Course: Pesticide management | Last Updates: 7th October 2015
A lot of effort and consideration goes into what you spray in the autumn. But what about the cans it comes in? Some farms will use many hundreds of pesticide containers in the space of just a couple of months. Quite apart from the consideration of ensuring these are not hazardous waste, so relatively easy to dispose of, there is also the question of how long it took to empty them.
This is time better spent on applying the sprays. Ideal spraying conditions make all the difference with grassweed herbicides, so downtime when filling the sprayer must be minimised. This may not be reason enough to switch from your ideal product, but packaging varies, and there's no industry standard. So it's always worth looking at what's available before you put in your order.
Why is packaging design important?
As well as potential downtime, pesticide containers and their handling are subject to stringent regulation. There are packaging design issues associated with each set of regulations.
This has its own implications in terms of downtime. To comply with regulations means you need a system that handles containers, from storage to usage, to cleaning and disposal. A review of this system could reveal ways in which to save time and do a better job.
This has been explored recently by the Container Management Working Group, a cross-industry forum within the Chemicals Regulation Directorate (CRD). All practical aspects of packaging design have been scrutinised, with the aim of making the job easier for the operator and more environmentally friendly, and there are a number of useful conclusions.
What containers store best?
The first thing to decide is what size of container to use. A product used at a 2-3 litre/ha rate could involve using a large number of five litre cans, that will take time to empty, rinse and dispose of. But large containers (20 litres and above) are often not well suited to pesticides – they are made to stack, so tend to have higher shoulders and smaller openings. This makes them difficult to rinse effectively and they will glug when poured. The cans are also stronger and do not squash easily, so are not favoured by some recycling contractors.
Consider also what shape of container you want. One that pours well may not stack easily in your store, unless well packaged. Again, cardboard may need to be flattened and bound, which takes time.
What containers are best to use?
There are three key features of packaging design that affect their use:
1. The handle
Avoid containers where the handle is moulded into the can and pesticide can pass within it. These are difficult to rinse completely. A better design is where the handle is crimped off from the rest of the can. The ideal is a carry loop around a central opening, such as on a Starane container.
2. The shape
The key aspect to look for is a shape that rinses easily. Avoid cans with high shoulders, although these are now relatively rare – the corners are difficult to reach with rinsing jets. A funnel shape rinses quicker, while round, milk bottle-shaped containers are ideal – these have no corners to trap residue.
3. The opening
The bigger the better, and again generally design has improved. A small opening means it will glug when poured, which has implications for both health and safety and contamination. A central opening is better than one offset to the side, for the same reason.
What issues affect their disposal?
The first consideration is that it must be 99.9% free of residue, which is generally achieved through triple-rinsing. This ensures it is not hazardous waste. Recycling is the preferred route of disposal, so you need to separate components into their different waste streams.
Foil seals remain a big problem for the industry. They are fiddly to use but must be handled carefully as a result of their potential to be a serious point source of pollution. Make sure residue is rinsed into the induction bowl. Then put all seals into a separate container for disposal as hazardous waste. If you can source containers that do not need them, you will save valuable time and hassle.
Labels are another problem. They should be separated from the can and placed in your paper/cardboard waste stream. This is not easy as they should be firmly fixed to the side and are often put in plastic wallets, which again should be separated. Some manufacturers now have plastic or easy-peel labels.
Different polymer types of plastic should ideally be separated. The two main ones are polyethylene terephthalate (PET) and high-density polyethylene (HDPE). These are usually marked on the can with a recycling symbol but can be hard to find. The ideal is when the lid, handle and can are all from the same polymer that is clearly marked.
What formulations are best?
Product formulation has a big impact on the downtime spent filling the sprayer, although generally this is improving. Try to avoid wettable powders – cheaper generics still come in this form. Some even require pre-mixing, which has health and safety, contamination and time implications.
The main aim with liquid formulations is to use those that rinse easily. Be wary of suspensions – they can separate if left in store. This is more an issue with some formulations than with others, depending on the other ingredients used by the manufacturer.
Emulsifiable concentrates generally rinse quite easily, although again specific formulations vary.
The Rolls-Royce formulations are soluble granules. Often these come in small packages to treat a large area. They dissolve easily and cans rinse well. Measuring part cans may be a problem, although metering pots are often supplied.
How has the industry addressed packaging issues?
Returnable containers have had a chequered past, and generally are not considered to be the solution to sprayer operator woes. Some manufacturers have tried soluble containers, such as sachets. These may have uses for gardeners or hobby operators, but it may not be practical to pass a large number of sachets through the induction bowl.
Manufacturers have had to address issues of stability, shape for stacking and transport. But usability and recycling issues have generally taken a back seat – the guidance given to manufacturers is 20 years old. Shape and type of plastic used is getting better, but the standard varies considerably.
- Handle pesticides carefully
- Look for containers that rinse well and don't glug
- Rinse containers well inside and out (if necessary) and drain them properly
- Ensure you and your staff are well-trained – NRoSO workshops give excellent guidance
- Put foil seals back into the container you took them from
- Mix different wastes – paper/cardboard, plastic, foils
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