Budgeting 12,000 m³ a Year Across Tanker, Evaporator and Gel Routes

Twelve thousand cubic metres a year is the volume where the three common leachate routes start to look comparable, and where a decision made on one number is usually wrong. At that scale a site 240 km from its nearest permitted disposal facility pays roughly $95/m³ to tanker, about $96/m³ to evaporate once capital is amortised and residue is counted, and about $83/m³ to solidify and landfill. A 12 percent spread is no landslide, so the choice has to rest on the lines outside the headline rate.

This article builds the three columns with every input visible, puts the hidden costs where they belong, and sets out the volume ranges where each route wins. The numbers are indicative for a temperate climate and a non-hazardous classification; substitute your own gate fees, power tariff and haul distance and the structure still holds.

Column One: Tankering, and the Lines That Do Not Appear on the Invoice

Tankering is priced per cubic metre and per kilometre, and at 240 km each way the transport component dominates. A typical rate of $0.16 per m³ per km for a 25 m³ tanker gives $77 for the round trip, plus a loading charge near $6/m³ and a disposal gate fee of $12/m³, for about $95/m³ and $1.14 million a year.

The lines that break the model are capacity and availability. A 25 m³ tanker making one round trip a day moves 6,000 m³ a year, so 12,000 m³ needs two vehicles running six days a week, and a single breakdown removes half the site’s disposal capacity. Add the wet-season peak, when volume can triple for six weeks and the same fleet cannot keep up, and the true cost includes a surge allowance that rarely appears in the per-cubic-metre quote. Tankering also fixes nothing at the site: the sump level still has to be managed, and every litre that leaves is a litre you paid to move.

Column Two: Evaporation, Where the Energy Is Only Half the Story

Evaporating a cubic metre of leachate takes roughly 640 to 900 kWh in a well-run unit, allowing for latent heat, preheating losses and the fact that leachate is not pure water. At 720 kWh and $0.11/kWh that is $79/m³, or $950,000 a year at 12,000 m³.

Capital sits on top: a 40 m³/day evaporator with heat recovery, condensate polishing and residue handling runs around $1.8 million, which is $120,000 a year over fifteen years before interest. Residue is the third line, because evaporation does not destroy salt. A 12,000 m³ feed at 1.5 percent solids leaves roughly 180 tonnes of residue a year, and if that is disposed at $90/m³ of slurry rather than as dry salt, the line is closer to $86,000.

The technical constraints matter as much as the money. Ammonia partitions into the condensate, so the distillate usually needs its own treatment before discharge, and chloride above 20,000 mg/L drives up corrosion rates in the heat exchanger to the point where tube life becomes an annual cost rather than a capital one.

Column Three: Polymer Solidification, Priced Honestly

At 20 kg/m³ and $2,150 per tonne, polymer costs $43/m³. Handling, mixing labour and equipment amortisation add about $9/m³ on a 12,000 m³ site running two batches a day. The line that surprises finance is disposal: solidification converts 1 m³ of liquid into 1.2 m³ of cake at 1.08 t/m³, and at a $22/t gate fee that is $28.50 per cubic metre of cake, or $31 per cubic metre of input.

Total: about $83/m³ and $996,000 a year, with the advantage that the equipment is a mixer, a tank and a pump rather than a permitted thermal plant. The route also scales down gracefully, which matters in a wet year, and it can be run in campaigns rather than continuously.

Which Column Wins at Which Volume

Below 3,000 m³ a year, campaigns win on capital: a trailer-mounted batch tank and a few pallets of polymer beat any permanent installation, and tankering is often cheaper still if the haul is short. Between 3,000 and 15,000 m³, the three routes sit within 20 percent of each other and the decision turns on haul distance, power price and permit conditions rather than on cost per cubic metre. Above 20,000 m³, on-site biological treatment with reverse osmosis almost always beats all three, and solidification is relegated to the concentrate sidestream.

Two adjustments flip the ranking faster than anything else. A haul distance under 80 km drops tankering to $40 to $50/m³ and it wins outright. A gate fee above $45/t pushes the polymer route to $100/m³ and evaporation becomes competitive again despite its capital. Run both sensitivities before committing, because a single contract renewal can move a site from one column to another.

Whichever column you land in, the polymer line is the one you can influence month to month. The SAP grades we supply for leachate work are quoted with absorption in real leachate rather than deionised water, which is the figure that turns a dose table into a defensible cost per cubic metre in a board paper.