The Quantification of Viral Adhesion to Activated Carbon

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					The Design of a Flow Test
Apparatus and Experimental
Methods for the Quantification of
Viral Adhesion to Activated Carbon
                     Erica Zerfoss

          The Department of Bioengineering
 The Department of Civil and Environmental Engineering

                  February 28, 2005
Project Motivation
 Contamination of drinking water by microorganisms represents a
 major human health hazard in both developed and developing
 countries.

 An estimated 3.4 million deaths a year are attributable to waterborne
 diseases (World Health Organization).

 In the U.S., the removal of viruses and protozoa from drinking water
 is 99.9% to 99.99% efficient from standard disinfection techniques;
 however, viruses have still been found in fully treated drinking water.

 A possible solution is to use Activated Carbon (AC) Point-of-Use
 filters at the tap and in the plant.

Need a method to quantify microorganism removal from
                  activated carbon
               Quantifying Bacteria Adsorption to
               Activated Carbon (AC)
                                         Goal:
                                            Calculate sticking coefficient (α) from mini-column
                                            flow test (Microbe and Radiolabel Kinesis (MARK)
                                            test).
                                            (The sticking coefficient is the fraction of particles that
                                            collide with the collector and are retained.)

                                         Methodology:
    AC
                                            The bacteria is radiolabeled with H-Leucine and
Silica Beads
                                            flowed through the column. Measure retention of
                                            bacteria in silica beads using scintillation counter.
                                            The sticking coefficient of the carbon is back
           Two Layer MARK test              calculated from the sticking coefficient of the
                                            silica beads.

               This method works for Bacteria; however, the bacteriophage MS2 will NOT
               take up radiolabel (H-Leucine).
My Design Project

Goal: Design a new experiment to calculate the sticking
  coefficient of viruses to AC that does not involve radiolabeling.

Proposed Solution: Instead of radiolabeling, quantify virus
   concentration before and after flow through a carbon packed
   column by serial dilution plating to determine fraction retained.

                                   Initial Virus [], No




                                         Carbon layer

                                         GF/D Filter



                                   Virus [] after flow through
                                   column, N
My Design Project

                          Vacuum Box used in bacterial
                          adhesion experiments.



                         Does not allow for collection of
                         filtrate.



A second vacuum box which does allow
for filtrate collection but cannot
hold a syringe.
My Design Project Goals

1)   Design of a new flow test apparatus to
     fit on top of new vacuum box.

2)   Design of new experimental methods.

3)   Alteration of current mathematical model
     and spreadsheet.
Criteria for Design

 Device must hold 3mL syringe upright with
 no leakage.
 Must have a mechanism for flow control
 (start/stop).
 The vacuum box must provide a flow of
 5mL/min ± 1mL/min (approximately 1 psi
 internal pressure).
 Reproducibility (p>0.05)
Alternatives

 Use a bacteriophage that can be
 radiolabeled.
 – Disadvantage: MS2 cited in literature as good model for
   human viruses.

 Use a different radiolabel.
 – Disadvantage: Radiolabel is expensive.
Design Evaluation

 Test that the new flow test apparatus meets
 the criteria (flow rate, no leakage, flow
 control) with carbon packed mini columns.

 Perform reproducibility tests (p>0.05) using
 bacteriophage MS2 and four variations of
 AC.
Deliverables                       Budget
New apparatus and
  experimental       New materials for
  method for viral   flow test apparatus               $60
  adhesion tests.
                     Testing materials

                     Pipettes (100)                  $20
                     Agar                            $80
                     Petri Dishes (500)              $140
                     GF/D Filters, 4cm diameter (50) $15
                                                   _______
                     TOTAL                     $255 $315
      Timeline
                                                              Current Stage




                                         January   February   March           April


Design of flow test apparatus


Production of new flow test apparatus.


Testing of new device


Design of new spreadsheet.


Run column experiments on MS2


Prepare poster presentation


             Design
             Testing
             Presentation
Current Progress: New Flow
Test Apparatus



  3”                              syringe (mini-
                                  column)                                        r = 0.875”

                                                                                 r = .0938”


  1”                              flow controller
                                                     Top view of plastic connector
                                 plastic connector
 1/8”

                                 metal box
1 1/2”


        Side view of flow apparatus
Current Progress: New Flow
Test Apparatus




                    Top View

   Side View
Final Stages

 Reproducibility Experiments using MS2
 on four variations of Activated Carbon.

 Statistical Analysis


               Questions?