Microbiology: A Systems Approach 4th Edition by Marjorie Kelly Cowan

Exercise 22

Critical thinking is the ability to reason and solve problems using facts and concepts. These questions can be approached from a number of angles and, in most cases, they do not have a single correct answer.
a. Summarize one beneficial use of sludge today, and discuss one potential environmental risk in the use of this substance.
b. Explain how waste is handled in the United States when the household is not connected to a sewage treatment facility.