Growing Magazine - December, 2012
Orchard Management: Keeping a Safe Chemical Storage Facility
Chemicals are a part of every orchard venture, whether the enterprise is organic or conventional. Storing and handling those chemicals safely should be a priority for every grower, and optimum safe storage begins with a dedicated facility.
NRCS District Conservationist Jim Gillis (left) and orchard owner Jim Travis discuss the benefits of a dedicated agricultural chemical storage facility.
Photos by Sally Colby.
The Natural Resources Conservation Service (NRCS) defines an agrichemical handling facility as a facility with an impervious surface that provides an environmentally safe area for the handling of on-farm agrichemicals. The goal of such a facility is to provide a safe environment in which chemicals can be stored, mixed and loaded, with provisions for retention of leakage in the event of an accidental spill.
Jim Gillis, NRCS district conservationist in Adams County, Pa., says that unlike many other cost-share practices, a chemical storage facility doesn't improve production or yields for the grower. However, a properly designed chemical storage facility reduces liability and improves convenience.
"That's what most people are telling us after they build one," said Gillis. "They can't believe they mixed for years with a hose out of the pond or the house, or next to the well near the house. It's a tremendous time-saver and convenience."
Gillis explains that the starting point for new facilities is viewing the site and determining that there's a concern, whether the issue is leaky chemical containers or a poor location.
"For example," said Gillis, "in orchards, they'll mix right at an irrigation pond because that's their water source. But if there's a spill, it could go into the pond or run below the pond and percolate into groundwater. Neither one is a good option."
Some facilities are constructed as a large containment pad with a curb for retaining liquid. At such a facility, there's no water source and no mixing - just storage and loading into a spreader. Other facilities are built so the grower can drive through, measure chemicals, and mix concentrate with water and load into a tank for application.
"Part of the location for these facilities, especially in orchards, is based on 'where is the water, and can we do it safely?'" Gillis explained. "Even though we're building something that should be spill-proof and should contain a spill, we don't want to build close to a water body or close to surface water."
Inside a building that is a dedicated chemical storage facility, there is a watertight concrete floor. Gillis explains that the floor is concrete injected with silica fume, which creates a watertight surface. Gillis points out that this method of sealing is different from pouring concrete and sealing it afterward with something such as paint used for swimming pools. "There's always going to be a seam or a gap, and you never get a watertight seal," he said. "The only way we can have 100 percent watertight confinement is to make the entire structure watertight."
Plans for chemical facilities include a sump box in the center of the outdoor drainage area, an extremely low point in the structure in which a submersible pump can be used to remove spilled material. "It gives us a low point that we can draw from," said Gillis. "It's always below the water point, and we can pump out or drain all the liquid that has accumulated on the pad. When they're finished pumping out, the only water left should be that .5-inch gap between the bottom of the submersible pump and whatever it's sitting on." The sump is located where the tank will be filled outside, because that's where a spill is most likely to occur.
The inside storage area will typically be designed for storing liquid materials, but doesn't provide for the same volume potential as the mixing area. In cases where the storage and mixing area are separate, a drain in the floor of the storage area channels liquid out to the mixing pad so the spill can be rerouted to the containment area. The mix pad is designed to hold 1.5 times the volume of the largest sprayer on the farm.
Gillis explains that if the water source is at the mix site, the water source cannot drain into the storage or mixing pad - it's always separate. The water source is typically large enough that the contents of the sprayer could be spilled several times. In the case of a pure water leak, the water can go where it would naturally go without becoming a surface or groundwater issue.
"These systems are overdesigned so that if there is a failure, it has to be a huge failure before it begins to exceed what the facility can hold," said Gillis, adding that the concept behind all structures is the same. "If someone is filling and doesn't realize that lines on the sprayer are broken, it may take them a while to catch it, so that's why it's designed for 1.5 times the capacity. If there is a spill or a leak, the liquid is captured and can be pumped back into the sprayer for field application as originally intended."
One of the most common reasons for spills is sprayer failure: A fitting isn't properly attached, a hose is cracked, or a line blows off when the tank is pressurized. Such spills can occur during mixing or in the field. A second scenario is when the chemical is in the tank and the operator is not paying attention, due to distraction or an accident.
According to Gillis, the focus for agricultural chemical storage facilities is on storage and the mixing site because by the time the chemical is diluted for field application, that chemical mix is much safer.
"The chemical is already diluted to the point that is determined to be environmentally acceptable, that can be applied in the field," said Gillis. "By comparison, a more dangerous time is when chemicals aren't diluted. Those spills can occur either in storage or at the mixing site."
When growers who construct a chemical storage facility are asked if they'd do anything different, most say they wouldn't. Gillis says that growers appreciate having a roof over their chemical storage area and having a well-lit area for working.
"A lot of them are spraying in early morning and may be mixing while holding a flashlight," said Gillis. "[Having a lighted area] makes it harder to make a mistake. They also like the storage aspect; it's easy to insulate the area, and they no longer have the issue of having to bring chemicals into a basement or garage for winter storage."
Gillis said, "We know we can't always prevent spills, so what we're aiming for is to prevent leaks when there is a spill. It's a win-win."
Storage facilities are a nationwide practice that NRCS supports. Check with your local NRCS office for details about cost-share options for chemical storage facilities.
The author is a frequent contributor and freelance writer who farms and raises Great Pyrenees in south-central Pennsylvania.