Heels, residue and the drain you must never use

Start with the vocabulary, because it matters on paperwork. A heel is the residual product left after normal discharge. Residue is the broader term for anything remaining in the container, including rinse water and whatever has mixed with it during storage.

Why the amount varies so much

The third row is the expensive one and it is entirely preventable. Put the caps back on before containers go out the back of the building.

The declaration

Ordinary industrial heels are standard work. They are evacuated under containment at intake and routed to licensed treatment. Nothing about that is unusual and it does not need special handling on your side.

Regulated or hazardous residue is different, and it needs to be declared before a truck is dispatched. Not because it is a problem — we handle it constantly — but because it changes the route, the paperwork and sometimes the vehicle.

The drain

Never put container residue, rinse water or wash water down a yard drain. Most yard drains are storm drains, most storm drains discharge to surface water, and the fact that something looks dilute is not relevant to whether it may be discharged.

This is the one line in this entire trade where there is no nuance and no cost-benefit conversation. Everything gets captured.

Our own residue evacuation happens over containment at intake and goes to licensed treatment. The wash line recirculates within its cycle and its effluent is captured, settled and routed the same way.

What a triple rinse is actually for

Three separate rinses, each filled, agitated and drained completely before the next. Each cycle dilutes what remains by roughly the same factor, so three short rinses beat one long one by a wide margin — a single long rinse recirculates whatever it has already picked up.

For many non-hazardous products, a properly executed triple rinse is what moves a container from residue-bearing to clean for handling purposes. It is not a substitute for a wash cycle and it does not make a container food safe.

Practical advice for a plant

• Drain containers fully at the point of use, while somebody still knows what is in them.
• Cap them. This single habit prevents the rain-plus-unknown category entirely.
• Label anything unusual, even informally. A marker pen on the cage is worth more than nobody remembering.
• Keep containers with regulated residue physically separate from the rest.
• Tell your collector before the truck is booked, not when it arrives.

What a rinsate actually is, and where it goes

Rinsate is the water plus dissolved and suspended residue produced by rinsing a container. It is not clean water with a bit of product in it — it is a dilute waste stream and it is regulated as one.

Where it goes depends entirely on what was in the container. For many non-hazardous products, rinsate can go to sanitary sewer under a permit or trade effluent agreement. For others it goes to licensed treatment. In no case does it go to a storm drain.

If you rinse containers on site, find out which category yours falls into before you start, not after somebody notices a sheen in a ditch.

Containment, practically

• Rinse over a bunded area or a portable containment pad, not on open hardstanding.
• Know where every drain in the rinsing area goes. Mark storm drains clearly.
• Keep absorbent and a drain cover within reach of the rinsing point.
• Collect rinsate in a dedicated container, labelled, not in whatever is nearest.
• Never mix rinsates from different product families without checking compatibility.

The compatibility warning

That last point deserves emphasis. Combining rinsates is how an inert waste stream becomes an energetic one. Acid rinsate and hypochlorite rinsate in the same drum produce chlorine gas. Acid and sulphide produce hydrogen sulphide.

If you are collecting rinsate from mixed products, keep the streams separate until somebody who knows the chemistry says otherwise.

Declaring residue when selling containers

Every row in that table is a routing decision rather than an obstacle. The only genuinely bad outcome is a driver discovering something on your dock that nobody mentioned.

Questions about residue

How empty is empty? For most purposes, drained through the outlet with the container tilted. That leaves ounces rather than gallons and is what we mean when we ask for containers to be drained.

Do we have to triple rinse before you collect? No. We are set up for heels and we would rather you did not, because rinsing removes the evidence of what was in it. Drain and cap, and tell us the product.

What if a container has been sitting for years? Tell us. Long-stored containers are the ones most likely to hold something dilute and unidentifiable, and it changes the handling and the price rather than the answer.

Who is responsible for the residue? Until title passes, the seller. That is why undeclared regulated residue is a genuine issue rather than a paperwork nicety — a driver cannot lawfully take something nobody has declared.