External Steam Agitation (ESA™) Technology Macerates Existing Technologies

By Glenn D. Reynolds
February 2005

The Author is the President and CEO of Bioservices Group Inc. in North Bay, Ontario, Canada. He has over 15 years in specializing in providing hazardous and infectious waste solutions.

External Steam Agitation (ESA™) technology is specifically designed for the treatment and destruction of liquid and solid infectious waste. The technology uses a new process that renders the contents both biologically inert and visibly treated. The units are a jacketed pressure vessel equipped with a motor driven shaft. An arm assembly is mounted to the shaft that rotates to macerate the internal waste contents. Steam is injected into the jacket and heat is transmitted to the macerated waste. The ESA™ contains the infectious waste from the beginning of the process to the end of the sterilization cycle, once completed the chamber will then depressurize.

The ESA™ process is designed with a state-of-the art control system. The first in the market place to provide unlimited pass-coded parameter changes to provide treatment for a variety of waste types. This allows pass-coded administration to set parameters based on utilities, making the system adaptable to any existing installation and more efficient.

The ESA™ units are designed to provide reliable and repeatable performance every cycle with an outcome of a 6log10 reduction of Bacillus stearothermophilus spores. More importantly this level of sterility is achieved by eliminating the release of airborne pathogens into a HEPA filter required by autoclaves and sterilizers.

This advanced processing system provides internal air displacement and a coarse grind, while eliminating additional cycles commonly used in past technologies such as pre-venting, pre-shredding, vacuums, HEPA filtering, autoclave bagging, sorting and loading specifications. By eliminating the required cycles and/or requirements used in other technologies the ESA™ systems reduce the risk of malfunction, parts replacement and downtime. The design promotes a safer operational environment for operators processing infectious waste.

External Steam Agitation
External Steam Agitation System

The advanced control system design considerable reduces the cost of processing. In the case of sterilizers and autoclaves air displacement and drying cycles require steam production and water consumption for vacuum cycles. The air displacement process is reduced by 50% or greater by the mere fact that this process occurs only one time in an ESA™ system as compared to 2 or more times in other systems. Drying by vacuum requires jacket steam and water consumption in sterilizers and autoclaves, the ESA™ uses jacket steam, but requires less water because a vacuum process is not required. The drying cycle is a specific operation of the ESA™ technology to eradicate all liquid contents. A typical drying cycle in a vacuumed (gravity systems do not provide drying) sterilizer or autoclave would be 30 minutes, compared to a 10 minute drying cycle in an ESA™ system.

The advancements of the ESA™ systems have been recognized internationally for the ability to achieve a sterility assurance level required by international regulations. Several communities require some form of unrecognizable product, which benefits public safety. However, regulations become inconsistent as to the requirement of the finished product. A misconception is, existing systems using standard medical waste shredders for pre-shredding or post-shredding produces an unrecognizable product even to the general public. Also, the end result of incineration is a reduced mound of complete ashes. The truth is medical waste looks like medical waste even from an incinerator, because low temperature incineration cannot melt metals (needles). BGI cannot turn rocks into diamonds. The ESA systems do produce a treated waste that is rendered both biologically inert and visibly treated. Low-density plastics shrink; high-density plastics disfigure; pathological wastes are finely shredded; liquid wastes are dehydrated. The result is a low moisture, homogeneously treated residue unrecognizable as medical waste.

The ESA™ technology will reduce the processed internal contents by up to 70% volume by compaction and liquid dehydration. Compaction through breaking the waste into smaller pieces occurs during the entire process. Our pressure vessels are manufactured under ASME code and our control systems hold the international Canadian Standards Association (CSA) stamp.


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