The waste water treatment plant in Burlington, NC has been making fertilizer from the solids at their facilities for years. I work next door and the trucks run non-stop taking it out to farmers. The only complaint I've ever heard is when the wind blows toward my office.
As an older backpacker I remember much of this same discussion in the late 60's and 70's. We were going to change the world but as you can see that didn't happen. I think even with the distrust my generation had for government and the establishment in general, we got caught up in day to day lives and paid more attention to feeding our own overweight children instead of the starving children of the world. We drove around in VW bugs that got amazing gas milage but now I see Hummers at 5 mpg running up and down the road. Even the gas efficient Toyota company introduced a new SUV last year to share in this market. That model get last mpg than there old 4-Runners. As for gas I paid 25 cents a gallon for in the 70's. We discussed alternatives but they have always cost just a little more than petro products. I think that will always be the case as Exxon and other oil companies reap record profits while shortages drive up the price.
If you really want to do something about the environment don't wait for someone else. Don't wait for it to be lighter. And don't wait for it to keep money in your pocket. Just do it. Ride a bike to work, carry your own bags to the store, combine several car trips into one. Why not carpool? I see cars pass me on my bike everyday with just one person. They all can't be going to different locations.
As for packpackers being green. Even if we are just a small (but growing) group, the biggest thing I see we can do is pick-up the trash. The environment in the back country does not need us to leave behind plastic baggies, paper wrappers or even human waste. I saw a place in the Smokeys were hikers had niether buried the waste or paper. It just laid on the ground. Learn to dispose of these things properly and burning them is not what I concider proper. As for fires I see fire pits at every shelter and campsite on the AT with aluminum foil, scraps of paper and even discarded clothes. The one just north of Wayah Bald had just been cleaned up by a trail crew. In the fire pit someone left their dental floss. How much trouble would that have been to pack out?
If you are concerned about the environment then consider this. Its not what gear you buy its where you leave it that counts! Even if you just sell it to another backpacker, isn't that recycling?

