EGG-SHAPED ANAEROBIC DIGESTION AN EMERGING TECHNOLOGY

In 1977 the city of Los Angeles embarked upon a plant upgrade, which included Egg-Shaped anaerobic digesters, at their Terminal Island facility. These vessels were the first units built in North America with the shape commonly referred to as the Egg-Shaped Digester (ESD™).The construction of Terminal Island led to two more projects in the late 1980's. However, it wasn't until 1989 that the ESD Technology began to take hold in North America. In recent years the number of ESD facilities have nearly doubled and there are more communities choosing the ESD technology for anaerobic digestion.Why has the ESD technology experienced such growth over the past few years?What are the factors considered when choosing this technology?Are Egg-Shaped Digesters a viable option for any size community?This paper will provide a brief history of the ESD technology in North America. As part of the historical review we will explore some of the issues that are driving the market for Egg-Shaped digesters. Some of these include:Benefits of the ESD technologyImprovements to the original process designsCost comparisonsOperating experience