The water supply for a midwestern city contains the following impurities: coarse sand, finely divided particulates, nitrate ions, trihalomethanes, dissolved phosphorus in the form of phosphates, potentially harmful bacterial strains, dissolved organic substances. Which of the following processes or agents, if any, is effective in removing each of these impurities: coarse sand filtration, activated carbon filtration, aeration, ozonization, precipitation with aluminum hydroxide?

Video transcript

Hey everyone were asked which of the following statements is true regarding the removal of impurities. Looking at our first statement, we have no filtration process is available to filter, dissolve nitrates and phosphates. This statement is going to be false and the reason why is because dissolved nitrates and phosphates can be rendered less harmful by adequate aeration. Looking at our second statement, we have activated carbon filtration or aeration can filter try halo methane. The statement is going to be correct and the use of activated carbon might be preferred only due to the fact that it does not involve the release of try halo methane into the atmosphere. Next looking at our statement three, we have fine sand filtration can filter coarse sand. This statement is going to be incorrect and the reason why is because coarse sand is filtered by coarse sand filtration. And lastly, looking at our statement for we have precipitation with aluminum hydroxide can filter bacteria and finally divided particles. This statement is going to be correct and the remaining harmful bacteria are removed by ozonation. So our true statements here are going to be two and 4. So I hope this made sense. And let us know if you have any questions