I thought I would share a couple of green event "party tricks" with you. One of my green event strategies is to save the coffee grounds from events/conferences/meetings for use as compost. I have a network of friends who are happy to receive the coffee grounds. Note: You can divide them up amongst a number of people. If I am working on an event out of town, I try to partner with a local organization and arrange for them to take the grounds (horticultural society, community garden, etc.)
It isn't a difficult strategy to achieve...you just need to arrange with your caterer to save the grounds and provide something for them to put the grounds in. I generally line a bin with a strong garbage bag (the wet grounds get heavy) and the caterer positions it beside the coffee maker. Believe me.....when you are serving coffee to 650 attendees, the grounds add up!
It occurred to me that my attendees didn't know what was happening behind the scenes. They didn't know that we were saving the coffee grounds. For some events I began posting a sign by the coffee station that informed the attendees that we were saving coffee grounds and what the grounds were going to be used for (use pictures to help to illustrate, perhaps a photo of a vegetable garden that received some of the rich compost).
You can take this one step further by having a chalk board or white board beside the coffee station where you can record daily, the weight of the coffee grounds going to compost. If your event is only a one day event, you can still do this.....simply post the results from the morning coffee and then the results from the afternoon coffee break. For multi-day events, you can share the impressive numbers via email in an "eco-daily". An "eco-daily" is an newsletter that informs the attendees of what has been accomplished each day.
If you don't inform your attendees, you can't influence them. Share the message, share the strategies, share the successes.
I believe that your attendee's have an inherent wish to "do good" and when you share with them that they are actually playing a part in something positive, they will respond positively.