APES Unit 4 FRQ's LATEST 2022

Identify one component of the sewage that is targeted for removal by primary treatment and one component of the sewage that is targeted for removal by secondary treatment. - One component targeted for primary treatment is sludge (dirt, rocks, stuff that sinks). And one thing that is targeted by secondary treatment is scum (stuff that floats or dissolved). For each of the pollutants that you identified in part A, describe how the pollutant is removed in the treatment process. - Sludge is removed by a settling tank or by putting the water through a semipermeable membrane. Scum/dissolved particles are removed by chlorination or by putting O2 in so aerobic bacteria break it down. Explain how sewage treatment plants create the solid waste problem that Dr. Goodwin mentioned in the article. - The plants have to dispose of the solid-waste somewhere and sometime it can make its way into water. Two common methods of disposing of solid waste from sewage treatment plants are transporting it to a landfill or spreading it onto agricultural lands. Describe an environmental problem associated with each of these methods. - Landfills cause groundwater contaminations of methane production (global warming). Agricultural use can cause runoff into freshwater sources (eutrophication). The final step in sewage treatment is disinfection. Identify one pollutant that is targeted during disinfection and identify one commonly used method of disinfection. - E.coli is target and treated by chlorine. Identify one US federal law that requires monitoring the quality of the t