Potassium dichromate and sodium dichromate

Potassium dichromate and sodium dichromate:

We have combined four questions to be answered here

• Determination of alcohol content in wine: A prac for this has been suggested for our Year 12 chemistry students. The prac asks for 0.04 M K2Cr2O7. Is this solution okay for the students to use? I have viewed the SDS for potassium dichromate and am also wondering about the fertility and other health risks to the lab technician in preparation of these solutions.
• Chemical cells: When making a chemical cell (Year 9 Energy—Electricity) using a zinc electrode and a carbon electrode in acidified potassium dichromate, what molarity should the dichromate be and how much sulfuric acid (what molarity) do I add to it to acidify it?
• Dichromic acid glass cleaner waste: I use concentrated sulfuric acid and sodium dichromate in the glass cleaner I make. I reuse the cleaner until it is no longer active and changes pH. The residue from the glassware is diluted with water when being washed and put down the sink. Should I be using a different glass cleaner or procedure?

Chemical disposal (chromium): I have a small amount of potassium dichromate and potassium chromate for disposal. What is the best way to do this?