Today we had our first technical visit of the dialogue.  For me, it was super interesting because I was able to see first hand everything that I have learned in class the past semester and on this dialogue.  It was also extremely cool to see how various waste streams are treated and all of the processes and machinery behind them as compared to the simplified examples that we see in class.  On top of that, the volume of waste that we saw today really puts into perspective the importance of proper waste management and why we as environmental engineers are needed.  The first stop on our trip was to a private paper recycling facility.  The facility accepts all types of paper products but I found it interesting that the highest price of paper that they obtain is cardboard.  The facility from my perspective was rather condense and small but apparently it processes roughly half of the total paper from Sardinia.  I also found it interesting that the facility not only processes and bales the paper, but makes new paper products on site.  To make the new paper, the mixed paper is added to water and turned to a pulp where it is filtered through a sieve.  The pulp mixture is then sent through a cyclone where heavy particles are settled out to make the mixture more pure.  The pulp then goes to a gravity separator followed by an even smaller screen and then sent to the press.  At this stage, the mixture is roughly 99 percent water and 1 percent paper.  The mixture goes through the press and the water is steamed off and the final product is the paper we know and love (Kinda).  The whole process only has a five percent loss of the original amount of paper.  Below is a picture of one of the unloading sites.

The next part of our tour was to the composting facility.  This facility handles the organic portion of the waste stream.  Initially, organics from food waste and yard waste are sent to a cell where they sit for 30 days as air is forced through the pile.  After the 30 days, the pile is sent outside to sit for 60 days where it is turned over to finish the process of composting.  One interesting thing to note is that at one point they have to heat the pile to 55  degrees Celsius and let that sit at that temperature for 3 days.  The facility also has a bio-filter of wood-chips to help null the odor of the compost.  One last interesting thing to note is that the facility only sells the compost for 2 Euros per ton due to the fact that it is a public facility.  Below is a picture of the compost piles undergoing the 60 day waiting period.  

Oh...and we met a cool friend along the way!

Our final stop along the trip was to the waste to energy facility.  The two cool things that stuck out to me was the shear amount of waste processed (450 tonne/day) as well as the air pollution control measures post combustion due to my air pollution class that I took this past spring.  The facility has two main combustion chambers, one to treat municipal solid waste, and the other to treat hazardous waste.  The MSW incinerator operated at 900 degrees Celsius and used a moving grate to transport the material whereas the hazardous waste incinerator operated at 1300 degrees Celsius and used a rotating kiln for more thermal contact.  As compared to the MSW incinerator that has only 2 air pollution control measures (Baghouse and Wet Scrubber), the hazardous waste incinerator air was treated by four control measures (ESP, Baghouse, Dry Scrubber, and more).  Below is a picture of the ESP (Off to the bottom left corner) as well as the hazardous waste exhaust stack (65 meters tall).

Overall, today was pretty darn neat.