Visiting the "Jersey" of Cagliari

May 20^th

Our class started off the morning with a field trip to Papiro Sarda a paper recycling facility across the harbor from downtown Cagliari. It consumes approximately half of the mixed paper, cardboard and office/printer paper from the city of Sardinia. The mixed paper and cardboard is used to make more cardboard whereas the fiber in office paper is of a higher quality than the mixed paper and can be used to make things such as recycled notebook paper. A majority of the paper they produce happens to be cardboard and there is only one paper mill in the facility, so they only produce the higher quality notebook paper about 1% of the time. In both cases the paper products are fed into the pulping machine where the paper is mixed with water in order to break the bonds between the fibers in the material and make it a homogeneous mixture.

As a liquid, contaminates and solid objects can be more easily filtered out of the mixture as the pulp passed through the sieve at the bottom of the pulp tank. From there the pulp passed through one last cyclone filtering out finer particles and then straight onto the production line where the water content was reduced to about 50% before it entered the drying drums were the moisture content is taken down to the final 5-7%.

During the process the final paper product weighs approximately 95% of the initial input mass and all of it is reused in either notebooks, paper bags or cardboard boxes.

After lunch we traveled to a waste to energy facility operated by Tecnocasic where both industrial and municipal waste is disposed of. Waste is taken from collection trucks and placed into a hopper. All waste is then ground up and homogenized so that it can be more easily burned. Steam produced from the incinerator runs two turbines that generate a combined 13MW. Fly ash and other contaminates are subsequently filtered out of the smoke which is then released into the atmosphere. Those byproducts are then landfilled or can be used in products like concrete.

In an adjacent facility also run by Tecnocasic organic waste is filtered and composted over the course of 90 days. The final compost is then sold to large local farms to be used to fer.

Both facilities in addition to a wastewater treatment facility consume 4 of the 13MW produced by the incineration facility while processed water is used as cooling water for the incinerator. The remaining energy produced by the facility is then sold back to the electric company.  All 3 facilities operate in a highly synergistic manner. With this model waste volume is dramatically reduced while the population benefits from having a cheap energy source and new nutrients for their food all while minimizing how much material is placed in their nearby landfill.