WEBVTT 

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Producers can use chemical injection, 

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also called chemigation, to treat water.

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In chemical injection, pumps combine chemicals with water in an irrigation system.

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Injection diaphragm pumps and peristaltic pumps 

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introduce any pumpable chemical that is approved by the EPA for controlling E. coli 

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or other target indicators in agricultural water.

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For example: chemigation with PAA, 

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which is actually a mixture of three antimicrobial compounds and water.

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PAA is also known as peroxyacetic acid.  

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When using a PAA mixture

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we typically only monitor for one of three compounds, 

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typically peracetic acid.

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Hydrogen peroxide is the second compound in PAA.

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The final compound is acetic acid, 

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the chemical found in vinegar. 

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All system components need to be able to resist corrosion, 

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so that they will withstand contact with chemicals such as PAA.

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Pump systems are effective at delivering small volumes of chemicals 

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to reach the desired concentration.

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This means making absolutely sure that flow rate 

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and compound concentrations are correct.

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When the flow rate and concentrations are correct, 

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you will have the proper amount of PAA introduced into the system. 

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When this is accomplished, 

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the acid makes contact with the microbial cells, oxidizing their components 

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and destroying them.

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Make sure to check the water pump and pump flow rates regularly. 

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Inside the diaphragm pump the diaphragm gets pushed by the air system, 

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causing one chamber to get rid of any fluid. 

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Meanwhile the second chamber gets filled with new fluid.

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Inside the peristaltic pump the rotor compresses and decompresses the hose, 

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creating a strong vacuum that draws chemicals out 

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and into the water.

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It’s important to take good care of the pump. 

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Given the oxidizing nature of many compounds, 

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tubing will wear, 

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becoming less elastic and more brittle over time, 

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and will need to be proactively changed for the system to work properly.

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It’s important to be mindful of the type of compound you are injecting. 

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In a diaphragm pump setup, 

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injection can be compromised if a chemical is producing a gas, 

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creating a gas lock.  

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A good example is the hydrogen peroxide, 

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which will be formed in PAA 

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and evolves when the product is under a vacuum.

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When used outdoors, choose a sturdy pump 

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and protect it from rain, wind, and snow.

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You validate the system when it is initially installed 

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or when big alterations are made 

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to make sure it is working similarly to what has been shown to be effective by scientists.

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Check the label for your product to make sure it's used as directed.

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All components should be monitored

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to make sure that the chemical is being continuously injected, 

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and that the compound is at the proper concentration in the water being applied to crops.

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Examples of monitoring events include checking diaphragm and peristaltic pump speeds, 

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water flow rates, 

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and the concentration of the compound in the treated water.

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Verify that your system is working as expected, 

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by reviewing the records to make sure the proper flow rates 

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and injection speeds were maintained during treatment– 

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for example, by checking your water pump and diaphragm pump flow rates.

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