Careful of caustic chemicals on the polished aluminum as permanant damage can result.Foamers are sometimes useful for stubborn staining and allows you to wash 2 units while the foam has reaction time.Car wash wax can easily be injected and leaves a nice job and is charged out with mark up too.
I'd get a good explanation of what they want for results, how clean they want them and how often , just once or an ongoing thing?
When washing fleets in close proximity to each other watch the wind direction for overspray and work with the wind.In addition if they can get the units spaced amply apart for use of a long wand without being crowded in as saves a lot of time.
Wastewater control isn't an issue up here yet for standard road dirt so I can't help you with that area but would require additional revenue accordingly.
I've offered a brief report of truck condition to my clients at each wash interval as to body damage or other anaomilies that may be noticed and not passed on by the drivers such as oil leaks etc etc. some clients like this and doesn't take too much extra to keep them happy.
I usually rate my fleet washing as compared to a Truck wash Facility.
Up here $1.20 a minute plus the wage by hour for their employee to take it there wash it and get back to the yard.
Example :
1 hr Truck wash $72 plus 1.5 man hrs @ $20/hr = $102 /hr.
This varies of course with condition of the trucks & locality to washing etc etc.
The conveniance factor to them is worth something also as no hassle scheduling and the trust you will perform faster - thus cheaper - then sending their guys (likely on overtime wage) to a wash facilty.
Rates here go from $110-$130 hr plus chemical charged by the liter (or gallon).
Night time washing and lighting may be an issue that needs to be addressed as many times the trucks require washed at night after their day's work.
Are other people bidding on this too?
I hear ching ching if you land this contract.
Don't bid too cheap, stress the quality of your work,live up to it.
Best of luck!
