The Hermitage Municipal Authority completed upgrades at their water pollution control plant that expanded wastewater treatment capacity and introduced a two-phase advanced anaerobic digestion (AAD) complex to its current plant operations. This complex optimizes the solids handling train by further promoting biosolids stabilization, biogas recovery, and generating both heat and power. Gas production and power generation are maximized when alternative feedstocks, including high-strength industrial waste, food waste, and grease, are combined with sewage sludge during digestion. Wanting to capitalize on the upgrades by increasing the amount of outside waste received, the Authority hired RETTEW to conduct a solid food waste depackaging study and implement the selected technology.
We evaluated six technologies for cost, volumetric throughput, and packaging separation performance and reviewed impacts to the AAD operations, biogas recovery, and power generation. The Authority pilot tested the selected technology. The equipment outperformed expectations and offered impressive results, revealing only trace amounts of organics on the packaging, capturing organics visibly free of debris, and yielding highly recyclable waste packaging. Since implementing this system, the Authority has increased its food waste receiving by approximately 3,000 tons per year and its biogas production by 18 percent. As only one of a few systems of its kind in the United States, the Authority is situated to escalate its food waste receiving, resulting in the production of more gas, increasing power production, and realizing operational cost savings.