BEM 4351 Unit I Assessment

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Review Test Submission: Unit I Assessment

Content

User  
Course BEM 4351-18F-2B20-S2, Environmental Technology
Test Unit I Assessment
   
   
   
   
   
Attempt Score Grade not available.  
Time Elapsed 20 hours, 45 minutes
Instructions Assessment Instructions
Results Displayed Submitted Answers, Correct Answers, Feedback

Question 1

40 out of 40 points

   
  Match each item to the appropriate answer.      
  QuestionCorrect MatchSelected MatchHardnessA. calcium and magnesiumA. calcium and magnesium5 mg/LJ. 5000 ppbJ. 5000 ppb500 mg/LE. 0.05%E. 0.05%Hudson River food chainD. PCBsD. PCBsFlood controlC. detention pondC. detention pondRachel Carson’s Silent SpringF. DDTF. DDTWaterborne diseaseI. choleraI. choleraMinamata BayH. mercuryH. mercuryDisinfectantG. chlorineG. chlorineInsect-borne diseaseK. malariaK. malaria      

Question 2

Needs Grading

   
  Describe dissolved oxygen, biochemical oxygen demand, and chemical oxygen demand. How are they different? What is the usefulness of knowing the concentration of each of them? Your response should be at least 200 words in length.      
  Selected Answer: According to Nathanson and Schneider, dissolved oxygen, usually abbreviated as DO, is generally considered to be one of the most important parameters of water quality in streams, rivers, and lakes. Just as people need oxygen in the air they breathe, fish and other aquatic organisms need DO in the water to survive. With most other substances, the less there is in the water, the better is the quality. But the situation is reversed for DO. The higher the concentration of dissolved oxygen, the better is the water quality. Oxygen solubility is very sensitive to temperature. Changes in water temperature have a significant effect on DO concentrations. The solubility of oxygen in water decreases as the temperature increases. Nathanson and Schneider describes Biochemical Oxygen Demand (BOD), as the amount of oxygen required by microorganisms to decompose organic waste in water. Bacteria and other microorganisms use organic substances for food. As they metabolize organic material, they consume oxygen. The organics are broken down into simpler compounds, such as CO2 and H2O, and the microbes use the energy released for growth and reproduction. Microbes need oxygen and the need for oxygen is called the Biochemical Oxygen Demand. The amount of organic pollution in water can be measured by using BOD. Nathanson and Schneider explain that chemical oxygen demand, or COD, is another parameter of water quality, which measures all organics, including the nonbiodegradable substances. The definition of chemical oxygen demand is the amount of oxygen needed to oxidize all the organics in a wastewater sample. Chemical oxygen demand is used to measure the level of organic pollution. COD is a chemical test using a strong oxidizing agent (potassium dichromate), sulfuric acid, and heat. The results of a COD test can be available in just 2 hours, a definite advantage over the 5 days required for the standard BOD test. Because most wastewater treatment plants are biological in their mode of operation, the BOD is more representative of the treatment process and remains a more commonly used parameter than the COD. Nathanson, J. A., & Schneider, R. A. (2015). Basic environmental technology: Water supply, waste management, and pollution control (6th ed.). Upper Saddle River, NJ: Pearson. Correct Answer: [None] Response Feedback: [None Given]      

Question 3

Needs Grading

   
  What are the benefits of a drinking water treatment plant? In your response, include the origins of municipal drinking water treatment. Your response should be at least 200 words in length.      
  Selected Answer: Clean water is provided by wastewater treatment plants. Wastewater treatment plants help the environment by cleaning water that would have otherwise been written off as unsanitary and disposed of. A significant amount of biodegradable material is remove from water in the treatment process. This can then be used to produce methane gas and be used as a source of electricity. According to S.M. Enzler’s History of water treatment on Lenntech.com, the origins of water treatment dates all the way back to 2000 BC. In the 1700s the first water filters made of wool, sponge, and charcoal were applied for domestic applications. In 1804 the first actual municipal water treatment plant designed by Robert Thom, was built in Scotland. The water treatment based on slow sand filtration, and horse and cart distributed the water. Some three years later, the first water pipes were installed. The suggestion was made that every person should have access to safe drinking water, but it would take somewhat longer before this was actually brought to practice in most countries. A discovery that a cholera epidemic spread through water in 1854 expedited the first government regulation for public water. British scientist John Snow found that the direct cause of the outbreak was water pump contamination by sewage water. This discovery led to governments starting to install municipal water filter. Lee, Danielle (2017, June 13). Hit News Center 4 environmental benefits of wastewater treatment. Retrieved from: http://www.hitnewscenter.com/featured/4-environmental-benefits-of-wastewater-treatment/ History of water treatment (n.d.) Retrieved from: https://www.lenntech.com/history-water-treatement.htm  +      



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