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32. Dispose of Excess Chemicals Safely

spraying field

You eliminate a lot of disposal and storage worries if you know the exact area to be treated, calibrate your sprayer, and mix only as much pesticide as you need. You reduce the chances of being left with haulback tank mixes—the unused pesticide mixtures left over from spraying.

If you still end up with excess chemical solution after spraying, apply it to the field, as long as it is in accordance with the label. Another option is to transfer a partial sprayer tank of material to a holding tank. Store the mixture for use at the first opportunity and keep a thorough record of the pesticide concentration in the holding tank.

sprayers When sprayers are empty, they usually still contain anywhere from 2 to 10 gallons, or more, of field strength spray that cannot be forced out of the boom nozzles. So always flush out your spray tank at the end of the day or whenever you switch chemicals.
spray tank diagram One way to do this is to attach a separate tank of clean water to your main spray tank so you can rinse out the tank when spraying is done. The rinsate from this procedure can be sprayed on the field as long as you don't exceed label rates.
holding tank If spraying on the field is not possible, store the rinsate in a holding tank. The best way to do this is to rinse your spray tank or pesticide containers on a rinse pad. Sumps would then direct the rinsate to the appropriate holding tank.
mixing tanks The next time you use the same type of chemical, you can use the appropriate stored rinsate as part of the carrier or mix water—as long as the recycled rinsate does not make up more than 5 to 10 percent of the spray mix.
pesticide label Consult the pesticide label for suggestions on how to clean the equipment, and beware of potential interactions between cleaning solutions. For example, mixing ammonia and bleach produces toxic fumes. So follow directions carefully.

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