cadmium adsorption by mixed culture biofilms under metabolizing and non metabolizing conditions l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Cadmium adsorption by mixed-culture biofilms under metabolizing and non-metabolizing conditions PowerPoint Presentation
Download Presentation
Cadmium adsorption by mixed-culture biofilms under metabolizing and non-metabolizing conditions

Loading in 2 Seconds...

play fullscreen
1 / 21

Cadmium adsorption by mixed-culture biofilms under metabolizing and non-metabolizing conditions - PowerPoint PPT Presentation


  • 186 Views
  • Uploaded on

Cadmium adsorption by mixed-culture biofilms under metabolizing and non-metabolizing conditions. Jose Roberto Diaz University of Puerto Rico at Mayaguez August 3, 2006 Advisors: Dr. Robert Nerenberg Dr. Jeremy Fein Mentors: Leon Downing Brian Ginn. Outline. Introduction

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Cadmium adsorption by mixed-culture biofilms under metabolizing and non-metabolizing conditions' - benjamin


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
cadmium adsorption by mixed culture biofilms under metabolizing and non metabolizing conditions

Cadmium adsorption by mixed-culture biofilms under metabolizing and non-metabolizing conditions

Jose Roberto Diaz

University of Puerto Rico at Mayaguez

August 3, 2006

Advisors: Dr. Robert Nerenberg

Dr. Jeremy Fein

Mentors: Leon Downing

Brian Ginn

outline
Outline
  • Introduction
  • Objectives
  • Experimental method
  • Results and discussion
  • Conclusions
  • Future work
  • Acknowledgements
introduction
Introduction
  • Heavy metals are a common cause of pollution
      • non-degradable
      • accumulate in the environment
      • causes of land and water pollution
  • Conventional treatment methods increasingly expensive

heavy metals in the atmosphere

introduction4
Introduction
  • microorganisms treat heavy metal-polluted wastes
      • accumulate trace levels of ions
      • major role in modification, activation and detoxification
  • Immobilized systems have higher surface areas and biological mass concentration
      • ability of mixed cultures to adhere
      • form biofilms
      • provide higher loading rates than suspended systems
introduction5
Introduction
  • Biofilms used in wastewater treatment systems
      • resistant to inhibitory and toxic metals
      • tolerant to high metal concentrations
      • high affinity for metallic cations
      • anionic nature of polymers inhibit entrance of cationic molecules to biofilm
  • Immobilized-cell bioreactor technology provides cost-effective means for eliminating pollutants
introduction6
Introduction
  • Live vs. Dead
objectives
Objectives
  • Determine extent of Cd adsorption onto mixed-culture bacterial system under two conditions:
      • biofilm growth, metabolically active
      • biofilm growth, metabolically inactive
experimental method

Biofilm Growth

Air is humidified to provide O2 as the electron acceptor

Experimental method

Acetate Feed = 16mM Phosphate buffer with 16.6356g CH3COOK (10 g/L acetate) to provide acetate as the electron donor

Air

N2

Q = 1mL/min

Retention time of 60 min

Continuous flow packed bed reactor

To waste

reactor is inoculated with Mishawaka activated sludge

experimental method9

Bulk solution:

  • no ammonium
  • 2 ppm Cd
  • 70 ppm Acet (dead)
  • 150 ppm Acet (live)

Cs-irradiation

35,000 rads/hr

Experimental method

Cd Adsorption

divide to test tubes

(5 mL each)

add one-tenth of a gram of biofilm to each test tube

mix for approximately 2 hours

centrifuge and filter

analyze samples

Acetate by

Ion Chromatography

Cd in bulk liquid by

ICP-OES

results and discussion
Results and discussion
  • Live or Dead?
  • Acetate consumption
  • Cd Adsorbed
live or dead
metabolically active

metabolically inactive

Live-Dead staining

Live or Dead?
discussion
Discussion
  • bacteria are surviving the radiation treatment
  • Non-metabolizing bacteria are still consuming acetate in some samples more than others
  • Metabolizing bacteria seem to be adsorbing less Cd (≈27%) than samples that have non-metabolizing bacteria (≈49%)
  • possible reasons why
conclusions
Conclusions
  • Radiation treatment is not effective in killing bacteria and must be modified
  • Non-metabolizing bacteria certainly showed an effect on how much Cd was adsorbed
  • Samples with varying amounts of acetate adsorbed around the same percent of Cd for metabolizing and non-metabolizing bacteria
future work
Future work
  • Different method of killing bacteria
  • Non-metabolizing vs. metabolizing in suspended growth system
  • Different electron acceptors and donors for growing biofilm
acknowledgements
Acknowledgements
  • EMSI
  • Dr. Valli Sarveswaran
  • Leon Downing
  • Brian Ginn
  • Dr. Jeremy Fein
  • Dr. Robert Nerenberg
  • CEST