There's a Reason They Call it Kitty "Litter"

2008-03-05 · Filed under intertwingled · Tagged compost, kitty litter, vermiculture, waste

We have two cute little kittens, Kinnie and Cali, a brother and sister team from the same litter. Well, they are not so little any more. They are 6 months old at this point and have grown like crazy. They are also getting very bratty, so maybe they are not so cute as they used to be, but heck, they have stolen our hearts anyways!

Kinnie is the orange tabby, and Cali is the calico.

As you may have already guessed from the title, the reason I’m writing this particular blog post is because pets produce waste. Lots of it. In fact, according to the book “In Defense of Garbage” by Judd Alexander, American cats produce over 2 million tons of kitty litter each year! (And that was in 1993… who knows what it is now?)

Of course, we have a litter box in our garage and a little cat door so they can get from the house to the garage. The litter box was filled with the clumping clay type of litter which works really well with the type of lifting sifter box we have. I estimate that 5 to 15% of our garbage is kitty litter based on a visual inspection of the volume of the garbage bin taken up by litter and garbage bags.

Okay, So There’s Waste. Big Deal. What’s the Problem?

There are a number of problems with traditional clumping litters:

1. Clumping kitty litter is typically made out of sodium bentonite. This is essentially clay. It works really well at absorbing liquids and clumping, but it has to be mined out of the ground to be produced. These mines are not particularly “green” — many are open cast mines.
2. Sodium bentonite is very dusty, and when cats follow their natural “burying instinct” after they are done, they kick up a lot of this dust. And then they breath it in. Not good.
3. Some cats ingest this litter, causing clumps and in rare cases even blockages in their digestive tracts when the bentonite soaks up all the usable moisture.
4. The used litter is non-compostable and non-reusable. So all you can really do is throw it out. It then finds its way into landfills. This biological material should be reused and recycled back into the ecosystem to help combat soil erosion, but instead it is sent out of the ecosystem for good.
5. Clay can get in between kitten’s toes and get stuck there, and if they have any injuries, it can get into the wound, clump, and then get infected. Vets recommend against clumping clay for cats with recent surgeries and for kittens.
6. Clumping litters often contain other rather-nasty chemicals in order to trap smells or otherwise neutralize odors. Some of these chemicals are toxic if ingested.

Basically, clumping clay is not sustainable. We mine it, use it, then throw it out. One day, we’ll run out of it. (Then the cats will start using your carpets or your flower beds for their litter box instead. Ew.)

Okay, So What to Do About it?

Well fortunately, there are biodegradable kitty litters out there. Usually they are based on one of these:

• pine wood pellets
• non-food grade wheat or wheat bran
• paper pellets
• sawdust
• corn cobs

All of these are sustainable, because we can just grown more and we can compost it when it’s done. The compost can then be used in gardens or other soils.

Composting? Well What About All those Nasty Bacteria?

That’s a very good point. Cat feces sometimes contains many types of fecal coliform bacteria such as the dreaded E. Coli, and also a very nasty bug called taxoplasma gondii which can survive in soils and eventually get into food growing in that soil. This particular taxoplasma bacteria is very nasty for pregnant women and their babies, and for that reason pregnant women should never be “doing the litter”. Unfortunately, us guys need to sign up for that household chore. (I was going to make a quip about “always dealing with the crap” but I realized my wife will probably read this posting!

Composting does get rid of a lot of bacteria, especially if you do worm composting (vermicomposting). But it does not get all of it. The safest thing to do if you are composting your litter is to use the resulting worm casting on non-food plants only, such as trees, shrubs, flowers, ornamentals, etc.

You can also sterilize the soil by essentially “cooking” it to kill off all the bacteria. This can be done in a green fashion via solarization. Solarization is a technique where you spread a thin layer of soil (or in this case, worm castings) out on a black surface and cover it with a transparent cover such as a thick plastic sheet. Then, you leave that out in the sun to “cook”. In sunny climes, this technique can raise the temperature of the casting up to as much as 140 to 150F. If this is left in the sun for a few weeks, pretty much all bacteria, fungus, weeds, and seeds will be sterilized. Also be very careful — the temperature must be above 140F for a few hours to ensure that the bacteria are all killed off. If you are not sure about it, don’t use this compost on your food crops. See the USDA web site for more details about killing off harmful bacteria in foods, some of which applies to killing bacteria in compost.

Alternately, you can cook the castings in the oven at 200F for 20 minutes to do the same thing. (Don’t worry, the worms have removed anything smelly!) This is what companies do to chicken and cow manure that you buy in those huge packs at your home and garden megastore.

The only problem is that cooking it in the oven probably uses electricity that causes carbon emissions. Solarization is the preferred “green” method if it gets warm enough where you live to raise the temperature sufficiently.

But there is a problem with cooking. Even the beneficial bacteria can be eliminated. All of its mojo is gone, baby!

So, the idea is that you would keep 2 compost heaps: one for kitchen wastes, and one for worm composting the kitty litter. When a batch of the worm compost is done, and then appropriately solarized or sterilized, then it goes directly into the kitchen compost heap to get its mojo back. The castings will pick up beneficial bacteria and also provide food and materials to help the bacteria break down the food wastes as well. The result should be usable on food gardens.

So What are You Doing, Edwin?

Well, step 1 is already complete: we have switched from the clumping clay litter to Swheat Scoop wheat litter. The cats didn’t seem to mind at all. The only thing I have noticed is that there is an ammonia smell when I change the litter that I didn’t smell before with the clay. Currently, we are still throwing the litter out in the garbage. (You can’t put it in the green bin for the same bacteria reasons listed above.) Also, the price seems to be competitive with the clay clumping litter. We pay perhaps a dollar more (that’s about 10%) to get this biodegradable stuff.

Step 2 is to get a 2 composting bins, one for food and one for litter. Then, we’ll use the food compost for the food garden, and the litter compost for the non-food parts of the garden.

Step 3 is to build or buy a solarization tray so that we can sterilize the litter compost with a high enough heat that we can use it for the food parts of the garden.

I’ll blog again when we have done parts 2 and 3.