The past couple of days I have had the opportunity to dive head first into the world of waste management. Throughout lectures, I have had the opportunity to learn about the basics of recycling(paper, plastic, glass, etc), composting, waste to energy treatments. I have learned not only how the waste is managed but also the basic policy the U.S. has for each topic. Today specifically I learned a lot visually by being able to visit several waste management plants in Cagliari.
First we visited a paper recycling plant where we were able to see the entire process of high quality paper being made from high quality paper. This was a special process running today and only accounts for about 1-2% of the paper they make. The rest of the products made use mixed paper/cardboard to make either mixed paper or cardboard. First, the paper is compressed into cubes, then put into a pulper and filtered physically. Then, the remaining pulp goes through a series of compressors and rollers and is heated to evaporate the water slowly throughout the process. Doing so eliminates the colors in the paper due to specific density of the particles and results in white, high quality paper. I expected more chemicals to be involved-surprised and fascinating to see it be done without them!
Next we went to the organic composting plant. Here we were able to see the composting of all food, which normally takes several years in nature. In the plant, they force air to the food, and in result the total process takes only 3 months. The process is divided up into 4 chambers, first is the collected chamber in which they separate the plastics and in organics from the retrieved food. Then the food sits in the next chamber for about 30 days indoors with the forced air. Then the product is sent to the refining state to get rid of any impurities. Lastly, the composting food sits outdoors for the remaining days. The food is kept track of and certain batches are sent to certain areas upon request. This is a non-profit process, selling a block only for 2 euros for the consumer! The government pays the company money as well though for taking the trash.
Lastly, we went to the waste to energy plant. In this plant, they make the waste into a sludge and dry the water out. Next, they send the remnants to the furnace and collect the steam that exits. The other remaining byproducts are treated with phosphate and NaOH to make inert and non-hazardous. The stream is then filtered through several steps to make it optimal for entering the turbine. Then it goes through the standard vapor-compressor/Rankine cycle to generate electricity. They are able to power their own plant as well was create about 9 additional MW. Interesting to see all the big machinery and finally see my thermodynamics textbook come to life!
Though I came to Italy knowingly wanting to study waste management, seeing all the trash really was impacting seeing that it doesn't magically disappear and knowing that it does go somewhere.
First we visited a paper recycling plant where we were able to see the entire process of high quality paper being made from high quality paper. This was a special process running today and only accounts for about 1-2% of the paper they make. The rest of the products made use mixed paper/cardboard to make either mixed paper or cardboard. First, the paper is compressed into cubes, then put into a pulper and filtered physically. Then, the remaining pulp goes through a series of compressors and rollers and is heated to evaporate the water slowly throughout the process. Doing so eliminates the colors in the paper due to specific density of the particles and results in white, high quality paper. I expected more chemicals to be involved-surprised and fascinating to see it be done without them!
Next we went to the organic composting plant. Here we were able to see the composting of all food, which normally takes several years in nature. In the plant, they force air to the food, and in result the total process takes only 3 months. The process is divided up into 4 chambers, first is the collected chamber in which they separate the plastics and in organics from the retrieved food. Then the food sits in the next chamber for about 30 days indoors with the forced air. Then the product is sent to the refining state to get rid of any impurities. Lastly, the composting food sits outdoors for the remaining days. The food is kept track of and certain batches are sent to certain areas upon request. This is a non-profit process, selling a block only for 2 euros for the consumer! The government pays the company money as well though for taking the trash.
Lastly, we went to the waste to energy plant. In this plant, they make the waste into a sludge and dry the water out. Next, they send the remnants to the furnace and collect the steam that exits. The other remaining byproducts are treated with phosphate and NaOH to make inert and non-hazardous. The stream is then filtered through several steps to make it optimal for entering the turbine. Then it goes through the standard vapor-compressor/Rankine cycle to generate electricity. They are able to power their own plant as well was create about 9 additional MW. Interesting to see all the big machinery and finally see my thermodynamics textbook come to life!
Though I came to Italy knowingly wanting to study waste management, seeing all the trash really was impacting seeing that it doesn't magically disappear and knowing that it does go somewhere.
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