Codigestion In Central Florida

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Courtesy of BioCycle Magazine

New digester in the Orlando region processes 130,000 tons/year of biosolids, fats, oils, grease and food waste, producing power, a Class AA granular fertilizer and phosphorous-rich struvite.

What is today a region in Central Florida teeming with theme parks, resorts, golf courses and over 50 million tourists annually was once an area considered too remote and uninhabitable for recreation-oriented development. Primarily woods and wetlands, the 25,000 acres about 20 miles southwest of Orlando was so secluded that the nearest power and water lines were 10 to 15 miles away. To help solve this predicament, the Florida legislature created the Reedy Creek Improvement District (RCID) in 1967 for the purpose of advancing the state’s economic growth by facilitating development of a world-class tourist destination. In less than three years, RCID installed roads, water lines, power and communication lines, as well as services such as water and wastewater treatment, electric generation and distribution systems. In 1971, Walt Disney World, along with two hotels, opened their doors.

Today 43 hotels and resorts representing more than 40,000 rooms and 2.4 million square feet of convention space along with hundreds of restaurants exist within RCID. In 2010, RCID invited Harvest Power, based in Waltham, Massachusetts, to evaluate the District’s composting system. Simultaneously, RCID’s wastewater consultant evaluated and then recommended anaerobic digestion for managing biosolids and food waste. Harvest Power then proposed a codigestion system to recover energy and nutrients from food waste, manage odors, process RCID’s biosolids and improve the fertilizer end product quality. Its proposal was accepted, and in late 2013, Harvest’s Energy Garden came on line. The anaerobic digestion facility, located at RCID’s 20 MGD wastewater treatment plant (WWTP), has capacity to process 130,000 tons/year of organic waste material and generate approximately 3.2 MW of installed power and 2.2 MW of recoverable heat from a biogas-fueled combined heat and power system (CHP).

“Turning organic waste into clean energy was a logical next step,” explains Bill Warren, administrator for RCID. “We are always looking for innovative ways to conserve natural resources and protect the environment.”

Two factors influenced the construction approach: First, RCID required rigorous performance standards. Second, investment tax credits under the federal Section 1603 financing program for renewable energy projects generating electricity required that all systems be operating by the end of December 2013. Harvest Power managed the project development including environmental permitting (air and biosolids/wastewater permit from the Florida Department of Environmental Protection, storm water permit from RCID and South Florida Water Management District), construction and term financing, contracting engineering and construction coordination, and feedstock acquisition.

Incoming feedstocks include biosolids, fats, oils and grease (FOG), and source separated food waste from industrial, commercial and institutional (IC&I) sources including local theme parks, hotels, restaurants and food processors. Harvest Power reached out to local haulers to prepare them for the increased demand for organic waste collection routes. Outreach and education training sessions were held with hotel and restaurant staff. In addition, educational materials such as informational posters and food waste collection bins were provided.

To build the facility, Harvest Power chose a design-build approach using Layne Inc. Heavy Civil as the lead in an Engineering, Procurement, Construction (EPC) contract. “It was an absolute necessity to have a single point of responsibility given the project’s complexity, its financing structure, short engineering and construction time and rigorous performance standards,” notes Alex MacFarlane, Vice President of Project Development at Harvest Power. Entec Biogas GmbH provided core process design on the anaerobic digestion and biogas management systems.

Read the full article in BioCycle Magazine

Customer comments

  1. By Samantha Goh on

    There is also an opportunity to treat the sludge at the end of the process into a high organic fertilizer in only 24 hours. There is this technology from Biomax Technologies based out of Singapore and they already have 15 footprints around the globe to treat all organics.....super fast!