The laundry room for BWV is on the first floor very near to the health club. When you exit the elevator, turn right and go into the hallway. You will quickly see it. The washers and dryers are free, but you must provide detergent and softening agent (if you use it). My advice is to bring your own (individual tablets are easy to pack or pick some up on your grocery stop) as the one load boxes in the vending machines are expensive, IMHO. Can't help with how busy they are - depends on time of day.
Someone else will tell you about OKW - we haven't stayed there yet.
Best wishes -