Forbes, Robert H.

Robert (Bob) Forbes is a semi-retired professional engineer and part-time consultant to Jacobs where he spent most of his career. He earned a BSCE at NC State with high honors and a MSEE at UNC-Chapel Hill. Bob remains active in the Water Environment Federation where he is a Life Member, and in biosolids research for the Water Research Foundation. He wrote Chapter 5-Design Approach in EPA WEFs Solids Processing Design and Management Manual (2011), and was lead author of Chapter 10-Digester Gas to Energy in WEF Manual of Practice No. 32-Energy in Water Resource Recovery Facilities (2021).

Titles from this speaker

Description: The Changing Landscape of Biosolids Management in North Carolina Over the 21st...

The Changing Landscape of Biosolids Management in North Carolina Over the 21st Century's First Two Decades

Abstract

The State of North Carolina, with its rich diversity, inviting climate, growing population, and substantial natural resources to protect, has been one of the fastest growing states in the Southeastern U.S. in the 21st century. A byproduct of that growth is an increasing volume of residuals and biosolids that are produced, in addition to the other organic by-products of North Carolina's economic activity such as food processing, forestry, farming, and other industries. The paper and presentation will review North Carolina's trends in biosolids management over the last two decades and discuss the emerging trends of energy and resource recovery, which are currently developing in many of the state's metropolitan areas such as Charlotte, Raleigh, Fayetteville, Greensboro, Winston-Salem, Asheville, and Hickory. Lesser known and smaller, but equally innovative projects and local initiatives in the state related to biosolids and organics management will also be discussed. The paper will summarize and compare data from the 1st (2004 data year) and 2nd (2018 data year) National Surveys of Biosolids Regulation, Quality, End Use and Disposal in the U.S., also known as the National Biosolids Data Project (NBDP). Information from the Environmental Protection Agency (EPA), the North Carolina Department of Environment and Natural Resources (NC-DENR), and North Carolina State University (NCSU), among other sources, will also be used to provide an overview of biosolids management for protecting the state's natural resources. A case will be made that biosolids will become greater economic drivers in the future as traditional, fossil sources of fuels and fertilizers continue to increase in cost. See Figure 1. North Carolina reported approximately 123,00 dry metric tons (DMT) of biosolids produced in 2004, increasing to approximately 130,000 DMT in 2018. Over the same period, the amount of biosolids treated to Class A pathogen-reduction standards increased by about 15%, while the amount of Class B biosolids beneficially used on land increased by about 50%. During the same 14-year period, the amount of biosolids incinerated in North Carolina decreased by about 15%, and the amount of biosolids landfilled decreased by almost 60%. Probable reasons and drivers behind these trends will be discussed in the paper and presentation. See Tables 1 and 2. Biosolids land application and composting programs have had a long and largely successful history in North Carolina spanning at least 50 years. Other biosolids processing technologies have entered the picture over the last 20 to 30 years, such as thermal drying, advanced digestion processes (both aerobic and anaerobic), and energy recovery systems. Specifically, the amount of biosolids being thermally dried and marketed in North Carolina has increased substantially during the last two decades, so the thermal drying facilities in North Carolina will be highlighted and discussed. The production and handling of fats, oils & grease (FOG), and septage have also grown substantially during the 21st century. About 75% of FOG and septage produced in North Carolina is land applied on permitted sites, while the remaining 25% is accepted and treated at water resource recovery facilities (WRRFs). The proportion of FOG and septage that is accepted at WRRFs, as opposed to being land applied, continues to increase as North Carolina's cities and water utilities build and expand trucked-waste receiving facilities at their WRRFs. The paper and presentation will also address the regulatory environment and public-acceptance challenges of biosolids and residuals management in North Carolina. Organized groups that voice opposition to the beneficial-use practices continue to remain active in the state. Several water utilities have stepped up their public information programs to proactively counter the opposition groups. The City of Raleigh and Charlotte Water will be cited and described as examples of utilities that have increased their public information and involvement efforts as part of their Environment Management Systems and related programs. Anticipated, future trends that will be discussed in the paper and presentation include: -Increased production of Class A biosolids to create market outlets besides agriculture -More focus on industrial pretreatment to remove micro-pollutants, including microplastics -Development of systems to reduce or eliminate per and polyfluorinated compounds (PFAS) from biosolids -More energy recovery from solids to reduce GHG emissions and net energy use at WRRF's, including production of biochars with little or no measurable micro-pollutants.

This paper was presented at the WEF/IWA Residuals and Biosolids Conference, May 16-19, 2023.

SpeakerForbes, Robert H.

Presentation time

8:30:00

9:00:00

Session time

8:30:00

11:15:00

SessionSession 18: Managing Biosolids in the Carolinas

Session number18

Session locationCharlotte Convention Center, Charlotte, North Carolina, USA

TopicManaging Biosolids in the Carolinas