Field Trip

We were given the opportunity to travel to three different types of environmental facilities.   First we visited a sewage treatment facility, next a recycling center, and finally a water treatment plant.   At each one our class was given a guided tour where we were able to see firsthand the inner workings of the facilities and given detailed descriptions on how the plant operates.
First was the wastewater treatment facility where all the raw sewage from the town is piped to so that it can be cleaned and released back into the environment.   It   includes physical, biological and chemical   processes to remove physical, biological and chemical contaminants.   It’s goal is to produce a waste stream and a solid waste or sludge that is suitable for discharge or reuse back into the environment.   Raw sewage includes household waste liquid from toilets, baths, showers, kitchens, sinks and so on that is disposed of via sewers.   In most areas, it also includes liquid waste from industry and commerce as well.   The sewage also comes from surface water from roofs or standing areas.  
Cleaning the water starts with the primary treatment.   This treatment first removes the materials that can be easily collected from the raw wastewater and disposed of.   These materials consist of fats, oils, greases, sand, and gravel.   This is done entirely with machine.   Also at this time a system of rakes and screens remove large objects that have been deposited in the sewer system such as sticks, cans, and rags.   There was also a sedimentation tank, in this tank solids can settle at the bottom while floating materials can be skimmed off the top.   The main purpose of this portion of treatment is so that the liquid can become generally homogeneous and easily treated biologically.
Secondary treatment is designed to substantially degrade the biological content of the sewage.   The majority of plants treat the settled sewage liquid using aerobic biological processes.   In order for this to work the...