Anaerobic Digestion + Some

The plant we visited today had four components to its waste management. It had landfills, an anaerobic digester, a composting plant, and a sewage plant. The combination of these components could in theory, lead to a fairly sustainable system. There were many problems me and some of my classmates had with the system present however. While it is great that they weren’t simply using landfilling (it is illegal after all), or going with the cheaper composting option to handle organics, they had many inefficiencies present. While the facility currently uses 3.7 million kWh per year, it only produces 2.5 kWh each year. The facility collects biogas from a closed landfill as well as from the anaerobic digestion process and has both solar and wind energy collection. Between all of these, I would hope that the plant could at least break even. My impression is that this is due to the sewage treatment and its high energy cost. Many of the inefficiencies are due to the changing requirements and additions over time. Looking at this plant gives me a lot of ideas about how I would organize and plan a better, sustainable collection of waste management treatment methods.