Bridging the GAPs: Approaches to Treating Water On Farms

Liquid injection: hypochlor ite or peroxyacetic acid

A second group of chemical treatments involves the use of liquid injection of a sanitizer. In this section we’ll talk about two types specifically, hypochlorite and peroxyacetic acid.

Any liquid that is recognized by EPA as a registered pesticide product can be injected into a water stream. These materials are not different. They must be liquids in order to be injected and they must have irrigation water treatment on their EPA registration label.

The most commonly used of these sanitizers will be sodium hypochlorite or peroxyacetic acid, therefore this content focuses on them.

Though we are only focusing on these two, there are other chemical sanitizers available, for example chlorine dioxide or hydrogen peroxide.

Recall the label as the law [Refer back to Module 2 for this]. This is a common expression and we covered this in some detail in Module 2.

Water (hydraulic) powered systems

Water (hydraulic) powered systems use the physical properties of the water flowing, in order to accomplish injection. These range from simple to more complicated. We will start with the simple Venturi system.

A venturi uses the pressure differential created by a constriction in the pipe, in order to draw a solution into the water flow through an open vacuum port. As the flow in the water is constricted, a pressure differential creates a vacuum. This vacuum draws the chemical from a reservoir up into the water flow. The flow rate dictates injection volumes. Venturi injectors will be sized for the minimum and maximum flow rates in gallons per minute (GPM). It is important to note that fluctuations in pressure mean variation in injection rates. This may impact the effectiveness of the sanitation process.

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