I just read a lens with the enticing title "Cat Crap Showcase" which was made by someone who works at the Monterey Bay Aquarium. It's about Toxoplasma gondii, a dangerous parasite found in cat poop. I was dismayed to find out here that flushing cat feces can cause these parasites to end up in the ocean where they attack the brains of sea otters. The typical municipal water treatments do not kill it, so if the final destination for your city's sewer waste is the ocean, the parasites will end up being flushed there. There it sinks to the bottom and is eaten by filter-feeding creatures such as crabs and sea stars - that are in turn eaten by sea otters.
California Sea otters once numbered about 15,000, but hunting in the eighteenth century brought them to the brink of extinction. Now, only about 2,500 live along the California coast, but an unusual number of adults in their prime breeding years have been dying. Between 1998 and 2004, a study found that 52 percent of dead sea otters found on the beach and 38 percent of live sea otters along the California coast were infected by the parasite. In 17 percent of dead otters examined by the state Department of Fish and Game, the parasite was the primary cause of death. (http://www.seaotters.org/CurrentIssues/index.cfm?DocID=319 )
This is the same parasite that can cause birth defects in humans, which is why pregnant women should not be on litter box duty for 9 months.
The solution for this tragedy as promoted on the linked website? Wrap the crap in plastic bags and toss it in the landfill-destined garbage! But that is another terrible idea, especially when you think about the 90,500,000 pet cats that live in the US today! That's a mountain of cat poop wrapped in plastic, UGH!
So I did some research on composting pet waste and found a lot of inconclusive information. Most basic compost guides, including all the government sponsored ones, will just tell you pet waste is a no-no to put in your compost heap. This is understandable because many people don't have a hot enough compost pile or manage it carefully enough to be sure that the potential pathogens will be killed. But if you make a separate pile, and if you manage it correctly (time plus temperature are the key factors), then you CAN compost pet waste. To be on the ultra safe side, don't use the finished compost on veggies or herbs, just flowers, trees and shrubs.
Here's the lens with the otter info: http://www.squidoo.com/catcrap
Here are directions for a simple pet waste compost system:
Sharon Slack's Dog Waste Composter
step by step with photos http://homepage.mac.com/cityfarmer/PhotoAlbum22.html
I would add grass clippings, leaves or sawdust to this regularly, and when it's very hot out, water it a bit.
Here's one you can buy all ready to go:
Doggie Dooley Pet Waste Digester System (scroll about 2/3 of the way down) They also sell "digester enzyme" for speeding up the decompostion. The system costs about 50.00, the enzme is 15.00 for a year's supply.
"The Humanure Handbook" is an entertaining and very informative booklet about composting human waste, another source of parasites and various dangerous critters. I think if his technique will kill human parasites, it'll kill cat parasites too.
The book is available in total online. Here's the page on temperature and time http://weblife.org/humanure/chapter7_19.html
Here's a quote:
"A sound approach to pathogen destruction when composting humanure is to thermophilically compost the organic refuse, then allow the compost to sit, undisturbed, for a lengthy period of time after the thermophilic heating stage has ended. The biodiversity of the compost will aid in the destruction of pathogens as the compost ages. If one wants to be particularly cautious, one may allow the compost to age for two years after the pile has been built, instead of the one year that is normally recommended."
Thermophilic composting is a system that creates high temperatures and rapid decomposition due to intense microbial activity.
Here's a good explanation of thermophilic composting if you want the gory details: http://cwmi.css.cornell.edu/chapter1.pdf (look at page 2 - 4)
According to A Guide to the Development of On-Site Sanitation. by the World Health Organization, "All fecal microorganisms, including enteric viruses and roundworm eggs, will die if the temperature exceeds 46°C (114.8°F) for one week."
ps - don't hose poop off your lawn or sidewalks either, because that drives it right into the storm drains and straight out to sea.