in a short answer.
if you really want to find a environmentally friendly sanitizer(that's proven) then use iodophor or star-san.
Depends on how sanitized you want things,
The FDA food code requires that restaurants sanitize any surfaces that come into contact with food. Although many green cleaners have sanitizing properties, the EPA and the FDA food code define “sanitization” of food-contact surfaces as a 99.999% reduction of disease-causing microorganisms within 30 seconds. Unfortunately, most green cleaners do not kill 99.999% of microbes, making it difficult for a restaurant to be “green” and still follow the codes. But that doesn’t mean that green cleaning is an impossible feat.
Chlorine solutions are without a doubt the fastest and cheapest of all
the approved sanitizers. However, they are also among the most toxic,
corrosive and dangerous of the solutions. Ammonia solutions are
generally better than chlorine for the environment, but they are
incompatible with many chemicals and other cleaners.
Choose an iodine solution. Among the three most common solutions,
iodine is by far the most environmentally friendly. Like the other
sanitizers, iodine is toxic in high concentrations and can vaporize
into the air. However, iodine occurs naturally around the world, and
the amount of iodine humans put into the air is nothing compared to
the quantities of iodine that vaporize off the surface of the ocean.
I personally use percarbonate sanitizer, that my LHBS sells. but if i could get it cheap I would use iodophor or star-san sanitizer. even tho i have not had any issues with the percarbonate sanitizer(cleaner), it is not FDA approved as a sanitizer , only a cleaning agent, which it does a great job with. you also may want to check out this previous question, Can OxiClean be used as a sanitizer?
also, environmentally friendly means you are also disposing the waste water, cleaner in the proper drains or drop off points, and not letting it run to the storm drains.