It is part of the settled material that is sent to the sludge handling facilities? | Waste activated sludge (WAS) |
| After the secondary clarifier the wastewater will be___? | Disinfected |
| The most common method of disinfection is___? | Chlorination |
| After secondary treatment the wastewater can be managed in two ways. What are they? | Disinfected and discharged into the environment or processed through tertiary treatment |
| This part of the process typically removes 80-99% of the BOD and suspended solids? | Secondary treatment |
| The primary objective of this part of the treatment process is intended to stabilize the sludge so that there is a low oxygen demand? | Sludge digestion |
| During the treatment process ___, will be created which must be further treated before final disposal? | Sludges |
| This is one of the more common methods of stabilizing the sludge that has settled in the primary and secondary clarifiers? | Anaerobic digestion |
| Primary treatment is not required when? | Waste is sent directly to a lagoon |
| This type of lagoon is shallow (around 3 feet) and has a high concentration of dissolved oxygen? | Aerobic lagoon |
| This type of lagoon is often used for high BOD loads, where the necessary area required for conventional lagoons is not available? | Aerated lagoons |
| In this type of lagoon aerators are used to increase the oxygen content of the lagoon in order to maximize aerobic bacterial action? | Aerated lagoon |
| Unlike other lagoons, this type of lagoon does not require a long retention time and may be operated with a continuous flow of wastewater? | Aerated lagoon |
| Some of these require a long retention time of wastewater, and thereby requiring discharge of wastewater on a seasonal basis? | Aerobic and anaerobic lagoons |
| In this type of lagoon, algae will use the energy from the sun to convert the wastewater nutrients into cellular mass? | Facultative lagoon |
| In this type of lagoon, dead algae cellular mass settles to the anaerobic zone where anaerobic bacteria break down the cellular mass into methane, organic acids, hydrogen sulfide and carbon dioxide? | Facultative lagoon |
| This wastewater treatment procedure can provide an economical alternative to conventional treatment, but it requires a large area of land and is less effective during the winter months? | Wastewater lagoons |
| If there is more than one lagoon in use, they can either be operated in two manners? | Parallel/series |
| It is a term that defines when several lagoons are operated independently? | Operated in parallel |
| It is a term that defines when several lagoons are operated in a manner whereby wastewater successively flows through several ponds before being discharged? | Operated in series |
| The connection point from a home/industry into a lateral or branch sewer is called? | Service connection |
| This will transport waste from the branch sewers to the larger trunk sewers? | Main sewers |
| When gravity cannot convey wastewater effectively, the wastewater is raised to a higher elevation using this type of wastewater collection facility? | Lift station |
| This type of wastewater collection facility normally contains two pumps and an alternative source of power? | Lift station |
| Without constant pumping ability in a lift station, wastewater may back up the sewer resulting in? | Flooded basements |
| It is a pressurized pipe in which wastewater is pumped from a lift station to a treatment facility or to an elevated gravity sewer? | Forcemain |
| List four methods of cleaning sewers? | High velocity jet cleaners, flushing, power rodders, or bucket machines |
| This type of pump should normally be started with the outlet closed? | Centrifugal pump |
| Radial vane, Francis vane, mixed flow and axial flow are what type of pump? | Centrifugal pump |
| This type of pump operates by pressurizing water in order to “throw it” at high speeds? | Centrifugal pump |
| This type of pump operates by “pushing” a fluid mechanically? | Positive displacement pump |
| This type of pump is normally started with the suction valve and discharge valve open? | Positive displacement pump |
| Screw, gear, piston, diaphragm and progressive cavity are what type of pump? | Positive displacement pump |
| This type of pump seal uses smooth contact surfaces to seal the fluid? | Mechanical seal |
| This is caused by a drop in pressure or negative mains pressure? | Siphonic backflow |
| This may be defined as any space to which exit by an injured person would be difficult? | Confined space |
| In wastewater treatment, temporarily diverting waste water around treatment processes is called? | Bypass event |
| This product can be used to detect leaks of chlorine gas, which when passed below the leak produces a white smoke? | Commercial ammonia |
| Alternative methods of disinfection, in order to avoid disinfection byproducts, include these three methods? | Ultraviolet light, ozone and chlorine dioxide |
| In wastewater treatment, this type of treatment is present in all municipal wastewater treatment facilities, no matter what other treatment processes are used? | Preliminary treatment |
| In wastewater treatment, this stage of the treatment process removes 30 to 40% of the BOD and 40 to 60% of the suspended solids? | Primary treatment |
| In wastewater treatment, this process is a physical process since it relies on gravity to separate large settleable materials from the liquid, including greases that float in surface? | Primary treatment |
| In wastewater treatment, the wastewater in this stage still contains a large amount of dissolved or un-settleable impurities? | Secondary treatment |
| This process stage removes 80 to 99% of the BOD and suspended solids? | Secondary treatment |
| It is the treatment stage which is intended to stabilize the sludge that is produced during the treatment process? | Sludge digestion |
| This sludge digestion method is where raw sludge is held for several weeks as part of the stabilization process? | Anaerobic sludge digester |
| Once sludge is stabilized in the sludge digestion process, what is the next treatment step? | Dewatering |
Created by:
Ironhawk893