• Where more than 99% of the microorganisms hide and live!
• Impacts pathogen control.

What is it?

• Sessile microorganisms embedded in gelatinous matrix.
• Anchored to the surface with polymeric sugars.
• Factors affecting biofilm formation include nutrient availability, hydrodynamics, composition of microbial community and cellular transport.

Where to find them?

Types and kinds of microorganisms present inside it

Aerobic bacteria -

• Slimers – Pseudomonas, Mucoids.
• Spores – Bacillis Subtilis.
• Fecal – Enterobacter.
• Ubiquitous – Anabena, Asterionella. 

Anaerobic bacteria -

• Sulfate reducing – Desulfovibrio.
• Iron reducing – Gallionella.

Protozoa -

• Consume bacteria.

Biofilm diversity

• It contains microorganisms in a broad spectrum with different metabolic states.
• Aerobic and anaerobic species are capable of co existing.
• Proliferating and dominant species can co exist.
• Single layer to 3 dimensional structures.
• Unicellular to multicellular.
• Biofilm remediation indicates that a weaker disinfectant (which penetrates) will be able to perform stronger than disinfectant that fails to penetrate.

Steps of biofilm life cycle

Biofilm Control

• A biofilm under low continuous stress may persist and continue to grow slowly.
• High stress and shock biofilms off the walls, resulting in complete disinfection.

Biofilms are resistant to chlorine

• The real barrier to chlorine penetration occurs when chlorine is neutralized in the surface layers of the biofilm faster than it diffuses into the biofilm matrix.
• Both chlorine and hydrogen peroxide are prone to transport breakdown.
• Chlorine and bleaching powder are consumed by useless side reactions.

Penetration of the biofilm layer by chlorine dioxide (EOXIDE LQ 85)

Chlorine dioxide (EOXIDE LQ 85) efficasy and chemical selectivity

HOCl, H2O2 and O3 are indiscriminant disinfectants. They react with all most all organic and inorganic species present.
Chlorine dioxide reacts selective. Reacts rapidly with sulfide and hydroxides. It is less effected by organic contamination.

Chlorine dioxide's (EOXIDE LQ 85) catalytic chemistry in a biofilm layer

ClO2 reacts rapidly with sulfides

• amino acids containing sulfide groups.
• (cystine, thymine, etc.) (cystine, thymine, etc.).
• di -sulfide linkage(s) in protein synthesis.
• H2S from anaerobic bacteria (SRBs).

ClO2 can penetrate biofilm “in search”of these chemical functionality