Can I compost dog & cat poo (faeces)?

Friday, 18 April 2014  |  HOTBIN Composting

Yes, all faeces from all animals is compostable

Can I compost dog / cat poo safely?

Yes but there are some rules

Can I compost dog / cat poo in the HOTBIN?

  • Yes Ensure your HOTBIN is running hot (>40C) before you start to add poo
  • Add plenty of shredded paper and bulking agent with the poo (to ensure the waste is not "too wet" for hot composting
  • Do not add any plastic bags (even compostable ones) into the HOTBIN
  • Ensure you wear gloves and follow the basic hygiene precautions Jump back to the HOTBIN product page.

Should I compost dog and cat poo, is it worth doing?

Yes. There are an estimated 9.6m cats and 6.8m dogs in the UK (1 in 2 households have one). This equals about to 1.2 million tonnes of poo most of which is currently scooped, bagged and sent to landfill.

Many composting sites advise not to compost dog or car poo.

Why is the HOTBIN different?

Most state composting faeces/poop poses a potential health risk. Some state it is OK to compost herbivore (plant eating) faeces but not poo from meat eating animals. All poo (faeces) from all animals including (humans) has the potential to be harmful as they can contain pathogenic bacteria (eg e-coli, salmonella), parasites such as roundworm or phytotoxic chemical (dangerous to plants).

Most human diseases have a poor life expectancy outside the human body / intestine; normally they survive hours or days. The main concern with dog and cat poo is parasite worms. On rare occasions, the worms can carry parasites that are dangerous to humans (eg Toxocara, or t-gondii (producing toxoplasmosis). These parasites produce egg oocysts which can survive up to a year depending on conditions in soil. If you ingest (eat) the egg, it can develop in the human body leading to medical issues. These eggs are destroyed faster in high temperature composting.

Assuming you follow the basic hygiene precautions, high temperature composting is much safer than cold composting.

What are the risks?

Defra has an excellent risk analysis for composting and pathogens. They seek to determine the 'minimal acceptable risk' - ie, so low the Government accept it. All pathogen destruction depends on time and temperature. The higher the temperature and longer time the greater the destruction.

At 60°C pathogen destruction is remarkably quick - hours! Toxocariasis is a rare infection caused by roundworm parasites (Toxocara), it impact is treatable and serious problems are rare - as summarised in by the NHS Website .

Now we know there is a small risk and the pathway is via ingestion of eggs in the poo or soil or compost. Applying a risk analysis process, you would normally seek to mitigate or remove the high risks before worrying about those posing the least risk. What we have done below is extend the risk analysis from pet ownership down to composting and then hot composting. YOU are the guardian of your safety - we are not experts in infection or risk analysis, all we can do is offer information to help you make your own judgement. Hopefully you will see that owning a pet, collecting faeces are high risk whereas if you ‘hot’ compost poo within 5-days after excretion, taking sensible hygiene precautions and not in a high-risk group, the risk is very low.

Risk Analysis - from high to low

There are many excellent web postings on the risks from toxoplasmosis
(eg www.icatcare.org/advice/cat-health/toxoplasmosis-and-cats).

Is your cat shedding oocysts?
Cats previously unexposed to T-gondii usually begin shedding oocysts between 3 and 10 days after ingestion of infected tissue, and continue shedding for around 10-14 days. Thereafter, exposed cats build up immunity and rarely shed oocysts (eggs) again. (Surveys indicate 20-60% of cats have been infected, and hence will not shed).

Do you remove litter/faeces daily?
If your cat is in the 10-14 oocyst shedding cycle, these eggs will undergo sporulation (formation of infectious sporozoites) only after 5 days in the environment). So removing the waste daily removes the risk.

Do you wear gloves when changing litter and wash your hands after?

Are you hot or cold composting?
The sporulated oocysts can survive up to a year in the environment. At 60°C, general pathogen destruction to acceptably safe levels takes less than 1 hour (see pathogen destruction). At 60°C, within 5 days (ie before sporulation) faeces and oocyst will be compost. (Most sites advise you not to compost cat faeces – and this is certainly wise advice if your heap only achieves 'cold' compost temperatures). Other direct ref “T. gondii is killed in 6mins at 49°C, in 44 seconds at 55°C, and in 6 seconds at 61°C”
ref - http://www.extension.org/pages/Toxoplasma

How much faeces waste is added to your heap versus other material?
(20g/2000g in a week (1:100 dilution)

Are you wearing gloves when composting?

How much diluted compost will get onto your hands?

Do you wash your hands after composting?
You have to transfer the oocyst from the diluted and sanitised compost into your stomach. The route is normally from your hands touching food and then eating the food.

Is the person pregnant and not previously exposed, or suffering from a severely weakened immune system?
(Toxoplasmosis - during the first few weeks' post-exposure, the infection typically causes a mild flu-like illness or no illness. Thereafter, the parasite rarely causes any symptoms in otherwise healthy adults. It has been estimated that about 30% of the UK population have been exposed to t-gondii. It is serious for those with a weakened immune system, such as those undergoing chemotherapy or pregnant women not previously exposed so lacking immunity. (It can transfer into the foetus with serious consequences such as congenital disorders or aborted foetus)