For the last few years that I did my own processing I also used the one shot method, using the Jobo CPE-2 Plus Processor for Film and Prints, but I did have all the different size print and film tanks.
As these tanks revolved in a thermostatically controlled water bath, maintaining a constant temperature was never a problem.
I also use the concertina type storage bottles. As for disposal, well this always went down the household drains.
Quote from the Ilford site "Amateur and home users in the UK should dispose of small amounts of used photographic processing solutions by dilution with plenty of water and washing them down the drain. Do not mix solutions." but not if you have a septic tank
http://www.ilfordphoto.com/applications/page.asp?n=48
Harry