At the risk of making half of you think I have again jumped the shark, I'm going to delve into cat sanitation with an eye toward environmental issues. I first thought about this back around Earth Day, but in my longstanding tradition of procrastination, I'm only now getting around to it.
Choice of cat litter:
I've always felt that clay litter was the most environmentally appropriate litter choice, being basically a natural mineral (bentonite) that is harmless in the environment. My only problem with it is when it gets flushed. Scoopable and regular clay litters can clog toilets, leading to major plumbing repair bills. I have noticed that if I just put the scoop litter-covered feces in the toilet bowl and let them sit a few minutes, the tiny bits of clay hydrate nicely and suspend in the water just fine, so I will flush the feces. I NEVER EVER flush the urine clumps, however, because that much dirt of any kind at one time is sure to clog up the works. And of course the larger pieces of litter in regular clay litter (non-scoop) cannot be trusted to soften up appreciably.
Other litters, such as the wheat or corn based, are probably flushable if the label makes that claim, but I would always be worrying about clogs, so would only flush feces if I were using them.
Let cat poop light the night:
You might ask why I bother to flush cat feces instead of landfilling them - it's because of THIS. LA DWP operates the Hyperion Wastewater Treatment Plant and the biogas-fueled electricity generating station that the sewage sludge fuels. So your cat's poop (and yours, too) helps to keep the power on. Hyperion has been operating in this way for over 50 years, and I would venture a guess that the majority of Angelenos haven't a clue.
If we toss cat feces in landfills, two major problems arise. First, if the feces harbor Toxoplasma gondii, a protozoan parasite, and rainwater washes through the landfill and runs to the sea (pretty much a given at times), that Toxoplasma winds up in the ocean where it is known to kill our very own beloved sea otters. I realize that feral cats probably contribute far more to any Toxo risk to wildlife than pet housecats do, but that's no excuse for us being lackadaisical and contributing to the problem unnecessarily.
Second, cat feces in a landfill are going to produce methane - that's a given. But in that landfill, there is no way to capture and utilize the methane gas - it just goes up into the atmosphere where it contributes to the greenhouse effect. In lovely weather like we are having right now, it's hard to get concerned about global warming, but the safest course of action is to act in a way right now that we know does less harm and requires no additional expense or effort , and we can debate about the magnitude of the problem at leisure.
Disposal of litter box scoopings:
I used to use all those plastic grocery bags for tossing my scoopings, but since I avoid them like the plague these days in favor of cloth totes, I have had to improvise. Fortunately, plenty of plastic bags still come through my doors in the form of grocery produce bags, ziploc food packaging, plastic wraps on magazines, bags from dried beans and rice and pasta, and just about every other food you can think of. It's ALL packaged in plastic. I also have found that I can twist a bag shut and store it under the bathroom sink with the litter scoop and other supplies, and use it for about 2 or 3 days' worth for my two cats (YMMV) without the slightest odor problem (I use PetSmart's Exquisicat Scoop brand), so I get great mileage out of the bags I DO use. And unlike the el cheapo flimsy white plastic grocery bags, my produce bags and such don't always seem to have HOLES IN THE BOTTOM. Oh, and I tie an overhand knot in my bags or zip them shut before tossing, so they don't stink up the wastebasket.
And just FYI and slightly off topic: I STILL hate those electric self-cleaning monstrosities.