In case the body have to stay in lower temperature for extended time period (more than 1 hour), how does the body regulate its response?

## In case the body have to stay in lower temperature for extended time period (more than 1 hour), how does the body regulate its response?

Arterioles transporting blood to external capillaries beneath the surface of … Read More...
5) _____ The walls of a food storage facility refrigerator are made of a 2-cm-thick layer of wood (k=0.1 W/m-K) in contact with a 5-cm-thick of polyurethane foam (k= 0.03 W/m-K). If the temperature of the inner surface of the wood is -10 °C and the temperature of the outer surface of the polyurethane foam is 20 °C, the temperature where the two layers are in contact is: a) 11°C b) 8 °C c) 3°C d) -2°C e) -7°C

## 5) _____ The walls of a food storage facility refrigerator are made of a 2-cm-thick layer of wood (k=0.1 W/m-K) in contact with a 5-cm-thick of polyurethane foam (k= 0.03 W/m-K). If the temperature of the inner surface of the wood is -10 °C and the temperature of the outer surface of the polyurethane foam is 20 °C, the temperature where the two layers are in contact is: a) 11°C b) 8 °C c) 3°C d) -2°C e) -7°C

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The Geographic Grid The Geographic grid is based on angular measurements from the center of the earth. Latitude measures the angular distance north and south of the plane of the earth’s equator. longitude measures the angular distance east and west of the prime meridian. The angular distance between any two locations on the earth’s surface is simply the latitudinal or longitudinal difference the two locations. Both longitude and latitude are measured in degrees ( o ), minutes ( ‘ ) and seconds ( ” ) of arc. Figure 1 shows the latitude and longitude coordinates of the earth in 10o degree intervals. There are 60′ minutes of arc in 1o . There are 60″ seconds of arc in 1′ minute of arc. One could therefore express the latitude and longitude of a place as 39o 50′ 10″ N, 77o 35′ 15″ W. 1. Using latitude and longitude coordinates, determine the location of the following places. a) Toronto, Ontario ( Canada ) ____________________________________________________________ b) Billings, Montana _____________________________________________________________________ c) Chicago, Illinois ______________________________________________________________________ d) Westminster, England _________________________________________________________________ e) Venice, Italy _________________________________________________________________________ f) Baghdad, Iraq _______________________________________________________________________ g) Tokyo, Japan ________________________________________________________________________ h) Rio de Janeiro, Brazil _________________________________________________________________ 2. Provide the name of the following places located at the given coordinates below. a) 13o 09′ 50.19″ S, 72o 32′ 45.58″ W ______________________________________________________ b) 33o 51′ 35.90″ S, 151o 12′ 40″ E ______________________________________________________ c) 71o 17′ 07.62″ N, 156o 45′ 57.98″ W _____________________________________________________ d) 41o 53′ 29.84″ N, 87o 36′ 01.78″ W ______________________________________________________ The geographic grid uses circles of two different types, great circles and small circles. All great circles pass through the geographic center of the earth. All meridians, the equator, and the circle of illumination are great circles. All parallels other than the equator are small circles. The direction of any grid lines ( meridians and parallels ) can be determined as either an azimuth or a bearing. Azimuths are read in a clockwise direction as degrees ranging from 0o at the North Pole, to 90o at East, to 180o at the South Pole, to 270o at West, and back to 360o at the North Pole. Azimuths only give a direction such as 45o . Bearings are read as quadrants from either the North or South Poles. Hence east is 90o from either North or South. West is also 90o from either North or South. A bearing shows the direction one is traveling as well as the magnitude of the angle from either North or South. Hence a azimuth of 45o is read as a bearing of N 45o E. An azimuth of 150o would as a bearing read S 30o E. Figure 1.2 shows the relationship between azimuths and bearings. 3. Convert the values below. Bearing Azimuth 20o S 500 20′ E 265o 30’ N 20o 20 W Longitudinal and latitudinal distances vary as a result of trying to fit a flat grid onto a spherical surface such as the earth’s curved surface. The grid is constant in a north-south direction, but varies in the east-west direction. The data below shows how the grid values vary ( rounded off to the nearest mile of distance ). 1o of longitude at the equator = 69 miles 1o of longitude at the 30th parallel = 60 miles 1o of longitude at the 60th parallel = 35 miles 1o of longitude at the 90th parallel = 0 miles 1o of latitude along any meridian = 69 miles 4. Determine by calculation the linear ( miles ) and angular ( degree ) distances between the following places. From To Angular Linear Quito, Ecuador Macapa, Brazil 0o S, 78o W 0o N, 51o W Cairo, Egypt Shiraz, Iran 30o N, 31o E 30o N, 52o E Seward, Alaska St Petersburg, Russia 60o N, 149o W 60o N, 30o E Hamhung, North Korea Ankara, Turkey 39o N, 127o E 39o N, 32o E Detroit, Michigan Morristown, Tennessee 42o N, 83o W 36o N, 83o W Sample problem We see that between Quito and Macapa that there is no latitude difference as both places are at 0 degrees latitude. Therefore the angular difference between the two places can only be calculated based upon the longitudinal difference. Seeing that both places are west longitude we simply subtract 78-51 = 27 degrees. Hence the angular distance between Quito and Macapa is 27 degrees. The linear distance is the number of miles ( feet,yards, kilometers, etc.) Quito and Macapa. Bothe places are on the equator so consulting the table above we find that in 1 degree of longitude ate the equator is equal to 69 miles. So multiplying the 69 miles/degree X 27 degrees, the degrees cancel and the remaining units are miles, and the numerical value is 1,863 linear miles.

## The Geographic Grid The Geographic grid is based on angular measurements from the center of the earth. Latitude measures the angular distance north and south of the plane of the earth’s equator. longitude measures the angular distance east and west of the prime meridian. The angular distance between any two locations on the earth’s surface is simply the latitudinal or longitudinal difference the two locations. Both longitude and latitude are measured in degrees ( o ), minutes ( ‘ ) and seconds ( ” ) of arc. Figure 1 shows the latitude and longitude coordinates of the earth in 10o degree intervals. There are 60′ minutes of arc in 1o . There are 60″ seconds of arc in 1′ minute of arc. One could therefore express the latitude and longitude of a place as 39o 50′ 10″ N, 77o 35′ 15″ W. 1. Using latitude and longitude coordinates, determine the location of the following places. a) Toronto, Ontario ( Canada ) ____________________________________________________________ b) Billings, Montana _____________________________________________________________________ c) Chicago, Illinois ______________________________________________________________________ d) Westminster, England _________________________________________________________________ e) Venice, Italy _________________________________________________________________________ f) Baghdad, Iraq _______________________________________________________________________ g) Tokyo, Japan ________________________________________________________________________ h) Rio de Janeiro, Brazil _________________________________________________________________ 2. Provide the name of the following places located at the given coordinates below. a) 13o 09′ 50.19″ S, 72o 32′ 45.58″ W ______________________________________________________ b) 33o 51′ 35.90″ S, 151o 12′ 40″ E ______________________________________________________ c) 71o 17′ 07.62″ N, 156o 45′ 57.98″ W _____________________________________________________ d) 41o 53′ 29.84″ N, 87o 36′ 01.78″ W ______________________________________________________ The geographic grid uses circles of two different types, great circles and small circles. All great circles pass through the geographic center of the earth. All meridians, the equator, and the circle of illumination are great circles. All parallels other than the equator are small circles. The direction of any grid lines ( meridians and parallels ) can be determined as either an azimuth or a bearing. Azimuths are read in a clockwise direction as degrees ranging from 0o at the North Pole, to 90o at East, to 180o at the South Pole, to 270o at West, and back to 360o at the North Pole. Azimuths only give a direction such as 45o . Bearings are read as quadrants from either the North or South Poles. Hence east is 90o from either North or South. West is also 90o from either North or South. A bearing shows the direction one is traveling as well as the magnitude of the angle from either North or South. Hence a azimuth of 45o is read as a bearing of N 45o E. An azimuth of 150o would as a bearing read S 30o E. Figure 1.2 shows the relationship between azimuths and bearings. 3. Convert the values below. Bearing Azimuth 20o S 500 20′ E 265o 30’ N 20o 20 W Longitudinal and latitudinal distances vary as a result of trying to fit a flat grid onto a spherical surface such as the earth’s curved surface. The grid is constant in a north-south direction, but varies in the east-west direction. The data below shows how the grid values vary ( rounded off to the nearest mile of distance ). 1o of longitude at the equator = 69 miles 1o of longitude at the 30th parallel = 60 miles 1o of longitude at the 60th parallel = 35 miles 1o of longitude at the 90th parallel = 0 miles 1o of latitude along any meridian = 69 miles 4. Determine by calculation the linear ( miles ) and angular ( degree ) distances between the following places. From To Angular Linear Quito, Ecuador Macapa, Brazil 0o S, 78o W 0o N, 51o W Cairo, Egypt Shiraz, Iran 30o N, 31o E 30o N, 52o E Seward, Alaska St Petersburg, Russia 60o N, 149o W 60o N, 30o E Hamhung, North Korea Ankara, Turkey 39o N, 127o E 39o N, 32o E Detroit, Michigan Morristown, Tennessee 42o N, 83o W 36o N, 83o W Sample problem We see that between Quito and Macapa that there is no latitude difference as both places are at 0 degrees latitude. Therefore the angular difference between the two places can only be calculated based upon the longitudinal difference. Seeing that both places are west longitude we simply subtract 78-51 = 27 degrees. Hence the angular distance between Quito and Macapa is 27 degrees. The linear distance is the number of miles ( feet,yards, kilometers, etc.) Quito and Macapa. Bothe places are on the equator so consulting the table above we find that in 1 degree of longitude ate the equator is equal to 69 miles. So multiplying the 69 miles/degree X 27 degrees, the degrees cancel and the remaining units are miles, and the numerical value is 1,863 linear miles.

F7.10 The flame spread rate through porous solids increases with concurrent wind velocity. decreases with concurrent wind velocity. is independent of concurrent wind velocity. F7.11 Surface tension accelerates opposed-flow flame spread over liquid fuels. True False F7.12 Opposed-flow flame spread rates over a solid surface are typically much smaller than 1 mm/s. around 1mm/s. much greater than 1 mm/s. F7.13 Upward flame spread rate over a vertical surface is typically between 10 and 1000 mm/s. True False F7.14 The Steiner tunnel test described in ASTM standard E 84 is used to assess the fire performance of interior finish materials based on lateral flame spread over a vertical sample. True False F8.1 Describe the triad of fire growth. F8.2 Liquid pool fires reach steady burning conditions within seconds after ignition. True False F8.3 The heat of gasification of liquid fuels is typically less than 1 kJ/g. between 1 and 3 kJ/g. greater than 3 kJ/g. F8.4 The heat flux from the flame to the surface of real burning objects can usually be determined with sufficient accuracy so that reasonable burning rate predictions can be made. True False F8.5 The mass burning flux generally associated with extinction is 0.5 g/m2s. 5 g/m2s. 50 g/m2s. F8.6 The mass burning flux of a liquid pool fire is a function of only the pool diameter. only the fuel type. pool diameter and fuel type. F8.7 The energy release rate of real objects can be measured in an oxygen bomb calorimeter. an oxygen consumption calorimeter. a room/corner test. F8.8 The peak energy release rate of typical domestic upholstered furniture can be as high as 3000 kW. True False F8.9 Draw a typical curve of the mass burning flux of a char forming fuel as a function of time. F8.10 A fast fire as defined in NFPA 72B grows proportionally to t2 and reaches an energy release rate of 1 MW in 75 sec. 150 sec. 300 sec. F9.1 Air entrainment into turbulent pool fire flames is due to buoyancy. True False F9.2 The frequency of vortex shedding in turbulent pool fire flames increases with pool diameter. decreases with pool diameter. is independent of pool diameter. F9.3 The height of turbulent jet flames for a given fuel type and orifice size is independent of energy release rate. True False F9.4 The exit velocities of fuel vapors leaving a solid or liquid pool fire surface are responsible for entrainment of air in the plume. True False F9.5 The height of a turbulent pool fire flame is a function of only energy release rate. only pool diameter. energy release rate and pool diameter. F9.6 Turbulent pool fire flame heights fluctuate in time within a factor of 2. True False F9.7 The Q* value for jet fires is 102 or greater. 104 or greater. 106 or greater. F9.8 The temperature in the continuous flame region of moderate size turbulent pool fires is approximately 820°C. True False F9.9 The temperature at the maximum flame height of a turbulent pool fire flame is approximately 1200°C. 800°C. 300°C. F9.10 The adiabatic flame temperature of hydrocarbon fuels is 1700-2000°C. 2000-2300°C. 2300-2600°C. F10.1 The stoichiometric air to fuel mass ratio of hydrocarbon fuels is of the order of 1.5 g/g. 15 g/g. 150 g/g. F10.2 Give two examples of products of incomplete combustion that occur in fires. F10.3 Slight amounts of products of incomplete combustion are generated in overventilated fires. True False F10.4 The CO yield of a fire is a function of only the fuel involved. only the ventilation conditions. the fuel and the ventilation conditions. F10.5 A carboxyhemoglobin level of 40% in the blood is usually lethal. True (doubt) False F10.6 Carbon monoxide is the leading killer of people in fires. True False F10.7 HCN is a narcotic gas. an irritant gas. a fuel vapor. F10.8 The hazard to humans from narcotic gases is a function of only the concentration of the gas. only the duration of exposure. the product of concentration and duration of exposure. F10.9 The effects on lethality of CO, HCN, and reduced O2 are additive. True False F10.10 Irritant gases typically cause post-exposure fatalities. True False F10.11 Visibility through smoke improves with increasing optical density. True False F10.12 Heat stress occurs when the skin is exposed to a heat flux of 1 kW/m2. the skin reaches a temperature of 45°C. the body’s core temperature reaches 41°C.

## F7.10 The flame spread rate through porous solids increases with concurrent wind velocity. decreases with concurrent wind velocity. is independent of concurrent wind velocity. F7.11 Surface tension accelerates opposed-flow flame spread over liquid fuels. True False F7.12 Opposed-flow flame spread rates over a solid surface are typically much smaller than 1 mm/s. around 1mm/s. much greater than 1 mm/s. F7.13 Upward flame spread rate over a vertical surface is typically between 10 and 1000 mm/s. True False F7.14 The Steiner tunnel test described in ASTM standard E 84 is used to assess the fire performance of interior finish materials based on lateral flame spread over a vertical sample. True False F8.1 Describe the triad of fire growth. F8.2 Liquid pool fires reach steady burning conditions within seconds after ignition. True False F8.3 The heat of gasification of liquid fuels is typically less than 1 kJ/g. between 1 and 3 kJ/g. greater than 3 kJ/g. F8.4 The heat flux from the flame to the surface of real burning objects can usually be determined with sufficient accuracy so that reasonable burning rate predictions can be made. True False F8.5 The mass burning flux generally associated with extinction is 0.5 g/m2s. 5 g/m2s. 50 g/m2s. F8.6 The mass burning flux of a liquid pool fire is a function of only the pool diameter. only the fuel type. pool diameter and fuel type. F8.7 The energy release rate of real objects can be measured in an oxygen bomb calorimeter. an oxygen consumption calorimeter. a room/corner test. F8.8 The peak energy release rate of typical domestic upholstered furniture can be as high as 3000 kW. True False F8.9 Draw a typical curve of the mass burning flux of a char forming fuel as a function of time. F8.10 A fast fire as defined in NFPA 72B grows proportionally to t2 and reaches an energy release rate of 1 MW in 75 sec. 150 sec. 300 sec. F9.1 Air entrainment into turbulent pool fire flames is due to buoyancy. True False F9.2 The frequency of vortex shedding in turbulent pool fire flames increases with pool diameter. decreases with pool diameter. is independent of pool diameter. F9.3 The height of turbulent jet flames for a given fuel type and orifice size is independent of energy release rate. True False F9.4 The exit velocities of fuel vapors leaving a solid or liquid pool fire surface are responsible for entrainment of air in the plume. True False F9.5 The height of a turbulent pool fire flame is a function of only energy release rate. only pool diameter. energy release rate and pool diameter. F9.6 Turbulent pool fire flame heights fluctuate in time within a factor of 2. True False F9.7 The Q* value for jet fires is 102 or greater. 104 or greater. 106 or greater. F9.8 The temperature in the continuous flame region of moderate size turbulent pool fires is approximately 820°C. True False F9.9 The temperature at the maximum flame height of a turbulent pool fire flame is approximately 1200°C. 800°C. 300°C. F9.10 The adiabatic flame temperature of hydrocarbon fuels is 1700-2000°C. 2000-2300°C. 2300-2600°C. F10.1 The stoichiometric air to fuel mass ratio of hydrocarbon fuels is of the order of 1.5 g/g. 15 g/g. 150 g/g. F10.2 Give two examples of products of incomplete combustion that occur in fires. F10.3 Slight amounts of products of incomplete combustion are generated in overventilated fires. True False F10.4 The CO yield of a fire is a function of only the fuel involved. only the ventilation conditions. the fuel and the ventilation conditions. F10.5 A carboxyhemoglobin level of 40% in the blood is usually lethal. True (doubt) False F10.6 Carbon monoxide is the leading killer of people in fires. True False F10.7 HCN is a narcotic gas. an irritant gas. a fuel vapor. F10.8 The hazard to humans from narcotic gases is a function of only the concentration of the gas. only the duration of exposure. the product of concentration and duration of exposure. F10.9 The effects on lethality of CO, HCN, and reduced O2 are additive. True False F10.10 Irritant gases typically cause post-exposure fatalities. True False F10.11 Visibility through smoke improves with increasing optical density. True False F10.12 Heat stress occurs when the skin is exposed to a heat flux of 1 kW/m2. the skin reaches a temperature of 45°C. the body’s core temperature reaches 41°C.

F7.10 The flame spread rate through porous solids increases with … Read More...
MAE 214 – Fall 2015 Homework 3 Due: October 1, 2015 – Thursday by 1:00 p.m. Total Problems: 4 (including Extra Credit), Total Points: 105 1. Make a solid works part model from the given figure below. All dimensions are in millimeters. All sketches must be fully defined. Also create a drawing sheet and dimension it as shown. You can use a hole call out option under annotation to dimension a counter bore hole. (30 points) Save your part files as follows: My Documents/Homework 3 Folder/Prob1_LastName.SLDPRT My Documents/ Homework 3 Folder/Prob1_LastName.SLDDRW 2. Make a solid works part of the given figure below and also make a drawing sheet – front, top and right side views using 3rd angle projection method. Dimension the views with appropriate dimension technique. All dimensions are in mm. (30 points) Save your part file and drawing sheet as follows: Documents/Homework 3 folder/Problem 2_Last Name.SLDPRT Documents/Homework 3 folder/Problem 2_Last Name.SLDDRW 3. Make a solid works part file for the given figure below. All sketches must be fully defined. Your design tree menu must have advanced features i.e. plane, mirror, and fillet. The spot facing (SF) must be defined in a problem. The inclined cut must be created with an offset sketch and extrude cut or a suitable sketch that uses “up to surface” option. (40 points) Your part model must stick to the isometric view as it is shown here. Save your part file into: My documents/Homework 3 Folder/Problem3_Last Name.SLDPRT Given: A = 76 B = 127 Unit: MMGS ALL ROUNDS (FILLET) EQUAL 6 MM 4. (Extra Credit) Make a solid works part from the given figure below. All sketches must be fully defined. Save your part file to Documents/Homework3 Folder/Prob#4_Last Name.SLDPRT All dimensions are in millimeters. (5 points)

## MAE 214 – Fall 2015 Homework 3 Due: October 1, 2015 – Thursday by 1:00 p.m. Total Problems: 4 (including Extra Credit), Total Points: 105 1. Make a solid works part model from the given figure below. All dimensions are in millimeters. All sketches must be fully defined. Also create a drawing sheet and dimension it as shown. You can use a hole call out option under annotation to dimension a counter bore hole. (30 points) Save your part files as follows: My Documents/Homework 3 Folder/Prob1_LastName.SLDPRT My Documents/ Homework 3 Folder/Prob1_LastName.SLDDRW 2. Make a solid works part of the given figure below and also make a drawing sheet – front, top and right side views using 3rd angle projection method. Dimension the views with appropriate dimension technique. All dimensions are in mm. (30 points) Save your part file and drawing sheet as follows: Documents/Homework 3 folder/Problem 2_Last Name.SLDPRT Documents/Homework 3 folder/Problem 2_Last Name.SLDDRW 3. Make a solid works part file for the given figure below. All sketches must be fully defined. Your design tree menu must have advanced features i.e. plane, mirror, and fillet. The spot facing (SF) must be defined in a problem. The inclined cut must be created with an offset sketch and extrude cut or a suitable sketch that uses “up to surface” option. (40 points) Your part model must stick to the isometric view as it is shown here. Save your part file into: My documents/Homework 3 Folder/Problem3_Last Name.SLDPRT Given: A = 76 B = 127 Unit: MMGS ALL ROUNDS (FILLET) EQUAL 6 MM 4. (Extra Credit) Make a solid works part from the given figure below. All sketches must be fully defined. Save your part file to Documents/Homework3 Folder/Prob#4_Last Name.SLDPRT All dimensions are in millimeters. (5 points)

1 CE 321 PRINCIPLES ENVIRONMENTAL ENGINEERING LAB WORKSHEET No. 1 Due: One (1) Week After Each Lab Section, respectively MICROBIOLOGY Environmental engineers employ microbiology in a variety of applications. Testing for coliform bacteria is used to assess whether pathogens may be present in a water or wastewater sample. Coliforms are a type of bacteria that live in the intestines of warm blooded mammals, such as humans and cattle. They are not pathogens, but if they are present in a sample, it is taken as an indication that fecal material from humans or cattle has contacted the water. If fecal material is present, pathogens may be present, too. In water treatment, coliform counts must average less than one colony per 100 milliliters of sample tested. In wastewater treatment, typical acceptable levels might be 200-colonies/100 mL. There are two standard ways to test for coliforms, the Most Probable Number test, MPN (also called the multiple tube fermentation technique, MTF) and the membrane filter test, MF. Several companies market testing systems that are somewhat simpler, but these cannot be used by treatment plants until they receive EPA approval. Two recently accepted methods are the Minimal Media Test (Colilert system), and the Presence-Absence coliform test (P-A test). Wastewater treatment plant operators study the microorganism composition of the activated sludge units in order to assess and predict the performance of the biological floc. A sample of mixed liquor from the aeration basin is examined under the microscope, and based on the relative predominance of a variety of organisms that might be present; the operator can tell if the BOD application rates and wasting rates are as they should be. For your worksheet, please submit the items requested below (10 pts. each): 1. Examine a sample of activated sludge under the microscope (To be done together in class). Use the Atlas, Standard Methods, or other references to identify at least 5 different organisms you observed. List them and sketch them neatly on unlined paper. Describe their motility and any other distinctive characteristics as you observed it. 2. Explain what types of organisms you might expect to find in sludge with a high mean cell residence time (MCRT), and explain why these would predominate over the other types. 3. How can the predominance of a certain kind of microorganism in activated sludge affect the settling characteristics of the sludge? Give several examples. 2 4. Explain why coliforms are used as “indicator organisms” for water and wastewater testing. Name two pathogenic bacteria, two pathogenic viruses, and one pathogenic protozoan sometimes found in water supplies. 5. There is also a test for fecal coliforms. Use your class notes and outside references to explain the distinctions between the tests for total and fecal coliforms. Explain why one would use the fecal coliform test instead of the test for total coliforms. 6. Using outside references, indicate typical coliform limits for surface waters used for swimming and fishing; potable water; and wastewater treatment plant effluent. 7). In the recent past, EPA instituted regulations designed to insure that Giardia are removed from the water. Using your text or other references, explain what kind of organism this is, and explain the way in which EPA has set standards to insure they are removed during water treatment. 8. What is meant by “population dynamics”? What two factors usually control the population dynamics of a mixed culture? 9. Use the MPN test data from the samples prepared for class prior to determine the number of coliforms present in the wastewater samples. Please show your work and explain your reasoning. Total Coliforms Raw Intermediate Effluent Sample Volume No. Positive No. Positive No. Positive 10 5 5 4 1 5 5 2 0.1 5 3 1 0.01 5 1 0 0.001 2 1 —- 0.0001 1 —- —- FecalColiforms Raw Intermediate Effluent Sample Volume No. Positive No. Positive No. Positive 10 5 5 2 1 5 4 0 0.1 5 2 1 0.01 1 0 0 0.001 0 0 —– 0.0001 2 —– —– 3 10. Use the membrane filter test data given in class to determine the number of total coliforms and fecal coliforms present in the sample. Please show your work and explain your reasoning. Total Coliforms Fecal Coliforms Dilution Colonies Dilution Colonies Raw Influent 0.1 mL/100 mL 58 1 mL/100 mL 47 Intermediate 1 mL/100 mL 13 10 mL/100 mL 28 Wetland Effluent 10 mL/100 mL 10 100 mL/100 mL 15

## 1 CE 321 PRINCIPLES ENVIRONMENTAL ENGINEERING LAB WORKSHEET No. 1 Due: One (1) Week After Each Lab Section, respectively MICROBIOLOGY Environmental engineers employ microbiology in a variety of applications. Testing for coliform bacteria is used to assess whether pathogens may be present in a water or wastewater sample. Coliforms are a type of bacteria that live in the intestines of warm blooded mammals, such as humans and cattle. They are not pathogens, but if they are present in a sample, it is taken as an indication that fecal material from humans or cattle has contacted the water. If fecal material is present, pathogens may be present, too. In water treatment, coliform counts must average less than one colony per 100 milliliters of sample tested. In wastewater treatment, typical acceptable levels might be 200-colonies/100 mL. There are two standard ways to test for coliforms, the Most Probable Number test, MPN (also called the multiple tube fermentation technique, MTF) and the membrane filter test, MF. Several companies market testing systems that are somewhat simpler, but these cannot be used by treatment plants until they receive EPA approval. Two recently accepted methods are the Minimal Media Test (Colilert system), and the Presence-Absence coliform test (P-A test). Wastewater treatment plant operators study the microorganism composition of the activated sludge units in order to assess and predict the performance of the biological floc. A sample of mixed liquor from the aeration basin is examined under the microscope, and based on the relative predominance of a variety of organisms that might be present; the operator can tell if the BOD application rates and wasting rates are as they should be. For your worksheet, please submit the items requested below (10 pts. each): 1. Examine a sample of activated sludge under the microscope (To be done together in class). Use the Atlas, Standard Methods, or other references to identify at least 5 different organisms you observed. List them and sketch them neatly on unlined paper. Describe their motility and any other distinctive characteristics as you observed it. 2. Explain what types of organisms you might expect to find in sludge with a high mean cell residence time (MCRT), and explain why these would predominate over the other types. 3. How can the predominance of a certain kind of microorganism in activated sludge affect the settling characteristics of the sludge? Give several examples. 2 4. Explain why coliforms are used as “indicator organisms” for water and wastewater testing. Name two pathogenic bacteria, two pathogenic viruses, and one pathogenic protozoan sometimes found in water supplies. 5. There is also a test for fecal coliforms. Use your class notes and outside references to explain the distinctions between the tests for total and fecal coliforms. Explain why one would use the fecal coliform test instead of the test for total coliforms. 6. Using outside references, indicate typical coliform limits for surface waters used for swimming and fishing; potable water; and wastewater treatment plant effluent. 7). In the recent past, EPA instituted regulations designed to insure that Giardia are removed from the water. Using your text or other references, explain what kind of organism this is, and explain the way in which EPA has set standards to insure they are removed during water treatment. 8. What is meant by “population dynamics”? What two factors usually control the population dynamics of a mixed culture? 9. Use the MPN test data from the samples prepared for class prior to determine the number of coliforms present in the wastewater samples. Please show your work and explain your reasoning. Total Coliforms Raw Intermediate Effluent Sample Volume No. Positive No. Positive No. Positive 10 5 5 4 1 5 5 2 0.1 5 3 1 0.01 5 1 0 0.001 2 1 —- 0.0001 1 —- —- FecalColiforms Raw Intermediate Effluent Sample Volume No. Positive No. Positive No. Positive 10 5 5 2 1 5 4 0 0.1 5 2 1 0.01 1 0 0 0.001 0 0 —– 0.0001 2 —– —– 3 10. Use the membrane filter test data given in class to determine the number of total coliforms and fecal coliforms present in the sample. Please show your work and explain your reasoning. Total Coliforms Fecal Coliforms Dilution Colonies Dilution Colonies Raw Influent 0.1 mL/100 mL 58 1 mL/100 mL 47 Intermediate 1 mL/100 mL 13 10 mL/100 mL 28 Wetland Effluent 10 mL/100 mL 10 100 mL/100 mL 15

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