The average person urinates about 500 liters and defecates 72.5 kilograms of excreta annually. Rounding the world population off to an even seven billion, that means that human beings produce approximately 3,500 billion liters of urine and 507.5 billion kilograms of feces every year. Impressive.
Many people can easily dispose of their wastes with the simple flush of a toilet. The World Health Organization estimates, however, that one billion people worldwide don’t have access to sanitation infrastructure, and instead practice open defecation in pits and drains. This gives human fecal matter and urine direct access to ground water, where they often contaminate drinking wells.
But what if people could keep organic waste out of the water and harness it to produce energy for farming, instead? A group of waste management and soil scientists from around the world met late last summer at the Hamburg University of Technology to discuss the possibility of developing safe and sustainable ways to use human excreta to fertilize farms and gardens, particularly in areas that lack other sewage infrastructure.
They talked primarily about a technology known as Urine Diverting Dry Toilets, or UDDT’s. The look and operation of these waterless toilets are designed specifically to target rural areas of the world where large numbers of people are living without sewage systems.
UDDT’s separate urine and feces into two distinct, airtight tanks. In the fecal tank, users mix feces with lactic acid bacteria to reduce foul odors and keep conditions as sanitary as possible. When this container is full, they take the feces out of the tank and compost it with worms and wood chips, to keep it dry. After three months, the compost is used to fertilize soils. While this may seem unsanitary, it is a long-term program: the land is not used to grow any food crops for a minimum of ten years after the fecal fertilizer is applied, to ensure the health and safety of the consumers.
When diluted, urine can also benefit soil fertility. On average, one person produces approximately 3.6 kilograms of nitrogen and 0.5 kilograms of phosphorus in their urine. Since urine is sterile, it does not need to go through the rigorous sanitation that fecal matter does. In many cases, diluted urine can be used directly in a farm or garden.
The UDDT system is based largely on areas in the Amazon Basin known as “terra preta,” or dark lands, where scientists and anthropologists believe Native Americans nourished soils with a mixture of feces and charcoal. These spots were fertilized centuries ago, but they still remain unusually high in nutritional content.
At the Hamburg conference, scientists were eager to discuss how UDDT’s could bring about similarly successful results today. In Nepal, for example, 3,000 families use these toilets to make their own urine-based compost instead of using expensive chemical fertilizers. These households’ crops are considered organic, and sell for higher prices at local markets. In the Eastern European country of Moldova, where only five percent of citizens in rural areas have access to working sewer systems, the introduction of UDDT’s has been very effective at protecting their water table.
The Rich Earth Institute in Vermont also recently started its own urine-composting program. They are promoting the use of UDDT’s to replace standard flush toilets, claiming that this technology has the potential to save over 15,000 liters of flushed water per person, per year.
Sign up for Food Tank’s FREE Weekly Newsletter. More than 110,000 Subscribers And Counting. Click HERE to join.
Everyone poops. But not many people really think about what happens to it. We flush the toilet and it is out of sight and out of mind. Sasha Kramer, on the other hand, has poop on her mind all the time. She is a sanitation revolutionary helping to transform human waste into fertile organic compost for agriculture and reforestation in Haiti. “Arguably,” Kramer says, “the most important thing in nature is soil, that’s where all life comes from.”
Kramer is an ecologist, human rights advocate, National Geographic emerging explorer, and the executive director of Sustainable Organic Integrated Livelihoods (SOIL). SOIL primarily focuses on promoting the use of ecological sanitation, a process that uses naturally occurring microbes and heat to convert human waste to rich compost. Ecological sanitation at SOIL means dry composting toilets, which can be simple and low cost so that it works even in crowded, informal settlement communities where there is little infrastructure.
So how exactly does this work? Kramer explains: “The way ecological sanitation, in general, works, is that people have a small in-home toilet, that basically has a five gallon bucket in it, where the poop falls. Each time you poop, instead of flushing with water (which is such a valuable resource), we use some sort of a dry carbon cover material. This would be some sort of agricultural waste that’s otherwise not being used. You basically cover it up and then that keeps the smells from coming out … and it keeps the flies from coming in.”
Each week, service agents pick up the buckets from each household, and give clean buckets with the cover material in it. Then those full buckets are transported to one of SOIL’s composting sites. The fleet of “poop mobiles” includes pick-up trucks and wheelbarrows, as some of the corridors in impoverished communities are too small for any type of vehicle. “At the composting sites, it’s wonderful because instead of relying on fossil fuel to treat the waste, we really rely on the power of ecological systems. Once we dump the waste most of the work is done by naturally occurring soil microbes.” These microbes take care of the treatment process, as they naturally heat the piles up to 170 degrees Fahrenheit, which kills the pathogens that make people sick. The staff turns the piles a few times and after about six months, voilà, the finished product is rich soil.
These bucket toilets are not some eco-alternative to other kinds of toilets: they’re often the only dignified option available. Thousands of people in Haiti don’t have a private place to go to the bathroom. “People do what they have to do. If you’re in a rural area, maybe you go out and you go behind the tree. Probably most of us have done that too,” Kramer says. “If you live in a very dense urban area, then usually what people do is they use a plastic bag. They go into the most private place they can find. Go in a plastic bag, then throw in that plastic bag in the least offensive place they can find. That usually means the canal, or an abandoned lot.” With a high water table, flooding, canals draining into rivers, and no water treatment, the human waste ends up in the water supply. “What that means is that the water people are using to drink, to bathe, to wash their clothes and to wash their dishes basically has poop in it.”
Turning poop into soil instead of letting it enter the freshwater supply has a direct relationship to public health. Some of Haiti’s toughest challenges include childhood diarrhea and cholera. Kramer said, “Haiti has the highest rate of childhood diarrhea in the entire world. The world. Which means that for children under five, this is a leading cause of sickness. It’s actually poop in the water that’s making them sick.” Since 2011, Haiti has been battling the world’s largest and most virulent cholera outbreak in recent history. “One in six people in Haiti in the last five years had contracted cholera,” Kramer says. The problem has reached the level it has because of the lack of sanitation.
Most people probably think flush toilets are the solution, but, as Kramer explains, “A toilet without waste treatment is just a way to displace the problem—even if you have a very nice flush toilet in your home. If that water is just being flushed out into a canal near your house, and then washed into the community downstream, yes, you may have provided a certain level of protection to your family. But on the community level, on a public health level, you only displace the problem.”
Where people go, poop follows, and so do the nutrients. What’s happening is the migration of people into urban areas means there’s actually a migration of nutrients as well. There is a problem with decline in soil fertility in rural areas, Kramer explains, and that can create dependency on foreign countries to send fertilizer to restore the soil. “The way to break cycle of environmental destruction is to take those nutrients and instead of allowing them to go into aquatic ecosystems, getting them back onto the soil . One way to do that is through compost production.”
Kramer says that she and the team at SOIL are excited about this work because it’s a way to simultaneously work toward solutions for both the problems of access to dignified sanitation and this problem of declining soil fertility. “One of the reasons that people in Haiti get really excited about ecological sanitation and the fact that we can transform poop into soil is because it means that Haiti is harnessing its own resources. This is a country where people take tremendous pride in independence and local production.” Instead of polluting, it’s an opportunity to rebuild.
“SOIL could never be as successful as we are without having strong connections to community leaders and the places that we work. I believe that the key to our success is that we hire people based on whether they are able to be community leaders. Ninety percent of our staff is Haitian.” Kramer has been living and working in Haiti since 2004 and is proud of SOIL’s mission to make sure the technologies are culturally and locally appropriate. “There are groups that are trying to have a cookie-cutter solution that they can just replicate all over the world. What gets in the way is that each culture is different. You need to be able to adaptively respond to those different needs. Really the best way to do that is to take these technologies and share them with locally based groups, locally based businesses, governments. People who really know the communities in which they’re working.”
It’s safe to say that the way SOIL is taking on the cycle of “the Poop Loop” is a win-win solution for Haiti’s communities and environment. Kramer seems as motivated as ever. “I have such an amazing team of dedicated, passionate, brilliant people around me everyday, that when you work in an environment like that, you can be knee deep in poop and it’s still the best job ever.”
Read more about the philosophy behind SOIL on their website.
Be sure to check out more episodes of our Best Job Ever digital series.
Producer/Editor: Carolyn Barnwell
Series Producer: Chris Mattle
Director of Photography/Field Producer: James M. Felter
Graphics: Chris Mattle
- RESEARCH ARTICLE Use of Human Excreta as Manure in Rural China
- Humanure Recycling: A Composting Toilet for Garden Compost
- Where To Responsibly Empty Your Composting Toilet
- Waterless toilets
- Types of composting toilets
- Maintenance of composting toilets
- Choosing a composting toilet
- References and additional reading
- How human waste is helping Aussie farmers get the best out of their land
- Soil ‘just keeps responding’
- Turns Out That Using Human Poop to Fertilize Crops Isn’t Such a Great Idea
Use of Human Excreta as Manure in Rural China
Empirical research has shown that the use of manure significantly improves crop yield, soil fertility and water and moisture conservation. Despite these documented benefits, however, there is a concern on the downward trend of manure use in agriculture in China. This paper examines factors contributing to this downward trend, with a particular focus on human excreta used in agriculture. Empirical analysis based on data from stratified random sampling of rural households in five provinces of China shows that about 85% of human excreta was still used as manure in agriculture in 2007 which was less than a decade ago when nearly all human excreta was used as manure. Econometric results suggest that income growth, rising population density and improvement in rural transportation significantly contribute to declining use of human excreta as manure in agriculture. These results imply that the current downward trend will continue given China’s rising economic growth, urbanization and rural infrastructural improvement.
Humanure Recycling: A Composting Toilet for Garden Compost
Care and Feeding of Humanure in Composting Toilets
Composting relies on aerobic (oxygen-loving) bacteria that work 10 to 20 times faster than the anaerobic (oxygenless) bacteria at work in septic tanks. The challenge of composting toilets is getting air to the composting process while minimizing human exposure to the contents. That calls for careful engineering of airflow, so air is taken in and then exhausted through the exhaust vent chimney, not through the bathroom.
Some management is also required: turning or batching the material, and adding coarse material (such as sawdust or dry leaves) to keep it porous, so the aerobic bacteria stay healthy and functional.
Keeping the material aerated also means it can’t be too wet, so only waterless or microflush toilets are used with composting toilet systems. Waterless toilets are usually just toilet stools with 8- or 10-inch openings that connect through a straight pipe into the composter. For those who want a toilet trap between themselves and the composter, a microflush toilet, such as the SeaLand Traveler 1-pint flush toilet, can be used, provided extra liquid in the composter is evaporated, drained to a septic system or used in subsurface irrigation. Other microflush toilets include foam-flush toilets, which use an aquarium-type air pump to bubble air through a soap-and-water mixture, creating lots of foam to move material out of the bowl.
Composting toilet systems are not a flush-and-forget technology. They require consciousness of what’s put into the toilet (No toxic chemicals, please!), some maintenance, well thought out siting and installation, and in many cases, electricity for operating fans and heaters.
The most common installation mistakes are siting them in cold places (unheated basements, for example), not draining away leachate (liquids) and installing systems that are too small for the usage they’ll get.
Humanure: Using the End Product
In composting toilet systems, most pathogens are destroyed through a combination of heat and retention time. But many states require the compost toilet end product either to be hauled off by a sewage hauler or buried under 6 inches of soil. To comply and still reap the nutrient benefits of human manure, most folks choose to bury the end product in the root zone of ornamental plants. Even without legal approval, some individuals choose to compost the end product further in an active, outdoor compost pile, or to use a pasteurizer, such as a solar oven, to destroy potential pathogens.
Will Brinton, Ph.D., of Woods End Research Laboratory has tested several samples from composting toilets in the past year. Most of the samples have undergone at least 1 1/2 years of retention time. “In all the samples of composted human manure we have tested, E. coli pathogens were not present at levels relevant to the Environmental Protection Agency’s pathogen test rule,” says Brinton. “Adequate composting time and/or temperatures generally will make human manure safe to use, even though local laws may not acknowledge this fact. We recommend individuals who wish to use composted human manure for surface application test for fecal coliform after the first round of composting.”
Types of Composting Toilets
There are several types of composting toilets. These systems are either self-contained (usually for cottages) or central (also referred to as remote and below-floor ).
With self-contained systems, the toilet seat and a small composter are all one unit. Due to their small size, they are typically used in cottages and seasonal homes. Because of their limited capacity, these systems require frequent emptying, which is accomplished simply by removing the small tray that sits underneath the toilet. The end product from these systems can be buried around trees and shrubs, or composted with other materials in an outdoor composting bin. Prices range from about $750 to 1,500 for these units. Self-contained systems include models available from Sun-Mar, Biolet and Envirolet.
In a central system, the toilet empties to a separate composting chamber, usually located in the basement or in its own enclosure to the side of the building. In these systems, frequent emptying is not necessary, although you may need to rake the contents occasionally. When the chamber fills (usually within a year), the contents — which have composed into a fine, crumbly product — can be removed with a shovel and wheelbarrowed out to an outdoor composting bin or buried in trenches outside. Commonly the choice of year-round homes and facilities with multiple toilets, central composting toilets range in price from $1,400 to more than $10,000 for large-capacity systems. Systems include AlasCan, Clivus Multrum, CTS, EcoTech Carousel, Phoenix and Sun-Mar Centrex.
Do It Yourself Toilet Systems
Many homeowners make their own systems. Some designs are simply copies of manufactured systems, such as a concrete version of sloped, single-chamber systems like the Clivus Minimus. Other designs use a batch approach with two or more interchangeable containers: When one fills, another is put into use, allowing the first container to process without fresh inputs. The containers are either fixed, as in aerated twin-bin systems made of concrete (CEPP Net Twin-Bin, Farallones System, Gap Mountain), or they are alternating containers, such as barrels and rollaway trash bins (CEPP NetBarrel, Sol-Latrine, Sunny John). The best designs feature some kind of management of the leachate and adequate ventilation for the composting process and odors (both the books listed in “On the Bookshelf,” page 91 of this issue, give detailed information on batch systems). All of these systems can be used with microflush toilets. The CEPP NetBarrel system, which can be integrated with a graywater system, can cost as little as $15 to construct. Add a 1-pint flush toilet, and the total is only $260. These systems provide as much capacity as one has containers.
Some users bypass composting toilets altogether and use a very low-tech system, collecting their human manure in a bucket housed underneath a small built-in cabinet. With a standard toilet seat and lid on a hinged top, the cabinet hides the bucket until it’s ready to be emptied. A cover material, such as well-rotted sawdust or finely ground leaves, is added after each use to act as an odor filter. When the bucket is full, it’s emptied into an outdoor composting pile. Distinguished from composting toilets, in which composting takes place within the chamber itself, these sawdust toilets are simple collection devices; the actual composting occurs along with veggie peels, grass clippings and other compostables in a separate, outdoor bin. Direct outdoor composting requires no fans or electricity, but does require management and lots of carbon-containing cover material (sawdust, rotted leaves and straw) to cover the manure for composting.
This method probably won’t gain approval from most health officials as a replacement for a flush toilet. Sawdust toilets are for people who are serious about nutrient recycling, don’t mind the regular job of emptying containers onto a compost pile and will responsibly manage the compost to ensure the compost pile achieves thermophilic conditions (more than 113 degrees) to destroy pathogens. Because his compost achieves high temperatures and undergoes two seasons of aging, organic gardener Joseph Jenkins uses his composted human manure as a garden soil amendment. In most other composting toilet systems, although some excreta breakdown occurs within the indoor chamber, materials usually do not heat up enough to reliably destroy pathogens. To comply with legal regulations, most manufacturers advise against using the end product in food gardens. Jenkins details the differences between sawdust collection systems and composting toilet systems in his book, The Humanure Handbook (See MOTHER’S Bookshelf, page 103 in this issue). Instructions for building a sawdust collection toilet can be found at www.jenkinspublishing.com/sawdustoilet.html.
The Current Laws
Plumbing and wastewater codes usually allow composting toilets when a conventional septic system or sewer service is already in place. For all other situations, property owners may have to get special permits, depending on the state. Maine, Massachusetts, Minnesota, New Mexico and Washington are among the most accepting. Although National Sanitation Foundation listed systems are preferred, many states also approve systems based on their own criteria. New onsite standards, which may be adopted nationally, will likely approve any model that features the capacity for two-year retention of the end product. Given enough information about the systems, most health officials are usually willing to work with homeowners. Legal acceptance of composting toilets is increasing rapidly, as their benefits become clear to all: no pollution, water and energy savings, and nutrient recycling.
For those of us who live in areas where composting toilets aren’t permissible yet, an alternative to water-wasting, high-volume toilets is low-flush toilets. If you are planning to build a home, federal law now requires 1.6-gallon low-flush toilets be installed. Older toilets suck down between 3 to 5 gallons of fresh water with each flush.
According to the American Water Works Association (AWWA), the average American uses 74 gallons of water per day. Almost one-third of this water goes to flushing toilets. Seem wasteful? It is.
As demand for pure water grows while fresh water supplies dwindle, conservation measures must be implemented. A 1.6-gallon low-flush toilet can cut household water usage by 20 percent or more. The AWWA estimates if every American household switched to water-efficient toilets 22.3 million gallons of water would be saved each year.
So what’s the holdup? Unfortunately, these watermisers weren’t designed well when they were introduced. Folks frequently faced the fate of double-flushing or, even worse, clogged toilets. “Back when the lowflush models were first mandated in 1992, the imported Swedish lowflush toilets worked great,” says David Del Porto, a designer of water conservation and alternative wastewater systems. “But U.S. manufacturers didn’t change their designs. They just made smaller tanks.” Coupled with old pipes and low pressure in many older homes, the first U.S. lowflush toilets were doomed to fail.
Now changes in design have produced high-performing low-flush toilets that can significantly reduce your home water use and take a load off your septic system.
“Today’s 1.6-gallon toilets — even the mediocre ones — are a lot better than the old 5-gallon flush toilets,” says plumber Terry Love, who has sold and installed low-flush toilets since 1974.
Love says the biggest problem is clogging. Some toilets have sharp edges in their drains that catch toilet tissue as well as items people drop in toilets, such as makeup pencils, pens and toys. For that reason, shop for toilets with smoother edges around the drain and more sweeping traps with gently angled drains. They simply perform better. (Toto and most high-end models qualify; see Love’s recommendations on page 92 in this issue).
Types of Low-Flush Toilets
Gravity-flush toilets are the most common, have the simplest design and are usually the least expensive, ranging in price from $50 to $420. When the toilet knob is pressed, a flush valve opens, and the water in the toilet tank drains into the bowl through rim openings. The force of the water pushes the waste through the trap and down the drain line. While they are less effective at removing solid waste than pressure-assisted toilets, they’re generally less expensive and easier to maintain, since most use standard, widely available parts.
Pressure-assisted toilets are suited for commercial buildings or in homes with poor drain line carry, where pipes aren’t pitched enough to allow waste to flow easily to the septic system or sewer line. When the toilet is flushed, the pressure of the water coming into the main tank compresses air in an inner tank, forcing water into the bowl and blasting waste down the drain. Some consider pressure-assisted toilets noisy, although Love says the whoosh of a pressure-assist is just unfamiliar compared to the gurgle of a gravity-flush toilet; Pressure-assisted toilets are more effective in removing solid waste and limiting odor and soil problems, but are also a bit more expensive than gravity-tank toilets; prices usually start around $230.
Perhaps the greatest advance in water-saving toilets are the dual-flush toilets, which feature two flush buttons: Press the dark one to flush feces with 1.6 gallons of water or press the light one to flush only urine with 8 gallon. Caroma’s dual-flush from Australia is now imported to the United States; prices start at $250.
Vacuum toilets use a vacuum pump to suck waste away. They are expensive and mostly found in ships, trains or buildings where waste must be moved without the benefit of gravity. The Seal-and microflush 1-pint toilet is one of a few toilets made for boats and recreational vehicles, and for use in composting toilet systems. These toilets can transport waste a long distance.
Before installing a low-flush toilet, check to make sure your drain system is working and does not block easily. If your drain system often clogs, have it fixed, but also specify a toilet that is rated high for drain line carry. If your home was built within the last 10 years, any of the low-flush toilets will work.
Love’s website (www.terrylove.com) describes his favorite low-flush toilets. His first choice? The UltraMax, a gravity-flush by Toto. “It is a good-looking one-piece that incorporates a 3-inch flush valve, instead of the standard 2-inch, which allows the waste to drop quicker. It meets commercial requirements, works well in a home and is quieter than the pressure-assisted models.” He says the only drawback may be less bowl wash. Priced around $350, its a little more expensive than some toilets, but he thinks it’s worth the money.
The economics of flushing with less is apparent: A New York City program that offers subsidized or free low-flush toilets in exchange for property owners’ 3- and 5-gallon toilets has saved millions of dollars in water costs since 1992. Nationally, the new low-flush toilets are credited with saving between 25 and 60 gallons of water per day each, saving consumers an estimated $50 to $100 on their annual water bills.
“Today’s low-flush toilets work,” Love says. “And these days, we just don’t have the water to waste.”
Carol Steinfeld is the co-author of The Composting Toilet System Book. Claire Anderson contributed research to The Humanure Handbook and is an assistant editor at MOTHER EARTH NEWS.
Composting Toilet Sources
CTS Composting Toilet
Envirolet Composting Toilet
Phoenix Composting Toilet
Composting Toilet Anatomy
The technology varies, but the typical components of a composting toilet system include:
1. A waterless toilet stool or a microflush toilet;
2. A composting chamber, where one or more dry or microflush toilets empty;
3. A screened ventilation inlet ;
4. An exhaust system, often fan-forced, to remove odors, carbon dioxide and water vapor; and
5. An access door (5) to remove the end product.
(See the composting toilet anatomy diagram in the image gallery.)
Where To Responsibly Empty Your Composting Toilet
This led me to make a lot of phone calls. Each agency I called I told them this about our composting toilet contents I’m trying to dispose of:
It content is dry materials only
There are no chemicals added to the content
It’s about ~5 gallons of solid material that’s a mixture of human waste and organic material such as coco pith and sawdust
The content is not fully composted
I called NC Environmental Quality and spoke to the section chief of solid waste. His response was that tossing a bag of humanure in the trash is fine. The quantity of poop we’re tossing out isn’t large enough to be of any environmental concern. The Air Head solid container can hold 5 gallons worth of stuff, about half of which is just coco pith. It would be a different situation if a trash company was picking up a whole dumpster full of poop, or if we were really sick. But a bag of poop now and then isn’t a problem. He said trash companies can refuse to pick up poop, but they have a permit to accept sewage sludge. Just make sure it’s properly bagged before disposing of it.
I also got in touch with North Dakota Department of Health (solid waste department) where I was told that contents from a composting toilet is considered “Class B biosolids” which is the same category that baby/adult diapers are in. The Texas Department of Environmental Quality told me that there aren’t any specific laws or regulations against tossing a bag of composting toilet poop in the trash for the landfill. The engineer I spoke to said that landfills see far worse stuff than poop. I also spoke to representatives from environmental agencies in Arizona, Oregon, South Dakota, Washington, Colorado, and Wyoming – they also said that as far as they are aware there are no rules or regulations against tossing a bag of human waste in the trash. They did specify that the waste can’t have liquids in it, it must be in small quantities (~5 gallons), and it must be securely bagged.
The next question naturally is how safe are landfills to our environment? This is a whole separate topic that I’m not going to go into. The simple answer is that landfills are regulated to minimize any negative environmental impact. But as with everything in life, the reality of the situation isn’t black and white.
But, after all the Googling, phone calls, and conversations, we’ve come to the conclusion that emptying our composting toilet into trash bags and then public trash cans is really the most sanitary way to do it. Since we hate using plastic bags, we use 100% compostable trash bags. A 13-gallon size bag is more than big enough and these bags have a thickness of 0.87 Mil. This way we can continue our eco-conscious efforts all the way to the landfill. Side note about the trash bags: I haven’t been able to find compostable trash bags in ~13 gallon sizes thicker than 0.87 Mil. The Primode trash bags we use work fine, but the toilet handle pin sometime catches the trash bag as we empty and puts a small tear in it – causing us to have to double bag it. (It sucks that we have to use two compostable trash bags, but we think two of those is still better than using one traditional plastic trash bag.)
If it’s required/suggested/recommended that the trash bag has solid waste only, what do you do if you don’t have a toilet that diverts liquids from solids (example: living in a van)? I found out about a product called Poo Powder from Kerri of @asolojourner. This powder is great for toilets don’t separate the pee and poop because it needs liquid to activate the powder. Once activated, the powder turns into a gel form and encapsulates the entire content. According to Carrie at Clean Waste, the powder creates a 99.9% barrier against pathogens like E. coli, MRSA, etc. when it encapsulates the material. It doesn’t kill pathogen, but Carrie said that one of the components in the powder does slow down the growth of any new pathogens.
The other method we’ve used and really prefer to get rid of our poop is adding it to an actual composting pile. When we were staying with friends on a farm, they started a poop composting pile. Only humanure was added to this pile and after it was properly composted, it would be used as fertilizer. This is obviously the ideal way to finish up what we started in our composting toilet.
Keep in mind that tossing a trash bag full of poop for the landfill isn’t currently an issue because it’s only a tiny percentage of the population doing this. Perhaps one day this issue will reach a tipping point and then there will be rules and regulations on how to properly dispose of composting toilet waste.
I hope this has helped clear up any questions or confusion about how to properly get rid of the contents of your compost toilet. Happy peeing and pooping!
Why You Should Pee On Your Plants
Gee Whiz: Human Urine is Shown to Be an Effective Agricultural Fertilizer
Fertilizing with Human Urine
Urine is Not Sterile, and Neither is the Rest of Your
Diseases Spread Through Bodily Fluid
Toilets that don’t use water for flushing can have even lower environmental impacts than water-efficient toilets and wastewater recycling systems. Waterless toilets or ‘dry sanitation’ systems do not use water to treat or transport human excreta. If appropriately designed, they conserve precious water resources and keep effluent and pollutants out of waterways and the general environment. They can also save money on your water bill.
Waterless toilets are a genuine, minimum energy, on-site alternative to centralised reticulated systems that transport the problem downstream. They can also reduce the site restrictions, and pollution and nutrient problems, of systems such as septic tanks.
They are often preferable to conventional toilets in environmentally fragile or water-scarce areas. For example, in the mid-north coast region of New South Wales, councils recommend householders install waterless toilets rather than conventional septic tank systems.
The most common type of waterless toilet, the ‘composting toilet’ (CT), has come a long way from the original pit latrine. The CT doesn’t smell if used and maintained correctly and can, in fact, be an elegant addition to a modern bathroom.
The composting toilet has come a long way from the pit latrine.
All CTs require a volume of space under the toilet floor which may necessitate the construction of either a pit or an elevated platform. They generally work best when kept warm so are ideally located on the sunny side of a house.
Waterless toilets can produce fertiliser if sufficient time is allowed and correct treatment conditions have been maintained. However, seek advice on its end use.
The CT often does more than the process that occurs in your garden compost heap. Decomposition in the holding tank or container of a CT takes place through a complex biochemical interaction of factors such as temperature, pH, desiccation and digestion by invertebrates, all taking place over an extended time period.
Photo: Stuart White, ISF
Waterless toilets conserve water and keep pollutants out of the environment.
Types of composting toilets
The many designs of CTs can be divided into three main types with characteristic advantages and disadvantages. Designs include commercial off-the-shelf units and owner-built systems that can be constructed using readily available materials.
Continuous composting toilets
These single container toilets receive excrement which decomposes as it moves slowly through the container and is removed as compost from the end-product chamber. Well-known designs with prefabricated models available for installation have health department approval in most parts of Australia. They may also be constructed by owner–builders.
Single containers are fitted under a bathroom and can easily replicate a flush toilet with little physical or social adjustment.
The container is permanently fitted under the toilet seat, and never has to be fully emptied as the compost can be gradually removed when it reaches the end-product chamber.
A disadvantage of the continuous system is that it may allow fresh material and pathogens (disease causing organisms) deposited on the top of the pile to contaminate the successfully decomposed end-product at the bottom of the pile.
Another drawback is that, if a problem occurs with the toilet, the system can be out of order until the problem is fixed because there is only one container. Sometimes the pile does not actually move down the slope of the container and can become compacted and very difficult to remove.
Continuous composting toilet.
Plans for continuous composting toilet.
Batch composting toilets
Batch CTs consist of two or more containers that are alternated so that the active container is being used while the pile in the fallow container has time to compost without the addition of fresh excrement and the potential for recontamination.
An example of an owner-built batch CT is the ‘wheelie-batch’. Containers are alternated underneath the toilet seat, and a perforated false floor is used to separate and drain off the liquid.
The owner-built wheelie-batch CT alternates containers underneath the toilet seat.
The fixed chamber batch is another example. Two containers are permanently in place and the seat is moved when the time comes to change containers.
The full containers in the batch system need to be replaced by an empty container. They must be disconnected from under a toilet seat or the seat moved over a new container. Batch systems can therefore take up more space in the bathroom or under the house.
Some commercially available batch CTs, including an Australian-made system, have approval for use in most parts of Australia. Some models have removable containers mounted on a turntable beneath the toilet for collecting waste, which saves space and simplifies container changeover.
The Windblad batch CT has removable containers mounted on a turntable beneath the toilet.
Self-contained composting toilets
Self-contained CTs are available for use where a composting chamber can’t be installed beneath the floor, such as an existing on-ground concrete slab. They are usually fitted with a small heater and fan to facilitate waste decomposition, and have the capacity to serve only households with a maximum of 3–4 people.
Self-contained composting toilets can be installed on an existing concrete slab.
Photo: Nature Loo
A self-contained composting toilet fits neatly into the modern bathroom.
Maintenance of composting toilets
The CT is relatively simple technically but requires more attention than a flush toilet.
Add some carbon-based material or bulking agent, such as dry leaves or softwood shavings, frequently to the container, preferably daily or with each use. This gives the proper carbon–nitrogen mix, helps aerate the pile and prevents compacting. Some commercial suppliers say this is not necessary for their design if their directions are followed but experience indicates the addition of bulking agent helps produce good compost.
A composting toilet that is working well and correctly maintained does not smell.
A CT that is working well and correctly maintained does not smell. Offensive odours usually indicate that something is wrong and trouble-shooting directions need to be followed. Often adding bulking agent in greater quantities or more frequently removes the smell.
The pile in a CT needs to be well drained. Diverting urine away from the compost can aid the composting process by reducing moisture levels and potential odours. Liquid runoff is often treated in a sealed evapotranspiration trench or a solar evaporating tray. If the liquids have been in contact with faeces, they must be evaporated, sterilised or otherwise treated before they can be recycled as fertiliser.
Council or health department regulations require appropriate drainage and disposal for residual moisture.
Vent pipes aerate the pile and can work passively using convection. Fans are not essential but are often included in off-the-shelf systems to aid ventilation and minimise odours. Check fans occasionally to ensure they are not choked with dust or insects.
The end-product or compost needs to be removed from the container when it is sufficiently decomposed. The frequency of removal depends on the size of container, how often the system is used and local climatic conditions. The minimum ‘fallow’ period should be six months. Depending on the design and usage, the container needs to be emptied every six months to three years.
Use the compost as fertiliser dug into your garden or dispose of it according to local council regulations.
CTs do not deal with greywater from showers, kitchen and laundry so a separate greywater collection and treatment system is needed (see Wastewater reuse).
Some safety precautions
It is safest to assume that the composted end-product contains residual disease-causing pathogens. The degree of decomposition and pathogen destruction is sensitive to a range of ambient conditions in the composting mass (such as temperature, moisture and pH levels) that are difficult for the toilet owner to monitor and control.
- Always use protective clothing such as gloves and mask when handling the composted end-product.
- Bury the compost under at least 10cm of soil.
- Do not use the compost for cultivating vegetables.
Choosing a composting toilet
For an off-the-shelf unit contact several suppliers. Tell them about the building, where the toilet will be located, how many people will be using the toilet and whether it will be on a continuous basis or only occasionally, such as in a holiday house. Ask them to recommend a suitable system for your needs and provide a quote. The cost can vary significantly depending on the design and features. Some suppliers also assist with greywater treatment systems.
Check if the supplier gives after-sales support. Ask if they have any customers with whom you could meet and discuss their experience with the CT. The cycle of usage and production of compost or end-product can take a couple of years. It is important to know that all stages of the process work satisfactorily.
Check with your local council and/or the supplier to confirm that CT design has approval in your area. Council attitudes and regulations vary, but common off-the-shelf units have state health department approval. Owner-built designs are usually cheaper to install and have been used widely for many years but often have not gone through the required approval process.
Avoid complicated designs. Simple passive systems with minimum moving parts are usually easier and cheaper to build, monitor and maintain. Designs that have more moving parts may require less maintenance if the system is working well. But if there is a problem, the more complicated designs can be more difficult to fix.
There are many types and applications of CTs. The published literature and manufacturers’ websites have more information and contacts for commercial units and owner-built designs.
References and additional reading
Booker, N. 2001. Greywater and blackwater treatment strategies. Environment design guide, TEC 11. Australian Institute of Architects, Melbourne.
Composting toilet buyers guide. 2010. ReNew, 104.
Del Porto, D and Steinfeld, C. 2000. The composting toilet system book: a practical guide to choosing, planning and maintaining composting toilet systems, a water-saving, pollution-preventing alternative. Updated edn. Center for Ecological Pollution Prevention, Concord MA.
Van der Ryn, S. 1999. The toilet papers: recycling waste and conserving water. Chelsea Green Publishing Co, White River Junction VT.
Windblad, U and Simpson-Hebert, M. 2004. Ecological sanitation, 2nd edn. Stockholm Environment Institute, Stockholm, Sweden. www.ecosanres.org
Principal author: Leonie Crennan
Updated by Geoff Milne, 2013
Sludge is generally applied to fields in spring and fall. This sludge came from Burlington’s Wastewater Treatment Plant and was spread onto the field by Synagro.
Dotting the verdant 400 acres of pasture at Braeburn Farm, on the outskirts of Snow Camp, are New Zealand Red Devon cattle and warmblood dressage horses like Thoroughbreds and Hanoverians. The farm is divided into 27 pastures where cattle graze every day. Rotating the cattle among the pastures allows the grass to grow and minimizes the need for spraying the fields with chemically loaded fertilizers.
Dr. Charles Sydnor, now a neuro-ophthalmologist, founded Braeburn Farm in 1975, fulfilling his dream of becoming a part-time rancher with his wife, Cindy, who began training horses and teaching riding lessons. Over the past 35 years Sydnor’s farm has become one of the Triangle’s leaders in the national locavore movement with its grass-fed beef, pasture pork, lamb and goats.
But Sydnor did not always use conservation principles and pasture rotations to preserve his farm’s integrity. Before he did a total remake of Braeburn Farm 10 years ago, Sydnor, like many North Carolina farmers, was using sludge, also known as biosolids, on his farm.
For 30 years, sludge has been applied to farmland throughout the U.S. to fertilize fields that grow food for livestock and, in some cases, humans. Yet it’s only in the last decade that sludge has garnered attention from citizens, scientists and the FDA because of the uncertainty of its contents.
Sludge isn’t just a byproduct of waste that creates optimal fertilizer; it can contain heavy metals, bacteria like staphylococcus (the cause of staph infection) and thousands of chemicals yet to be tested for safety by the FDA.
Sludge begins as human waste, manufacturing chemicals, landfill runoffessentially, anything that flows down a drain, which makes knowing its contents nearly impossible. Sludge infiltrates the food chain through livestock that ingest sludge while grazing on sludge-applied fields or eating food grown in those fields. Sludge comes full circle when people eat the crops grown in the field, consume the meat or drink the milk of animals that directly or indirectly ingested the sludge. It can also enter waterways used for drinking water or irrigation.
In the Triangle, thousands of acres of farmland are spread with sludge generated from wastewater treatment plants and then hauled and applied by Houston-based Synagro Technologies, Inc., the largest recyclery of waste in the United States and a company with a problematic environmental record. While there are federal and state rules governing sludge, there is little enforcement or monitoring of the practice. And local governments have no voice in regulating the sludge that is sprayed on fields in their jurisdictions.
In the early ’90s, the National Federation of Wastewater Treatment Plant Operators held a marketing contest to find a new, more appealing name for sewage sludge. From 250 suggestions, “biosolids” was chosen, but frankly, sewage sludge is largely shit. Manure. Dung. Guano. You can change the name, but it still smells the same.
If sludge were only manure, it would be less alarming. But sludge can contain thousands of chemicals, including arsenic, lead and mercury; parasites, radioactive material (found in urine from patients receiving chemotherapy) and microbes that cause diseases such as hepatitis A and food poisoningeven after the sludge has been treated at the wastewater treatment plantaccording to the American Society of Civil Engineers.
Sludge can include triclosan, an antibacterial chemical found in many soaps, toothpaste, mouthwash, toys and plastic kitchenware. Because triclosan been linked to “superbugs,” immune deficiencies, birth defects and other health problems, the FDA in April announced it’s investigating the chemical’s safety. (Many European countries and Canada have banned it from supermarkets and in materials that touch food.)
The waste heads to a municipal wastewater treatment plant, which could receive materials from sources as varied as factories, schools, hospitals, laboratories and funeral homes, as well as runoff from landfills, septic systems and storm drains.
Solids and wastewater are separated. Liquid leftovers are recycled. Solids remain on the bottom of the treatment tank. Sludge is what can’t be recycled any further.
Wastewater treatment plants are required to analyze sludge according to regulatory requirements before giving it to farmers. However, testing involves looking for just a handful of chemicals, some toxic metals, levels of nitrogen, phosphorus and potassium, and coliform bacteria, which can indicate the presence of other pathogens in the waste.
“Nothing specific, like MRSA or any other specific diseases that could be present,” says Sue Dayton, N.C. Healthy Communities director for Blue Ridge Environmental Defense League (BREDL).
Contaminants in sludge, particularly triclosan, can survive treatment at the wastewater plant and end up in farmland sludge. Recent studies by John Hopkins University researchers estimate that more than 100,000 pounds of triclosan are spread on farmland each year. When exposed to sunlight, triclosan is converted into dioxin, which, at high levels of exposure, can cause cancer, and at low levels, a range of serious health problems.
Despite the uncertainty of sludge’s contents, municipalities have to find some method of disposing of it. They give it away to farmers, who, already cash-strapped, can use it as free fertilizer instead of expensive commercial products.
“No one really knows what is in any particular batch of sludge/ biosolids,” said Dr. Jeffrey White, associate professor at N.C. State University’s Department of Soil Science. “The list of potential pollutants and pathogens in sludge is a long one, and currently there are no regulatory standards and associated analytical requirements for many of them. The same is true of drinking water, although the regulatory standards for drinking water are much stricter than those for biosolids.”
Sam Groce, Chatham County’s livestock agent with the N.C. Cooperative Extension Service, acknowledges he is concerned about biosolids containing heavy metals, but says he is more worried about Chatham farmers who can’t afford fertilizers and lime.
“It is a viable fertilizing source,” Groce says. “I’ve heard all this debate that’s going on, and it’s making the farmers out to be the bad guys. Who’s generating these biosolids? People who live in town.”
In the ’90s, Sydnor was approached by Synagro about using sludge/ biosolids on his farm. He agreed to try it.
“When you look at fertilizer you are basically looking at the nitrogen, phosphate and potassium levels,” he says. “The reason any farmer will go to biosolids is that one of the most expensive components of fertilizer is phosphate, and biosolids are very high in phosphate.”
Although he saved money on fertilizer, after a few years Sydnor grew concerned. “I noticed areas of grass that wouldn’t do well, and the stench was awful; if you went near it your eyes would burn.”
Sydnor called Synagro, which had supplied the sludge, and asked for someone to visit his farm. “Their representative just could not answer my questions about what was in it, and as a physician I had some questions about pesticides and pharmaceuticals,” Sydnor says. ” I realized they didn’t know what was in the biosolids.”
According to Jean Creech, Synagro’s North Carolina technical services manager and spokesperson, the company explains the composition of biosolids to farmers before they receive material.
“Biosolids are typically about 70 percent organic matter and provide two of the three primary nutrients that plants need to grow nitrogen and phosphorus,” Creech says.
When pressed about the term “organic” matter, Creech explains, “When I used the term ‘organic’ I was saying that biosolids are ‘of, relating to or derived from living organisms.’ This is the traditional definition of ‘organic.’ It is an accurate description of the biosolids.”
Dayton notes that it is misleading to say “biosolids is organic, because many people believe ‘organic’ means ‘natural’ or ‘toxic free.'”
Synagro has contracts with more than 600 municipal wastewater treatment plants, including those in Burlington and Durham, in 37 states. The company has a checkered environmental record nationwide. Within the last 10 years, according to EPA documents, the Maryland Department of the Environment fined the company $27,000 for violating air regulations; Pennsylvania environmental officials fined it $35,000 for sewage sludge storage and land application violations, which included failing to prevent runoff from entering nearby waterways and spreading sludge on a landowner’s property without permission. In Virginia, dozens of complaints have been filed against the company over allegations of road damage, odor, groundwater issues and truck traffic.
(The company wields enormous financial and political power. According to The Michigan Citizen, a Detroit City Council member plead guilty to charges of conspiracy to commit bribery after switching her vote to grant a $1.2 billion waste disposal contract to Synagro. Coincidentally, before the vote, she received $6,000 from Synagro.)
Since Sydnor couldn’t confirm what was in the sludge, he stopped using it. He says farmers should question what’s in the product, “even if Synagro and the EPA tell them it’s fine.”
It’s Memorial Day weekend, and Elaine Chiosso, Cynthia Crossen and Daniel Tolfree stand knee-deep in the swirling waters of Cane Creek. With a net, Crossen, the Haw River Watch coordinator gently scoops debris and leaves into a 12-quart plastic basin, while Chiosso, the Haw Riverkeeper, examines the underside of slick river rocks she gathers along the creek bed. “Here’s a freshwater sponge,” she says, “and look at that leech!” She places the leech in a petri dish filled with creek water, and Tolfree, an organic farmer, peers through a plastic magnifying glass to look at the creature more closely.
Crossen and Chiosso are teaching Tolfree how to look for signs of a healthy creek. For Tolfree, whose farm lies downstream from fields being applied with sludge, runoff concerns have led him to contact the Haw River Assembly and find out if the creek is healthy or ailing.
Cane Creek cuts its way through the heart of Alamance County farmland, following an ancient path within the Haw River watershed. In 2007 in Alamance County, 969 acres of farmland were deluged with more than 19 millions of gallons of sewage sludge. Some of that sludge was produced by Burlington’s Water Resources Department, which generates 10 million to 14 million gallons of sludge annually. Farmers generally use about 13,000 gallons of sludge per acre, according to the city’s Water and Sewer Operations Manager Eric Davis.
Under contract with the Burlington Wastewater Treatment Plant, Synagro trucks those solids from the WWTP to fields in Alamance, Orange, Guilford, Chatham, Caswell and Randolph counties, where it is applied.
For the past 30 years, Tolfree has nurtured his 23-acre organic homestead, Millarckee Farm, in southern Alamance County; his produce is a regular feature at the Carrboro Farmers’ Market. Upstream from Millarckee, farmers grow corn for ethanol, and leased fields are routinely spread with sewage sludge. Tolfree, who uses Cane Creek for irrigation, worries about what’s draining from those fields and flowing downstream to his farm.
Since state environmental officials don’t regularly test parts of Cane Creek, Tolfree says, “I have no idea on whether this creek is getting more or less polluted.”
Back at Millarckee Farm, Crossen has calculated Cane Creek’s water quality score ranks as good, with 20 points on a scale of 0 to 22. Tolfree says he’s relieved to have the tools he needs to monitor the creek’s health, but he still worries about the practices of farmers upstream. Near Cane Creek, fields of corn have just been fertilized, and what lurks beneath the soil is unknown.
“It is impossible to get a lot of testing down without deep pockets,” Tolfree says.
The N.C. Department of Environment and Natural Resources hasn’t tested Cane Creek since 1998. The state Division of Water Quality recently tested nearby bodies of water but skipped Cane Creek; the portion near Tolfree’s farm, according to a DENR spokesperson, isn’t part of the agency’s monitoring plans.
“North Carolina currently operates one of the most extensive water quality monitoring programs in the nation,” says Susan Massengale, public information office for N.C. DENR. “Comprehensive monitoring challenges remain.” She called monitoring the vast number of the state’s streams and rivers lakes, estuaries, wetlands and groundwater “a formidable task.”
“DENR isn’t questioning Synagro,” counters Tolfree, who as a farmer earns about $25,000–$30,000 a year. “As long as they follow the 503 rules and do the proper paperwork, it doesn’t matter that a small farmer like me is irrigating out of a creek that is downstream from those fields getting sludged.”
Under federal law, the soil of sludged farmland is tested only once a year, and the EPA requires monitoring for only nine toxic metals.
At the wastewater treatment plant, state law requires that biosolids be tested every two months, says Davis of Burlington’s wastewater treatment plant. Each month, the city also tests sludge destined for farmland, even though it may not haul sludge to the farms as frequently.
However, N.C. State soil scientist Dr. White cautions that while existing regulations about sludge may have previously been adequate, “they are outdated” considering what is now in municipal waste and new information about the “potential pollutants and pathogens that may be in biosolids.”
State and federal laws govern sludge applications, but there is little oversight of the practice, and enforcement is lax.
Prior to sludge application, farmers must sign a landowner agreement with N.C. DENR stipulating that before each planting season, the landowner or a representative will inform the state about any changes in the intended use for the land. For example, if a farmer switched from fescue to corn, he or she would be required to notify the state.
However, there is virtually no oversight of the sludge application program. The operator in charge of the program inspects the site after sludge is applied, but there may be no follow-up inspection.
“The program is a self-monitoring and relies on notifications by the landowner, applier, permittee and public observation,” says Chonticha McDaniel, environmental engineer with N.C. DENR.
For example, although cattle are required to stay off a field for 30 days after sludge is applied, it’s difficult to ensure they do. Sludge can’t be spread within 24 hours of an area receiving measurable rainfall, but there’s no guarantee that the applicator will follow the law.
“There is no one out there watching,” Chiosso of the Haw River Assembly says. “If you have a truck of sludge that’s made its way from Burlington and reaches the farm just as it starts to rainor heavy wind kicks upchances are that truck isn’t going to turn around and go back; they will go ahead and spread the sludge.”
The application permits also require that “adequate provisions” be taken to prevent wind erosion and surface runoff onto adjacent land and water, but as McDaniel points out, “due to the unpredictability of the weather, rain events large enough to result in runoff from application sites do occur on occasion.” If that happens, the permittee, usually the farmer, is expected to report the violation to the state, but, again, there’s no way to monitor it.
This lack of monitoring and oversight cost the City of Raleigh millions of dollars. For years, the city applied biosolids on local sludge fields, and the runoff contaminated the Neuse River. In 2002, the state fined Raleigh $80,000 for spraying too much sludge on fields in southern Wake County. The city has since spent $15 million to extend water lines to residences that had contaminated water.
The overuse of sludge happened because “someone had put out more than was recommended,” says Tim Woody, City of Raleigh Public Utilities reuse superintendent. Moreover, federal law governing sludge applications wasn’t formalized until 1990, after much of the damage had occurred.
Woody says the city has changed its application practices, and it has added an outside environment management auditing system. “Unfortunately it takes mishaps and problems coming to the surface to get funding for implementing more on-site regulations. We don’t do the things we did 30 years ago.”
While Raleigh is constantly changing its treatment processes, Woody acknowledges there are new contaminants that are entering wastewater treatment plants. “We’re being asked to measure for things we don’t even have the instruments to measure with.”
The state Division of Water Quality itself is violating a 1992 law, the Water Supply Watershed Protection Act, by allowing fields to remain permitted for sludge application in critical watersheds in Orange, Alamance, Gaston, Caldwell, Catawba and Wake counties.
On June 21, state Sen. Ellie Kinnaird (D-Orange and Person) and the Blue Ridge Environmental Defense League called for DWQ to enact an immediate moratorium on sewage sludge being spread in those critical watersheds. DWQ did not respond to follow-up calls for comment, but Dayton says the division has not responded to BREDL’s request.
Local governments have little say-so over sludge application. Last fall, the Orange County Board of Commissioners discussed the practice but learned they are largely hamstrung by state law.
In 2006, Orange County agreed to pay $10,000 to the UNC School of Public Health to test air and water quality where sludge was being spread, but the study never happened due to what the county characterized as “complications.”
That complication is a state law that prohibits counties from regulating sludge.
According the federal Clean Water Act, sewage sludge is a pollutant and, as such, allows states to control permitting and enforcement of it. However, North Carolina doesn’t allow local cities and counties to regulate sludge in their jurisdiction, even though federal law permits it and other states have done so.
A 2005 state appellate court decision put the kibosh on local governments’ attempts to regulate their sludge. In Granville Farms, Inc. v. The County of Granville, the court ruled that state regulations are comprehensive and local laws are unnecessary. “Since that is the current law, Orange County’s options and all other counties’ options in regulating sludge are severely limited,” says Orange County Attorney John Roberts.
In Orange County, where, in 2007, 19.3 millions of sludge were sprayed on 1,817 acres, options are expensiveand onerous.
“The only way Orange County could take control of the situation would be to enact its own ordinance and then face significant and costly litigation defending the ordinance, sue the State of North Carolina, again at significant cost, or attempt to form a regional solid waste management authority with another local government,” he adds.
Regional solid waste management authorities can regulate sludge with the state’s permission, but, Roberts says, establishing such an authority would be expensive. “I don’t think any of these options are realistic at a time when Orange County is facing budget shortfalls and cutting jobs, funding and services.”
In Chatham County, the Environmental Review Board is urging county commissioners and the health department to require companies such as Synagro to notify adjacent landowners before spraying begins.
Chatham County Commissioner George Lucier, former associate director of the National Toxicology Program, says there should be a notification of intent to spray and better characterization of what’s in sludge.
“It’s important to note we won’t do anything to adversely affect the farmers in Chatham who are struggling,” he said. “Most farmers want to be good environmental stewards of their land, and they need to be given a better idea of the contents of sludge.”
Currently, landowners next to sludged fields don’t have to be notified about them, and signs alerting the public to the application are optional.
The Blue Ridge Environmental Defense League has composed a list of recommended changes to rules, although Sue Dayton says state environmental officials have not replied. The suggested changes include written notification to residents who live or own property within a one-mile radius of fields being spread with sewage sludge. If the property owner opposes the land application, the owner may request that a public hearing be held regarding the permit to apply sludge.
Other recommendations include posting signs to limit public access to fields that are being sludged.
While many of Alamance County’s citizens have spoken publicly about their concerns, Linda Massey, chair of the Alamance County Board of Commissioners, says the board has not extensively discussed the sludge issue. “The EPA is controlling that, and as long as they say it’s in compliance then I’m fine with it,” she says. “We don’t control the sludge. It’s coming from the city of Burlington, and Graham and the county isn’t involved in that. We feel like that’s what the EPA’s for. We depend on them to tell us if it isn’t OK.”
Massey says farmers should be able to choose if they want sludge applied on their fields. “They don’t have to do it,” she said. “I wouldn’t let them dump it on me if they weren’t paying me to take it.”
While Americans continue to generate copious amounts of waste, sludge application on farmland continues as the main, albeit highly flawed, solution to getting rid of it. In 1988, the EPA banned dumping sludge in the ocean after scientists discovered it was destroying marine habitats.
“Incineration promotes the generation of garbage, it does not promote conservation or reuse or the recycling of waste,” adds Dayton. She says “clean” incineration does not exist. “We are now seeing a rush to burn everything: trees, tires, garbage, manure, chicken poop, sewage sludgeeverything and anything that will burn.”
Activists stress that the laws need reformed and enforced.
In April 2009, state Rep. Curtis Blackwood, a Republican from Union County, introduced HB 1170 “Study Land Application of Septage and Sludge.” It would direct the state agriculture department to study how much sludge is being applied to farmland in North Carolina. It would also require the state to examine whether changes in the permitting process are needed to protect rural communities from the waste and whether the regulations are adequate to protect human health and the environment.
Blackwood’s bill never made it past the agriculture committee, where it died. “Someone pulled it before it even got heard,” says Rep. Blackwood, who believes the unknown properties in sludge make the product a public health concern.
These unknowns are too great for farmer and former sludge user Charles Sydnor. “I spent half of my life creating a farm that follows natural principles,” he said. “And what a horrible thing, for me to wake up and realize that I was destroying it.”
1 of 2
Photo by Rebekah L. Cowell
Cynthia Crossen and Daniel Tolfree test the water running through Millarckee Farm.
2 of 2
Photo by Cindy Sydnor
Charles and Cindy Sydnor raise cattle and on Braeburn Farm. Charles used to have sludge spread on his pastures, but has since stopped.
How human waste is helping Aussie farmers get the best out of their land
By Gavin Coote
Posted September 09, 2017 06:12:12
It’s great for agricultural crops and a bit on the nose, but it’s not your standard manure.
About 180,000 tonnes of biosolids are generated from Sydney’s sewage each year, but authorities are having no troubles with getting rid of it.
Biosolids, which is a by-product of the sewerage treatment process, is proving a hit with New South Wales farmers who want to improve soil health and boost yields.
Harvested from 23 of Sydney’s sewerage plants, the waste is processed through reactors which also create renewable energy that is fed back into the system.
It is then trucked out to about 20 farms in the state’s central west, as well as several mine rehabilitation sites.
Stuart Kelly swapped synthetic fertilisers for human biosolids on his family property at Newbridge, near Blayney five years ago.
He said his soil was healthier than ever and the farm was booming.
“My thing is healthy soils and healthy pastures is going to come back to healthy stock,” Mr Kelly said.
“If you get healthier stock, more lambs on the ground, more calves growing quicker, we’re in front.”
Mr Kelly said while he still got raised eyebrows for using the sewage, it was helping complete the production cycle between city and bush.
Soil ‘just keeps responding’
Agronomist Roger Crisp said the use of biosolids across central west farms was paying massive dividends, with stock capacity and output more than doubling for many producers.
Farmers have battled dry conditions and frosts this winter, sheep farmer Gordon Nash, biosolids have offered significant protection.
His land at Wattle Flat near Bathurst was once “just like gravel”, but now he said biosolids had significantly improved moisture retention in the soil.
“It just keeps responding, you might get 5mm of rain and it just starts producing, whereas untreated pastures, they’re just getting hammered with frosts and not doing anything,” Mr Nash said.
The NSW Minister for Energy and Utilities Don Harwin said not only was it helping the environment, but also helping to improve efficiency for Sydney customers by reducing energy costs.
Sydney Water spokesman Gavin Landers stressed using human waste on crops was safe, with no issues reported in the past two decades.
“Ironically, the production and application of biosolids is more highly regulated than any application of other fertilisers, so there’s a lot of protections in there to ensure we don’t any problems,” Mr Landers.
Turns Out That Using Human Poop to Fertilize Crops Isn’t Such a Great Idea
If you talk to its proponents, and there are lots of them, sewage sludge fertilizer is a great way to divert human waste from landfills and to grow crops, despite the unappealing picture it may conjure. The US Environmental Protection Agency has a nicer name for the muck that’s left over after processing our shit—”biosolids”—and has encouraged its widespread use as a cheap, effective way to fertilize crops and recycle human waste. But while the EPA requires that bacteria and viruses are killed off before sludge is applied to farm fields, other contaminants, like pharmaceuticals and metals, are only minimally regulated, if at all.
New research suggests this could be a problem, as contaminants are now showing up in treated sludge—and, in lower levels, even in some animals that have fed off the plants it fertilizes.
“I don’t think the present rules are even remotely adequate,” Murray McBride, a soil contaminant researcher at Cornell University, told me. “There are a lot more toxic metals on the periodic table than what they decided to regulate.”
According to him, the EPA’s rules are outdated. They regulate only nine metals with known health risks—including lead, cadmium and arsenic. And metals are just the beginning. Pharmaceuticals and other organic chemicals found in biosolids are cause for even greater concern, he said. Others agree. “If you look at what potentially regulated by EPA, it’s just a tiny fraction of the universe of the chemicals we live in,” David L. Lewis, a former EPA scientist who is now a fierce critic of the agency, told me.
“What the EPA regulates is negligible.”
Cities like San Diego turn their sewage into fertilizer. Photo: William Garrett/Flickr
EPA officials haven’t said whether the rules will be revised, but agency spokesperson Robert Daguillard noted in an email that the agency plans to assess the risks posed by pharmaceuticals in sludge. While they haven’t yet determined these risks, they do know what’s in it. An EPA sludge survey, Daguilllard said, includes “92 pharmaceuticals, steroids, and hormones.” But none of those are actually subject to enforceable limits under current rules.
For many farmers, biosolids are a cheaper alternative to synthetic fertilizers. Municipal governments like them, too: since some cities divert as much as 50 percent of sludge to farms, they can reduce the amount of waste they have to pay to landfill. San Diego, Portland and Edmonton, among many others, process their waste to produce biosolids.
It makes sense, then, that demand has been increasing. While the EPA hasn’t recently estimated the size of the market, it put biosolids production at 7.2 million tons in 2004, up four percent from six years earlier. If that growth rate has continued roughly apace, production would be near 8 million tons today. Organic farmers can’t use biosolids as fertilizer without risking their organic certification, but it’s relatively easy for others to get, often via local organizations.
Biosolids boosters say the fertilizer is effective. “If there are any small negative impacts , they are overwhelmed by the positive effects” on crop yields, said Ned Beecher of Northeast Biosolids and Residuals Association, which promotes its use. He believes that the EPA rules are adequate as-is, noting that the agency has already considered the risks posed by dozens of sludge contaminants, and judged them minimal. “Just because there is no limit set, doesn’t mean risk assessment hasn’t been done,” Beecher told me.
“What’s happening in natural environments is long term exposure to low concentrations”
Before sewage sludge is used on farm fields, the EPA requires that it undergo two processes aimed at destroying pathogens: anaerobic digestion—in which bacteria break sludge down in the absence of oxygen––and high-heat sterilization. Even so, some suggest that enough bacteria may survive to contribute to the spread of antibiotic-resistant strains. That’s a major concern, because when these “superbugs” spread in livestock farms and hospitals, disease can run rampant. And the bacteria can’t be easily killed with penicillin or other antibiotics.
Edo McGowan, a retired environmental scientist and outspoken critic of biosolids, is concerned about research showing antibiotic-resistance genes in soils treated with biosolids. These genes, he said, are easily spread by farm equipment or wind, winding up in bacteria that can be ingested by people and animals. “Some of these bugs are resistant to pretty much anything you can throw at them,” he told me.
Not all experts agree that using biosolids as fertilizer is hurting the effectiveness of antibiotics, mostly because we still don’t know how much disease resistance occurs naturally in soils. “It’s just speculation at this point,” said Marc Habash, who researches microbes in biosolids at the University of Guelph in Ontario. “Antibiotic resistance genes are in our soil. There are a lot of natively-occurring bacteria that possess these genes.”
Earthworms seem to have picked up some contaminants. Photo: schizoform/Flickr
Research has backed up some of the critics. A 2012 study led by environmental chemist Chad Kinney of Colorado State University, Pueblo, found that earthworms in soil treated with biosolids contained a variety of manmade compounds, including pharmaceuticals and personal care products, like the antibiotic drug trimethoprim (used to treat urinary tract infections and other conditions) and the disinfectant triclosan (a common ingredient in antibacterial hand soap).
Whether those synthetic compounds actually harm earthworms is unknown, and Kinney notes that the concentrations are low. But he said their presence shows that manmade contaminants in biosolids are moving up the food web. This suggests they could be reaching humans, too.
Despite his worrisome findings, Kinney said that the risks of biosolids are mostly speculative and hard to measure, while the benefits are clear: it’s a way to keep sewage sludge out of landfills and return nutrients to soil. “If sludge isn’t meeting the regulatory requirements as biosolids, it has to be disposed some way. But then you lose all that valuable organic carbon and nutrients that can be released into a soil environment.”
Any health risks associated with recycling contaminants in fertilizer and sending them up the food web may not be known for generations—if ever, according to Kinney.
Part of the problem, he said, is that most studies look only for immediate damage or death, not slower, less obvious effects like reductions in fertility. “Most of the toxicology is based on acute studies of one compound in short-term exposure,” Kinney told Motherboard. “What’s happening in natural environments is long term exposure to low concentrations, so you’re not going to see those acute effects per se. We’re not going to see typical things like lethality.”
“It’s going to be slower, subtler effects,” he said, “that have generational effects.”
Using human urine and faeces as fertiliser may seem an unappetising concept but it’s been common practice for centuries. In the sewage systems of today, which deal with millions of tonnes of domestic waste and industrial effluent, this human fertiliser comes in the form of treated sewage sludge.
Promoting a waste product that some consider hazardous as a resource to grow your food may seem like a paradox, but in Britain, a world leader in recycling sewage into agriculture, it is recognised by the government and the EU as the best environmental option. It diverts waste away from oceans and landfill and provides essential plant nutrients to the soil. Nevertheless, EU organic regulations don’t permit the use of sewage sludge on organic farms. So, what are their concerns? Is this form of manure safe for agriculture? Are we putting our health and our soils at risk when we spread human waste on land?
“1% of wastewater is waste. The rest is wasted water.”
Human urine and faecal matter are a rich source of essential plant nutrients. Historically, human excreta, ‘nightsoils’, were collected from towns and villages and spread in raw or composted form on fields in the surrounding farmland. This informal treatment is still practiced in some areas of China, South East Asia, Africa and Latin America, where municipal sewage works don’t exist or are poorly functioning. In the 1850s, Europe’s growing urban populations and the discovery of the link between raw sewage and cholera led to the implementation of large-scale sewage systems. These water-based systems combined all domestic waste, industrial effluent and road surface run-off. For the next century the resulting sewage sludge was disposed of in landfill and directly into the oceans. Eventually, in the 1970s, growing awareness of the environmental impact of sewage on aquatic life led to widespread bans on ocean dumping across the developed world. Since then, research, technology and regulation of wastewater management have progressed to a high standard.
In Britain, sewage sludge goes through a tertiary anaerobic digestion process that kills off up to 99.99% of pathogens. The treated sewage sludge this produces is referred to as ‘biosolids’ and most commonly comes in the form of dried cake digestate.
Matt Taylor is an environmental scientist and consultant at ADAS, Britain’s largest independent provider of environmental solutions, services and consultancy on recycling materials to land. He says that “the most common outlet for biosolids is agricultural recycling. Around 1 million tonnes of dry solids (that’s equivalent to 3.5 million tonnes of fresh solids) were used as fertiliser in 2013.”
Biosolids can increase agricultural yields and improve soil condition. They provide nitrogen, phosphorous and potassium in a less soluble form than farmyard manure and artificial fertilisers, which means they remain in the soil for longer and are less prone to leaching into groundwater or run-off, which pollutes waterways. Biosolids also contain useful levels of sulphur and magnesium and trace levels of micronutrients. Unlike artificial fertilisers, biosolids contain 20%–80% organic matter, which is critical for the health of soils.
Could biosolids replace our reliance on artificial fertilisers?
Manufacturing fertilisers requires fossil fuels, so as the price of fuel increases this has a knock-on effect for the price of artificial fertilisers, food production and ultimately the price of food. Our reliance on mined phosphorous is a major concern. The extraction of phosphate rock is not only a very toxic and energy intensive process but it’s also a non-renewable resource that’s predicted to reach peak supply in 2033. After that the price of phosphorus will increase significantly, bringing the price of food up with it. According to the Soil Association’s peak phosphate report, without mined phosphate, crop yields in conventional farming could be reduced by half.
On a global scale we could be recovering much more phosphorus from human waste. It’s estimated that only 10% of the phosphate lost from human excreta is recycled back to the land due to inefficiencies in wastewater treatment or the absence of wastewater treatment altogether. Results from a 2009 study in Chemosphere suggest that, if properly collected, the phosphorus available from urine and faeces could account for 22% of the total global phosphorus demand.
Already in Britain we recycle 77% of our sewage onto agricultural land. Could biosolids eventually replace the need for artificial inputs?
According to Taylor, “biosolids can play a role but it’s not going to replace other forms of fertiliser. We could do more but we are using the vast majority of sewage sludge already.” However, with improved technology we could extract more nutrients. “We’re getting more phosphorous out of waters in the form of struvite. This is a mineral build up on pipes, which causes blockages in pipelines. Thameswater has started harvesting this struvite as it contains phosphorous.”
Wastewater treatment is improving all the time in Britain as regulations become more stringent and require treatment plants to remove more nitrogen and phosphorous from sewage. As a result the volume of biosolids produced is increasing every year, making more fertiliser available for agriculture.
But is it safe?
There are understandable concerns from farmers, consumers and food retailers about pathogens, heavy metals, pharmaceuticals and other hazardous organic chemicals in sewage sludge. The good news is that biosolids are the most researched and well regulated of organic materials applied to land in Britain and the framework for regulating sewage sludge is more stringent than that of farmyard manures. Numerous pieces of legislation and best practice guidelines, like the Safe Sludge Matrix, must be adhered to by everyone involved in the treatment and use of sewage sludge.
Heavy metals are the main concern. These are strictly monitored, however, and regular testing shows that the levels of heavy metals in soils fertilised with biosolids are significantly below the maximum permissible levels. In fact the levels are so low now that the Soil Association has recommended the European Commission lifts the ban on using biosolids in organic farming. The Soil Association still recognises that the existence of other potential contaminants from organic compounds, such as GMOs and pharmaceuticals, need to be considered.
But there’s still a big question mark hanging over the impact of industrial chemicals and personal care products in domestic waste as well as the huge amounts of medicines that pass through the human system. Whilst the vast majority of these are biologically degraded in the treatment process, trace levels of some persist.
WaterUK, a member organisation of the water utilities, states “there are no reported cases of human, animal or crop contamination due to the use of sludge on agricultural soils.” Yet studies have found the artificial hormones used in birth control pills affect the endocrine systems of fish exposed to sewage effluent water, which affects fish fertility. There’s concern about how this would affect livestock that graze on grassland treated with sludge. Despite the lack of scientific evidence to prove long-lasting damage, there is also not enough evidence to prove it’s 100% safe either.
Sanitation fit for the future
The risk of chemical contaminants and pharmaceuticals could be reduced by preventing human waste from mixing with all other domestic and industrial waste in the first place. Ecological sanitation systems are starting to come into use all over the world that separate human excreta from other waste streams. Ecological sanitation (ES) includes urine diverting toilets, high-tech vacuum systems and composting toilets. These inexpensive systems can be used in various contexts from small villages to large municipalities. ES separates greywater, human faeces and urine and stores them in underground tanks.
A great advantage of ES is this separation. The majority of nutrients in human excreta are in urine – if uncontaminated by faeces it’s relatively sterile and can easily be used on crops with little treatment. This low-cost solution makes most sense in rural areas where houses are not connected to centralised sewage systems or in close proximity to agricultural land.
It’s harder to justify the cost of retrofitting ES into existing centralised sewage systems that already supply safe drinking water and recycle waste to a sufficient level. WaterUK estimates the total value of nutrients in biosolids recycled to agricultural land in Britain at £40–£50 million per annum. The value of preserving life in our oceans, the health of our soils and the quality of our water is priceless, and as water and energy become more scarce and costly, and phosphorous reserves run out, ES could become a much more attractive and cost-effective prospect.
According to the UN 90% of wastewater in the developing world is expelled, untreated, into the oceans. Whilst rich countries have had the finances and governance to manage sewage effectively, there’s still a long way to go in making this universal. How will we, as a global community achieve it? Perhaps that will give you something to ponder when you’re next on the toilet.
Photograph: Chesapeake Bay Program
Sign up to our Newsletter
Stay up to date with the latest SFT views and news