To answer the question posed above ... I tie the tarps, corner to corner, and carry to my trailer. I use a pickup with a cap (store all my hand tools, trimmer, blower, ect), with a 6 1/2 X 12 trailer. I use the front four feet of the trailer for debris, the rear eight feet for my equipment. I work solo, only mow 900-1200 per year, so can't afford a dump truck, or second vehicle to pull around dump trailer.
Handling the clipping is a real pain, but some customers demand that part of the service (please -- no starting a long list of posts about "why are you bagging at all - just mulch"). I have several HD barrels on the trailer, put clippings in there directly from the baggers, or leave the tied tarps in tact, getting them home. I have a debris trailer at home to dump the barrels and tarps. Once per week, or as needed (trailer hauls 3 cu yds), I haul the clippings to a dump, and fork off.
I know, I know -- much heavy work, and TIME. But, when one barely makes a living at this work, spending large money for alternatives is just not possible. I am unable to implement all the suggestions made in these kind of threads, "... buy this," "buy that," etc. We who are small operators don't have the financial resources to spend lots of money, just "because it would make things easier." And, I am 62, so cannot plan for a long term (5-10 year) lawn service business. Buying up much equipment, with strong possibility of a year or two of use, then selling isn't a good idea -- can't recover all the cash.