The tender document asks for estimated annual tonnage of offensive waste, and the trust’s answer is a number that three people have independently described as a guess. It was derived, as far as anyone can tell, by multiplying bed numbers by a figure from a 2011 benchmarking report. The bidders will price against it, and the contract will be wrong from day one.
Gel changes the shape of that number, and the facilities team usually has the data to fix it, sitting in bin weights and delivery notes that nobody has ever joined up.
What bidders actually need
A waste contractor prices on lifts per week, container size, weight per lift and the frequency of ad hoc collections. Tonnage matters, but it is a derived figure. Give them the four inputs and they can price properly; give them a tonnage and they will add a risk margin.
- Litres of urine collected per occupied bed-day, by ward type.
- Containers per week, by size, and the average fill level at collection.
- Weight per container at collection, sampled over a fortnight.
- Number of ad hoc call-outs in the last twelve months and their causes.
The fill level is the one that gets left out and the one that changes the price most. A contractor who expects 80% full bins and finds 45% full ones is paying to move air, and will price for the worst case.
The water you are no longer paying to move
Before gelling, a 5 litre container holds 5 kg of liquid. Gelled at 25 g per litre, the same container holds about 5.1 kg of solid, which sounds like no saving at all until you look at what happens next.
The saving is not in the container. It is in the frequency. A gelled container can wait two days without becoming a problem, which means collections can be scheduled rather than reactive, and the ad hoc call-outs for leaking bags stop. In one 120-bed site, call-outs fell from nineteen a quarter to four after gelling was introduced across all wards, and the contract was renegotiated on that basis rather than on weight.
Put a dose figure in the specification
If the trust buys powder separately from the waste contract, the two documents can contradict each other. One asks for a wetter, heavier waste stream; the other is priced on tonnage. Someone eventually notices, usually an auditor.
The fix is a single line in the waste specification: gelled at a nominal 25 g per litre, containers presented lidded and bagged, no free liquid. That one sentence tells a bidder what they are collecting, and it gives you a defensible position if a load is rejected.
Add the pack format too. Sachets and drums produce different presentation, different spill rates and different training needs, and a contractor who has only seen drums will price sachets as an unknown.
Sample properly before you write the numbers
Two weeks, three wards, one scale. Weigh every container at collection, record the fill level from the mark on the side, and count the containers. Twenty to thirty data points will give you a mean and a range that will survive a challenge.
Do not sample only the medical wards. The number that skews a tender is usually the one from a unit nobody thought to include, such as a renal or urology outpatient area where volumes per patient are high and collection frequency is low.
A district general hospital did this exercise and found that 31% of its offensive waste by weight came from two departments that accounted for 6% of its beds. The tender had been priced on bed numbers for a decade. The renegotiated contract recovered roughly the cost of the gel for the whole site.
Put three questions to each bidder. Ask how they handle a rejected load, what their policy is on free liquid in a container, and whether their transfer station accepts gelled polymer without pre-treatment. The third question separates bidders who have handled this material from those who have not, and it is worth asking in writing so the answer is on file.
Ask, too, what data they would like that you have not provided. The good ones will ask for fill levels and call-out reasons, which tells you they intend to price it properly rather than pad it.
If you are drafting a specification this month, the SAP powder specifications give the dose ranges to quote, and your own bin weights give you everything else.
Weigh twenty containers before the document goes out. It is the cheapest part of a tender and the part that decides whether the price holds.
Da maohua
Zhengzhou Flor New Materials Co., Ltd. specializes in SAP super‑absorbent polymer products. Serving personal hygiene, agriculture & horticulture, pet supplies and other industries, we leverage supply‑chain resources to provide particle‑size selection, performance matching and customized solutions based on clients’ practical requirements.
