Biosolids Facility TBL Analysis


Overview

For decades, the Germantown and Salemtown neighborhoods in Nashville suffered from persistent challenges associated with sewage waste management—heavy truck traffic, pervasive odors, and significant community disruption. Nashville Metro Water Services responded with a bold $136 million investment in a cutting-edge Biosolids Facility that would fundamentally reimagine urban waste processing.

Prior to this innovative facility, raw sewage sludge was transported long distances, often facing disposal challenges that resulted in backups, odors, and increased municipal liability. Due to the facility’s decision to invest upfront in a better design, the long-term economic, social, and environmental benefits will prove transformative.

Wilmot’s Role

Wilmot conducted a Triple Bottom Line analysis to evaluate the impact of the Biosolids Facility, revealing a remarkable $493 million in total benefits. Our team's assessment went beyond traditional infrastructure evaluation, demonstrating the project's multifaceted value.

Key benefits identified included:

  • Environmental Improvements

    • Significant reductions in greenhouse gas emissions

    • Mitigation of criteria air pollutants

    • Reduction of nitrogen runoff

    • Potential for future biogas reuse

  • Economic Advantages

    • Substantial operations and maintenance savings

    • Sludge disposal cost reductions

    • Revenue generation from biosolid pellet production

    • Savings to the agricultural industry

    • Increased property values

    • Avoided legal liabilities

The facility now processes sewage sludge into fertilizer pellets, creating a valuable soil amendment used in agriculture, erosion control, and landscaping. By transforming a problematic waste stream into a resource, Nashville demonstrated how innovative infrastructure can simultaneously address environmental, economic, and community challenges.

Results

  • $493M Triple Bottom Line benefits over 20 years

  • Benefit-cost ratio of 1.77

Client

Metro Water Services

Location

Nashville, TN

Markets

Municipal

Water/Wastewater

Services

Triple Bottom Line Cost Benefit Analysis

Economic Impact Analysis

Geospatial Analysis

What is Wilmot’s Triple Bottom Line analysis?

A full-cost accounting of environmental, social, and economic impacts, providing a dollar value cost or benefit for each aspect your project is considering.