Since the 40 CFR, Part 503 regulations were promulgated in 1993, utilities and engineers have considered thermophilic anaerobic digestion configurations to produce Class A biosolids from municipal wastewater sludges. As thermophilic anaerobic digestion is not listed in the regulation as a process to further reduce pathogens (PFRP) other options have been used in order to achieve Class A biosolids. The most viable options are: • Alternative 1: Time and Temperature • Alternative 3: Documented Virus and Helminth Ova Destruction • Alternative 6: Treatment with an PFRP-Equivalent Process The plants, utilities and private entities described in some detail within this paper include: • City of Los Angeles, CA: Hyperion and Terminal Island Wastewater Treatment Plants (WWTPs). • Columbus Water Works – Columbus, GA: South Columbus Water Resource Facility. • District of Columbia Water and Sewer Authority (DCWASA) – Washington, DC: Blue Plains Advanced Wastewater Treatment Plant (AWWTP). • Greater Vancouver Regional District (GVRD) – Vancouver, BC: Annacis Island WWTP • Inland Empire Utilities Agency (IEUA) – Rancho Cucamonga, CA: Regional Plant Number 1. • Metropolitan Sewerage District – Madison, WI: Nine Springs WWTP. • Infilco Degremont’s 2PADTM process. • Orange Water and Sewer Authority (OWASA) – Chapel Hill, NC: Mason Farm WWTP.
The State of the Practice of Class-A Anaerobic Digestion: Update for 2005
Authors: John Willis, Perry Schafer, and Michael Switzenbaum