February 7th, 2014

Don’t pooh-pooh pet waste

7 minute read

by Steve Watson

 

When I took my first step onto the property ladder last summer, I thought it would also help my ascent of Lansink’s Ladder: without numerous housemates’ dubious waste management practices to worry about, my residual bin seemed set to remain as sparsely populated as my unfurnished new home. However, I hadn’t counted on the arrival of fuzzy feelings of domesticity that led to the acquisition of an equally fuzzy companion. It wasn’t until my kitten was climbing around in my recycling bin that I started to realise just how much waste the little fellow was going to produce.

According to a report commissioned by the Pet Food Manufacturers’ Association, 13 million UK households (45%) keep pets of some kind.  Cats and dogs are each kept by 8.5 million households (these numbers are not additive, as some will of course keep both). Can those of us who want both the joys of animal companionship and waste minimisation, find ways to cut down, or better manage, the huge amount of pet waste generated in the UK every year?

 

Pooper snooper

I’ve not conducted a personal compositional analysis and won’t guess at percentages, but thanks to the good recycling collection in my area, my residual waste seems composed almost entirely of tightly tied bags of kitty litter. With so many cats and dogs in the UK, pet poop must represent a significant mass of organic matter within the residual waste stream.

Does this waste represent a floater in the residual waste stream by necessity—due to inherently unpleasant and possibly dangerous characteristics of the waste—or is it only there out of convention and squeamishness? I’ve written before about the relationship between waste management and squeamishness, and talking about faeces really brings the point home. There are some undoubtedly nasty pathogens present in pet faeces, notably the parasites Toxocariasis and Toxoplasmosis. But might these be safely killed off by the temperatures reached in anaerobic digestion (AD)? If so, provided any litter and bags were made of organic matter, might pet waste be collected along with food waste?

I began by contacting a local authority waste officer, but was told that no one had asked this question before, and that I might be better off talking to AD plant operators. This I did, but most seemed similarly baffled by my query.  However, one mentioned that AD digestate goes through a pasteurisation process, where it is heated to a temperature of 70oC for one hour, in order to make it safe for land application. I also attempted to contact some technical specialists in the field, but to no avail.

There are some theoretical indications that this pasteurisation should be sufficient. Hanna Mizgajska-Wiktor and Shoji Uga’s  essay Exposure and Environmental Contamination states: “Anaerobic waste treatment kills Toxocara spp. eggs at temperatures in excess of 45oC”, well below the 70oC mentioned by my operator. The susceptibility of Toxoplasma to heat is less clear, although numerous internet sources suggest this can be killed in meat by cooking at 66oC. So far, then, I haven’t confirmed or falsified my initial inkling, and so the collection of pet waste in the municipal organic stream remains a theoretical possibility. I’d certainly be interested to hear the thoughts of any experts in the Isonomia readership.

 

Recycling Cat crop

Feline contamination of the paper stream. Photo by Doc Tropics, via Wikimedia Commons

Motivated dog owners  can already turn their pet’s waste into a resource within their own home. The website London Worms explains how you can turn your dog’s poo into rich and useful vermicompost, although it warns that the results will only be suitable for use on non-edible plants.

 

Foul pay

Household pet droppings may still be largely fated for disposal, but even when binned this waste is at least moving through proper waste management channels.  Unfortunately, not all pet poo is binned, and we have real data measuring public perceptions of the disamenity resulting from dog fouling. For most, the presence of this unwelcome waste in our streets, parks and footpaths is of much higher concern than its diversion from landfill.

A 2011 Defra-funded study on local residents’ willingness-to-pay — via an increase in council tax — for improvements across a range of environmental factors found that dog fouling was the third most important issue out of the presented range (with litter and fly-tipping taking first and second place). Surveys were conducted in inner-city, suburban and rural/semi-rural areas around London, Manchester and Coventry.

In order to move from the current level of dog fouling to the best possible scenario, it was found that inner-city residents would on average be willing to pay £8.87 per month, suburban residents £7.79 per month, and rural residents £2.72. Combining these figures with population statistics allows us to place a disamenity value on dog fouling. National statistics only allow for an urban-rural split, but based on a 2012 Defra rurality study which found that 18.9% of the population lives in rural areas, we can calculate that across England, we would collectively be willing to pay £462m per year to achieve best case scenario improvements in dog fouling.

This somewhat crude calculation gives an indication of the perceived disamenity of dog fouling. Presenting the matter in terms such as these may allow economically minded policy makers a means of engaging with this important street scene issue and evaluating the costs and benefits of interventions.

 

Food for thought

Let’s wash our hands of poo (with plenty of soap and warm water) and look to the other end of the pet waste problem. According to a report published by WRAP, the UK uses around 75,000 tonnes of primary packaging annually. This holds 1,263,000 tonnes of wet and dry cat and dog food, of which 9,000 uneaten tonnes are thrown away. Although this wasted food constitutes less than 1% of the total sold (if only we were as careful with food for human consumption) the estimated cost to the consumer is still £21m a year.

WRAP examined a number of designs intended to cut to down on the amounts of both pet food and packaging thrown away. A major problem with packaging design is the need to account for portion sizes, which vary from animal to animal and change depending on age and level of activity. Single serve packaging may actually lead to regular food wastage if the portion provided is too big for a particular pet; indeed, this is a problem I am experiencing with my own cat, whose appetite seems to fluctuate wildly (don’t panic, the vet has given him a clean bill of health). Re-sealable packaging that allows owners to dish out meals in accordance with the changing appetites of their pets is therefore preferable.

The material that packaging is made of is also significant: for example, relatively heavy tins are recyclable, whereas lightweight plasticised plastic foil packets are not. Pet food and its packaging can be pushed up the waste hierarchy by simply choosing a recyclable and resealable container which will allow them to adequately provide for the appetite of their pet. However, these issues are likely to be given less weight compared with health, convenience and cost in the minds of most householders. The onus has to be on manufacturers to develop packaging which is both low cost and easily recyclable.

 

Love pets, hate waste?

People love animals, but are rather less keen to engage with pets as an environmental issue. Leaving aside questions of whether it is sustainable for so many of us to have pets at all, there are clearly ways in which we can reduce their impact. The convenience of single serving pouches of pet food seems to win out over more recyclable and waste-avoiding alternatives, although pet owners might be willing to change their choices if presented with a better option.

While worrying about recovery options for cat poo might seem somewhat academic, it may be easier to tackle than dog fouling. It might even help to tackle the common psycho-social root of both issues. Cultural distaste perhaps lies behind the lack of information available on dealing with household pet waste, and the persistence of dog fouling as a street scene issue. Things were very different in Victorian London when “pure finders” earned a living by seeking out doggie doo to supply the tanning trade. But for us this kind of waste is a disagreeable fact of life which we deal with as simply and with as little thought as possible. But as a nation of animal lovers, it’s our responsibility to engage with the waste management issues our pets present.

 

Steve Watson

 

Steve Watson

 

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5 Comments on "Don’t pooh-pooh pet waste"

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Nicolay Kiselev
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I agree with Mr.Tamzin Phillips that any land which had composted dog poo on it would be deemed contaminated land within 2 years.

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Fred Holdsworth
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Check out: https://asunews.asu.edu/20120501_dogpark. Every neighborhood & park should have one of these.

Tamzin Phillips
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There is another problem in that many of the dog food manufacturers add crushed bones to dog food as a cheap filler. The bones contain high levels of phosphorus – which isn’t digested by pooch and deposits out on the ground, only to leach away into water courses. Many of the algal blooms we see in inland waters are as a result of pollution from phosphorus from pooch. This is why a number of the water companies have banned dog walking from around their drinking water reservoirs. It is cheaper to take the flak from a few disgruntled dog walkers… Read more »
John smith
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Is it even sustainable to own pets? You discuss the “waste”, but following the waste hierarchy, we should prevent waste being generated. Do a LCA on the ownership of a cat(or dog), and excluding the emotional element, and it becomes clear that it is not an environmentally good choice.

Of course, the emotional element (fluffy friends and talk of “a member of the family”) overrides environmental concerns. I can understand why, when you had your “fuzzy feelings” that you did not do an LCA before deciding to own a cat.. or does the cat own you? 🙂

Steve Watson
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John, I think your comment raises some important problems concerning where environmental ethics fit into one’s overall moral outlook. There’s an obvious reductio ad absurum argument to be made that if we take the waste hierarchy to be the ultimate guide of our actions then we should be concentrating on wiping out the human race, as that would surely be the greatest waste prevention measure conceivable! So, considerations of care for life must come in at some point. Where exactly is surely the difficult point. Not many people would want to let a kitten starve, and I’m inclined to think… Read more »
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