(Biological fouling)
Undesired deposition of material Inorganic fouling on surfaces Materials obtained fro
organic matter of soil produce by decomposition of plant o animal matte
Precipitation of inorganic crystals
Organic fouling Deposition of fat, oil, protein etc
Particle fouling Deposition of clay, humic particles etc
Biofouling
Deposition and growth of microorganis on surfaces – particles that can multiply the expense of nutrie
Undesired accumulation of microorganisms, plants, algae and animals Why is this important? What are the effects of biofouling? Why should we study this? Because Biofouling has a bright future
Slime and mold behind washing soap intake box Slime formation in tubes Clothes are smelly if not dried properly
Toilet rinsing water reservoir red and dark brown colour: Bacterial and fungal biofilms in Calciferous incrustations Potential problem: Dispersion of aerosols when flushing
Inner tubes of showers
Keratitis due to non-compatible biofilm on contact lense
Biofouling on teeth: cause for bad smell and caries
Biofouling in dialysis unit Microbial contamination of an injection syringe
Contamination pathways in catheter application
Hole due to slime
Biofouling in Paper mills
Biofouling: a serious problem for cooling cycles in energy industry Reduced Heat transfer ncreased Drag resistance Biocorrosion
Biofouling in water supply
Also in power stations
Fouling community Micro fouling • Biofilm formation • Bacterial adhesion
Macro fouling
Attachment of layer organisms Ex: Barnacles Anthropod in sea Mussels Many bristles for attachmentPolychaete worms Bryozoans – sea mats Sea weeds
Biofouling affects ships severly Leads to • Decreased carrying capacity • Increased (30%) fuel consumption • Increased cost in maintenance of shipping industry • Increased (50%) marine transport cost
How to tackle the problem? Antifouling Strategies?
Remove accumulation
Prevent accumulation Not so effective
• Primarily used – “Organotins” (Tin with hydrocarbons) • Most widely used example for organotins – “TBT” or “TPT” Tri Butyl Tin Tri Phenyl Tin
• Most commonly used antifouling agent • Used as coatings in ships • Very effective – Get rid of biofouling once forever
Coatings toxic to marine environment So used in lower concentration – not effective
an d
Defective shell growth in Oyster (> 20 ng/l) Before
After
• Development of male characters in female dog whelk (> 1 ng/l)
So, organotins banned !
Then what are the other methods? • Cupronickels (Cu – 90% & Nickels – 10%) – tried for biofouling prevention. Safety yet to be proved. • Selection of metals – Ex. Zebra mussels find Aluminium bronze distasteful. So they avoid such metals Disadvantages • Not effective in ships that travel long distance • Biological and chemical nature of microorganisms must be studied
Other methods… • Titanium • Chlorination • Pulse laser irradiation – not species specific
Fight nature with nature itself (from worms) – 1.Nemertine pyridyl alkaloids may be used for inhibition of Barnacle larvae 2. Purified extract from Carribean sponges – inhibit bacterial attachment 3. Distaplia nathensis extract – inhibits mussel 4. Pseudoalteromonas sp. (marine bacteria) – produces bioactive compounds with inhibitory effect on algae and on barnacles
All the best - Benedict