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On the tail end of animal waste

Biodegradable bags and compost bins are alternatives for some pet owners.

February 26, 2011|By Susan Carpenter, Los Angeles Times
  • The question has crossed the minds of a more than a few eco-minded pet owners: Is it better to flush pet waste instead of throwing it away? Can it be composted? Or must it be sent to the landfill?
The question has crossed the minds of a more than a few eco-minded pet owners:… (Don Kelsen / Los Angeles…)

With the dogs and cats, the horses and goats, rabbits and, of course, chickens, Los Angeles is a sort of domestic zoo. There are at least 2 million dogs and 3 million cats kept as pets in L.A. County, according to 21st Century Animal Resource & Education Services. Add in lizards and other critters, and it's more than likely domesticated animals outnumber humans.

There's no doubt animals add a lot to their owners' quality of life, but they also contribute something else — poop. Most of it goes to landfills.

Estimates for animal waste are, not surprisingly, difficult to locate. The U.S. Environmental Protection Agency doesn't track it. Nor does L.A.'s Bureau of Sanitation, except for horses, which generate about 25,200 tons of manure annually in L.A.

Extrapolating U.S. Geological Survey figures for the 2.14 million tons of clay that is mined for use in kitty litters each year and L.A. County's human population of roughly 9.85 million, I estimate at least 50,000 tons of cat litter are sent to L.A. area landfills every year.

As for dogs, the amount of doo they generate varies by animal size, but the average is 274 pounds annually, according to a report from the Natural Resources Conservation Service. In L.A., that's 548 million pounds of dog doo that is wrapped in plastic, tossed in the black bin and trucked to oblivion.

I do not have a dog or a cat. An unfortunate biting incident involving an Afghan greyhound when I was a teenager pretty much swore me off canines. And I opted against replacing my Maine Coon cat after her tragic death in the jaws of a pit bull a few years ago. But a surprising number of readers wrote me after the kickoff to Garbage Maven last month asking: Is there a better way to handle all this waste?

Maybe.

It's against the law in L.A. to leave dog waste on public or private property unless there is consent from the property owner. Violations are punishable with fines of $20, for not picking it up, and $1,000 (or imprisonment) for polluting stormwater, which, in addition to common decency, is why so many people pick it up, put it in plastic bags and trash it.

Although letting nature run its course might seem like the most natural option, it isn't, because animal waste contains bacteria. And that bacteria comes with health risks, not only for humans but rivers, lakes and oceans. A study by the Bureau of Sanitation found that 60% of the bacteria in a Marina Del Rey waterway was because of animals, domesticated and feral.

Still, there are alternatives to the routines most pet owners follow. There are several flushable cat litters, but a 2007 provision to California's Fish and Game code prevents cat litter flushing in the state because the T-gondhii parasite in cat feces is not eradicated through sewage treatment and kills sea otters. There are also water-soluble, biodegradable dog-poop bags that are billed as toilet friendly.

If humans can flush away their waste, it seems sensible to be able to do the same, perhaps, for dog waste. Many wastewater treatment plants generate methane gas as the waste breaks down and capture that gas to turn it into electricity. As for the leftover solids, they're treated to remove pathogens and transformed into fertilizers spread on farms. At least in theory, there seems to be some benefit to flushing, rather than trashing, dog poop.

But flushing plastic bags got a mixed reception from the Bureau of Sanitation. According to the Bureau's chief operating officer, Traci Minamide, flushing plastic bags runs the risk of sewer clogs and overflows. Worse, she says, it confuses residents to tell us some things can be flushed, i.e. poop, and other things — kitchen grease and pharmaceuticals among them — cannot. The city prefers a black-and-white message.

Although Minamide agreed there was a potential electricity-generation benefit to flushing animal waste, she said a similar benefit exists at landfills, many of which also capture and convert methane gas to electricity. Biodegradable bags probably aren't worth the extra money. When sent to the landfill, they aren't likely to break down in the years that a landfill is active and producing methane that is captured.

There had to be a better way.

As mentioned, I do not own a dog. I own a rabbit, which my 8-year-old hoodwinked me into adopting two years ago. Big Fluff is a herbivore, as are goats, cows, horses, chickens and guinea pigs – all of whose waste is compostable. I just throw Big Fluff's into my compost bin, where the nitrogen of her waste combines with the carbon of her ripped-up-newspaper and straw bedding, along with the other organic materials in my bin, to make gardener's gold. Many cities, including L.A. and Long Beach, compost horse manure and provide it to gardeners.

It's meat-eating animals that are difficult. Carnivores are more likely to have pathogens that could infect humans, and the two most practical ways to destroy those pathogens are with chemicals or with heat.

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