Bridging the GAPs: Approaches to Treating Water On Farms

1. Environmental Protection Agency (EPA) regulations

For water treatment, either by chemical (such as chlorine or peroxyacetic acid, for example) or device (such as filtration or UV light), EPA approval will be required to assure safe-handling and efficacy of the intended use. EPA requires that any chemical that claims to reduce or kill organisms must be registered and approved for use; a manufacturer of a pesticide device must have an EPA establishment number. Financial investment Growers must consider the cost of set-up, continued use, and maintenance. Microbial water testing will also be required to prove efficacy and verify the system is working as intended to reduce the risk of pathogen contamination. Management of system According to the Produce Safety Rule, once a treatment is in place, growers will be required to monitor and verify the effectiveness of treatment. As mentioned, this will include microbial testing as well as routine monitoring to assure the system’s parts are working correctly. Application method Various application methods exist depending on the type of treatment that is chosen. For chemical treatments, this could include injectors through the use of pumps or using a venturi system. Other methods, such as devices, could include filtration, UV light, or ozonator units. Source of water The efficacy of treatment often depends on the source, i.e., the amount of organic matter and initial microorganism levels. For example, some surface waters may have higher amounts of organic matter (soil, plant debris, etc.) and microorganism levels where treatments may not be effective. The use of UV light, for example, with high solids content in water may not be effective without the use of a prior filtration step. Infrastructure Choosing an appropriate method, one has to account for the equipment required to implement a system. For example, the availability and storage of chlorine gas must be considered in such a treatment. Additional piping or pumps may be needed as well. Crop sensitivity The use of chemicals for irrigation water treatment can impact the quality of both the soil, as well as the crop. For example, while research is limited, continued use of chlorine can damage sensitive crops and the continuous use of residual chlorine in water may impact crop yield and leave behind the build-up of toxic halogen compounds.

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Worker Safety It is important for growers to be aware of worker safety and hazards that are associated with use of

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