Biofouling systems

Removing suspended solids, decreasing cycles of concentration, and clarification all may be beneficial in reducing deposits. Biodispersants and biocides should be used in biofouled systems. Simple pH adjustment may lessen precipitation of certain chemical species. The judicious use of chemical corrosion inhibitors has reduced virtually all forms of aqueous corrosion, including underdeposit corrosion. Of course, the cleaner the metal surface, the more effective most chemical inhibition will be. Process leaks must be identified and eliminated. 

Patel, T.D., 1986, Film structure and composition in biofouling systems. PhD Thesis, University of Birmingham. 

Corrosion associated with the action of micro-organisms present in the corrosion system. The biological action of organisms which is responsible for the enliancement of corrosion can be, for instance, to produce aggressive metabolites to render the environment corrosive, or they may be able to participate directly in the electrochemical reactions. In many cases microbial corrosion is closely associated with biofouling, which is caused by the activity of organisms that produce deposits on the metal surface. 

Biofouling of extraction wells can reduce system performance... 

Bioadhesion is an area of research important in the selection of biomaterials (e.g., for implants). It is also critical in the development of the new biofouling coatings. A system for bioadhesion studies was developed, in which silicones with chemically and topologically (microengineered) modified surfaces were evaluated in the studies of the response to such surfaces of a diverse set of organisms.559-561 A new study of micropatterning and surface modification of PDMS to control bioadhesion has been reported.562... 

In a steam electric power plant, cooling water is utilized to absorb heat that is liberated from the steam when it is condensed to water in the condensers. The cooling water is withdrawn from a water source, passed through the system, and returned directly to the water source. Shock (intermittent) chlorination is employed in many cases to minimize the biofouling of heat transfer surfaces. Continuous chlorination is used only in special situations. Based on 308 data, approximately 65% of the existing steam electric power plants have once-through cooling water systems. 

Chemicals such as sulfuric acid are used to control scaling in the system. Biofoulants such as chlorine and hypochlorite are widely used by the industry. These additives are discharged in the cooling tower blowdown. 

Chlorine and hypochlorite are used to control biofouling in both once-through and recirculating cooling water systems. The addition of chlorine to the water causes the formation of toxic compounds and chlorinated organics, which may be priority pollutants. 

Webster DC, Chisholm BJ, Stafslien SJ (2007) Mini-review combinatorial approaches for the design of novel coating systems. Biofouling 23 179-192... 

System s polymer film properties and free oscillation as a fluidized array resists biofouling and iron clogging... 

In some instances, site-specific conditions prevented the demonstration of PACT systems. Some systems have encountered problems with biofouling. Iron concentrations above 10 parts per million (ppm) may host slime-producing bacteria that can clog the pores in the activated carbon. Suspended solids, pH, and temperature can also impact system performance. Metals removal may be limited. In an application at the Lowry Landfill site, manganese and cobalt were not removed during treatment. 

For heat pumps based on flooded mine systems, where the heat abstracted is replenished seasonally by inputs from solar radiation and geothermal gradient, the longevity of the reservoir is, in principle, limitless. The sustainability of the operation will only be limited by the durability of the infrastructure (e.g., biofouling, clogging or physical instability of boreholes, longevity of collector coils). 

Biofouling involves the formation of biofilm, whereby hydrated algal- or bacterial-based slimes adhere to water-wetted cooling system surfaces and often contain scales, corrosion products, or other debris embedded within a polysaccharide matrix. The role of biofilms in reducing cooling system efficiency and life span is still imperfectly understood. 

High planktonic (CFU/ml) levels within the cooling system indicate that suitable conditions for rapid reproductive growth exist and thus planktonic organisms may further rapidly proliferate, adding greatly to the source of biofoulant load. 

Today, automatic biocide application, actuated by reference to real-time biofouling monitoring equipment, is available in some countries and may provide better (if very expensive) microbiological control than 7- to 28-day timer-controlled systems. 

Geesey/Lewandowski/Flemming, Editors. Biofouling and Biocorrosion in Industrial Water Systems. Lewis Publishers, USA, 1990. 

Sterilization of a membrane system is also required to control bacterial growth. For cellulose acetate membranes, chlorination of the feed water is sufficient to control bacteria. Feed water to polyamide or interfacial composite membranes need not be sterile, because these membranes are usually fairly resistant to biological attack. Periodic shock disinfection using formaldehyde, peroxide or peracetic acid solutions as part of a regular cleaning schedule is usually enough to prevent biofouling. 

Flow-Based Systems Needle-type sensors with a fluid flowing over the sensor tip seem to resist biofouling and extend sensor lifetime.31 There are numerous methods that have been investigated for flow-based sensors, such as microperfusion systems,75 microdialysis,76 77 and ultrafiltration.78 Reduced fouling was found with an open microflow system where slow flow of protein-free fluid over the sensor surface at the implant site is effected.73 Different from the other flow-based sensors, the open microflow is controlled by the subcutaneous tissue hydrostatic pressure and does not require a pump. 

Oxidizing agents TBA assessment of the acute toxicity of ozone, an alternative to chlorination to control biofouling in cooling water systems of power plants, to fish larvae of three species and to D. magna. F,F,F,I (Leynen et al., 1998)... 

---