{"id":16353,"date":"2021-11-17T02:11:16","date_gmt":"2021-11-17T02:11:16","guid":{"rendered":"https:\/\/assignmenttutors.net\/blog\/environmental-environmental-science-homework-help\/"},"modified":"2021-11-17T02:11:16","modified_gmt":"2021-11-17T02:11:16","slug":"environmental-environmental-science-homework-help","status":"publish","type":"post","link":"https:\/\/assignmenttutors.net\/blog\/environmental-environmental-science-homework-help\/","title":{"rendered":"Environmental | Environmental science homework help"},"content":{"rendered":"
\n

\u00a0<\/p>\n

7) If the temperature of a sample increases, the BOD5<\/span>\u00a0will:<\/p>\n

Decrease<\/p>\n

8) An increase in temperature causes the DOs<\/span>\u00a0(saturation concentration of DO) to:<\/p>\n

Stay the same<\/p>\n

Decrease<\/p>\n

Increase<\/p>\n

9) As you move down the stream in a DO sag curve problem, which of the following changes (assuming constant temperature)?<\/p>\n

a)\u00a0DO<\/span><\/p>\n

b)\u00a0<\/span>k<\/span><\/p>\n

c)\u00a0<\/span>L<\/span>0<\/span><\/p>\n

d)<\/span>DO<\/span>s<\/span><\/p>\n

10) What best describes the environmental impact of releasing wastewater with high level of BOD into a river?<\/p>\n

a) The oxygen levels in the river will decrease and that will damage aquatic life.<\/span><\/p>\n

b)\u00a0<\/span>The pH will increase and that will damage aquatic life.<\/span><\/p>\n

c)\u00a0<\/span>Solid material will accumulate on the river floor.<\/span><\/p>\n

d)\u00a0<\/span>Toxins will be released that will damage aquatic life.<\/span><\/p>\n

\u00a0<\/span><\/p>\n

11)\u00a0<\/span>Algae have the formula C6<\/sub>H15<\/sub>O6<\/sub>N.\u00a0 In the presence of oxygen and microbes:<\/span><\/p>\n

a C6<\/sub>H15<\/sub>O6<\/sub>N + b O2<\/sub> <\/span>\u00e0<\/span> c CO2<\/sub> + d H2<\/sub>O + e NH3<\/sub><\/span><\/p>\n

NH3<\/sub> + 2 O2<\/sub> <\/span>\u00e0<\/span> NO3<\/sub>–<\/sup> + H+<\/sup> + H2<\/sub>O<\/span><\/p>\n

a.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>Balance the chemical equation.<\/span><\/p>\n

b.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>Calculate the ultimate CBOD for a 100 mg\/L solution of algae. (97.5 ppm)<\/span><\/p>\n

c.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>Calculate the NBOD for a 100 mg\/L solution of algae. (32.5 ppm)
Calculate 5-day BOD of a 100 mg\/L solution of algae with a k = 0.2 day-1<\/sup>. (61.6ppm)<\/span><\/p>\n

d.\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>If you were measuring the 5-day BOD in the lab, how many mL of this solution would you add to a 300 mL BOD bottle to ensure that the final DO doesn\u2019t drop below 1 ppm?\u00a0 Assume that the initial DO is 8.26 ppm. (35.4 mL)<\/span><\/p>\n

\u00a0<\/span><\/p>\n

12)<\/span>\u00a0 \u00a0<\/span><\/span>A mixture consisting of 30 mL of waste and 270 mL of seeded dilution water has an initial DO of 8.55 mg\/L; after five days, it has a final DO of 2.40 mg\/L.<\/span><\/p>\n

a.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>Graph the DO vs. time and the BOD vs. time in the mixture bottle.\u00a0 Assume the rate constant is 0.2 day-1<\/sup>. (hint: first you will need to calculate BOD5<\/sub> and Lo<\/sub> in the bottle.\u00a0 Also \u2013 the time should go from 0 days to 12 days. Please include the excel graph in your solutions.<\/span><\/p>\n

b.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>At what time will the oxygen be zero in the mixture bottle? (10.5 days)<\/span><\/p>\n

c.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>This sample requires a seeded BOD test.\u00a0 Given an example of the kind of samples that required a seeded BOD test.<\/span><\/p>\n

d.\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>The seeded bottle contains just the seeded dilution water and has an initial DO of 8.75 mg\/L and a final DO of 8.53 mg\/L. Find the five-day BOD of the waste. (59.5 ppm)<\/span><\/p>\n

\u00a0<\/span><\/p>\n

13)\u00a0\u00a0\u00a0<\/span><\/span><\/span>The Metropolitan Wastewater Treatment plant in St. Paul (180 MGD; BOD5 = 220 mg\/l, DO = 3 ppm) discharges into the Mississippi River (flow = 18,000 ft3\/s; mean depth = 14 ft; mean width = 0.3 miles).\u00a0 <\/span>The dissolved oxygen in the river is at the saturation concentration of 9.0 ppm and has an ultimate BOD of 2.0 mg\/L.\u00a0\u00a0 <\/span>The deoxygenation rate for BOD is 0.23 day-1<\/sup> and the re-aeration rate is 0.15 day-1<\/sup>. <\/span><\/p>\n

a.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span>Calculate the ultimate BOD in the Wastewater discharge. (322 ppm)<\/span><\/p>\n

b.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span>Calculate the ultimate BOD in the river at the point where the discharge and the river meet.\u00a0 <\/span>What is the value of the initial deficit to be used in the DO sag curve? (0.09 ppm)<\/span><\/p>\n

c.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span>Graph DO (in ppm) as a function of distance in miles<\/span>.\u00a0 <\/span>Print out the graph and attach it to the homework.\u00a0 <\/span><\/span><\/p>\n

d.\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span>What is the distance where the concentration of DO would be a minimum?\u00a0 <\/span>(feel free to just label the graph) (70 miles)<\/span><\/p>\n

e.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span>Calculate the minimum DO at the critical time (feel free to label the graph) \u00a0<\/span>(5.87 ppm)<\/span><\/p>\n

f.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span>What is the minimum DO concentration if kr<\/sub> is 0.1 day-1<\/sup> instead of 0.15
day-1<\/sup>? (To answer you can either print out a new graph or solve the equation to find the answer.) (5.33 ppm)<\/span><\/p>\n

g.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span>Name one assumption that you made to solve this problem.\u00a0 <\/span>What would happen if this assumption is not true? (note: You can use the givens as assumptions since in the real world you would need to question these givens.<\/span><\/p>\n

14)\u00a0 \u00a0\u00a0<\/span><\/span><\/span>Wastewater from a paper mill contains many organic compounds including lignin C31<\/sub>H34<\/sub>O11<\/sub>.\u00a0 <\/span><\/span><\/p>\n

a.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span>Calculate the ultimate BOD resulting from 150 ppm lignin.<\/span><\/p>\n

b.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span>Assume that you using an unseeded BOD\u00ad5<\/sub> test.\u00a0 <\/span>You know the ultimate BOD is 200 ppm.\u00a0 <\/span>What volume of sample would you add to a 300 mL 5-day BOD bottle if you want the final DO after 5 days to be 2 ppm?\u00a0 <\/span>Assume the initial DO is 9 ppm and the k = 0.15 day-1<\/sup>. <\/span><\/p>\n

c.\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/em><\/strong>Now assume that the discharge has a 5-day of 180 ppm and a DO of 2.5 ppm.\u00a0 <\/span>This water is discharged at a rate of 0.2 MGD into a river with DO =\u00a0 <\/span>DOs<\/sub> of 9.09 ppm and no BOD.\u00a0 <\/span>The river has a flow of 1 million gallons per day before the discharge.\u00a0\u00a0 <\/span>kd<\/sub> = 0.18 day-1<\/sup> and kr<\/sub> = 0.2 day-1<\/sup>.\u00a0 <\/span>The area of the river is 100 ft2<\/sup>.At what distance downstream will the DO be a minimum? <\/span><\/p>\n

Imagine that initially the temperature is 25 \u02daC and then it changes to 20 \u02daC.\u00a0 Explain in words what would happen to the DO when the temperature changes.<\/span><\/p>\n<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

\u00a0 7) If the temperature of a sample increases, the BOD5\u00a0will: Decrease 8) An increase in temperature causes the DOs\u00a0(saturation concentration of DO) to: Stay the same Decrease Increase 9) As you move down the stream in a DO sag curve problem, which of the following changes (assuming constant temperature)? a)\u00a0DO b)\u00a0k c)\u00a0L0 d)DOs 10) […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[31],"tags":[],"class_list":["post-16353","post","type-post","status-publish","format-standard","hentry","category-homework-help"],"_links":{"self":[{"href":"https:\/\/assignmenttutors.net\/blog\/wp-json\/wp\/v2\/posts\/16353","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/assignmenttutors.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/assignmenttutors.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/assignmenttutors.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/assignmenttutors.net\/blog\/wp-json\/wp\/v2\/comments?post=16353"}],"version-history":[{"count":0,"href":"https:\/\/assignmenttutors.net\/blog\/wp-json\/wp\/v2\/posts\/16353\/revisions"}],"wp:attachment":[{"href":"https:\/\/assignmenttutors.net\/blog\/wp-json\/wp\/v2\/media?parent=16353"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/assignmenttutors.net\/blog\/wp-json\/wp\/v2\/categories?post=16353"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/assignmenttutors.net\/blog\/wp-json\/wp\/v2\/tags?post=16353"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}