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Pet Waste Composting

If you’ve read a fair bit about backyard composting you will likely know by now that one of the cardinal rules is “don’t add pet waste to your compost bin”. This advice certainly has merit, at least as far as a regular compost bin goes (i.e. one you add your kitchen waste to, and eventually empty for the garden). After all, these materials can contain various pathogens, and aren’t exactly all that enjoyable to work with.

I should mention that the term “pet waste” is actually far too broad to be used in this context. There are many different types of pets out there, and a lot of them produce waste materials that make for an excellent addition to your compost piles. Really, any of the herbivorous rodents (is there such a thing as a carnivorous rodent – haha?) – such as rabbits, gerbils, hamsters, guinea pigs – will create some quality compost fodder for you. It will be very easy to work with (not wet and smelly) and there won’t be the same risks involved.

I think the ‘no pet waste’ rule is definitely more applicable to carnivorous (or at least omnivorous) animals. Of course, the two most popular pet poop produces that fall into this category would be cats and dogs. Both of these animals produce wastes that are not only unpleasant to work with in general, but they can also contain nasty microbes as well.

Cat waste in particular warrants extra caution, since it can contain a parasitic protozoan called Toxoplasma gondii. This organism is relatively harmless for many people who become infected, but it can be a serious threat for pregnant woman (it can harm the unborn child) or those with compromised immune systems. Just so you know, most cases of Toxoplasmosis actually result from the consumption of raw meat, NOT from contact with cat feces (see http://www.metrokc.gov/HEALTH/prevcont/toxoplas.htm), so there’s no need to get ultra-paranoid about it – unless of course you like your steaks rare!

While I definitely DON’T recommend adding dog and cat waste to your ‘regular’ bins, I do in fact recommend setting up a completely separate system to handle these wastes – after all, why bag it up and send it off to the landfill when you can easily process it yourself and take advantage of the extra source of plant nutrients as well.

A pet waste composter should be set up a good distance away from your other composting systems and vegetable gardens, and as far as possible from the nearest water body (at least a good 100 yards or more). You can start by simply digging a hole in the ground – perhaps 2-3 feet deep and 2 feet across. Once the hole is dug you should add a nice thick layer of shredded cardboard, or some other carbon-rich, absorbent material (coir, shredded paper, aged straw etc) in the bottom. I would also recommend using some sort of enclosure over top. A regular plastic backyard composter will work fine. Aside from leaving you in control of the amount of water added (the last thing you want is to let it get flooded), this will also allow you add a lot more material, and should even help to ward off any curious children/animals.

Now all you have to do is start adding your poop (well, not YOUR poop – although I suppose you could – haha!), along with more bedding material and a sprinkle of water with each deposit. If you leave one of these systems to sit for a couple weeks or so without adding any more fresh waste (you might want to start up a second system), you could also add some composting worms. The worms would help you turn the material into compost much more quickly than would occur by simply letting it sit – but the worms definitely need a buffer zone from the fresh waste materials (hence the suggestion to let the system age for a bit) since it is a little too potent (with ammonia etc) for their tastes.

I wouldn’t personally harvest the compost from these composters – I would more likely try to put them in a strategic location so that surrounding trees/shrubs could take advantage of the rich compost being produced.

[tags]pet waste, dog poop, cat poop, pet waste composting, composting, composter, backyard composting, worm composting, vermicomposting, pathogens, toxoplasmosis, compost bins[/tags]

Written by Compost Guy on May 7th, 2008 with comments disabled.
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Get your own gravatar by visiting gravatar.com Simon
#1. May 8th, 2008, at 2:08 PM.

Although I’ve not started doing this myself yet I have recently taken part in a similar discussion with one extra being add a layer of Bokashi bran every now and then so that the EM’s can get to work on the stuff as well, thereby helping to neutralise the smell as well speeding up the composting process as well.

Well, that’s the theory…

Get your own gravatar by visiting gravatar.com Satori
#2. May 18th, 2008, at 4:21 PM.

Although you were just joking when talking about composting “YOUR” poop, it actually is possible.

Get your own gravatar by visiting gravatar.com Peter Ritchie
#3. June 9th, 2008, at 1:20 PM.

I tried one of the commercially available plastic sump affairs to which you add water and a composter liquid. The concept is that it should have stones and drainage around it by way of a pit so that the poo dissolves and drains away. It worked for a bit but blocked up after a relatively short time and is therefore useless. Sounds like you need a lot of space for yours to keep it away from everything, not to mention the smell. I would love to find a solution. Currently I have a bucket with water to which I add the poo and empty it down the culvert in the road – not my favourite job and prone to someone objecting ( I do wash it away well). There must be a better way.


Get your own gravatar by visiting gravatar.com Robin
#4. July 2nd, 2008, at 11:58 PM.

Could you elaborate on the ‘buffer zone’ ? I’ve recently set up one of the green plastic worm farms (separately) for pet waste as my house is on a hill and I’m not comfortable with setting up a digester pit. I set it up with 1 yr old leaf bedding. I’m unsure of the proper layering etc. Also, one article mentioned the ideal temp to kill pathogens for pet waste compost was 164F? I’m assuming the artice was referring to a non vermiculture compost pile. Are there any emzymes etc that could be added to the resulting vermicast to neutralize the pathogens?

Get your own gravatar by visiting gravatar.com Melissa Amlin
#5. July 3rd, 2008, at 12:45 PM.

I want to compost my pet’s waste (2 cats, 2 ferrets & 1 dog) in a seperate composting area – I’m wondering about the “bedding materials” – will I have to add extra bedding materials like cardboard, newspaper, etc. if the cat & ferret wastes are including their litter materials (presently the ferrets use “yesterdays news” and the cats use “swheat scoop”, but if you recommend a better cat litter to use (like the corn ones or something) I could switch them) The yesterday’s news is broken down newspaper already, so would that mostly take care of the bedding needs itself? Would it be too much bedding? Should I be adding some food scraps to this composter as well, or just purely pet waste? How can I deal with the fresh “loads” every day if they need to sit for a while before being introduced to the worms? Please give me some guidance, as I hate the fact that I’m using “enviromentally friendly” litter only to pickle it in plastic in a landfill!!

Get your own gravatar by visiting gravatar.com teri
#6. July 31st, 2009, at 12:58 AM.

I don’t quite understand, I have a vermicomposting bin I use the castings for vegetable garden. I wanted to compost ferret poo and newspaper bedding but unsure about it. he eats only dry ferret pellet type food. so I dont know if he would be considered a carnivore i guess I should look at food ingredients? I don’t know can his poopoo go on my veggie garden? his poopoo that worms have eaten and poopooed into castings? It seems like such a “waste” ha ha. can I put it in?? Thank You

Get your own gravatar by visiting gravatar.com Melissa Amlin
#7. September 2nd, 2009, at 3:19 AM.

In regards to Teri’s question and your reply – yes, your ferrets are carnivores, or at least they should be, they are actually supposed to be MORE carnivorous than cats. While the pelleted food (aka kibble) probably has a lot of grain/crap/filler in it, as do the many cat & dog food kibbles out there, the diet is supposed to be meat based. I can imagine that the same reasons for concern about using the feces of dogs & cats also applies to ferrets in this case. In fact, if the ferret or dog or cat was fed a purely raw meat diet, their feces would probably decompose and dissolve much easier and quicker and would probably not even need the worms’ help, it’s all the fillers in the kibble that slows things down and makes it more unpleasant to handle.
Anyhoo, so yes ferrets should be included in the probably don’t want to put on your food garden plants.
But I would still like to know about my question about the included bedding???

Get your own gravatar by visiting gravatar.com Niel
#8. April 11th, 2013, at 11:25 AM.

I refill my cat’s litterbox every day with sand on our plot. then in the morning empty it out and refill . I usually empty it (sand and waste) in one heap. What I want to know is, if i empty it in a spot where there is a lot of sunlight during the day will i be able to use the same sand again in the litter box at a later stage. Should i perhaps spread the sand out a bit or mix it so that the sun can affect the waste more adequately. I am afraid of using the same sand again and that it might still have some diseases from the old waste in it, causing illness for the cats and me.