Pure intentions

Happy dogs

Aiming for more ethical and sustainable dog ownership

So, this is, apparently, the post many of you have been waiting for… how to deal with dog poo. Owning a dog is not the most sustainable choice, although it’s more sustainable than having children! But, for those of us who do have a canine companion, we can do all sorts of things to minimise its impact on the planet. First, rescuing a dog rather than buying one and thus encouraging breeding is by far the most sustainable option: there are plenty dogs in the world, let’s not support people creating any more of them simply for profit. Second, have your dog neutered, so that it doesn’t create any more puppies. When we start to run out of dogs, then we can think about creating more of them. Third, food choice is important – we have moved over to feeding Sam and Max minced organic offal as part of their meat diet, for example, because this is often regarded as ‘waste’ as it’s not a very popular human food. Having filled them up with yummy organic food, however, there are consequences! What goes in, has to come out and so there is poo to deal with.

In days gone by, dog excrement was considered a valuable resource and was used in leather tanning. Interestingly it was known as ‘pure’ or ‘puer’ in the nineteenth century and Julian Walker cites Hotten’s Slang Dictionary, 1865 as containing the following definition: Pure Finders – street-collectors of dogs’ dung. These days, however, leather is produced without the use of ‘pure’ and pure is generally regarded as a waste product – often bagged up and placed in refuse destined for landfill or simply left to contaminate our streets (shame on you, irresponsible dog owners).

I think this is a real pity, because by treating ‘pure’ as waste, we are missing out on a valuable source of fertility. Responsible dog owners already collect up their dog’s waste, so choosing to take an extra step and compost it is not an enormous leap.

If you read around the subject you will find dire warnings about the health issues associated with using dog (or cat) waste in the garden, but if you understand the issues, then you can create an appropriate system and minimise risks.

The two main problems you are likely to find highlighted are Toxocariasis and Toxoplasmosis, so let’s deal with these two things first.

Toxocariasis is, according to NHS Choices, ‘a rare infection caused by roundworm parasites. It is spread from animals to humans via their infected faeces. Roundworm parasites are most commonly found in cats, dogs and foxes…’ In general, the infection causes no or mild symptoms, but in rare cases it can lead to eye problems (ocular toxocariasis) or damage to the central nervous system or organs (visceral toxocariasis). Roundworm eggs can remain viable in soil for several years if the conditions are moist and cool. You should make sure your dogs are wormed and ensure good hygiene anyway, so ideally there won’t be any toxocara in their poo.

Toxoplasmosis is found in the faeces of infected cats (and other animals). The NHS Choices web site states: ‘Toxoplasmosis is an infection caused by a common parasite called Toxoplasma gondii … Most people who get toxoplasmosis don’t have symptoms. Around 10-15% of people develop symptoms similar to mild flu or glandular fever, such as a temperature, sore throat and muscle aches… Toxoplasmosis is more serious in people with weakened immune systems, such as those who have had an organ transplant, those with HIV and AIDS, and those receiving certain types of chemotherapy treatment.’ A major issue is pregnant women passing the infection to their unborn child and resultant damage to the child’s nervous system and it is generally recommended that woman who are pregnant never handle cat waste. The eggs that are passed by a cat can remain viable in moist soil for 18 months or longer.

I do not have experience with composting cat waste, but I see no reason why you couldn’t use the same techniques as for dog waste, with the proviso that anyone who may be more susceptible to Toxoplasmosis does not attempt this.

In addition, dealing with faeces of any sort means that you are handling gut bacteria. Remember that good hygiene is essential – use your common sense and never apply faeces to soils around crops that you are going to consume uncooked.

However, with all those warnings out of the way, and with the note that other approaches (like wormeries) are available here is my technique for PURE COMPOSTING:

Our poo bin

Our poo bin

Our poo bin is an old wormery with a reservoir at the bottom and a tap, plus it has a lid with a clip to keep it closed. It does not, however, contain composting worms any longer.

We collect all our dogs’ poo on walks in kitchen paper. We place it in a plastic bag for transport and on return home we drop the paper and poo (not the bag) into the poo bin. If the dogs poo in the garden, we collect it  and transfer it directly (unpackaged) into the bin. We tried using biodegradable bags and are still suffering from their unsightly remains in our soil.

In addition, the poo bin receives wood shavings and chicken poo from cleaning out the chicken house, plus shredded paper and wood ash from our storm kettle. We put in less ash than poo. The wood shavings and paper act as a good source of carbon. If you don’t keep chickens, paper alone is fine, and you could also add cardboard or finely chopped/shredded woody prunings. The ash helps to balance the pH and you should only use wood ash – coal ash is too acidic.

We just keep adding to the bin until it is full. It does not smell. We use a compost aerator tool to make sure that the contents of the bin are turned regularly and there is plenty of oxygen available for decomposition. Because of the ingredients, the compost can be very dry and if this is the case, I add human urine – this also gives a nitrogen boost and speeds up decomposition.

We regularly drain the liquid  to ensure that the base of the compost does not get waterlogged. This liquid is diluted 10:1 and used as a root feed – it seems to work well for tomatoes, peppers, chillies and fruit trees and bushes. We do not use this as a foliar feed.

more on this in an up coming post

This is what it looks like once transferred to the standard compost bin. There is no bad smell.

When the bin is full, we leave it for a couple of months –  aerating occasionally – before transferring the contents into the bottom of a standard compost bin, where it will remain for about a year, with other material being composted on top. Alternatively, we leave the poo bin closed up for six months and then use the compost for planting fruit trees or in the bottom of a bean trench.

The two-stage method (either moving it to a new bin or burial for continued decomposition) should minimise health risks. If you are unsure – simply compost for longer. If you have two suitable poo bins, and your dogs aren’t too ‘productive’ you should be able to have one bin in use and one rotting down in a constant cycle.

As I say, other methods are available, but this is the one that works for us using the resources that we have to hand. It produces a good compost and there are no bad smells during composting or with the finished product. In addition, we have had no problems with flies in the bin.

Pups - not completely unsustainable!

Pups – not completely unsustainable!

Dog poo experiments

My inspiration - Dr Andrew Agnew

My inspiration – Dr Andrew Agnew

One of my lecturers at university, the person who inspired me to become an ecologist, was Dr ADQ Agnew. He was (and still is) the epitome of a dotty professor… one day he came in to the department wearing two ties because he’d forgotten that he’d put one on and so he donned a second before leaving the house. He would sing to us in lectures (I particularly remember a rendition of ‘I’m a Gnu‘) and deliver anecdotes… he even took us on a field trip to the Low Countries (Holland, Belgium, Luxembourg, France and a bit of Germany) that involved him and seven female students all in their early 20s… which probably wouldn’t be allowed these days! Anyway, Andrew often claimed to have studied the effects of population density by examining dog turd predation by lawnmowers in a park… I can find no published paper on this subject (and, believe me, I’ve looked), but it may exist somewhere. I might ask him about it next time I see him.

Max - a source of pollution

Max – a source of pollution

My experimentation, in contrast, has a rather more practical bias. One of the waste products that we have to deal with on a daily basis is, indeed, from our dogs, Sam and Max. They are terriers, so there isn’t a huge volume, but even so it is something that we do not feel happy about sending to landfill.

It is easy enough these days to buy plastic ‘poop’ bags that are biodegradable and simply to throw these away with all the rest of the trash. I wondered whether it might be possible, however, to collect the dog poo this way and then just place the entire bundle on a compost heap to break down. However, some trials revealed that even after a year, the bags were still identifiable, although the content had often disappeared. Anyway, whilst trying to reduce our impact on the environment, it seems inappropriate to ‘consume’ plastic bags in this way.

What we wanted was a composting system that was contained (to avoid flies and smells) and that was separate from our standard composing bins, so that the end product could be used separately. It’s generally recommended that you don’t use humanure on food crops and I assume that the same goes for doganure (ooh look, another new word!). However, whilst I don’t want to apply it to salad crops, for instance, I see no problems with using this type of compost when planting fruit trees and bushes, or in a bean trench.

I have written in the past about my wormery, but I have become increasingly aware that I don’t really need one except for the liquid feed: pretty much all the compostable material we produce can go on a ‘normal’ compost heap and with the aid of grass clippings, we manage to get these hot enough to break down quite quickly. In addition, I’m an increasing fan of in situ composting… so that the heat generated can be utilised by growing plants. So, the wormery has become superfluous and, thus, available for use in the composting of dog waste.

Some limited research suggested that dog waste is acidic (I haven’t tested this, but perhaps I will once I can work out the best way to sterilise my pH meter afterwards) and that some means of raising the pH would be appropriate. One of the suggestions was that adding wood ash would work – something that we produce from our Kelly Kettle and that we normally add to the compost or put straight on the garden. I was inspired by Deano’s approach to this problem at the Sustainable Small Holding, but decided to use shredded paper for some bulk rather than the Miscanthus that he has access to. We collect the faeces in a bucket round the garden, but when we are out on a walk, they are picked up in paper and transported in a plastic bag before being added to the bin, complete with the paper wrapping as an additional source of carbon.

Initially, I only added the three dry ‘ingredients’: faeces, ash and paper. But Deano’s suggestion to add urine as well seems to have been well-founded: a recent agitation of the content of the bin revealed that it was very dry and did not seem to be very active, although there was no unpleasant smell. In addition, there was no sign of the worms that I had added. So, with this in mind, I have been adding urine for the past couple of weeks, now that I have a ready source. I will give it another stir in a week or two and see how decomposition is progressing.

Despite the slow composting process and the dryness, I had extracted about a litre and a half of liquid feed from the reservoir at the bottom of the bin prior to starting to add additional liquid in the form or urine. This extract has been used to feed peppers and tomatoes… applied to the soil not the foliage… and is the only feed that I have provided them with so far this year, with good results.

Although I had hoped that decomposition would be quicker than it has been so far, I am hopeful that this will turn out to be a valuable way to add fertility to the soil and will be a real case of turning something initially perceived to be a pollutant into a valuable resource. In the past urine and dog faeces were used in the tanning industry, but since this is not an option for me, I think I’ll stick with increasing soil fertility!

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