Fluidized Bed Reactor

Envirogen To Supply Fluidized Bed Reactor System For Perchlorate

Biological treatment system will address groundwater in Henderson, Nevada, with high-performance, low-cost ‘green' technology

Envirogen Technologies, Inc. (Envirogen) announced recently that it has been awarded a contract by American Pacific Corporation (AMPAC) to provide a large-scale fluidized bed bioreactor (FBR) system for the biodegradation of perchlorate and other constituents from groundwater in the area of a former manufacturing facility in Henderson, Nevada. The 1.2 million gallons per day (MGD) capacity system will replace a smaller biological-based system in operation since 2006, and utilize Envirogen's patented FBR technology in a custom configuration to reduce influent concentrations of perchlorate to non-detectable levels prior to surface discharge. Currently in the design phase, the new treatment system is scheduled for start-up in December 2011.

According to Robert Stark, South Region Vice President for Envirogen, this latest project underscores increasing industry awareness and acceptance of the FBR as a reliable and environmentally sustainable solution to groundwater remediation needs. "This innovative ‘green' technology continues to distinguish itself as the best answer to heavily perchlorate-laden groundwater in both remediation and drinking water applications. In this instance, we are targeting perchlorate as the primary contaminant, but are able to remove both chlorate and nitrate with the same process," Stark said. "With a number of installations providing trouble-free operation over the past 13 years, the FBR's benefits are well-proven. These systems are designed to provide robust treatment in a small footprint, with acceptable waste rates and reduced energy and chemical consumption. The technology's flexibility to handle multiple constituents and varying flow characteristics also bodes well for its potential to treat other significant emerging contaminants such as selenium, hexavalent chromium or chlorinated solvents," he continued. According to Joseph Carleone, President and CEO of AMPAC, the decision to go with Envirogen for this perchlorate treatment facility was based on the company's track record and its commitment to performance. "We are very pleased with the Envirogen equipment, which treats organic waste streams at our Sacramento facility, and are looking forward to working with them on our Henderson, Nevada, project," he said

Proven technology for perchlorate removal
Perchlorate is a highly soluble anion that is used in the manufacture of solid rocket propellant, fireworks, road flares, explosives and other products. Envirogen's FBR is a fixed-film bioreactor in which biological media is suspended, or fluidized, within the reactor vessel by the upward flow of water through the system. The suspended media provides a large surface area for microbial growth and allows a biomass density several times greater than that of other bioreactor designs under similar loading conditions. Microorganisms in the reactor completely destroy influent perchlorate and other targeted contaminants under anoxic conditions, without generating hazardous waste by-products.

New technique recycles 100 percent of household plastic

This Christmas, chances are you’ll save the plastic film and blister packs that your presents come encased in and send it all off for recycling. According to scientists from the University of Warwick, however, only about 12 percent of plastic sent to depots actually gets recycled. Because of problems such as glued-on paper labels, or different types of plastic being combined in one product, the rest of it goes to the landfill or is burnt as fuel. Those same scientists have now devised a system that could recycle 100 percent of household plastic.

The Warwick system is based around a unit that utilizes pyrolysis within a fluidized bed reactor. Pyrolysis is the use of heat in the absence of oxygen for the decomposition of materials, while fluidized bed reactors pass a gas or liquid through solid granular material at high velocity, causing it to behave like a liquid.

The researchers shoveled a wide variety of mixed plastics into the reactor, which were then broken down into useful elements that could be retrieved (in some cases) through distillation. Those elements included wax, which could be used a lubricant; original monomers such as styrene, that could be used to make new polystyrene; terephthalic acid, which could be repurposed in PET plastic products; methylmetacrylate, that could be used to produce acrylic sheets; and carbon, which could be used as Carbon Black in paint pigments and tires. The char left over at the end of the process could reportedly also be sold as activated carbon.

“We envisage a typical large scale plant having an average capacity of 10,000 tonnes of plastic waste per year,” said lead researcher Prof. Jan Baeyens. “In a year, tankers would take away from each plant over £5 million (US$7.7 million) worth of recycled chemicals and each plant would save £500,000 (US$777,291) a year in land fill taxes alone. As the expected energy costs for each large plant would only be in the region of £50,000 (US$77,729) a year, the system will be commercially very attractive and give a rapid payback on capital and running costs.”

This is being done on a commercial level already.

-Actually, just started a day ago.

In this case, however, the plastic is converted into gasoline, diesel, butane, and very few other trace gases. -With a 1% non-toxic residue going to landfill. About 1 kilo of plastic (mixed) is converted to one litre of fuel.

Fluidized Bed Reactor

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