Sustainability · November 16, 2022
What 92% Water Recovery Actually Means
Washing containers could easily be a water disaster. Here's the plant that stops it being one, and the honest reason the number isn't 99%.
The short version
Solids settle through staged traps, water is filtered and returned to the wash cycle, and what can't be recycled is treated and discharged under permit. Recovery averages 92% across the year — higher on rinse-only cycles, lower on food-grade work where potable rinse water can't go back in.
A thorough container wash consumes between sixty-five and a hundred and ten gallons depending on the standard. Multiply that by our annual throughput and you get a number that would be difficult to defend in a state that spends most summers in some stage of drought.
The plant, plainly
- 1Wash water drains from the pad into a first trap where heavy solids and grit drop out by gravity.
- 2It passes through a second and third settling stage with progressively longer residence time, taking out finer suspended material.
- 3Oils and floating material are skimmed at the surface between stages.
- 4The clarified water is filtered and pH-adjusted, then returned to the wash cycle reservoir.
- 5What can't be returned — chiefly food-lane potable rinse water — is treated and discharged under permit.
None of that is exotic. It's settling, skimming and filtration, which is the same sequence used in a hundred other industries. What makes it work is sizing the stages generously enough that residence time does most of the job, so the filters aren't carrying a load they'll clog on.
Why the number isn't higher
This is the part that gets left out of most sustainability claims, so here it is.
| Standard | Water per cycle | Recovery | Why |
|---|---|---|---|
| W1 rinse | ≈ 28 gal | 100% | Cold rinse, straight back into the loop |
| W2 triple rinse | ≈ 65 gal | 92% | Some carry-off in drainage and evaporation |
| W3 hot detergent | ≈ 85 gal | 88% | Chemistry load requires periodic bleed |
| W4 caustic CIP | ≈ 110 gal | 84% | Potable rinse water can't be recycled into the food lane |
The ninety-two percent headline is an annual average across the mix. It's higher on the rinse-heavy end and lower on food-grade work, and the reason it's lower there is a deliberate choice: recycling rinse water back into a food-lane container would be cheaper and would compromise exactly the thing that lane exists to protect.
Evaporation, which nobody counts
On a 105°F August afternoon in Austin, a surprising amount of what lands on a wash pad simply leaves. It isn't a loss you can engineer away without enclosing the whole operation, and it's a meaningful slice of the eight percent that doesn't come back.
We mention it because it's the sort of thing that gets quietly excluded from recovery figures elsewhere. Ours includes it.
What it cost and whether it paid
The plant went in during 2019 and it's the capital investment we'd make again first, for three reasons that have nothing to do with marketing.
- Water cost. At our throughput, an eight-fold reduction in draw is a line item you notice.
- Discharge cost and permit exposure. Less volume out means a smaller, simpler, cheaper permit position.
- Drought resilience. When restrictions arrive — and in Central Texas they do — an operation drawing an eighth as much water keeps running.
The honest framing
We aren't water-neutral and we don't claim to be. We run a process that consumes water, in a state that doesn't have a surplus of it, and the responsible version of that is to consume as little as the process allows and to say plainly how much that is.
Ninety-two percent, measured at the meter, evaporation included, averaged across the year. If we get it to ninety-four we'll say so, and if a bad summer drops it to ninety we'll say that too.
Published November 16, 2022 · Filed under Sustainability
