Wastewater Engineering 1 Flashcards
Branch of engineering with the transportation and cleaning of sewage or consumed water
Wastewater Engineering
Introduction of a substance to the environment leading to a lost beneficial use of resource
Pollution
Mass flux of a pollutant
Load
control of pollution from human activity
Water quality management
Revised water usage and classification
dao 34
For maintaining the quality of Philippine waters
Water usage and classification
Identifiable sources of pollution
Point source
Multiple pollution sources
Non-point source
Consumed water
Sewage/Wastewater
Raw wastewater coming into a treatment plant
Influent
Treated water discharged from a wastewater treatment plant
Effluent
Sanitary conveniences of dwelling, residential, commercial, institutional and similar facilities
Domestic wastewater
Wastewater that comes from industries that contain high strength waste
Industrial wastewater
Liquid flowing in sewers during or after rainfall
Storm sewage
Consists of a combination of sanitary wastewater and storm water runoff
Combined wastewater
Water discharged into a sewer pipes or service pipes
Inflow
Groundwater entering sewers through broken joints and/or broken pipes
Infiltration
Sum of direct inflow at any point in the system plus any flow discharged
Total inflow
Stormwater that may require several days or more to drain thru the sewer system
Delayed inflow
Consumed water in kitchen, bathroom and laundry
Greywater
Feces and urine
Black water
Urine separated from black water
Yellow water
Black water without yellow water
Brown water
BOD range for domestic
300-500 mg/L
TSS for domestic
300 mg/L
COD for domestic
500-1000 mg/L
Industrial wastewater characteristics
HIgh or low pH, color and high temperatures, high heavy metals, and inorganic chemicals
Sewage composition
99.9% water 0.1% solid
Solid composition in sewage
Organic and inorganic materials
Organic composition in sewage
Carbohydrates, Proteins, Fats & Oil and Nutrients
It refers to the reproducibility of an analytic technique when it is repeated on a homogenous sample without regard to actual value
Precision
Correspondence between the measured value and the actual value
Accuracy
The rate of growth is constant
Arithmetic Method
The rate of growth follows a geometric or logarithmic relationship
Geometric Method
Involves graphical projection of the past population growth curve
Curvilinear Method
The logistic curve used in modeling population trends that has an s curve
Logistic Method
Assumes that the city has a limiting saturation population, it has deficits in population
Declining Growth
All the matter that remains as residue upon evaporation at 103 to 105 deg C
Total Solids
The residue left in the vessel after a sample is ignited at 550 deg C
Fixed solids
The weight loss after a sample is ignited at 550 deg C
Volatile solid
Solids in water that can be trapped or retained in a standard glass fiber filter
Total Suspended Solids
Suspended solids that will settle to the bottom of a cone shaped contained (imhoff cone) in one hour
Settleable Solids
Solids that does not settle readily
Colloidal Solids
Solids in water that can pass thru a glass fiber filter
Total Dissolved Solids
Solids lost on ignition
Volatile Suspended Solids
Inorganic fraction that remains behind as ash after ignition
Fixed Solids
Caused by gases produced by the decomposition of organic matter
Odors
Odor of Amines
Fishy
Odor of Ammonia
Ammoniacal
Odor of Diamines
Decayed Fish
Odor of Hydrogen Sulfide
Rotten Eggs
Odor of Mercaptans
Decayed Cabbages, skunk
Odor of Organic Sulfides
Rotten Cabbage
Odor of Skatole
Fecal matter
Color of fresh wastewater
Gray
Color of septic/stale wastewater
Black
Type of color that is due to suspended solids
Apparent Color
Type of color that is due to the dissolved solids that remain after suspended solids
True color
Unit of measurement of Color
True color unit and Platinum cobalt unit
A measure of light transmitting properties of water
Turbidity
It is a negative logarithm of hydrogen ion concentration
pH
A variety of organic substances including hydrocarbons, fats, oils, waxes and high-molecular weighty fatty acids
Fats, oils and grease (FOG)
DENR Standard of FOG
less than 5 mg/L
Instruments used for measuring FOG
Soxhlet Extraction Flasks
Solids are derived from both the animal and plant kingdoms and the activities of man as related to the synthesis of organic compounds
Organic Matter
The principal constituents of the animal organisms
Proteins
Includes sugars, starches, cellulose and wood fiber
Carbohydrates
Large organic molecules that are slightly soluble in water and cause foaming in waste-treatment plants
Surfactants
Causes taste problems in drinking water
Phenols
The oxygen required by biochemical processes to completely aerobically decomposes organic matter
Biochemical Oxygen Demand
It is a measure of oxygen content
Dissolved Oxygen
The amount of oxygen required to decompose all of the organic material after “infinite time”
Ultimate BOD
Oxygen consumption due to carbon
Carbonaceous BOD
Oxygen consumption due to nitrogen oxidation
Nitrogenous BOD
The amount of oxygen required to oxidize and stabilize organic and inorganic content of the sample solution
Chemical Oxygen Demand
Used as a strong oxidizing agent
Potassium dichromate
Based on stoichiometric arrangement of organic matter in wastewater, which is generally a combination of oxygen, hydrogen, carbon, and nitrogen
Theoretical Oxygen Demand
Applicable to small concentration. The test is performed by injecting a known quantity of sample into a high temperature furnace
Total Organic Carbon
It is a constituent of proteins, chlorophyll and many other biological compounds
Nitrogen
The sum of nitrogen, ammonia and ammonium
Total Kjeldahl nitrogen
Blue Baby syndrome is caused by what
Methemoglobinemia
Domestic Wastewater Color
Gray
Domestic Wastewater characteristics of Odor
Musty
Domestic Wastewater characteristics of DO
Greater than 1 mg/L
Domestic Wastewater characteristics of pH
6.5 to 9
Domestic Wastewater characteristics of TSS
100-350 mg/L
Domestic Wastewater characteristics of BOD5
100-300 mg/L
Domestic Wastewater characteristics of COD
200-500 mg/L
Domestic Wastewater characteristics of Total Nitrogen
20-85 mg/L
Domestic Wastewater characteristics of Total Phosphorus
8-20 mg/L
Domestic Wastewater characteristics of fecal coliform
500,000-3,000,000 MPN/100ml
SIngle-celled plants which metabolize soluble food and reproduce by binary fission
Bacteria
The adjustment phase of microorganism
Lag Phase
Microogranism multiply since there is an ample supply of food
Log growth Phase
The point at which the food is largely depleted and food becomes the limiting factor in further growth
Declining growth Phase
Food = Microogranism -
Stationary Phase
The total mass of microoragnisms will slowly decrease
Endogenous Phase
It oxidizes organic matter utlizing the electron acceptors other than oxygen
Anaerobic Bacteria
It utilizes free oxygen as an electron acceptor
Aerobic Bacteria
It is most of the bacteria encountered in wastewater it can function in both anaerobic and aerobic environment
Facultative Bacteria
Denitrifying bacteria. Important in biological nitrate removal in treatment works
Pseudomonas
Helps through its slime production in the formation of flocs in aeration tanks
Zooglea
It cause sludge bulking in the aeration tanks
Sphaerotilus natans
Stores large amounts of phosphate under aerobic conditions and release it under anaerobic condition
Acinetobacter
Nitrifying bacteria that converts NH4 to NO2
Nitrosomonas
Transforms NO2 to NO3
Nitrobacter
Photosynthetic microorganisms that produce oxygen and organic cell mass from inorganic chemicals
Algae
They are single celled protists which reproduce by binary fission. These include amoebas, flagellates, and free-swimming stalked cilates which are important to sanitary engrs.
Protozoa
Multicellular nonphotosynthetic plants
Fungi
Simplest multicellular animals. Their presence is a good indication of the relative stability of a treated waste
Rotifers
They are rod shaped bacteria thriving inside the intestinal tract of a man
Coliform Organism
All aerobic, anaerobic, and facultative gram-negative, non-spore forming, rod-shaped bacteria that ferment lactose with gas formation within 48 hrs
Total Coliform
Test procedure for determining the presence of coliform based on the ability of the coliform group to ferment lactose broth, producing gas
Presumptive test
Test procedure for determining the presence of coliform consist of growing cultures of coliform bacteria on media that supress the growth of other organisms
Confirmed test
An accepted method for determining the number of coliform organisms that is present in a given volume of water that has been used in a long time and is based on a statistical analysis of the number of positive and negative results obtained when testing multiple portions of equal volume and in portions constituting a geometric series for the presence of coliform
Most Probable Number
An accepted method for determining the number of coliform organisms that is accomplished by passing a known volume of water sample through a membrane filter that has a very small pore size
Membrane Filter Technique
Sample is taken at random with no particular time
Grab Sampling
It is a mixture of grab samples taken over a period of time, with the volume of individual samples
Composite sampling
Sample represents diversion of a small fraction of the total flow over some period of time
Continuous Sampling
The treatment or removal of contaminant is brought by the physical or mechanical sources
Unit Operation
The treatment occurs predominately due to chemical and biological reactions
Unit process
Treatment methods in which the application of physical forces predominate
Physical unit operations
It is an example of physical unit of operation wherein the racks or bar screens are the 1st step in WTP. They are used to remove large objects
Screening
It is an example of physical unit of operation where it is used to remove heavy material such as sand, gravel, eggshell and etc.
Grit Removal
It is an example of physical unit of operation where it is used to remove setteable solids
Primary sedimentation
It is an example of physical unit of operation where it is used to polish the effluent. TSS and turbidity are removed
Filtration
It is an example of physical unit of operation where it is a demineralized process applicable to production of high quality water from effluent
Reverse Osmosis/Ultrafiltration
Treatment methods in which the removal or conversion of contaminants is brought about by the addition of chemicals or other chemical reactions
Chemical Unit Processes
An example of chemical unit process where the treatment is accomplished by producing a chemical precipitate that will settle
Chemical Precipitation
An example of chemical unit process where the removal of specific compounds from the wastewater on solid surfaces using the removal of specific compounds from the wastewater on solid surfaces using the attraction between bodies
Adsorption
An example of chemical unit process where it is used to reduce the number of water borne pathogens in the effluent
Disinfection
An example of chemical unit process where ammonia nitrogen is oxidized to nitrogen gas in a mixing basin
Break point chlorination
Treatment methods where the removal of contaminants is brought about biological activity of action of microorganisms
Biological unit process
An example of biological unit process where it is used to removed dissolved organics. The principal variation is activated sludge
Suspended growth biological reactor
An example of biological unit process where it is used to removed dissolved organics. The principal variation is trickling filter
Attached growth biological reactor
An example of biological unit process where the process is used to convert ammonia to nitrate. Achieved in suspended or attached biological reactor
Nitrification
An example of biological unit process where the nitrite and nitrate are reduced to nitrogen gas by microorganisms. Achieved under anaerobic conditions in suspended or attached growth biological reactor
Denitrification
It is a graphical representation of a particular combination of unit operation and processes
Flowsheet
Key criteria used as a basis for sizing the individual unit operation and processes
Process loading criteria
It is determined by identifying the quantities of solids entering and leaving each unit operation
Solid balance
It is used to identify the elevation of the free surface of the WW
Hydraulic profile
It is the spatial arrangement of the physical facilities of the treatment plant in the flowsheet
Plant layout
Elements of Plant Analysis and design `
Flowsheet, Process loading criteria, solid balance, hydraulic profile, and plant layout
It provides protection to WTP equipment
Preliminary Treatment
The part of the preliminary treatment where it is used for the removal of coarse and setteable solids by inception
Screening
A type of screen that is composed of parallel bars or rods which maybe hand cleaned or mechanically cleaned
Racks/Bar screens
A type of screen that is a wire/cloth mesh
Fine screens
It is the average flow rate over a period of time
Average Daily Flow rate
Highest flow rate measure in 24h period
Peak Hourly Flow rate
Maximum daily design flow over a period of time
Maximum daily flow rate
The part of the preliminary treatment where the grinding of coarse solids turn into a more or less uniform size
Solids grinding/Comminution
It is a combination of a bar screen and comminutor.
Barminutor
Devices that are used to cut up solids in wastewater
Comminutor
It is an enlarged channel where the velocity of wastewater flow is controlled to allow only the heavier solids to settle
Grit chamber
Maintains a constant volumetric flow of wastewater from pre-treatment to other downstream operation
Equalization basin
It provides tools for modeling the production, transport and fate of pollutants in the environment; Mathematical representation of the Law of conservation of matter
Mass Balances
It is a tool for modeling the production, transport and fate of energy in the environment; Mathematical representation of the Law of conservation of energy
Energy balance
They are significant tools in understanding and in scientific qualification of the behavior of environmental systems
Mass Balance and Energy balance
The tanks in which physical, chemical and biochemical reactions occur
Reactors
A specific region of space which has boundaries across which the terms min and mout are determined
Control Volume
The rate at which mass enter or leaves the system
Mass flux
It means that the properties of the system do not change with time
Steady State
It means the mass is in the control volume which varies in time
Non-steady state
The pollutant does not change form over time; no reactions
Conservative Pollutant
The pollutant changes over time due to the chemical, physical or biological reactions
Non-conservative Pollutant
It is the reaction rate that is due to the biological degradation
Decay Rate
Time dependent reactions
Kinetic Reactions
They have no chemical formation or loss within the control volume
Conservative
The rate of loss of the compound is constant
Zero-order decay Rate
It is defined as the time required for the concentration of a chemical to decrease by one-half
Half-life
It refers to the use of mass balances to analyze pollutant concentrations in a control volume that is either a chemical or a natural system modeled as a chemical reactor
Reactor Analysis
Three general types of reactors in water and wastewater treatment
Batch Reactor, Plug flow reactor, and Continuous-Flow Stirred tank reactor
It is a type of reactor that is fully mixed reactor with no flow in or out of the reactor
Batch Reactor
It is a type of reactor that is used to model the chemical transformation of compounds as they are transported in systems resembling pipes
Plug Flow Reactor
It is a type of reactor with flow through and that is completely mixed. It is immediately mixed throughout the entire volume of the reactor
Continuous-Flow Reactor
It is the first process in the wastewater treatment plant to remove a significant fraction of organic particulate matter
Primary Treatment
It consists of grease, oil, plastic. leaves, rags, hair, and other floatable material
Scum
Primary treatment removal efficiency of setteable solids
90-95%
Primary treatment removal efficiency of suspended solids
50-65%
Primary treatment removal efficiency of BOD
20-35%
It is the oldest and most widely used unit operation in wastewater treatment. It is the process used in both primary and secondary wastewater treatment that takes place when gravity pulls particles to the bottom of a tank
Sedimentation
The objective of this treatment is to remove readily available setteable solids and floating materials and thus reduce the suspended solid content
Primary Sedimentation
A type of sedimentation tank that serves as combined settling and skimming tanks and as an unheated unmixed anaerobic digester
Septic Tank
A type of sedimentation tank that is similar to a septic tank in the removal of setteable solids and the anaerobic digestion of solids.
Two Story (Imhoff) Tank
A type of sedimentation tank that optimizes the settling process. Sludge is removed from the tank for processing in other downstream treatment units
Plain Settling Tanks (Clarifiers)
In this type of tank wastewater is introduced either in the center or around the periphery, center feed type and is more commonly used
Circular Tanks
It is a type of clarifier where the solids settle to the bottom of a clarifier and is usually scraped to one end
Rectangular Clarifier
The part of a circular clarifier that stops the flow to the center
Influent control gate
The part of a circular clarifier that transports wastewater to the clarifier
Influent channel
The part of a circular clarifier that receives the flow from the influent pipe, reduces flow velocities and distributes
Influent well
The part of a circular clarifier that ensures equal flow
Effluent weir
The part of a circular clarifier that collects the settled wastewater
Effluent trough
The part of a circular clarifier that skims or collects floating materials
Skum Skimmer Arm
The part of a circular clarifier that allows the collected scum to flow from the skimmer box to a scum tank or a pump
Scum pipe
The part of a circular clarifier that causes the collector to rotate
Drive Unit
The part of a circular clarifier that transmit power to drive unit to the sludge collector pit or sump
Sludge collector mechanism
The part of a circular clarifier that scrapes sludge from bottom clarifier to sump
Blades and Scraper Squeegees
The part of a circular clarifier that collects the sludge before the withdrawal
Sump
The part of a circular clarifier that removes the sludge from the clarifier and usually connected to a sludge pump
Sludge withdrawal pipe
Factors affecting the settling of solids
Time, volume, flowrate and types of solids and characteristics of wastewater
A type of settling phenomena in wastewater where the particles settle without the interaction and occurs under low solids concentration
Discrete
A type of settling phenomena in wastewater where particles literally settle independently but causes the solid to change in form in the depth of the clarification unit
Flocculant
A type of settling phenomena in wastewater where forces are sufficient to hinder settling of neighboring particles
Hindered or zone
A type of settling phenomena in wastewater where the particle concentration is so high
Compression
It is a natural force that has natural repelling force that holds particles in suspension
Zeta Potential
It is a natural force that has a natural attracting forces that we want to enhance
Van der Waals
It is defined as Flow rate over Surface Area
Surface loading Rate
It is the amount of water leaving the settling tank per linear foot of water; Flowrate over Weir Length
Weir overflow rate
It is the period of time that a water or wastewater flow is retained in a basin, tank, or reservoir; Volume of Tank over Flow Rate
Detention Time
It is used to indicate the amount of solids that can be removed daily by a clarifier for each square foot of clarifier liquid surface area
Solids loading
Air bubbles are added or caused to form
Flotation
It is the injection of air while the liquid is under pressure of several atmospheres
Dissolved air flotation
It is where air bubbles are formed by introducing the gas phase directly into the liquid phase
Dispersed air flotation
It is the saturation with air at atmospheric pressure
Vacuum Air Flotation
A type of secondary treatment where activated sludge process is present
Suspended Growth Biological Treatment
A type of secondary treatment where trickling filter and rotating biological contactor is present
Attached Growth Biological Treatment
A type of reaction where the reactants are distributed uniformly throughout the fluid
Homogeneous Reaction
A type of reaction that occurs between one or more constituents that can be identified with specific sites
Heterogeneous Reaction
The principal type of reactor where the flow is neither entering nor leaving the reactor
Batch
The principal type of reactor where the fluid passes through the tank and are discharged in the same sequence in which they enter
Plug-flow or Tubular Flow
The principal type of reactor where the reactants are entering the reactor and the products are flowing out from the reactor are considered to be continuous
Continuous-flow stirred tank reactor
The principal type of reactor where any degree of partial mixing between plug flow and complete mix
Arbitrary flow reactor
The principal type of reactor where it is filled with inert packing media for the growth of biomass
Packed bed reactor
The principal type of reactor where it is filled with the packing material that expands and gets fluidized when the wastewater moves upward in the reactor
Fluidized bed reactor
It is a combination of attached growth and suspended growth
Fluidized bed biofilm reactor (FBBR)
A type of FBBR where biomass is grown inside polyester foam pads and pads can be periodically removed and biomass can be squeezed
Captor
A type of FBBR where sand particles are used as support medium and sand is allowed to overflow and is cleaned and then recycled
Oxitron
It is a treatment wherein to remove the soluble BOD that escapes primary treatment that utilizes microoraganisms to provide further removal of the suspended solids
Secondary Treatment
One of the two basic approaches to biological treatment wherein the organisms and wastewater are mixed together
Suspended growth reactors
One of the two basic approaches to biological treatment wherein the organisms are stuck to a support structure and the wastewater is passed over the organism
Attached growth Reactor
It is a biological treatment process which speeds up the waste decomposition
Activated sludge process
It is sludge that produced in wastewater in the growth of the aeration tanks
Activated sludge
They created the activated sludge process in May 3, 1914
Adern and Lockett
A process wherein the microorganisms derive energy from carbonaceous organic matter in aerated wastewater for the production of the new cells
Synthesis
It is the releasing of energy through the conversion of this organic matter into compounds that contain lower energy such as carbon dioxide and water
Respiration
Microorganism obtain energy by converting ammonia nitrogen to oxygen
Nitrification
A physical component of activated sludge where the biological reactions occur
Aeration Tanks
A physical component of activated sludge where it may be provided by pure oxygen, compressed air, or mechanical aeration that provides oxygen and mixing
Aeration Source
A physical component of activated sludge where the activated sludge solids separate from the surrounding wastewater by the process of flocculation and gravity sedimentation
Secondary Clarifier
A physical component of activated sludge where it must be collected from the secondary clarifiers and pumped back to the aeration tanks before the dissolved oxygen is depleted
Returned Activated Sludge System
A physical component of activated sludge where the activated sludge contains an overabundance of microorganisms which must be removed or wasted w/ the use of the pump
Waste Activated Sludge System
It is the mixture of activated sludge and the wastewater in the aeration tank
Mixed liquor
It is the concentration of suspended solids in activated sludge mixed liquor that can be driven off by combustion at 550 C which indicates the concentration of microorganism available for biological oxidation
Mixed liquor volatile suspended solids
It is also called soilds retention time where the average amount of time that microorganisms are kept in the system
Mean cell residence time
It is where the oxygen transfer efficiency is accomplished by mixing pressurized air and with water within a jet nozzle and then discharging the air-liquid into the tank
Jet Aeration
It is the aeration source where it is either surface or submerged
Mechanical Aerators
It is a type of mechanical aerator where oxygen is entrained from the atmosphere
Surface Aerators
It is a type of mechanical aerator where the oxygen is entrained both from the atmosphere and from air or pure oxygen introduced at the bottom of the tank
Submerged Aerator
It is an aeration source that is designed to produce fine, medium, or coarse bubbles
Diffusers
Sludge particles produced in wastewater by the growth organisms in aeration tanks
Activated Sludge
A condition where oxygen is present
Aerobic
Sludge that forms clouds in the secondary clarifiers when the sludge does not settle properly caused by filamentous bacteria
Bulking
Biological conversion of the carbonaceous organic matter in wastewater to cell tissue and various gaseous end products
Carbonaceous BOD Removal
Clumps to bacteria
Floc
Agitating wastewater to introduce the small, suspended particles to bunch together into heavier particles and settle out
Flocculation
A quantity of material added to the process at one time
Loading
Activated sludge mixed with raw wastewater
Mixed liquor
Pre-manufactured treatment facility small communities to treat wastewater
Package plant
The solids that settle out during the process
Sludge
To denote the organic matter or nutrients that are converted during biological treatment or that may be limiting in biological treatments
Substrate
The liquid that is removed from the settled sludge
Supernatant
Removing excess microorganisms from the system
Wasting
Microorganisms that must have oxygen as the terminal electron acceptor. When wastewater contains oxygen and can support it
Obligate aerobes
Microorganisms that cannot survive in the presence of oxygen. They cannot use oxygen as a terminal electron acceptor
Obligate Anaerobes
Can use oxygen as the terminal electron acceptor and under certain conditions, the can also grow in the absence of oxygen
Facultative Anaerobes
A group of facultative anaerobes called denitifiers utilizes nitrite, nitrates, as the terminal electron acceptor
Anoxic Microorganism
The process wherein nitrite nitrogen is converted to nitrogen gas in the absence of oxygen
Anoxic Denitrification
It releases energy via the conversion of organic matter into compounds
Heterotrophic
When in activated sludge it reduces oxidized carbon compounds such as carbon dioxide for cell growth. These bacteria obtain their energy by oxidizing ammonia nitrogen to nitrate nitrogen in a two stage conversion process known as nitrification
Autotrophic bacteria
bacteria that convert ammonia (NH3) to Nitrogen Nitrite (NO2) Nitrogen
Nitrosomonas
Bacteria convert Nitrite Nitrogen to Nitrate Nitrogen
Nitrobacter
They are able to use light as energy source
Phototrophs
Chemical reactions as energy source
Chemotrophs
Obtain energy from the oxidation of reduced inorganic compounds
Chemoautotrophs
Obtain energy from the oxidation of organic compounds
Chemoheterotrophs
it refers to all the chemical reactions occurring within a cell
Metabolism
Any molecule that is a nutrient
Metabolite
A category of metabolic reactions that involves the breaking of binds and whenever chemical bonds are broken energy is released
Catabolism
A category of metabolic reactions that involve the creation of bond, it takes energy to make chemical bonds
Anabolism
A series of linked biochemical reactions that occur in a stepwise manner
Biochemical Pathways
Organism that generate energy by enzyme-mediated electron transport to an external electron acceptor
Respiratory metabolism
Internal electron acceptor is used and it is less efficient energy yielding process compared to respiration
Fermentive metabolism
The use of NO2 or NO3 for electron acceptors under anaerobic conditions
Anoxic
When they can use O2 or NO2/No3 as electron acceptor when O2 is not available
Facultative Aerobic
Organism that can generate energy by fermentation and can exist in either the presence or absence of molecular oxygen
Facultative Anaerobic
They can shift from fermentive to aerobic respiratory metabolism
True Facultative Anaerobes
They have a strictly fermentive metabolism and are relatively insensitive to the presence of molecular oxygen
Aerotolerant Anaerobes
organic catalysts produced by the living cell. They are proteins or protein combined with either inorganic or organic molecule
Enzymes
It is the conversion of substrate that can be transported into the cell
Extracellular Enzyme
It is involved in synthesis and energy reactions within the cell
Intracellular
It refers to amount of water entering the aeration tank.
Hydraulic Load
Its to maintain a sufficient concentration of activated sludge in the aeration tank
Return-sludge Requirement
30 minutes of settling of a liter sample of mixed liquor in a graduated cylinder
Settleability Testing
It is the accumulation of settled sludge in the clarifier
Sludge blanket
They are usually found in systems with long aeration periods
Rotifers and nematodes
The predominate in young sludges
Amoeboids
They are free swimmers and pre-dominate in liquid mixed liquors
Flagellates
They predominate as the Food:Microbe ratio decrease
Free-swimming Ciliates
They can cause the sludge not to settle properly
Filamentous Bacteria
Consists of an aeration tank, a secondary clarifier and a sludge recycle line
Conventional Plug-flow Activated Sludge
