Wastewater Engineering 2 Flashcards
It is the modification of of conventional plug-flow process
Tapered Aeration
Settled wastewater is introduced at several points in the aeration tank to equalize Food:Microbe ration, thus lowering the peak oxygen demand and peak hydraulic loads
Step Aeration
Identical with conventional or tapered aeration, but uses shorter aeration times (1.5 to 4 hours) and higher F:M ratios are used
Modified Aeration
Uses two separate tanks or compartments for the treatment of ww and stabilization of the activated sludge
Contact Stabilization
Process is used extensively for prefabricated package plants for small communities. No primary sedimentation
Extended Aeration
Process modification in which high MLSS concentrations are combined w/ high volumetric loadings. Uses turbine mixers for adequate mixing in the reactor
High Rate Aeration
It is an extended aeration process consists of a ring or oval shaped channel and is equipped w/ mechanical aeration devices
Oxidation Ditch (Racing Track)
Aerating the supernatant from the sludge digesters, digested sludge and a portion of RAS in a separate reaeration tank approx 24 hrs converting NH3 to NO3
Krauss Process
Vertically mounted mechanical aerators are used to impart oxygen and to provide sufficient horizontal velocity to the liquids to prevent settling of solids in aeration channel
Carroussel Process
Pure oxygen is used as a substitute for air in the activated sludge process
High purity oxygen
It is a “fill and draw” activated sludge process for wastewater treatment system. In this system, wastewater is added in single “batch” reactor, treated to removed undesirable components and then discharged
Sequential Batch Reactor (SBR)
Utilizes a solid medium on which bacterial solids are accumulated in order to maintain a high population
Attached Growth Process
They are no longer used by large communities because of the extensive area required
Intermittent Sand Filter
Consist if a bed of highly permeable media to w/c are attached and through w/c wastewater is percolated or trickled
Trickling Filter
It is used for loadings less than 40 kg BOD5 / m3 per day
Low rate filters
It is used for loadings up to 50 BOD5 / 100 m3 per day
Intermediate-rate Filters
Used for loadings up to 480 kg BOD5 / m3 per day
High rate filters
it is used for loadings more than 160 BOD5 / 100m3 per day
Roughing Filters
the surface of the disk is covered with a biological slime similar to that on the media of a trickling filter
Rotating Biological Contractors (RBC)
In a fixed-bed reactor the catalyst pellets are held in place and do not move with respect to a fixed reference frame
Packed bed reactor
The solids formed when microorganisms are used to treat wastewater. it includes organisms, accumulated food materials, and waste products from the aerobic decomposition process
Activated Sludge
It is to produce an extremely high quality discharge
Advanced waste Treatment
The only source of oxygen is combined oxygen is combined oxygen such as that found in nitrate compounds
Anoxic
Solid organic matter recovered from a sewage treatment process and used especially as fertilizer
Biosolids
A substance or solution which resists changes in pH
Buffer
The theoretical time water remains in a tank at a given flow rate
Detention time
The removal or separation of a portion of water present in a sludge or slurry
Dewatering
The monthly report required by the treatment plant’s National Pollutant Discharge Elimination System (NPDES) discharge permit
Discharge Monitor Report
An activated sludge process control calculation based upon the amount of food available per pound of mixed liquor volatile suspended solids
Food-to-microorganism ratio
Heavy inorganic solids such as sand, gravel, egg shells, or metal fillings
Grit
Water discharged from cellar and foundation drains, cooling water discharges, and drains from springs and swampy areas
Steady Inflow
Those types of inflow that have a direct stormwater runoff connection to the sanitary sewer and cause an almost immediate increase in wastewater flows
Direct flow
Mineral materials such as salt, ferric chloride, or treatment process
Inorganic
A certificate issued by the state board of waterworks or wastewater works operators authorizing the holder to perform the duties of a wastewater treatment plant operator
License
The average length of time a mixed liquor suspended solids particle remains in the activated sludge process
Mean Cell Residence Time
The combination of return activated sludge and wastewater in the aeration tank
Mixed Liquor
the suspended solids concentration of the mixed liquor
Mixed Liquor Suspended Solids
The concentration of organic matter in the mixed liquor suspended solids
Mixed Liquor Volatile Suspended Solids
The amount of oxygen required to biologically oxidize nitrogen compounds under specified conditions of time and temperature
Nitrogenous oxygen Demand
Substances required to support living organisms
Nutrients
The concentration of suspended solids in the sludge flow being returned from the settling tank to the head of the aeration tank
Return Activated Sludge Solids
A device to measure wastewater flow
Weir
It includes the availability if substrates and nutrients
Nutritional Factors
It includes pH, temperature, and response to free molecular oxygen
Physical factors
Acid loving organisms grow at pH values lower than 5.4
Acidophiles
Grow at pH values 5.4 to 8.5
Neutrophiles
Grow at pH values from 7 to 11.5
Alkalinophiles
With increasing sludge age, the necessary cellular compounds needed to stick together or agglutinate
Floc-forming Bacteria
These are motile or gliding filamentous organisms in the activated sludge process that contribute to settleability problems
Gliding Bacteria
The feed upon dead organic matter
Saprophytic Bacteria
Consist of a chain of gram-negative cells that are surrounded by a transparent tube
Sheath Bacteria
Miroorganism in the activated sludge process use oxygen as they consume the substrate. The rate st which use oxygen
Oxygen Uptake Rate
The combination of OUR with MLVSS
Specific Oxygen Uptake Rate
A balance between floc-forming and filamentous bacteria results in strong flocs that keep their integrity in the aeration basin and settle well in the sedimentation tank
Normal Flocs
It is the most predominate form of bulking that occurs and is caused by the growth of filamentous organisms or organisms that can grow in a filamentous form under adverse conditions
Filamentous Bulking
It is a white or a colorless filamentous organism and is associated more commonly with fixed film system processes
Beggiatoa
View the mixed liquor under the microscope to determine what type of microbial growth changes or floc structure changes can be related to the development of bulking sludge
Process Control
It is caused by an excessive amount of extracellular biopolymer, which produces a sludge with a slimy jellylike consistency
Viscous Bulking
Light fluffy sludge particles, small, almost transparent, very fluffy, buoyant solids particles
Straggler Floc
It is the condition describing a buildup of foam or froth on the surface of the aeration tank
Foaming/Frothing
A type of foam that has moderate amounts of crisp, white foam are usually associated with activated sludge processes producing an excellent final effluent
Fresh, crisp, white foam
A type of foam that indicates an old sludge that is overoxidized, has a high mixed liquor concentration and has a waste rate that is too high
Thick, greasy, dark tan foam
A type of foam that has a large amounts of a white, soap suds-like foam indicate a very young, underoxidized sludge
White Billowing Foam
A group of filamentous, fungus like bacteria, gram positive and spore forming bacteria
Acinomycetes
It is a relatively shallow body of water contained in an earthen basin of controlled shape, for the purpose of treating wastewater
Stabilization Ponds or Lagoons
Shallow pond less than 1 m in depth, where dissolved oxygen is maintained throughout the entire depth by the action of photosynthesis
Aerobic ponds
Deep ponds that receive high organic loading such that anaerobic conditions prevail and surface reaeration
Anaerobic Ponds
The two dominant biological reactions
Acid formation and Methane Fermentation
It is used to combat these odor
Sodium Nitrate and Grease Crusts
the 2 types of facutative ponds
Primary facultative ponds and Secondary facultative ponds
The type of facultative pond that receive settled wastewater
Secondary Facultative Ponds
The type of facultative pond that receive raw wastewater
Primary Facultative Ponds
1 to 2.5 m deep which have an anaerobic lower zone facultative middle zone and aerobic upper zone maintained by photosynthesis and surface reaeration
Facultative Ponds
It is known as finishing or polishing ponds since they are used for polishing effluents fromother biological processes
Maturation or Tertiary Ponds
Ponds oxygenated through the action of surface or diffuses air aeration
Aerated Lagoons
Artificially created water bodies
Constructed Wetlands
Composed of a network of sewer pipes, conduits, tunnels, structures, devices, equipment and appurtenances for the collection, transportation and pumping wastewater
Wastewater Collection system
A pipe or conduit, generally closed, but normally not flowing full, when carries sewage
Sewer
The entire system used for collection, treatment and disposal of wastewater. This includes pipes, manholes, and all structures used for the above mentioned purposes
Sewerage
Serves all abutting properties
Common sewer
Pipe conveying wastewater from an individual structure to a common sewer rot other point of disposal
House sewer
No tributary flow except from house sewer
Lateral sewer
Carries discharge from two or more laterals
Sub-main sewer
Collects flow from several sub-mains as well as laterals and house sewers
Main/trunk sewer
it’s for combined sewers
Intercepting sewer
It receives discharges from all collecting system and conveys it to the point of final
Outfall sewer
Water which is unaccounted for in the usage of the clients
Loss and waste
Transport wastewater by gravity along a downward sloping pipe
Gravity sewer
Transport wastewater by pressure through pumps
Pressurized sewers
Uses the differential pressure between atmospheric pressure and a partial vacuum maintained in the piping network and vacuum station collection vessel.
Vacuum sewers
Using unit values for plumbing fixtures
Fixture unit flow
Using population of a community to determine the flow rate
Average per capita flow
Using the peak flow for the process of activity involved
Industrial wastewater flow
A device meant to admit the storm water or surface wash and convey it into a storm sewer or a combined sewer
Inlets
A special type of inlet in which a basin is provided which allows grit, sand and debris flowing in with storm water settle out
Catch basin
Located at the junction of sewers and changes in grades, sizes or alignment
Manhole
The one which are about 0.75 to 0.9m I depth; Type of manhole
Shallow manholes
Those which are about 1.5 m in depth; Type of manhole
Normal manholes
Deeper than 1.5 m; Type of manhole
Deep manholes
A special type of manhole on a sewer line which is constructed to provide a connection between a high level branch sewer to a low level main sewer
Drop manholes
Special openings, constructed to join a hole in the sewer and the ground for the purpose of lowering a lamp inside a sewer
Lamp hole
Holds water and then throws it into sewer for the purpose of flushing it
Flushing tanks
To exclude grease and oil from sewage before they enter the sewer line
Grease and oil traps
Sewer lines dips below the hydraulic grade line
Inverted siphon
Barrier of earth or concrete erected between the watercourse and property to be protected
Leeves and floodwalls
Reduce flooding by temporarily storing flood waters behind dams or in storage or detention basins
Reservoirs and detention
New channel that sends floodwaters to a different location
Diversion
Excavation activity usually carried out underwater, in shallow seas or freshwater areas w/ the purpose of gathering up bottom sediments and widening
Dredging
Method of river engineering that widens or deepens rivers to increase the capacity for flow volume at specific sections of the rivers
Channelization
Revised Effluent Regulations of 1990
DAO35
Protected waters cause it requires disinfection to meet requirements
Class AA
Could be drinkable but requires complete treatment
Class A
ntended for primary contact
Class B
for fishery, boating activities or agriculture
Class C
navigable waters
Class D
