Environmental Engineering Flashcards
A determination of the concentration, of carbon-based (i.e., organic) compounds aimed at establishing the relative “strength” of wastewater [e.g., biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), and oil and greasé (O&G)].
Organics
A measurement of the concentration of particulate solids that can dissolve or suspend in wastewater [e.g., total solids (TS), total suspended solids (TSS), total dissolved solids’ (TDS), total volatile solids (TVS), and total fixed solids (TFS)]
Solids
A measurement of the concentration of targeted nutrients (e.g., nitrogen and phosphorus) that can contribute to the acceleration of eutrophication (i.e., the natural aging of water bodies)
Nutrients
Analytical tests designed to measure a varied group of constituents directly impact wastewater treatability (e.g., temperature, color, pH, turbidity, odor).
Physical Properties and Other Impact Parameters
TKN
Total Kjeldahl Nitrogen
test that measures oxygen consumption after 60 days or more is sometimes required in wastewater permits.
UBOD (ultimate biological oxygen demand) test
based on the accurate measure of DO (dissolved oxygen) at the beginning and end of a five-day per a five-day period in which the sample is held in dark, incubated conditions
BOD test also known as BOD5
The change in DO concentration over five days represents the “__________” for respiration by the aerobic biological microorganisms in the sample.
oxygen demand
is an inherent disadvantage of the test because wastewater treatment system personnel cannot use it to make real-time operational adjustments.
five-day completion window
is the most popular alternative test to BOD for establishing the concentration of organic matter in wastewater samples.
COD (chemical oxygen demand)
The COD test should be considered an ________ of the organic matter in a wastewater sample rather than a ______ for the BOD test.
independent measure; substitute
The COD test uses a chemical (__________) that ‘oxidizes” both organic (predominate) and inorganic substances in a wastewater sample
potassium dichromate in a 50% sulfuric acid solution
TRUE OR FALSE
COD concentration results higher than BOD concentration for the same wastewater sample since only organic compounds are consumed during BOD testing.
TRUE
is gaining popularity because it only takes 5-10 minutes to complete.
TOC (Total Organic Carbon)
In the TOC test, organic carbon is converted to carbon dioxide (CO2) and typically measured with __________.
infrared analyzer
Like COD, the TOC test can be used to rapidly estimate BOD concentration once a consistent ________ is established on a particular wastewater stream.
TOC to BOD ratio
consists of a group of related constituents that are of special concern in wastewater treatment due to their unique physical properties and highly concentrated energy content.
O&G (Oil and Grease)
COD is a good estimate of
a 20-day BOD
b. cBOD
c. nBOD
d. Ultimate BOD
D. Ultimate BOD
Pick out the wrong statement
a. BOD is a characteristic and not a constituent of water
b. BOD is a measure of the amount of oxygen which will be
demanded & used in 5 days by the biological decomposition of the
organic matter present in water stream present as food for the living
organism
c. BOD is expressed in mg/L
d. None of these
d. None of these
Only sample collection containers that can be used to collect O&G samples
glass since O&G adheres to plastic
are generally hydrophobic (i.e., “water-hating”) and thus have low solubility in wastewater, resulting in relatively low biodegradability by microorganisms.
O&G (Oil and Grease)
Wastewater generated by commercial, industrial and institutional facilities is typically referred to as “_________” compared to typical household wastewater.
high-strength
Pick out the wrong statement.
a. The waves used in the long distance radio communication are reflected back to earth by stratosphere,
b. The concentric atmosphere layer just above troposphere is called stratosphere, which is rich in ozone.
c. Mesosphere is characterized by very low atmospheric pressure and low temperature,
d. Troposphere is a dusty zone containing water vapour and clouds.
a. The waves used in the long distance radio communication are reflected back to earth by stratosphere,
is characterized by very low atmospheric pressure and low temperature, and is a high-altitude layer with very thin air and very cold temperatures.
Mesosphere
is the lowest layer of the atmosphere, where weather phenomena like clouds and dust occur, and it contains water vapor
Troposphere
is the layer above the troposphere, and it contains a significant concentration of ozone.
stratosphere
radio waves are reflected by the ________
ionosphere
The best procedure for determining the DO of a plant effluent is to analyze
a. Several grab samples at various flows
b. A grab sample of the effluent at high flow
c. A grab sample of the effluent at low flow
d. A 24-hour composite sample of the effluent
a. Several grab samples at various flows
measures the concentration of oxygen dissolved in a water or wastewater sample.
DO test
DO measurement most often takes place using _________ with a specialized _______.
an electronic meter fitted; DO probe
The concentration of DO in a water sample is significantly influenced by
Temperature, salinity, pressure
Relationship of DO with respect to:
1. Temperature
2. Salinity
3. Pressure
- inversely proportional
- inversely proportional
- directly proportional
The correct relation between TOD, BOD and COD is given by
a. TOD > BOD > COD
c.BOD > COD > TOD
b. TOD > COD > BOD
d.COD > BOD > TOD
b. TOD > COD > BOD
measures the total amount of oxygen required to completely oxidize all organic and inorganic compounds in a water sample through high-temperature oxidation.
TOD test (total oxygen demand)
Pick out the correct statement
a. BOD5 is the ultimate BOD
b. BOD5 is greater than BOD4 keeping other conditions same
c. BOD5 is less than BOD4 keeping other conditions same
d. BOD5 is equal to BOD4 keeping other conditions same
c. BOD5 is less than BOD4
The rate of BOD exerted at any time is
a. Directly proportional to BOD satisfied
b. Directly proportional to BOD remaining
c. Inversely proportional to BOD satisfied
d. Inversely proportional to BOD remaining
b. Directly proportional to BOD remaining
measures the oxygen consumed by microorganisms during the biological breakdown of organic matter
BOD
measures the total oxygen required for chemical oxidation of all organic and inorganic matter
COD
refers to the amount of biodegradable organic matter that is still present in the water sample after the incubation period, meaning it hasn’t been fully oxidized yet.
BOD Remaining
represents the amount of oxygen that has been consumed by microorganisms during the incubation period to break down the organic matter.
BOD Exerted
BOD remaining can be calculated by?
subtracting the BOD exerted from the initial (or ultimate) BOD.
The ratio of BOD5 to ultimate BOD is about
a. 1/3
b. 2/3
c. 4
d. 3/4
b. 2/3
is a standard measurement and is generally considered to be about 68% of the total (or ultimate) oxygen demand
BOD5
What would be the effect on a BOD determination if the dilution water used contained either copper or chloride?
a. BOD would be higher
c. DO level would increase
b. BOD would be lower
d. DO level would decrease
b. BOD would be lower
is a heavy metal that is toxic to microorganisms, including the bacteria responsible for breaking down organic matter in the BOD test.
Copper
While ______ itself is not directly toxic, high concentrations of ________ can interfere with the BOD test by inhibiting the growth of certain microorganisms. Furthermore, _________ (a common disinfectant) can also inhibit bacterial growth and should be neutralized before BOD testing.
Chloride
Assertion (A): The determination of pH value of sewage is important.
Reason (R): The efficiency of certain treatment methods depends upon availability of pH value.
a. Both A and R are true and R is the correct explanation of A
b. Both A and R are true but R is not a correct explanation of A
c. A is true but R is false
d. A is false but R is true
a. Both A and R are true and R
The efficiency of many sewage treatment processes, especially biological ones, hinges on maintaining a specific pH range, typically between ___________, for optimal microbial activity and contaminant removal.
6.5 and 8.5
Maintaining the appropriate pH can also help prevent ______ of pipes and equipment in the treatment plant.
corrosion
pH Dependent Process
Activated Sludge Systems, Heavy Metal Removal, Filtration
In sampling waste water for a BOD test, the best results are obtained from
a. A grab sample
b. A 24-hour composite sample
c. A sample made of 2 to 4 portions taken at time of high flow
d. A sample taken at time of low flow
b. A 24-hour composite sample
Samples should be maintained at a temperature of _______, but not frozen, both during the sampling period and until analysis begins
6°C or lower
If chlorine is present, a dechlorination chemical like ___________ should be added before testing.
sodium sulfite
is required if the hourly flow varies by more than 10% over the sampling period.
Flow Proportioning
If a grab sample is desired for process control purposes, it does not need to be refrigerated if analyzed within _________.
2 hours
The three measurements that are essential in calculating the solids and organics on a waste water treatment plant are
a. Flow, BOD, DO
b. Flow, BOD, SS
c. BOD, SS, DO
d. BOD, SS, pH
b. Flow, BOD, SS
Evaporation of Filter =
TSS (Total Suspended Solid)
This disease is caused by poisoning of a certain chronic chemical that impairs kidney function and progressively causes osteomalacia, a calcium deficiency. What is disease and what heavy metal causes it?
a. Mercury -Minamata disease
b. Cadmium- Itai-ltai disease
C. Silver- Argyria
d. Chromium - Chromium toxicity
b. Cadmium- Itai-ltai disease
Evaporation of Filtrate =
TDS (Total Dissolved Solid)
Sum of TSS and TDS
Total Solids
Burned TDS or TSS
VDS/VSS (Volatile) or FDS/FSS (Fixed)
Sum of FSS and FDS
TFS (Total Fixed Solid)
Sum of VSS and VDS
TVS (Total Volatile Solid)
Sum of TFS and TVS
TS (Total Solid)
meaning “ouch-ouch” in Japanese, is a chronic cadmium poisoning condition characterized by severe bone pain and osteomalacia, primarily affecting the Jinzu River basin in Toyama Prefecture, Japan, due to environmental contamination
Itai-itai disease
is a neurological disorder caused by mercury poisoning, specifically methylmercury, stemming from the consumption of contaminated fish and shellfish from Minamata Bay in Japan. Symptoms include sensory disturbances, ataxia, and visual and hearing difficulties.
Minamata disease
The source of the mercury pollution was the industrial wastewater discharged from a chemical plant (_________) into Minamata Bay
Chisso Corporation
is a global agreement that aims to reduce mercury pollution and protect human health and the environment
Minamata Convention
is a rare condition characterized by a bluish-gray discoloration of the skin and other tissues due to the accumulation of silver deposits, often resulting from prolonged or excessive exposure to silver or silver compounds.
Argyria
The best procedure for determining the SS of a plant effluent is to analyze
a. A series of grab samples taken at different times during the day
b. A grab sample of the effluent at high flow
c. A grab sample of the effluent at low flow
d. A 24-hour composite sample of the effluent
d. A 24-hour composite sample of the effluent
