Green Components Drive Plant Expansion to Sustainable Solution

About the Program

Category: County Resiliency (Best in Category)

Year: 2011

The Douglass L. Smith Middle basin (DLSMB) wastewater Treatment Plant, located in the heart of a residential community, was recently expanded from 12 million gallons per day (MGD) to 14.5 MGD and upgraded to meet strict total nitrogen and phosphorus effluent goals. A key objective of this project, undertaken after the plant expansion, was to expand and enhance the plant’s anaerobic digestion process to cost-effectively treat solids from the upgraded liquid treatment stream expansion. In addition, Johnson County Wastewater’s (JCW’s) commitment to triple-bottom line sustainable infrastructure enabled integration of additional systems into the project to: eliminate landflling and provide beneficial reuse of biosolids trucked in from another plant; provide a convenient receiving station and beneficial reuse of FOG waste streams; nearly eliminate flaring and wasting of digester gas through installation of a combined heat and power cogeneration system that provides about half of the electricity required by the plant; reduce the plant’s carbon footprint; and minimize noise, visual , and odor aesthetic impacts on neighbors. The project includes an anaerobic digester, a methane gas cleaning system, a gas storage sphere, two cogeneration units, and FOG receiving and storage system.