Ridgway, "Biological fouling
of separation membranes used in water treatment applications," in AWWA Research Foundation, Denver, CO, 2003.
The effects from biological fouling
and corrosion were reduced by treating the cooling tower water with a sufficient amount of chlorine and Tolytriazole, which is a chemical additive that prevented corrosion (Hollander and May 1985, Walker 1976).
Copper bearing tube materials can lessen certain kinds of biological fouling
. Generally, copper tubes are used for a DX evaporator with fresh water flowing outside the tubes.
Because biological fouling
and corrosion are usually prevented by using an inhibitor, the deposit rate in a condenser cooled by water circulating through a cooling tower is dominated by precipitation and particulate fouling mechanisms.
In the first stage of biological fouling
, organic molecules, such as polysaccharides and proteins, rapidly accumulate over the surface to form a "conditioning film," Bacteria and single-cell diatoms settle on this modified surface to form a microbial biofilm.
Box 1 Evaporative cooling * Lower cooled medium temperatures * Most efficient method for heat rejection * Lower fan power * Requires make-up water and water quality management Dry Cooling * Eliminates water and chemical treatment * Eliminates effluent charges * No visible plume * Eliminates scale and biological fouling
* Higher cooled medium temperatures By combining the cooling methods in box 1 Evapco says it can keep the advantages of the two technologies thus providing an ideal cooling solution.
Chemical treatment, such as chlorine, may be used to control these growths to avoid a reduction in heat transfer capabilities and to minimize biological fouling
on metal surfaces.
The problem of sensor drift due to biological fouling
may be severe in some regions, and methods to prevent fouling are just being developed.
First, there is the problem of biological fouling
. While this does not affect the cooling efficiency of the fluid as it would in a heat exchanger, it can lead to underdeposit corrosion, i.e., when metal parts are covered with a film of dirt, corrosion will act more rapidly.
The requirements for marine coating systems carry a tall order, including the protection of vessels and structures in harsh and diverse environmental conditions (saltwater immersion, extreme temperatures, ultraviolet radiation exposure, humidity, physical impact from wave action, biological fouling
Several primary modes of fouling have been observed in heat exchangers (Characklis et al., 1981), including: particulate fouling, crystalline or precipitation fouling, chemical reaction fouling, corrosion fouling, and biological fouling
The hydrodynamic cavitation treatment [9, 10] of the water also controls biological fouling
. According to the obtained results, high temperatures and changing pressures generated by the cavitation process are sufficient to destroy the microorganisms that would otherwise cause bacterial, algal, and fungal blooms.