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EDS Critical Elements of Effluent Decontamination System Design Tuesday, October 09, 2007 Joe Wilson, Luke Wilson, Brandon Gulley American Biological Safety Association 50th Biological Safety Conference Nashville, Tennessee 1977 1980 30 years of Biohazardous Waste System Innovation 1983 1994 1987 2000 2003 2005 2006 Present Why are we specializing only in EDS? We are changing the way the industry thinks about EDS Our passion: to protect the safety of the maintenance person who, 15 years from now has to repair a part on our equipment……. His safety, and the safety of his family That’s our Responsibility An EDS can be the single most expensive item of equipment specified for a bio-containment facility Will a malfunctioning EDS shut your facility's research activities down if it fails? Can you become an expert on EDS before you participate in the decisions necessary to select a system? What are some of the critical elements of design that can impact the life, reliability, and safety of an EDS? What current design practices should be better understood before the selection process? We have reviewed numerous EDS systems in the U.S., Canada, Europe, and Asia and have listened to users about problems they have experienced. Which Configuration is Best? Items that can cause problems in EDS equipment Chemicals Some Acids (HCL, phosphoric) All Chlorides (particularly to vessels made from type 304 or 316- L stainless steel) IMPACTS METALLURGY Solids Hair, bedding, plastic, glass, sand, metals, staples, paper clips, feces, toilet paper, other paper, gloves, tubing, bandages, tissue, toys, media, goo, calcium, dirt, food, bones, string ............ IMPACTS DESIGN Redundant or not? A $ question. • Two cookers Non-Redundant • One collector / one cooker • Three or more cookers Redundant • One collector / two cookers A common design flaw Use of load cells to determine volume of effluent in the cooker Why? Requires flexible pipes Corrugated pipe is weaker, corrodes and perforates much easier than the main piping The result is much greater chance of a biohazardous leak onto the equipment below We have extensive experience with load cells on high temperature pressure vessels and EDS is a misapplication of load cell technology Reliable level measurement Liquid level control by Liquiphant Piezoelectric tuning fork level switches Redundant Self monitoring / self diagnosing Precise level reading A fail-safe design No load cells or radar units to fail (a common problem) A common design flaw Single isolation valve feeding cooker, and no fresh water power flush of the primary isolation valve Can result in an isolation valve that will leak steam back into the effluent header Reliable effluent transfer Double valves feeding the cooker 1. The first valve from the header or collector (a trash valve) closing 2. Then a fresh water power-flush Power flush line of the isolation valve Trash valve 3. Then closing of the Isolation valve This prevents fouling of the isolation Isolation Valve valve A common design flaw A man-door that is difficult to open / close for inspection Makes routine vessel interior inspection difficult Difficult to re-seal / confirm sealing We have seen many without swing davits; these doors can weigh hundreds of pounds Inspection made easy A davited swing-bolt door Inspection made easy Inspection made safe Double o-ring seal with integral air test Allows easy inspection and service of the vessel and heating system Solids; the end of the line Integral strainer basket There is no other raw material strainer that is safe Catches solids Sterilizes anything it catches Self monitoring Eliminates problems with discharge systems and sensors A design fallacy; and unnecessary biosafety risk Air pressure testing the vessel to determine integrity Very low resolution of >2% of vessel volume (cannot see even a large leak) Pressure vented through the HEPA system (forcing pressure through contaminated filters); why risk it? Contaminated condensate in the vent line recontaminates the vessel during pressure relief. Again, why? Before 5 gallons removed After 5 gallons removed Reliable leak testing Double door seal air test (0.1 ml resolution) Assures door is closed and sealed properly prior to loading with effluent Double discharge valve air test (1 ml resolution) Informs of any leak on one of the discharge valves Another design fallacy; A vertical discharge ball valve A little grit, or a little sand. This will score the ball and it will leak. Why have an EDS if it leaks? How do you know it leaks? Cook Vessel Sediment Wrong Ball design valve You paid for treatment of every drop of effluent Heated drip leg with thermocouple No cold spot down here Double horizontal discharge ball valves Prevents damage by sand; nothing escapes without detection Heated drip Decon Port and leg and Automatic Air Test thermocouple Decon Port Port Second Discharge Primary Horizontal Valve Discharge Valve Heating the EDS; Jackets v.s. an Internal Coil Heating through a jacketed vessel is the most common design. We believe this is a misapplication of technology for EDS. We recommend heating through an internal steam coil; more efficient, stratifies less, is safer, and has many other advantages A jacketed EDS vessel after 2 months of operation (this client used carbon steel waste lines) • Fights the vessel when heated; ultimately the vessel wins • Difficult to de-scale without chemicals • Jackets lead to pitting and corrosion at the welds • Inefficient; most suitable for an autoclave – not EDS Welds Scale deposits Internal steam heating coil: Full Mark Hot • Flexes • Can double vessel life Full Mark Cold • Automatic descaling • Automatic leak detection (but still Thermocouple at safe even with a top 2” of full leak) cold line is essential • Easy to repair or replace • Suitable for EDS; Thermocouple in not autoclaves very bottom of vessel is essential All stubs should be large diameter but very short. Stainless steel skin permits impenetrable welded construction. Accept no less. One instrument per stub; one instrument only! Trees belong in the forest, not on an EDS Route pop-off to a safe place; Tanking and HEPA filtering costs $$$ and is unnecessary! At over 370 degrees F at 125 psig, for more than 1 hour contact time, this is not a biosafety issue. It is only a safety issue. Please don’t be fooled; contact us for further details. How will you safely decontaminate any component on the EDS? With a standard steam decontamination kit. How will you know to use it correctly? By following the provided Decontamination Manual written for your specific EDS. Your safety is the responsibility of the EDS designer / builder. Good design and properly located (highest and lowest point) thermocouples, give you confidence of a thoroughly even process temperature throughout. PERFECT! What should you expect from your EDS system provider? Good Advice! Value Long life (how do you know?) The very best design for your specific effluent profile Expert advice that extends beyond the equipment up into to the facility Excellent service Pharmaceutical grade vessels and pipes Cutting edge technology All stainless construction Easy, SAFE access doors Steam decontamination kit and manual State of the art controls with modern ethernet communications protocol; and internet accessibility and reporting What next? Questions………. We believe that it is our Bio-Responsibility to educate the bio-containment community about EDS design. Ask us for our free EDS Design Tutorial www.bioresponsesolutions.com
"Critical Elements of Effluent Decontamination Design"