The Johnson City Regional Wastewater Treatment Plant (JCRWWTP) was originally constructed in 1978 with a capacity of 1.5 MGD. Due to the continuous growth in residential and commercial development and the city’s goal to take a proactive approach in meeting tighter discharge limits, using biological nutrient removal (BNR), the city partnered with SSR. Working with city leaders, the SSR team reviewed the treatment needs for the community and examined possible upgrade options for the plant.

Our research indicated that with aging equipment and growth projections that indicated sustained development in the area, considerable changes to the treatment process were necessary. Keeping in mind the city’s need for a budget conscious sustainable design, SSR stressed to provide cost effective and energy efficient solutions into the expansion and renovation of JCRWWTP. Because the existing treatment process needed to remain in service during construction, careful coordination and phasing was imperative to ensure a seamless transition with no interruption in service.

To reduce costs the expansion was designed to remain within the existing site boundaries, requiring no additional land acquisition. With the intent of minimizing the carbon footprint, single stage high efficiency centrifugal blowers, fine bubble diffusers, and variable frequency drives on large equipment motors were incorporated. Additionally, the installation of a decanter centrifuge for on-site dewatering of the plant’s biosolids significantly reduced the number of trucks required to haul processed sludge to the landfill. By incorporating radial vane blowers and the fine bubble diffusion grid technology together, they provide significant reductions in the overall energy consumption at the new plant compared to the old facility.

SSR provided all engineering design and construction administration services for the expansion and renovation of the JCRWWTP. Due to its extensive improvements, the plant is now rated at a capacity of 6.0 MGD, and can handle hydraulic surges of 15.0 MGD.  Since completion in 2010, SSR has continued to work with the City of Johnson City to improve the plant performance and reduce the operational costs.