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Critical Elements of Effluent Decontamination Design


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
30 years of
Biohazardous Waste
System Innovation






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

  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


      Some Acids (HCL, phosphoric)

      All Chlorides (particularly to vessels made from type 304 or 316-
      L stainless steel)
                                        IMPACTS METALLURGY

      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


      • One collector / one cooker

      • Three or more cookers


      • One collector / two cookers
         A common design flaw
Use of load cells to determine
volume of effluent in the cooker
Requires flexible pipes
    Corrugated pipe is weaker, corrodes and
    perforates much easier than the main
    The result is much greater chance of a
    biohazardous leak onto the equipment
We have extensive experience with load
cells on high temperature pressure vessels
and EDS is a misapplication of load cell
         Reliable level measurement

Liquid level control by
Liquiphant Piezoelectric tuning
fork level switches
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
   Can result in an isolation
   valve that will leak steam
   back into the effluent
Reliable effluent transfer

  Double valves feeding the cooker
 1.   The first valve from the header
      or collector (a trash valve)
 2.   Then a fresh water power-flush
                                                       Power flush line
      of the isolation valve                                              Trash valve

 3.   Then closing of the Isolation
  This prevents fouling of the isolation
       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
         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
    Assures door is closed and sealed properly
    prior to loading with effluent

Double discharge valve air test (1 ml
    Informs of any leak on one of the discharge
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


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

        Scale deposits
 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
• Easy to repair or
• Suitable for EDS;            Thermocouple in
  not autoclaves               very bottom of
                                   vessel is
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

What should you expect from your
EDS system provider?
Good Advice!
Long life (how do you know?)
The very best design for your specific effluent
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

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