4.4 Container Rinsing, Triple-Rinse & Equipment Cleanout

Container Rinsing, Triple-Rinse & Equipment Cleanout

The job of a pesticide applicator is not finished once the spraying stops. Proper cleanout of equipment and safe disposal of empty pesticide containers are legal requirements and critical steps in preventing environmental contamination and human exposure. An improperly cleaned sprayer can severely damage the next crop it sprays, and a discarded, unrinsed pesticide container is a hazardous waste liability.

Cleaning Empty Pesticide Containers

When a liquid pesticide container is emptied into a spray tank, a significant amount of concentrated residue remains clinging to the inside walls. By law, empty liquid pesticide containers must be thoroughly rinsed immediately after they are emptied. If a container is properly rinsed, it is classified as regular solid waste and can be recycled or sent to a standard landfill. If it is not rinsed, it retains its hazardous waste classification, making disposal illegal and highly expensive. Furthermore, rinsing containers immediately allows you to pour the rinse water (rinsate) directly into your spray tank, ensuring you use all the product you paid for.

There are two legally accepted methods for cleaning empty containers: Triple-Rinsing and Pressure Rinsing.

The Triple-Rinse Procedure

Triple-rinsing is the standard manual method for cleaning containers:

1. Empty the container into the spray tank and let it drain for 10 seconds.
2. Fill the container roughly 1/4 full with clean water (or the designated carrier).
3. Secure the cap tightly and shake the container vigorously for at least 30 seconds, ensuring the water hits all interior surfaces.
4. Pour this rinsate into the spray tank and let the container drain for 10 seconds.
5. Repeat steps 2 through 4 two more times (for a total of three rinses).
6. Puncture the container to render it unusable. Puncturing prevents the container from being scavenged and used to store drinking water or food, a dangerous practice that has led to fatal poisonings.

The Pressure-Rinse Procedure

Pressure rinsing is faster than triple-rinsing and is highly recommended if you process many containers. It requires a specialized pressure-rinse nozzle attached to a water hose.

1. Empty the container into the spray tank and let it drain for 10 seconds.
2. Puncture the bottom or side of the container with the sharp probe of the pressure-rinse nozzle.
3. Hold the container over the spray tank opening so the rinsate will drain directly into the tank.
4. Spray clean water into the container at a pressure of at least 40 PSI for a minimum of 30 seconds. Rotate the nozzle to ensure all interior surfaces are washed.
5. Drain the container thoroughly. The container is already punctured and ready for disposal or recycling.

Container Recycling

The Ag Container Recycling Council (ACRC) operates programs across the country to collect and recycle properly rinsed, punctured plastic pesticide containers. Recycling is heavily preferred over landfilling. ACRC contractors inspect containers upon collection; any container that shows visible pesticide residue will be rejected.

Equipment Cleanout Procedures

Leaving pesticide mixture in a spray tank overnight or for an extended period is a recipe for disaster. The chemicals can settle out, form immovable sludge, corrode metal parts, deteriorate rubber hoses, and become extremely difficult to remove. A contaminated sprayer used to apply a sensitive crop herbicide can destroy the entire field.

General Cleanout Steps

Sprayer cleanout should be done on a dedicated wash pad with a sump to collect the contaminated wash water, or performed in the field where the pesticide is registered for use.

1. Drain the Tank: Spray out all remaining pesticide mixture over a legally approved site (the target site). Never dump excess mixture on the ground.
2. First Rinse (Flushing): Add clean water to the tank (about 10-20% capacity). Agitate vigorously. Flush this water through the booms, hoses, and nozzles. Spray the rinsate out over an approved site.
3. Add Cleaning Agent: Fill the tank halfway with water and add a specific cleaning agent as directed by the pesticide label.
   • Household Ammonia (1 qt per 50 gallons): Excellent for neutralizing and penetrating specific herbicides, particularly sulfonylureas.
   • Commercial Tank Cleaners / Detergents: Contain surfactants that dissolve oily residues and suspend dry formulations better than water alone. Never mix ammonia with chlorine bleach; this produces deadly chlorine gas.
4. Circulate and Flush: Agitate the cleaning solution for 15-30 minutes. Flush a small amount through the booms and nozzles. Let the solution sit in the tank and lines (sometimes overnight, if the label recommends it) to break down hidden residues.
5. Remove Nozzles and Screens: Remove all nozzles, strainers, and screens. Clean them manually using a soft brush (like a toothbrush) in a bucket of cleaning solution. Never use wire or a knife, as this will damage the precise orifice of the nozzle.
6. Final Rinse: Drain the cleaning solution (spray it over an approved site). Fill the tank with clean water, flush the entire system thoroughly, and drain.

Managing Rinsate

Rinsate is the water mixture created from washing containers or equipment. It contains diluted pesticide and must be treated with respect. The best and most common way to dispose of rinsate is to apply it to a site that is listed on the pesticide label, ensuring that the total amount of pesticide applied to that site does not exceed the legal maximum label rate. Rinsate can also be stored in dedicated holding tanks and used as make-up water for future spray batches of the same pesticide.