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Synagro Technologies ESD™ Egg-Shaped Digester



APTIM was awarded a turnkey contract to design, supply, construct and start up an anaerobic Egg-Shaped Digester facility for Synagro Technologies, Inc. of Houston, Texas. The ESD facility is part of Synagro's new biosolids treatment plant located near Honolulu, Hawaii's Sand Island wastewater treatment plant. Synagro's Honolulu plant is the first application of ESD technology in Hawaii, and the second application of ESD technology at a biosolids pelletizing plant in the U.S. Synagro's biosolids treatment plant in Honolulu converts up to 10,000 dry tons per year of effluent that would otherwise be land-filled from the wastewater treatment plant into a nutrient-rich, pelletized Class A organic material that meets federal and state standards for beneficial re-use as a fertilizer. The ESD facility supplied by APTIM comprises the front end of Synagro's plant, providing the wastewater digestion operation that is needed prior to de-watering and pelletizing. APTIM's scope of work included a 2.4 million gallon ESD, a dome roof tank to store digested biosolids, and a dry seal gasholder to store digester gas, along with associated piping, foundations, mechanical systems, electrical/control systems and startup services. The digestion process is beneficial for biosolids drying projects since it significantly reduces the volume of biosolids to be dried and disposed of, reduces purchased fuel costs by using self-produced digester gas to fuel drying operations, and produces higher quality, more marketable pellets. ESDs are particularly beneficial since they are gas-tight, compact, small-footprint units that maximize gas production while minimizing maintenance.

Contracting Entity: Synagro Technologies