Chlorine and its various forms (chlorine gas, chloramine, chlorine dioxide, calcium hypochlorite, sodium hypochlorite, etc.) have been utilized as disinfectants in public water supplies for about a century. In poultry, there is a growing focus on oxidation reduction potential (ORP) levels without consideration of the water’s pH. Growers are actually over chlorinating their water to reach target ORP levels. This is significant because recent studies have shown that chlorine may directly or indirectly be the principal cause of many forms of cancer.
The EPA adopted a trihalomethane regulation in 1979 to limit the allowable level of carcinogenic disinfection byproducts (DBP) in drinking water. Although chlorine is a good disinfectant, it also can form trace amounts of a DBP called trihalomethane (THM) (Swichtenberg , 2003). THMs are chemicals that are formed when organic materials (e.g., decaying trees and leaves as well as urban farm run-off) combine with free chlorine. This has caused great concerns about using chlorine in recent years and the EPA and water companies have searched for ways of reducing these byproducts.
Chloramines are actually used as DBP inhibitors in 30% of the nation’s surface water supplies and are expected to grow to 65% within 10 years (Long, 2005). Chloramines are formed by the mixture of chlorine and ammonia in water. However, chloramines have their drawbacks as well. According to the California Professional Association of Specialty Contractors, chloramines contribute to pitting, pinholes, and potential failure of copper pipe (ibid). It is believed that this reaction only occurs when there is aluminum present in the water (ibid). Chlorine dioxide can also be utilized as a DBP inhibitor. When added to chlorine, a reduction in total trihalomethane (TTHM) has been observed (Rittman, et al., 2002). At the same time, chlorine dioxide is known of producing chlorites that are identified as causing hemolytic anemia (Condie, 1986). Currently, the maximum contaminant level for total THMs is 0.1mg/L in public drinking water.
Ozone has also received a lot of attention recently. It is highly effective for deactivating all groups of organisms (particularly viruses and bacteria) and it can treat high volumes of water. Ozone may be the strongest and most capable disinfectant against cryptosporidium. However, it does have its disadvantages as well. Ozone can produce excessive bromates (which is a potential carcinogen) if the water contains bromide (Siddiqui, et al., 1995). It also possesses a reduced efficacy in cold water. Ozone also does not provide a persistent residual disinfection capability, may require high capital investments, and has relatively high operating and maintenance costs (Funyak, 2003).
All of the previously mentioned additives need a post treatment. What makes them affective is their ability to oxidize contaminants in the water. This does not only apply to living microorganisms, but to inorganics as well. Once inorganics are oxidized (iron manganese, etc.) they precipitate and fall out of the water molecule. This can cause problems by clogging up well pumps, water distribution lines, nipple, foggers, and cool pads. This problem can only be resolved by adequate filtration or infusion of polyphosphate blends or other sequestering agents.
Ultraviolet (UV) disinfection is becoming more popular and economical than ever before. UV light is a point-of-contact disinfection system that is highly effective in the inactivation of protozoa (viruses remain most resistant) and does not require the addition of any chemicals, requires short contact times, and posses no known DBPs. It does this without altering the chemistry, taste, and quality of water. Turbidity (defined as a decrease in the transparency of a solution due to the presence of suspended and some dissolved substances, which causes incident light to be scattered, reflected, and attenuated rather than transmitted in straight lines) however, does affect the quality of disinfection because of what is known as the shadowing effect. Also, as in the case of ozone, UV has no residual disinfection capacity.
Acidification of water using sodium bisulfamate or citric acid has shown promise of reducing bacteria in poultry water. However, acidification is not a disinfection process. Its affect provides a less habitable environment in which microorganisms can grow. It was widely accepted that acidification of water led to increased feed conversion. A recent study has reported the opposite (Watkins et al, 2005). Also, research on pathogen reduction has shown that chickens fed with acidified feed developed a relative growth retardation that increased during the first two weeks before it stabilized (Heres et al, 2004). It is then plausible that when broilers are provided acidified water combined with acidified feed, it could detrimentally affect feed conversion and possibly lead to a condition of acidosis. Water with too low of a pH could also corrode plumbing, nipples, foggers, and shorten the life of cool cells.
In the United States and abroad, transition metal ionization (TMI) has been used for years as an alternative to chlorine for disinfection in many applications. Copper-silver ionization has been proven to be very effective against some of the most resistant organisms, such as Legionella, in hot water systems and has proven long lasting residual disinfection capabilities. Copper ions, in the form of copper salts, have been utilized for years in livestock feed to kill/prohibit the growth of salmonella, e-coli, and campylobacter. Research on copper surfaces in processing facilities has shown its ability to control Salmonella enterica and Campylobacter jejuni (Faundez, et al., 2004).
Even though the hazards associated with chlorine are known, it is still the most common disinfection method. There is sufficient evidence that TMI can offer superior disinfection capabilities over currently utilized methods without producing harmful disinfection byproducts. The TMI disinfection method will provide required nutritional trace elements to living beings can help build immunity and asist with the propagation of oxy]gen through out the bloodstream. The USEPA is spending millions of dollars to research disinfection alternatives that do not produce DPBs. The industry focus does not need to be on the reduction of DBPs such as TTHM, but on eliminating it altogether.
