Thanks to Waste MINZ for researching and providing this factsheet. This is an abbreviated version.

The public is starting to take a real interest in alternatives to plastic bags, which means that Councils are frequently getting asked questions like:

“But how will I collect my dog’s poo if there are no plastic bags?” “Compostable bags aren’t plastic right?”
“Can I compost my dog poo at home now I’ve got compostable bags?”

We’ve compiled some facts to help you answer queries and make decisions about whether to encourage the use of compostable dog poo bags, some alternatives to using any kind of bags, and examples of what councils are doing around the country.

But first, an important health and safety announcement:

The key points:

  • Under the new plastic bag phase out dog poo bags will still be able to be sold. So theoretically people can carry on with their usual methods, unless they used old supermarket bags.
  • There are alternatives which we’ve listed below.
  • For the health reasons outlined above the key message to residents is the importance of picking up your dog poo rather than leaving it to biodegrade in the open environment.
  • Many people are confused by the whole issue of compostable plastics, so use the guidelines below.

1. Home compostable dog poo bags:

  • All dog poo bags currently on the market are made from plastic. Some of them are made from plant material and may be advertised as compostable or biodegradable. Others are made from oil and may be advertised as degradable. However, regardless of the claim, all of these bags are a type of plastic and if littered they can pose a threat to marine and river life as they won’t necessarily break down quickly in water.
  •   As with all bags, any dog poo bags advertised as “degradable” or “biodegradable” (without specifying a compostability certification) should be avoided as they have no environmental benefit, and may break down into microplastics.

Dog faeces can contain campylobacter, E. coli and salmonella type bacteria, along with various parasite worms, which can all be transferred to humans. For these reasons dog faeces should never be left in the open environment where it can be eaten by other dogs or enter waterways. It should also not be added to a compost system where the compost is to be used on vegetable gardens or fruit trees. If you want to compost your dog’s faeces at home use a separate system and apply to flower gardens only.

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  • Dog poo bags that are labelled “certified commercially compostable” will not, at this stage 2019, be accepted by any of the New Zealand industrial composters who accept compostable packaging. Therefore, these bags need to go to landfill.
  • The best choice then is certified home compostable dog poo bags. However, as noted above, residents should know that they need to compost these in a separate system at home.
  • Certified home compostable plastic can still take a very long time to break down in home compost systems and even longer if littered.
  • See WasteMINZ’s Quick Guide to environmental claims for more facts on compostable and biodegradable products and packaging.

2. Flushing dog poo in a domestic toilet

You will need to check with your water treatment facility manager regarding their policy on flushing dog poo. While at some facilities dog poo on its own can be flushed down the toilet, this must never be in bags, even if they are so-called flushable bags (or compostable) as they will cause a blockage in the pipes.

At other water treatment plants dog poo even on its own is not acceptable due to the high level of BOD (biological oxygen deprivation) which can compromise the balance of water
treatment. Encouraging residents to flush their dog’s poo may lead to bags being flushed as well so perhaps it is best to avoid this recommendation (or discuss with your waste water team).

3. Dog poo bag alternatives

Some residents will be looking for alternatives to using any kind of plastic bag, so we have compiled some ideas from the Zero Waste New Zealand community.

At home:

Collect poo using tongs, a shovel, pooper scooper or loo paper and drop into a pet waste composting system. You can purchase a system or make your own.

If providing compostable dog poo bags in public parks, the bags must be labelled “home compostable only” and the bag itself must include advice to the public that they cannot be added to a compost system where the compost is to be used on vegetable gardens or fruit trees.

Ensopet pet waste composting kit is available from Zing Bokashi, which uses the same principles as a traditional bokashi with an enzyme sprinkled over to help poo break down.

NB: Zing Bokashi recommends NO bags are used with this system, even if certified home compostable.

DIY:

This option uses a bucket and compost worms known as tiger worms and is suitable for smaller dogs. Home- made compost with bought pooper scooper from NZ sustainability blog Home Grown Happiness

The option below is more suitable for larger dogs and uses a barrel and a pipe and buries the compost underground. Find out how to make this on https://www.instructables.com/id/Big-Dog- Poop-Composter/

Out and about:

This is probably the biggest challenge because alternatives to disposable bags will generally involve needing to wash out whatever is used to collect the poo. But here are some ideas:

  •   Use a tin with lid or small plastic container and keep inside a bag with tongs to collect poo while out walking.
  •   Scoop it up in newspaper or a paper towel or reuse a paper bag, pop into a washable wetbag and discard the newspaper/paper towel parcel in separate compost system at home.
  •   Get a pooper scooper that includes a lid or make your own out of an old bottle.

Due to the human health risks extreme care needs to be taken with any item that is being washed and reused, such as a scooper or reusable bag, to make sure it is free of pathogens. If advocating these options advise residents that reusable bags tins and scoopers need to be thoroughly washed in hot water.

These options are probably only going to appeal to those residents who are passionate about waste minimisation. So, for the rest, the best option is to collect small plastic bags such as bread bags, frozen veg bags, or paper bags that you got your lunchtime pie in. Keep them in a bag where you hang your dog’s leash and have one tied on (if it’s plastic) or inside your dog’s treat bag.

When you have collected your dog’s poo in the bag, tie it up and attach it to the collar end of your dog’s leash. They don’t mind the smell (in fact, they like it…)

4. Summary:

  • Dog poo is better off in landfill than left out in the environment where it can contaminate other dogs, water, etc with pathogens transferrable to humans.
  • Even compostable plastics are still plastics that can cause damage to the environment if they get into waterways, etc – so they must be disposed of properly (which means into a rubbish bin unless there is a dog poo composting option available).
  • If people are choosing to compost, they must ensure that the dog poo (and bags) are not composted with compost intended to grow food.