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Controlling Odors at MBT Waste Handling Plants

The largest waste authority in the U.K. is using emission control untis to meet strict European odor restricitons at its mechanical biological treatment waste handling plants.

MEGTEC Systems, Inc. today announced that it has shipped the first two VOCSIDIZER® emission control units for a new MBT (mechanical biological treatment) waste handling installation that is under construction on the landfill site at Longley Lane in Manchester, England. The Greater Manchester Waste Disposal Authority (GMWDA), the largest of the six UK waste authorities, wants to meet the strict European odor emission restrictions. 

Costain Ltd., who built the MBT plant, ordered the emission control system from HAASE Energietechnik AG, Germany. HAASE emission control components for MBT facilities are in operation at more than 30 locations in several European countries using MEGTEC VOCSIDIZER technology. 

According to Ulrich Seibt, MEGTEC Sales Manager for Central Europe, this initial installation at Longley Lane, Manchester, is the first of three built by HAASE Energietechnik AG on GMWDA MBT sites and will be operational later this year. The other MBT plants in Oldham and on Cobden Street in Manchester, will also feature two MEGTEC tandem VOCSIDIZER systems, each.  Units for Cobden Street will ship next month; all three MBT operations are expected to be on-line by mid-2011. 

The GMWDA is the largest UK authority charged with waste management functions, serving approximately 973,000 households and more than 2.27 million residents from nine Districts in the Manchester, England, area. Around 360,000 tons of household waste, about 30 percent of the area’s total annual waste volume of 1.2 million tons, will be processed at the three MBT sites. With homes nearby, control of the resulting methane odor is a prime concern. 

Strict Standards 

“In the MBT process, bacteria break down wet household waste, generating methane gas,” explains Seibt. “The English call it a ‘rotting system.’ Methane concentration is relatively low, but the odor is unmistakable and definitely undesirable in populated areas. That’s where our VOCSIDIZER units come in.” 

Although UK standards limit methane emissions to 2,000 Odor Units per normal cubic meter (OU/Nm3), the GMWDA has taken its cue from a European standard originating in Germany, which restricts emissions to a much lower 500 OU/Nm3

“Patented technology in our VOCSIDIZER system has been customized to meet this standard,” Seibt says. “These units have been successfully performing at other MBT plants with technical components by HAASE Energietechnik AG since 2003. We now have about a dozen in Germany and elsewhere in Europe. GMWDA representatives visited a system that has been running for five years with homes nearby, and there have been no problems with odor. 

“In order to meet the 500 OU/Nm3 standard and eliminate the odor, our system must have a cleaning efficiency of at least 99.7 percent.  The VOCSIDIZER unit is specially designed to deliver this high level of thermal efficiency. To keep the running costs at a minimum, the system is designed for 95 percent heat exchange efficiency.” 

While odor control in the surrounding area is the uppermost issue at MBT sites, Seibt notes that several other factors (and MEGTEC system advantages) played key roles in the GMWDA decision. “Household waste flows vary and are constantly changing; you never know exactly what’s in there.  Our VOCSIDIZER units can handle virtually any of this material, including effluent that other systems can’t. 

“For example, there are silicone compounds in household waste that can ‘block’ conventional RTOs (Regenerative Thermal Oxidizers).  Different technologies have been devised to try to overcome this issue, but the unique operating principle of the VOCSIDIZER systems have been proven to be the best at effectively managing the silicone. In many cases where the MEGTEC/HAASE emission control system was implemented, there have been no problems resulting in the need to clean or change the media with our systems.” 

Wet household waste flows also contain sulfur and other highly corrosive materials, Seibt points out.  That’s why, unlike other RTOs — or even MEGTEC VOCSIDIZER systems in different applications — VOCSIDIZER units for MBT installations are made of stainless steel.  “We have found through testing as well as experience over the years, that these stainless steel systems can withstand corrosive elements like no other.  The VOCSIDIZER concept is due to the compact design of a very cost efficient solution using stainless steel, which is more expensive than carbon steel used in other applications.” 

Such long-term operational and maintenance efficiencies certainly interested GMWDA decision makers. From the beginning, they have looked toward the future.  Insisting on odor control limits four times lower than current UK regulations is one example.  Another is keeping in mind that, by 2020, landfills throughout Europe must close for waste which can be recycled. Landfills in Germany already are and nothing can be added to any landfill there. In addition, EU regulations require a reduction of biological waste to 35 percent of the amount from 1995 until 2020. 

The program launched by GMWDA’s 25-year recycling and waste management contract, finalized in April, 2009, will divert more than 75 percent of Greater Manchester’s municipal waste from landfill.  GMWDA’s emphasis is on recycling, with an integrated network of facilities at 27 sites, the majority of which are recycling centers for aluminum, glass and the like. The primary recycling component for wet household waste flows is the trio of MBT installations with emission control systems by HAASE Energietechnik AG using MEGTEC VOCSIDIZER technology. 

Environmental System Collaborations 

The six MEGTEC VOCSIDIZER units at MBT locations for GMWDA will bring the total of MEGTEC products in emission control systems built by HAASE Energietechnik AG to more than 30 throughout Europe, including Germany and the UK as well as Italy, Switzerland, France and Austria. The two firms initially joined forces to handle landfill emissions prior to collaborating on MBT waste handling systems. 

“We have partnered with HAASE Energietechnik AG to address numerous environmental and energy-related challenges for years,” observes Mohit Uberoi, MEGTEC President & CEO. “We have specially engineered MEGTEC systems to meet ever-tighter cleanup standards, and pilot tested landfill as well as MBT systems prior to installation. Our joint track record of success speaks for itself.  We look forward to implementing the entire GMWDA project, and continuing to partner with HAASE Energietechnik AG in leading the way for the waste management industry.”