Animal waste from meat processing plants could be powering homes and businesses once Stellar, a Jacksonville, Fla.-based design, engineering, construction and mechanical services firm, finishes building renewable energy systems to convert waste to energy.

According to Stellar, the modular systems will serve a range of industries, including food and beverage processing; petrochemical; biofuel refining; pharmaceutical and bioscience; dairy, meat, poultry and crop farms; coal mining; and waste management and wastewater treatment. These industries produce organic waste such as sludge, animal and food waste that can be put to use.

For example, landfill sites generate biogases (mostly methane) as the waste buried in them undergoes the natural process of anaerobic digestion, or the breakdown of organic material in the absence of oxygen. If this gas is not harvested through a renewable energy system, it escapes into the atmosphere, where it can be 20 times more potent and harmful to the environment than carbon dioxide.

Pending U.S. legislation (both federal and state) and international protocols such as the Kyoto Protocol, are expected to dictate more restrictive emission rates and expanded renewable energy requirements for manufacturers and other producers. According to Stellar, without a waste-conversion process in place, these companies could see a financial impact that includes higher energy rates and waste disposal costs. In addition, company reputations could suffer as a result of growing consumer awareness of whether or not a company has "green" energy programs.

To transform waste into energy, the waste must be pretreated, separated and stored in enclosed tanks that decompose and break down organic matter by excluding oxygen, which produces a biogas. The biogas is combusted in an engine to generate electricity, heating and cooling. The electricity produced through this process can be used by the producer (as well as the heating and cooling), sold to a nearby facility or redistributed to a nearby electrical grid.

"In addition to lowering overall energy costs and generating additional income through the sale of the excess electricity or thermal energy produced, these systems support sustainability initiatives, offer alternatives to waste reduction and lower greenhouse gas emissions," said Kurt Liebendorfer, Stellar senior vice president. "In addition, they offer an efficient and safe way to destroy pathogens and eliminate odors that can sometimes negatively affect a community."

The biogas systems from Stellar are modular, constructed at Stellar's 60,000 ft2fabrication facility in Jacksonville and transported to the customer's site. The modular systems will be pretested before arriving on-site, thus minimizing site impact during installation and commissioning. A shortened construction schedule enables opportunities for a lower project cost.

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