Producers can use chemical injection,
also called chemigation, to treat water.
In chemical injection, pumps combine chemicals with water in an irrigation system.
Injection diaphragm pumps and peristaltic pumps
introduce any pumpable chemical that is approved by the EPA for controlling E. coli
or other target indicators in agricultural water.
For example: chemigation with PAA,
which is actually a mixture of three antimicrobial compounds and water.
PAA is also known as peroxyacetic acid.
When using a PAA mixture
we typically only monitor for one of three compounds,
typically peracetic acid.
Hydrogen peroxide is the second compound in PAA.
The final compound is acetic acid,
the chemical found in vinegar.
All system components need to be able to resist corrosion,
so that they will withstand contact with chemicals such as PAA.
Pump systems are effective at delivering small volumes of chemicals
to reach the desired concentration.
This means making absolutely sure that flow rate
and compound concentrations are correct.
When the flow rate and concentrations are correct,
you will have the proper amount of PAA introduced into the system.
When this is accomplished,
the acid makes contact with the microbial cells, oxidizing their components
and destroying them.
Make sure to check the water pump and pump flow rates regularly.
Inside the diaphragm pump the diaphragm gets pushed by the air system,
causing one chamber to get rid of any fluid.
Meanwhile the second chamber gets filled with new fluid.
Inside the peristaltic pump the rotor compresses and decompresses the hose,
creating a strong vacuum that draws chemicals out
and into the water.
It’s important to take good care of the pump.
Given the oxidizing nature of many compounds,
tubing will wear,
becoming less elastic and more brittle over time,
and will need to be proactively changed for the system to work properly.
It’s important to be mindful of the type of compound you are injecting.
In a diaphragm pump setup,
injection can be compromised if a chemical is producing a gas,
creating a gas lock.
A good example is the hydrogen peroxide,
which will be formed in PAA
and evolves when the product is under a vacuum.
When used outdoors, choose a sturdy pump
and protect it from rain, wind, and snow.
You validate the system when it is initially installed
or when big alterations are made
to make sure it is working similarly to what has been shown to be effective by scientists.
Check the label for your product to make sure it's used as directed.
All components should be monitored
to make sure that the chemical is being continuously injected,
and that the compound is at the proper concentration in the water being applied to crops.
Examples of monitoring events include checking diaphragm and peristaltic pump speeds,
water flow rates,
and the concentration of the compound in the treated water.
Verify that your system is working as expected,
by reviewing the records to make sure the proper flow rates
and injection speeds were maintained during treatment–
for example, by checking your water pump and diaphragm pump flow rates. Note this is the last line of text