Creating a Sustainable Biosolids Management Plan

A city with a population of approximately 12,500 operates two advanced wastewater treatment facilities (WWTF) with a combined treatment capacity permitted at 2.75 million gallons per day (mgd). Each facility discharges 100% of the effluent generated onsite to the reuse system for use throughout the city. Biosolids at each facility are aerobically digested and the city uses an independent contractor to dewater and dispose of the residuals. The process and disposal of the city’s biosolids currently meet all state regulations; however, due to changing land application rules and the desire to develop a more sustainable management plan, the city commissioned an evaluation to provide technical guidance and expertise concerning biosolids treatment and process handling from the two WWTFs. To meet the city’s needs, the evaluated processes had to be capable of producing an EPA Biosolids Rule 40 CFR Part 503 Class AA fertilizer. Potential environmental impacts, including odors and vector attraction at the site were also analyzed. A benefit scoring method was used to identify the most promising alternatives. The evaluation identified a selected process and included an economic analysis of the construction cost of the facility, regulatory and permitting requirements, the expected operation and maintenance costs, the expected quality and quantity of the product and the expected savings and revenue from implementing the change. In this presentation, attendees will learn how a municipality evaluated and selected a sustainable biosolids management plan, and will review the data the city used—including operations and management requirements and cost estimates of three solar drying options as well as alternative technology options—in making its decision.