Are you curious about turning human waste into a valuable resource for your garden? It might sound unconventional, even a little daunting, but composting humanure is a sustainable practice with a long history. For centuries, communities have safely managed human waste, and modern composting techniques make it more accessible and reliable than ever.
If you’re looking for a way to reduce your environmental footprint, close the nutrient loop on your property, and create incredibly rich fertilizer, then learning how to compost humanure is an excellent step. This guide will demystify the process, addressing your concerns and providing clear, actionable steps to ensure safety and success.
Understanding Humanure Composting
Composting humanure, often referred to as the “Humanure Handbook” method, is a system for safely transforming human feces and urine (collectively called ‘night soil’) into a pathogen-free, nutrient-rich compost. This is not about simply burying waste; it’s a carefully managed biological process that relies on heat and time to break down organic matter, including any harmful microorganisms.
The core principle is to add a generous amount of carbon-rich “brown” material (like sawdust, straw, or shredded paper) to the humanure. This carbon material absorbs moisture, neutralizes odors, and provides the energy source for the composting microbes. The urine, rich in nitrogen, also contributes to the composting process.
Why Compost Humanure? The Benefits
The advantages of properly composting humanure are significant:
- Environmental Sustainability: Reduces the burden on wastewater treatment plants and prevents nutrient pollution in waterways.
- Nutrient Cycling: Closes the loop by returning valuable nutrients (nitrogen, phosphorus, potassium) from our bodies back to the soil, enriching it for plant growth.
- Reduced Reliance on Synthetic Fertilizers: Creates a free, high-quality fertilizer, saving money and avoiding the environmental impacts of chemical fertilizer production and use.
- Water Conservation: Composting humanure can be part of a system that uses less water than flushing toilets.
- Empowerment and Self-Sufficiency: Offers a tangible way to live more sustainably and take control of waste management.
Safety First: Addressing Concerns About Pathogens
This is, understandably, the biggest concern for most people. However, the science behind composting humanure is robust. When the composting process is managed correctly, the high temperatures reached (ideally between 131°F and 160°F or 55°C and 71°C) are sufficient to kill most harmful pathogens, including bacteria, viruses, and parasite eggs.
The “Humanure Handbook” by Joseph Jenkins is the foundational text for this practice. Jenkins emphasizes the importance of: (See Also: How To Add Carbon To Compost )
- Sufficient Carbon Material: Always covering fresh waste with at least an inch of carbon material.
- Adequate Curing Time: Allowing the compost to mature for a minimum of one to two years before use.
- Proper Pile Management: Ensuring the compost pile is large enough to generate and retain heat.
- Avoiding Use on Edible Roots: Generally, it’s recommended not to use humanure compost directly on root vegetables or leafy greens that are eaten raw, especially in the initial years of practice. Focus on fruit-bearing plants or ornamental gardens.
Setting Up Your Humanure Composting System
The most common and recommended method for home composting of humanure involves using a dedicated composting toilet or a “bucket system.” The bucket system is often favored for its simplicity and low cost.
The Bucket System: A Step-by-Step Guide
This system utilizes a simple five-gallon bucket with a tight-fitting lid. The key is to have a constant supply of carbon material readily available.
- Choose Your Bucket: A sturdy, food-grade five-gallon bucket is ideal. Ensure it has a secure, locking lid.
- Prepare Your “Browns”: Gather a generous supply of carbon-rich materials. Excellent options include:
- Sawdust: From untreated wood.
- Shredded Paper/Cardboard: Non-glossy newspaper, junk mail, egg cartons.
- Straw or Hay: Chopped into smaller pieces.
- Wood Chips: Small, aged chips.
- Establish a “Browns” Container: Keep your chosen carbon material in a separate, easily accessible container next to your composting toilet or bucket. This makes it convenient to add after each use.
- The Process of Use:
- After defecating into the bucket (or a designated receptacle), immediately cover the waste with a generous layer (at least 1-2 inches) of your “browns.”
- Urine can be added directly to the bucket, or if you have a separate urine-diverting toilet, it can be managed differently (more on that later).
- For women, menstrual pads can also be composted, but it’s best to let them dry out somewhat and break them up before adding to the bucket.
- Adding to the Compost Pile: Once the bucket is full (or after a week or two, depending on usage), it’s time to transfer the contents to your main compost pile. This is where the real composting magic happens.
The Dedicated Compost Pile
You’ll need a dedicated composting area for your humanure. This should be a separate pile, away from your primary garden compost, especially during the initial curing stages. A “batch” system is often recommended, where you fill one container (like a bucket or a dedicated bin) and then let it cure for an extended period before starting a new one.
Key features of a good humanure compost pile:
- Size: The pile should be at least 3 feet x 3 feet x 3 feet (1 cubic yard) to generate enough heat. Larger piles are even better.
- Location: Choose a well-drained spot that receives some sun but isn’t constantly baked. Avoid areas where water runoff could contaminate other water sources.
- Materials: Layer the contents from your bucket with more carbon-rich materials. You can also add other organic kitchen scraps (avoiding meat, dairy, and oily foods) and yard waste.
- Moisture: The pile should be damp, like a wrung-out sponge, but not soggy.
- Aeration: Occasional turning can help, but the “Humanure Handbook” method relies heavily on passive composting with sufficient carbon.
Curing Time Is Crucial
This is non-negotiable for safety. The compost must cure for a minimum of one to two years. During this time, the biological processes continue, and temperatures should periodically rise, killing off pathogens. The compost should be dark, crumbly, and earthy-smelling before it’s considered safe for use.
Advanced Considerations and Alternatives
While the bucket system is popular, other methods and considerations exist. (See Also: How Do Worms Change Garbage Into Compost )
Urine Diversion Systems
Some composting toilet designs separate urine from feces. This can offer several advantages:
- Odor Reduction: Urine is largely sterile and doesn’t produce the same odors as feces when mixed with carbon.
- Fertilizer Potential: Separated urine can be diluted (1:10 with water) and used as a potent nitrogen-rich liquid fertilizer.
- Drier Feces: Removing urine can lead to drier fecal matter, which may compost more efficiently and with less odor.
However, managing urine separately adds complexity. If you choose a urine-diverting system, ensure you have a plan for its safe collection and use.
Composting Bins and Tumblers
While traditional compost bins and tumblers can be used for humanure, they require careful management to ensure they reach and maintain the necessary temperatures. Many home composters find the dedicated bucket and pile system simpler and more reliable for humanure.
What Not to Compost with Humanure
To maintain safety and prevent contamination, avoid adding the following to your humanure compost pile:
- Meat, Fish, and Dairy Products: These can attract pests and harbor harmful bacteria.
- Oily Foods: Can create anaerobic conditions and slow down composting.
- Diseased Plants: To prevent spreading plant diseases.
- Weeds with Seeds: Unless your compost pile consistently reaches very high temperatures, seeds may survive.
- Chemically Treated Materials: Such as treated wood or glossy paper.
Monitoring Your Compost Pile
While not strictly necessary for the “Humanure Handbook” method, monitoring temperature can provide reassurance. A compost thermometer can indicate if your pile is heating up sufficiently. If the temperature doesn’t reach at least 131°F (55°C), it suggests your pile might be too small, too wet, too dry, or lacking sufficient nitrogen (which the humanure itself provides). Turning the pile can sometimes help re-establish aerobic conditions and heating.
Using Your Finished Humanure Compost
After the mandatory curing period of 1-2 years, your humanure compost should be: (See Also: How To Build Compost Box )
- Dark and Crumbly: Resembling rich, dark soil.
- Earthy Smelling: No longer smelling of feces or ammonia.
- Pathogen-Free (when managed correctly): The heat and time have done their work.
How to use it:
- For Fruit-Bearing Plants: Excellent for trees, shrubs, and plants that produce fruit (tomatoes, peppers, berries).
- For Flowers and Ornamentals: Safe and beneficial for all decorative plants.
- For Soil Amendment: Mix into garden beds to improve soil structure, water retention, and fertility.
- Avoid Direct Contact with Roots: When planting, it’s best to mix the compost into the soil rather than placing it directly against plant roots.
- Consider a “Second Stage” Compost: Some people prefer to compost the humanure compost for another 6-12 months in a regular compost pile before using it, for an extra layer of safety and to further refine the material.
Legal and Social Considerations
Before embarking on humanure composting, it’s wise to check your local regulations. While many rural areas are more permissive, some urban or suburban areas may have restrictions on composting human waste. Open communication with neighbors can also help alleviate any potential concerns.
Troubleshooting Common Issues
Even with the best intentions, you might encounter a few hiccups.
| Problem | Possible Cause | Solution |
|---|---|---|
| Bad Odors (Ammonia/Rotten Eggs) | Too much nitrogen, not enough carbon, or anaerobic conditions (too wet, not enough air). | Add more carbon material (sawdust, shredded paper). Turn the pile if possible. Ensure it’s not waterlogged. |
| Pile Not Heating Up | Pile is too small, too dry, too wet, or lacks nitrogen. | Increase pile size. Add water if dry, or carbon material if wet. Ensure adequate nitrogen from the humanure. |
| Pests (Flies, Rodents) | Waste is not adequately covered, or the pile is too accessible. | Always cover fresh waste immediately with a thick layer of carbon material. Ensure the compost pile is in a secure location. Use a well-sealed bucket. |
| Slow Decomposition | Lack of moisture, poor aeration, or insufficient “activators” (like nitrogen-rich materials). | Check moisture levels. Turn the pile for aeration. Add more nitrogen-rich materials if needed (though humanure is inherently nitrogen-rich). |
Remember, the “Humanure Handbook” method is designed to be relatively low-maintenance, relying on the natural processes of decomposition. Patience and consistent application of the core principles are key.
The Role of Microbes and Fungi
The transformation of humanure into safe compost is a complex biological process driven by a diverse ecosystem of microorganisms. Actinomycetes, bacteria, and fungi work in succession. Initially, thermophilic (heat-loving) bacteria and actinomycetes break down proteins, fats, and carbohydrates, raising the temperature. As the pile cools, mesophilic organisms take over, and then fungi and other microbes further break down more resistant materials. This multi-stage decomposition is what ultimately sanitizes the material.
Understanding Curing Stages
The curing process is vital and can be broken down into phases:
- Active Thermophilic Phase: This is when the pile heats up significantly, ideally above 131°F (55°C), for several days or weeks. This phase is critical for killing most pathogens.
- Cooling and Mesophilic Phase: As the easily decomposable materials are consumed, the temperature drops. Mesophilic organisms (those that prefer moderate temperatures) then take over, continuing the decomposition.
- Maturation Phase: This is the longest phase, where the compost stabilizes. Fungi and other complex decomposers break down tougher materials, and the compost develops its characteristic earthy smell and crumbly texture. This phase is essential for the breakdown of any remaining pathogens and for creating a stable, humus-rich material.
The recommended 1-2 year curing period ensures that all these phases are thoroughly completed, providing a significant buffer for safety.
Final Verdict on Humanure Composting
Composting humanure is a powerful method for sustainable waste management and soil enrichment. By understanding and rigorously applying the principles of ample carbon coverage, proper pile management, and a minimum of one to two years of curing, you can safely transform human waste into a valuable, nutrient-rich compost. It’s a commitment to ecological responsibility that yields significant rewards for your garden and the planet.
