The Last Resort

Yesterday we drove about an hour to go see how another method of waste management is done. This is the last method on the European Union's hierarchy of waste management systems, the one used when there is no other option. We went to a landfill. 

The road was quite bumpy but once we got there we were able to go outside and see the gigantic area that the waste occupied (see Figure 1). I learned that this land was previously used to store waste and then covered with a clay top for the placement of hazardous waste. 

         Figure 1: Waste Storage Area 

The hazardous waste is ash that was obtained from an incinerator and then chemically treated for any hazardous substances before being placed in the ground. There is still however a little bit of  chemicals that are left in the ash that would become leachate when it rains. The leachate is collected by placing perforated pipes at the bottom of the waste and sloping the ground towards them. 

What was unique about this landfill is that it uses both vertical and horizontal collection systems one for collecting the leachate and the other collected the biogas that comes from the ash decaying. The leachate is stored in the containers shown in Figure 2 and then sent to a municipality for treatment while the gas is used as energy both electrical and thermal. The electrical is sold back to the grid and then thermal is used to treat the GHG. 

       Figure 2: Leachate Storage Tanks

There are a lot of things that can come from using a landfill which I found very interesting. I always thought that landfills were just mountains of garbage, but this landfill is actually being utilized well and the energy recovery generated is key to environmental sustainability.