1 / 23

Slime, Slime, Slime!

Slime, Slime, Slime!. Toni Glymph Environmental Toxicologist Wisconsin DNR. Slime Bulking. There is a condition in wastewater treatment often called slime bulking. Occurs when bacteria “over-produce” the lipopolysaccharide normally found outside the bacteria cell wall.

Download Presentation

Slime, Slime, Slime!

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. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Slime, Slime, Slime! Toni Glymph Environmental Toxicologist Wisconsin DNR

  2. Slime Bulking • There is a condition in wastewater treatment often called slime bulking. • Occurs when bacteria “over-produce” the lipopolysaccharide normally found outside the bacteria cell wall. • Found most often in industrial wastewater treatment systems, but may also occur in municipal systems.

  3. Slime Bulking • What makes the bacteria “over-produce” lipopolysaccharide? • Lack of sufficient nutrients (mostly nitrogen) • Excess organic acids

  4. Slime Bulking Gram (+) Gram (-) Polysaccharide “Slime Layer” Lipopolysaccharide “Slime Layer” Cell Wall Phospholipid Lipoprotein Cell Wall Cell Membrane Cell Membrane

  5. Slime Bulking • 3 main elements are required in the development of the cell wall components. • They make up 18% of the dry weight of the cell components. • Nitrogen (15%) • Phosphorus (2%) • Sulfur (1%)

  6. Slime Bulking • Nitrogen is required to makeup the lipoprotein layer • Phosphorus is required to make up the phospholipid layer. Gram (-) Lipopolysaccharide “Slime Layer” Phospholipid Lipoprotein Cell Wall Cell Membrane

  7. Slime Bulking • When Phosphorus is deficient, a small amount of extra lipids (fat) is added to the slime layer. Gram (-) Lipopolysaccharide “Slime Layer” Lipid Lipoprotein Cell Wall Cell Membrane

  8. Slime Bulking • When Nitrogen is deficient a larger amount of “fat” is added to the slime layer.. Gram (-) Lipopolysaccharide “Slime Layer” Lipid Lipid Cell Wall Cell Membrane

  9. Slime Bulking • When slime bulking occurs, nitrogen and phosphorus are the nutrients that are usually deficient. • Slime bulking is more severe when nitrogen is deficient. • Nutrient ratio 100:10:1 (BOD:N:P)

  10. Slime Bulking • Excess Organic Acids • A ready food source that does not contain nitrogen • Usually added through sludge processing recycle streams (anaerobic digester supernatant) • Any other anaerobic process side stream

  11. Slime Bulking • India Ink stain • When India ink is added to a drop of mixed liquor the carbon black particles penetrate the floc from outside to inside • The lipopolysaccharide prevents the India ink from penetrating the floc particle.

  12. Slime Bulking India Ink Stain

  13. Slime BulkingIndia Ink Stain

  14. Slime Bulking Case Study • Industry • 2 SBRs • excessive filamentous bacteria • severe nutrient deficiency (nitrogen) • severe bulking problems • discharging 60% of the flow to WWTP

  15. Slime Bulking Case Study • WWTP • very few filamentous bacteria • severe bulking problems • having difficulty dewatering sludge

  16. Slime Bulking (Industry Tank #1)

  17. Slime Bulking (Industry Tank #2)

  18. Slime Bulking (WWTP Mixed Liquor)

  19. Slime Bulking (WWTP Digester Supernatant)

  20. Slime Bulking Case Study - Conclusions • Due to poor operations and severe nitrogen deficiency, excess lipopolysaccharides were being produced in the SBR tanks. • This slime was being discharged into the WWTP and accumulated over time. • Present in the aeration basin, clarifiers and digesters.

  21. Slime Bulking • Operational Considerations • The solution involves adding the deficient nutrient • Ammonia to provide nitrogen • Phosphoric acid to provide phosphorus

  22. Slime Bulking • Operational Considerations • There is no nutrient deficiency if, in a filtered (.045 um) effluent sample: • ammonia + nitrate is > 1 mg/L and, • soluble orthophosphate is > 0.5 mg/L

  23. Slime Bulking • The excess lipopolysaccharide can only be wasted out of the system. • You have to stop the bacteria from producing the excess amounts. • Making sure sufficient nutrients are available • Adding anaerobic recycle streams slowly and/or add more organisms (increase return) when excessive amount of organic acids are present.

More Related