Fouling bacteria

One of the reasons why it is important to remove suspended solids in water is that the particles can act as a source of food and housing for bacteria. Not only does this make microbiological control much harder but, high bacteria levels increase the fouling of distribution lines and especially heat transfer equipment that receive processed waters (for example, in one s household hot water heater). The removal of suspended contaminants enables chemical treatments to be at their primary jobs of scale and corrosion prevention and microbial control. 

Septic A condition produced by anaerobic bacteria. If severe, the wastewater turns black, gives off foul odors, contains little or no dissolved oxygen and creates a high oxygen demand. 

Biological growth can present a potentially hazardous fouling, since it can provide a stickier surface with which to bond other fouling sources. In many cases, however, treatment of the fluid can reduce the amount of biological growth. The use of germicides or poisons to kill bacteria can help. 

The use of direct steam injection into air is a common method of increasing humidity levels for both commercial and industrial applications. The process kills most types of bacteria and similar organisms that may contribute to fouling, health, or other indoor air quality (IAQ) problems. Where amines are present in the steam, however, even small concentrations can be detected by their odor and may be objectionable, even though they may be well under guidelines for concentrations in air. 

Effluent pretreatment is necessary when RO is used as tertiary treatment in order to prevent membranes filters form being blocked or abraded. UF offers a powerful tool for the reduction of fouling potential of RO/NF membranes [57]. A typical pretreatment consist of a MF allowing the removal of the large suspended solids form the WWTP effluent followed by UF unit which removes thoroughly suspended solids, colloidal material, bacteria, viruses and organic compounds from the filtrated water. The UF product is sent to the RO unit where dissolved salts are removed. 

Organic carbon may serve as an energy source for indigenous or injected bacteria, resulting in rapid population growth and subsequent fouling. 

The principal factor of complexity is obviously related to the origin of the wastewaters and to the presence of fouling and/or clogging materials (Table 6). Even if raw suspended matter seems to be at first responsible for preventing measurement, some other components such as soluble substances (grease, petroleum by-products,...) or living organisms (from bacteria to mussels) can be the main problem. 

Hoffman LR (1960) Chemotaxis of Oedogonium sperms. Southwestern Nat 5 111-116 Holmstrom C, James S, Egan S, Kjelleberg S (1996) Inhibition of common fouling organisms by marine bacterial isolates with special reference to the role of pigmented bacteria. Biofouling 10 251-259... 

Thomas RWSP, Allsopp D (1983) The effects of certain periphytic marine bacteria upon the settlement and growth of Enteromorpha, a fouling alga. In Oxley TA, Barry S (eds) Biodeterioration 5. John Wiley Sons, Ltd., New York, pp 348-357... 

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