Florida Water Environment Association - Event Information
FWEA West Coast Chapter 2018 Fall Luncheon
West Coast Chapter
Presentation Title: Pasco County Biosolids Facility: Achieving Class AA Biosolids Treatment Via Solar Drying Paired with Limited Fossil Fuel Pasteurization
Speaker Names: Justin Roessler of Pasco County, Blake Merrell of Merrell Bros.
Pasco County: One of the fastest growing areas in the greater Tampa Bay region, Pasco County features a unique blend of undeveloped, open spaces in close proximity to the modern, vibrant communities that makes it a great location to live, visit, and do business. Pasco County Utilities seeks to deliver reliable, cost-effective solutions to its residents. Pasco’s leadership has sought solutions to its current and future utility challenges.
Merrell Bros., Inc.: Merrell Bros., Inc. has been solving wastewater biosolids challenges since it was established in 1982. With nationwide experience, Merrell Bros. passionately purses agriculturally oriented methods of residual management, custom tailored to environmental, regulatory, and geographical factors. The partnership with Pasco County allowed Merrell Bros. to combine globally proven methods of biosolids treatment, in a unique way and has been an excellent testament to their foresight and preparedness in an ever changing industry.
On April 11, 2012, the Pasco County Purchasing Department, at the request of the Utilities Services Administration, solicited competitive sealed proposals for the disposal and recycling of biosolids resulting from Countywide wastewater treatment processes. The intent of this solicitation was to identify innovative solutions that would reduce the costs associated with transportation and disposal of biosolids materials, and to ensure the County had a solution in place years into the future. After a lengthy process, Merrell Bros. was awarded a project that would combine enclosed, odor controlled greenhouse structures, used to dry incoming biosolids substantially, paired with a gas burning pasteurizer facility, that would achieve the temps needed to meet FDEP Class AA acceptance. These greenhouses receive dewatered biosolids from multiple County sources, and dry that biosolids with sunlight, greenhouse affect temperature escalation, routine mechanical agitation, and robust air exchanges. Moist, wet air is evaporated from the 16%-solids biosolids, and is pushed out of the buildings through bio-filters, filled with carbon media, along the north end of the greenhouse. These pre‐drying greenhouse structures increase the solids content of the sludge from the delivered average of 16% to approximately 60%-solids prior to pasteurization. The patented combination of this solar drying is used in conjunction with a second stage of treatment: oven pasteurization. A specially designed oven system is then used to heat the biosolids to the required temperature and duration for pasteurization, under the requirements of USEPA Part 503 regulations. Through the pasteurization process, additional moisture in the sludge cake is evaporated resulting in a further increase in solids content. This combination results in a dry, agriculturally-desired fertilizer that has 7% nitrogen, 4% phosphorous, and is easily applied granularly to sod, citrus, pasture, sugar cane, and other fertilizer input applications. This fertilizer product exceeds all criteria needed for FDEP approved class AA treatment.
11:30 AM - 1:00 PM Eastern
Columbia Restaurant 2117 East 7th Ave. Tampa, FL 33605 UNITED STATES