Prepared by: Lyn Taylor, Director
National Capital Coalition for People and Dogs
September 16, 2004
The purpose of this proposal is to explore the possibility of finding a more user and environmentally-friendly alternative to deal with the issue of pet waste disposal. It proposes a solution which the National Capital Coalition for People and Dogs believes is:
- acceptable to dog owners, NCC, city officials, all users of public spaces
- friendly to the environment
- economically feasible
The objectives are as follows:
- To set up on-site composting system(s) to test whether dog waste can be successfully composted to produce an end product which is pathogen free, and safe to use as a soil amendment and fertilizer
- To produce a guide to composting dog waste based on the results of the project
In the City of Ottawa, the issue of dog "waste" disposal has become very contentious. An amendment to the Poop and Scoop By-Laws , which were enforced in April 2003, requires that dog owners take home their dogs' waste from public parks and dispose of it on their own premises. They are no longer allowed to dispose of it in garbage containers in public places. Flushing it down the toilet is the method of disposal recommended by the City. Also, the National Capital Animal Regulations (May 2002) require that dog waste be removed from their property and discarded at home.
Unfortunately, these new by-laws have started to create more problems than they were designed to solve. Judging from the increased amount of pet feces being left on the ground in dog walking areas such as Conroy and Bruce Pits, more and more pet owners are less inclined to pick it up at all - a retrogressive step since the poop and scoop by-law had, until now, been quite successful in reducing the amount of pet waste. And those who do take it home are more likely to put it in their own garbage containers than to flush it, so it still has to be picked up and hauled to the landfill. Nor is flushing it down the toilet an ideal solution, as this only increases water usage, and adds to the problem of sewage pollution. In a book entitled "Diary of a Compost Hotline Operator", the author Spring Gillard reports that in Vancouver, B.C., the sewage treatment plants are not all that hot on flushing. It seems the "nuggets" (as they are called) are rock hard and gum up the whole sewage system. Plants have to be retrofitted at great expense with special masticators to grind the material up.
In the City of Ottawa there are between 60,000 and 80,000 (Source: Citizen article, March 23, 2003). If each dog produces an average of ¾ pound of waste per day, that is approximately 52,500 pounds total per day, or over 8,000 metric tons per year in Ottawa alone. That is a lot of manure! By treating it as a "waste" product and putting it into landfills, or flushing it down the drain, are we throwing out a valuable resource that could be put to good use?
Composted horse manure, cow manure, sheep manure, and even "humanure" in some places are considered to be a valuable agricultural resource to improve soil structure and fertility. Why not dog manure? Is it possible to change our thinking about dog feces as a "waste" product and start to think of it as a renewable resource? Can we recycle it and turn it into compost, thus keeping it out of the environment and underground?
If dog manure could be turned into compost, there would be many benefits. These include:
- Eliminating disposal problems and reducing the amount of waste going to landfills and into the sewers;
- Providing nutrients to fertilize plant growth, and organic matter to improve soil structure, drainage, and water retention;
- Lowering the risk of contaminating surface and ground water;
- Making parks, and public walking areas more desirable and reducing the antagonism between dog owners and non-dog owners.
Composting Dog Waste (the Scoop on Dog Poop)
Almost without exception, dog waste is listed as a "no-no" when it comes to composting. It contains bacteria and pathogens that can be harmful to humans. Of greatest concern are parasitic worms, and of particular concern are roundworms, tapeworms and hookworms. Also, like other animal manures, dog manure is high in nitrogen so it significantly affects the ratio of carbon to nitrogen ratio, which significantly affects the decomposition process. (The bacteria and fungi in compost digest or "oxidize" carbon as an energy source, and ingest nitrogen for protein synthesis.)
But what if we could create conditions in the compost pile where temperatures were high enough to kill the pathogens, and the addition of materials high in carbon created the required C/N?
The Alaska Experience
In 1991, the Fairbanks (Alaska) Soil and Water Conservation District started a study to determine the feasibility of composting dog waste in Interior Alaska. With an estimated population of over 20,000 dogs within a 7,000 square mile Borough where dogs are used for transportation, recreation and competitive sports, the volume of dog manure and its disposal were becoming a major problem as pollution from dog waste can pose a severe threat to water quality, wildlife and public health.
Kennel owners were recruited to participate in a number of field studies. Several composting systems were used (e.g. wire bins, rigid plastic bins, and open piles). Carbon sources were identified (straw, chopped straw, birch sawdust, and hardwood sawdust), and various ratios of dog waste to carbon sources were tested (1:1, 2:1, 1:2, 3:1). The dog owners were instructed to add dog manure to the bins, mix it thoroughly with a carbon source and add small amounts of water until the compost mixture was "as moist as a wrung out sponge" (50-60%). They continued adding ingredients until the compost was 2 to 3 feet deep, then placed a cover over the mixture and let the temperature rise. No fresh materials were added after the bin was full.
Average internal temperatures were recorded daily with long-stemmed thermometers. When the temperature dropped below the ideal composting range (deemed to be 130 to 170 degrees), the compost was turned to reintroduce oxygen and to assure that the waste on the outside of the pile got a chance to cook. This process was repeated until it turned into a crumbly, black, dirt-like mixture. Cooking time varied, but was usually from 4-8 weeks.
Laboratory analysis proved that the resultant compost was free of Toxicara canis, or large roundworms (one of the most heat-resistant pathogens found in dog manure and the most difficult to kill). This was true for the dog waste which was known (by testing) to have contained the parasite prior to composting. Nutrient analysis showed that the composted waste was high in nitrogen, phosphorous, and potassium. Salt levels were high but this is common in compost made from most materials. The pH of the finished compost was consistently close to neutral.
They concluded that "good composting" of dog waste is possible. It reduces the volume of waste by over 50% and produces compost, which is essentially odourless and pathogen free, thus eliminating the need to transport the waste to a disposal facility, saving time, energy and landfill space. The compost makes an excellent soil amendment but the high salt levels are too high for it to be used as fertilizer, although they acknowledged that curing it over winter or for a year would reduce the salt levels.
To set up test situations, it is clear that there are many factors that will need to be carefully considered in the planning stages. These include (in no particular order):
Carbon Sources - Type and Quantity
As mentioned earlier, carbon must be added to the high nitrogen dog waste to achieve the appropriate carbon to nitrogen ratio needed for micro-organisms to thrive. The C:N ratio is critical for achieving high temperatures and the rapid decomposition of the waste. No matter what the source of carbon, the experiment in Alaska found that a ratio of two parts (by volume) of dog waste to one part carbon was the ideal combination. (However, it should be noted that the Alaska study was done with working dogs with a high protein diet, so ratios of dog waste to carbon need to be evaluated for other types of diets.)
Sources of carbon rich materials will need to be found which are available in sufficient quantities, accessible, and affordable. (Possibilities include straw, sawdust, leaves, etc.)
Different types of bins have advantages and disadvantages but they need to be able to produce enough mass to retain heat. A 3 foot square is recommended in the Alaskan study.
Whatever type of bin is used, it needs to provide adequate ventilation so the compost will reach high enough temperatures to destroy pathogens. Other factors to consider are ease of turning, heat retention, and protection from the elements (rain, sun and wind).
The test site will probably need several containers, which will be at different stages of decomposition over time. They will need to be located in secure positions where they can be managed carefully and systematically to ensure the proper process is followed.
Location of Bins
Bins will need to be located where they are accessible but will not interfere with park users. Aesthetically, it would be better if they were screened from view. They should be protected from drying winds and in partial sunlight to help heat the pile.
The temperature of a compost mixture is very important as it reflects the level of microbial activity. Daily temperatures of 130 - 170º F for several days are needed to destroy weed seeds and pathogens . It is proposed that a compost thermometer be used to monitor the temperature of the compost mixture on a daily basis.
Volume of dog waste
The Alaska study concluded that it takes at least 10 dogs, preferably 20, to generate enough waste a pile large enough (3-5" cube) to provide insulation and keep temperatures at the center of the pile.
A mixture that is 50-60% water is recommended, so a source of water will be required (e.g. rain barrels?). The more wind and sun exposure, the more water will be needed.
A long curing period after the thermophilic stage will probably need to be built in to add a safety net for pathogen destruction.
Flies and Odours
Odours and flies can be controlled by covering the compost with a layer of sawdust or finished compost. Once the pile heats up it is too hot for fly eggs to survive.
Composting in Winter
In colder weather, the compost process slows down and eventually stops so dog waste will build up in the winter months. However, with planning, the build-up can be effectively composted in the warmer months. The Alaskan report suggests: picking a composting site in the sun; avoiding mixing excess snow with the dog waste; storing the compost ingredients in bins over winter and turning them in spring to begin the composting process.
Careful monitoring and proper management of the compost is important to ensure that the compost which is produced is safe and meets all the standards and regulations , with particular emphasis on the pathogen analysis and C/N ratio.
Compliance and Waste Collection
A major consideration will be how to get dog owners to cooperate in the project, to pick up the waste and dispose of it properly in the bins provided.
As most dog owners use plastic to pick up their dog's waste, there will need to be an education component to ensure that dog owners fully understand the importance of keeping plastic and other non-biodegradable materials out of the system.
To address this problem, attempts will be made to find sources of biodegradable bags which are fully compostable, and to find a sponsor who will fund supplies for the duration of the test. Also, a "sorting process" will need to be built into the management of the project.
Disposal of End Product
Consideration will need to be given to how and where end product can be put to good use. If it is deemed that the end product is safe to use, there are a number of possibilities for this. For example, display gardens could be set up to demonstrate its effectiveness and value. Depending on the outcomes (quality and quantity), there is even a possibility of building in a cost-recovery component.
Proposed Action Plan
- Review literature and research options for dog waste disposal
- Identify and approach potential partners and project advisers/consultants; set up Advisory Group
- Identify and approach potential funders (project grants and/or sponsorship of supplies)
- Identify potential sites and solicit permission to set up sites as required
- In consultation with advisers, develop "protocol"/logistics, e.g. compost "recipes", collection methods, management, appropriate containers, location of bins, monitoring, data collection and recording, etc.
- Develop educational and information materials to deal with compliance issues
- Prepare sites
- On-going management of sites, data collection, etc.
- Test end product
- Distribute end product
- Follow-up - share learnings from the project (guides, brochures, information packages, seminars, etc.)
Composting may be a safe and effective method for disposing of dog waste, given proper conditions and careful management (e.g. composters installed in secure areas; additions of appropriate carbon sources; proper loading, monitoring and mixing; disposal of output, etc.). The NCCPD believes that further investigation and testing are warranted to determine the feasibility and cost effectiveness of composting as a viable option for the problem of dog waste disposal in public areas in the National Capital Region.
Sections 37 & 38 (Stoop, Scoop and Remove), Municipal Animal Care and Control By-Law & Section 8 of the National Capital Commission Animal Regulations
"Diary of a Compost Hotline Operator", Spring Gillard, New Society Publishers, 2003, pages 124-125
"The Humanure Handbook: A Guide to Composting Human Manure", Joseph Jenkins, Jenkins Publishing, 1999
Composting Dog Waste, Fairbanks, Alaska, Final Report, March 1997
Composting Dog Waste, Fairbanks, Alaska, Final Report, March 1997
See "The Four Criteria for Compost: Maturity, Foreign Matter, Trace Elements and Pathogens" on the website of the Composting Council of Canada (www.compost.org/standard.html)
For more information, please contact:
Director, National Capital Coalition for People and Dogs
19 Centennial Blvd.
Ottawa, ON K1S 0M6
Telephone: 613.232.0875 E-mail: email@example.com
Chairperson, National Capital Coalition for People and Dogs
160 Oakridge Blvd.
Ottawa, ON K2G 2V2
Telephone: 613.228.7764 E-mail: firstname.lastname@example.org
page last updated October 2004