RSS FeedApr 30 2009
Composting Toilets: All You Ever Wanted To Know
Many people have a lot of misconceptions when they hear the words “composting toilets”. Immediately they think “outhouse” or imagine a hole in the ground. Yucky, smelly, and a little drafty.
Well, the composting toilets of 100 years ago (the outhouse) and the composting toilets of today are completely different creatures.
Today’s composting toilets are sleek, efficient, and entirely odor-free. So hang on. We’re going to go take an in-depth look at our stinkier side, and learn how composting toilets can allow us to become more eco-friendly and completely “waste free”.
The Facts On Our Waste
According to the Environmental Protection Agency, septic tanks are a big cause of groundwater pollution. On average, a family of 4 puts 150 gallons of water into a septic tank each day.
According to the Environmental Protection Agency, septic tanks are a big cause of groundwater pollution. On average, a family of 4 puts 150 gallons of water into a septic tank each day.
You’ve probably never really thought about it, but where does all that water go, anyway?
Well, septic tanks are designed to have a “leach field” or “drain field” around them. Here’s how it works:
Most septic tanks are 1,000 gallons or larger. Wastewater flows in the tank on one end, and is drained into the surrounding area through the other.
At the bottom is the sludge layer. I’ll let your imagination tell you what’s down there.
At the top is the scum layer (no I did NOT make up these terms, that’s really what it’s called).
In the middle of those two yucky layers is the wastewater that gets drained out. That is, the excess water is drained into the dirt below, and the solid “waste” is left behind to dissolve in the tank.
Think that excess water is 100% pure? Hardly. It’s loaded down with pollutants like bacteria, phosphates, and nitrates, all of which harm local watersheds. Yuck.
According to the “Humanure Handbook“, up to 1,460 billion gallons of this water is leached out of septic tanks each year in America.
That’s an awful lot of dirty water that’s going into our streams and rivers. Yikes.
Now, the soil is a natural filter. Out in the country, there’s plenty of open space for the land to naturally filter all these contaminates out. The problem comes in densely packed urban areas, such as subdivisions. If 30 homes in a neighborhood all have a septic tank, the soil can’t handle all the leach water. So, pollution occurs.
Benefits To Using A Composting Toilet
The cool, amazing thing about composting toilets is that they cut all of this mess out. There’s zero pollution, zero waste, and zero lost water.
Here’s the rundown:
Envirolet estimates that composting toilets reduce household water use by 60%
In fact, Sun-Mar composting toilets estimate that an average family of four flushes 70 gallons of water down the toilet every day, which is a whopping 25,000 gallons per year. They estimate that based on all the composting toilets they’ve sold in the past, their company alone is saving 6,103 gallons of water every minute.
They also keep you from “depending” on your septic tank or city wastewater treatment facility. Ever been in a natural disaster, when the city couldn’t process your water (and thus you couldn’t flush your toilet)? That dependence is completely eliminated with compost toilets.
You can also use the system to compost food scraps and lawn clippings. Try putting those things down your current toilet. Yeah right.
They’re truly environmentally friendly. Neat.
Now the only downside here is that if you live in an apartment, or you’re renting a home, installing a composting toilet isn’t going to be an option. But perhaps your landlord might be interested to hear just how much water these babies save per year. Those savings really add up, and these composting toilets pay for themselves in just a few years.
How Do Composting Toilets Work?
Composting toilets work by quickly dehydrating 90% of the liquid that’s in our waste, and then composting the remaining 10% solids that are left. We can then use those solids, called “humus”, as additive for lawns.
Think I’m kidding here? It’s no joke. You really can turn your poo into garden soil. Let’s continue onward for more detail…
Types of Composting Toilets
There are 2 broad “types” of composting toilets.
Batch systems, or self contained systems (like the picture up above, on right), are “all in one” units. The waste is composted in a tray at the bottom. See that pipe sticking up behind the toilet? That a ventilation pipe. A small wind turbine that’s at the top of that pipe, on your roof, is what keeps the unit completely odor-free.
These systems are designed for lighter use (two person households, or occasionally used vacation cottages). They’re completely waterless. And don’t worry; when you lift up the lid, you don’t see what’s composting in the tray. These toilets have a cover that separate your eyes, and your bum, from what’s being broken down below.
Another perk to these system is that they require no winterization. If you live in a cold climate, then you don’t ever have to worry about your pipes freezing.
Batch systems may only have one tray for composting, or they may have several depending on which model you choose. And how often you have to empty these trays largely depends on how much you use the toilet, and how many people are in your household.
Continual process systems are designed for larger households (pic on right). These can handle more waste, and are perfect if you have a basement or your house is built above ground.
The picture on right is part of a waterless system by Envirolet. It can handle waste from up to 10 people per day, and only has to be emptied every six months or so.
Low Water Systems
Some companies, such as Envirolet, also make low water composting toilets. If you squirm at the thought of letting your waste just go down a hole, then you might want to consider these systems.
They work on the same design as the continual process systems in the sense that there is a large composting unit outside the home. But the difference is that your waste is “flushed” down with a mere pint of water. With the Envirolet system, you can install up to three low flush toilets on one line.
Can I Put Toilet Paper Down There?
As far as I can tell, you can put unbleached toilet paper into composting toilets. But, feminine hygiene products are a no-no.
How Much Do Composting Toilets Cost?
Composting toilets run anywhere from $500 to $2,000. Just like anything else, you’ve got your choices. Every brand and maker is different, and they’ve all got different bells and whistles.
Of course, you could try making your own for far less money. Many people do (see the Resources section below…)
Composting Toilet Resources
These vendors make good composting toilets:
And here’s some resources if you want to try making your own…
Last Word…
I never, ever thought I would actually have “feelings” for a toilet, but I truly love these systems. You can bet I’m incorporating a waterless compost toilet into our micro home design, and I can’t wait to get one!
Many people have a lot of misconceptions when they hear the words “composting toilets”. Immediately they think “outhouse” or imagine a hole in the ground. Yucky, smelly, and a little drafty.
Well, the composting toilets of 100 years ago (the outhouse) and the composting toilets of today are completely different creatures.
Today’s composting toilets are sleek, efficient, and entirely odor-free. So hang on. We’re going to go take an in-depth look at our stinkier side, and learn how composting toilets can allow us to become more eco-friendly and completely “waste free”.
The Facts On Our Waste
According to the Environmental Protection Agency, septic tanks are a big cause of groundwater pollution. On average, a family of 4 puts 150 gallons of water into a septic tank each day.
According to the Environmental Protection Agency, septic tanks are a big cause of groundwater pollution. On average, a family of 4 puts 150 gallons of water into a septic tank each day.
You’ve probably never really thought about it, but where does all that water go, anyway?
Well, septic tanks are designed to have a “leach field” or “drain field” around them. Here’s how it works:
Most septic tanks are 1,000 gallons or larger. Wastewater flows in the tank on one end, and is drained into the surrounding area through the other.
At the bottom is the sludge layer. I’ll let your imagination tell you what’s down there.
At the top is the scum layer (no I did NOT make up these terms, that’s really what it’s called).
In the middle of those two yucky layers is the wastewater that gets drained out. That is, the excess water is drained into the dirt below, and the solid “waste” is left behind to dissolve in the tank.
Think that excess water is 100% pure? Hardly. It’s loaded down with pollutants like bacteria, phosphates, and nitrates, all of which harm local watersheds. Yuck.
According to the “Humanure Handbook“, up to 1,460 billion gallons of this water is leached out of septic tanks each year in America.
That’s an awful lot of dirty water that’s going into our streams and rivers. Yikes.
Now, the soil is a natural filter. Out in the country, there’s plenty of open space for the land to naturally filter all these contaminates out. The problem comes in densely packed urban areas, such as subdivisions. If 30 homes in a neighborhood all have a septic tank, the soil can’t handle all the leach water. So, pollution occurs.
Benefits To Using A Composting Toilet
The cool, amazing thing about composting toilets is that they cut all of this mess out. There’s zero pollution, zero waste, and zero lost water.
Here’s the rundown:
Envirolet estimates that composting toilets reduce household water use by 60%
In fact, Sun-Mar composting toilets estimate that an average family of four flushes 70 gallons of water down the toilet every day, which is a whopping 25,000 gallons per year. They estimate that based on all the composting toilets they’ve sold in the past, their company alone is saving 6,103 gallons of water every minute.
They also keep you from “depending” on your septic tank or city wastewater treatment facility. Ever been in a natural disaster, when the city couldn’t process your water (and thus you couldn’t flush your toilet)? That dependence is completely eliminated with compost toilets.
You can also use the system to compost food scraps and lawn clippings. Try putting those things down your current toilet. Yeah right.
They’re truly environmentally friendly. Neat.
Now the only downside here is that if you live in an apartment, or you’re renting a home, installing a composting toilet isn’t going to be an option. But perhaps your landlord might be interested to hear just how much water these babies save per year. Those savings really add up, and these composting toilets pay for themselves in just a few years.
How Do Composting Toilets Work?
Composting toilets work by quickly dehydrating 90% of the liquid that’s in our waste, and then composting the remaining 10% solids that are left. We can then use those solids, called “humus”, as additive for lawns.
Think I’m kidding here? It’s no joke. You really can turn your poo into garden soil. Let’s continue onward for more detail…
Types of Composting Toilets
There are 2 broad “types” of composting toilets.
Batch systems, or self contained systems (like the picture up above, on right), are “all in one” units. The waste is composted in a tray at the bottom. See that pipe sticking up behind the toilet? That a ventilation pipe. A small wind turbine that’s at the top of that pipe, on your roof, is what keeps the unit completely odor-free.
These systems are designed for lighter use (two person households, or occasionally used vacation cottages). They’re completely waterless. And don’t worry; when you lift up the lid, you don’t see what’s composting in the tray. These toilets have a cover that separate your eyes, and your bum, from what’s being broken down below.
Another perk to these system is that they require no winterization. If you live in a cold climate, then you don’t ever have to worry about your pipes freezing.
Batch systems may only have one tray for composting, or they may have several depending on which model you choose. And how often you have to empty these trays largely depends on how much you use the toilet, and how many people are in your household.
Continual process systems are designed for larger households (pic on right). These can handle more waste, and are perfect if you have a basement or your house is built above ground.
The picture on right is part of a waterless system by Envirolet. It can handle waste from up to 10 people per day, and only has to be emptied every six months or so.
Low Water Systems
Some companies, such as Envirolet, also make low water composting toilets. If you squirm at the thought of letting your waste just go down a hole, then you might want to consider these systems.
They work on the same design as the continual process systems in the sense that there is a large composting unit outside the home. But the difference is that your waste is “flushed” down with a mere pint of water. With the Envirolet system, you can install up to three low flush toilets on one line.
Can I Put Toilet Paper Down There?
As far as I can tell, you can put unbleached toilet paper into composting toilets. But, feminine hygiene products are a no-no.
How Much Do Composting Toilets Cost?
Composting toilets run anywhere from $500 to $2,000. Just like anything else, you’ve got your choices. Every brand and maker is different, and they’ve all got different bells and whistles.
Of course, you could try making your own for far less money. Many people do (see the Resources section below…)
Composting Toilet Resources
These vendors make good composting toilets:
And here’s some resources if you want to try making your own…
Last Word…
I never, ever thought I would actually have “feelings” for a toilet, but I truly love these systems. You can bet I’m incorporating a waterless compost toilet into our micro home design, and I can’t wait to get one!
Anna Edey’s “Solviva” book and website (http://www.solviva.com/) are a bit of an eye opener on the subject of the harm done by septic tanks and also interesting on other more-or-less related topics.
My wife and I own a Sun-Mar Excel (the 120 Vac model, not the NE). I would not recommend it. Do yourself a favor and look elsewhere.
It has failed and leaked raw sewage three (3) times now. The first failure was the very first time it was used (after about 4 or 5 days’ part-time use)!
What happens is the heater t-stat fails. The toilet relies on both heat and air flow to evaporate excess liquid. When the heater fails, there is no warning. Liquid builds up in the base and when it reaches the bottom of the clean out drawer it leaks out onto the floor. That’s your first and only indication that something is wrong.
Sun-Mar’s response has been to replace the t-stat — leaving us to clean up a foul disgusting mess and deal with the resulting property damage. They act like they are doing us a favor.
Keep in mind that our Excel is installed in a guest room above our garage. It gets very little use — nowhere near the 3/4 adults fulltime that Sun-Mar claims its capacity to be.
Based on our experience I cannot imagine that the NE would work any better. After all, it has no fan and no heater. Each time ours failed the fan was still working, so it had as much or more airflow as the NE would under ideal conditions.
These toilets do have an “emergency drain”. We were told several times by a Sun-Mar authorized dealer that there was no reason to
hook it up unless we were going to be overloading the toilet or there were extended power outages (neither is the case). Now, after the sale, Sun-Mar is saying that it should be hooked up.
Here’s the problem — we would not have purchased the Excel if we had known we would have to rely on the emergency drain, for several reasons:
1) It is against our local health department regulations. Frederick County, MD, does not even allow grey water systems and this
is BLACK water, urine and feces.
2) We live on a mountain. Most of the land in our area will not pass a ‘perc test’. In many cases people cannot build because a septic system simply will not work.
3) Even _if_ we could get permission from Frederick County to install the “recycling bed” (aka cesspool), the soil is clay and rock. Digging is extremely difficult.
4) Due to the nature of the soil, the slope, and the fact that water typically runs down the mountain just under the surface, a “recycling bed” (essentially a small cesspool) would likely be an unsanitary health hazard.
5) In the winter the drain line would freeze and we would have the same problem.
Sun-Mar’s dirty (literally) little secret is that their toilets are not fail-safe. There is no warning that the heater has failed and/or that liquid is building up in the base. Therefore, the “emergency” drain must be connected. I repeat, it MUST be connected.
This puts Sun-Mar in a tight spot. If they were honest and told prospective customers the truth — that the drain must be connected to a home-made cesspool to prevent indoor ‘haz-mat’ spills — it would cut into their sales because many/most people in the US could not legally do that. Many prospective customers who aren’t necessarily concerned with the law would still be unwilling to buy a Sun-Mar because of the work/cost involved in digging a cesspool and installing a drain line between it and the toilet, below the frost line (generally 32″ or deeper depending on location). Others may be willing to ignore the law and willing to do the work (or pay a contractor) but do not have the proper soil conditions (the ground will not absorb the moisture).
Sun-Mar is fully aware of all of this. They have chosen to mislead people. The owner of Sun-Mar apparently thinks that by “suggesting” or “recommending” that the drain be connected they are covered. If a county, state, or federal agency says anything Sun-Mar can legitimately claim that they did not say the drain _must_ be connected. If a customer (like yours truly) has a toilet that fails (over, and over again) causing putrid raw sewage to leak onto the floor, Sun-Mar can point to their literature and say that they ‘recommend’ that the drain be connected.
The bottom line is this:
The Sun-Mar Excel does work, most of the time. It is a pretty good design, but it has a fatal flaw — it is not fail-safe. No piece of equipment is perfect. Everything has failures eventually (or immediately in my case). That’s to be expected. A well designed composting toilet should be fail-safe — it should produce an audible and/or visible alarm when there is a failure. There is simply no excuse not to have some indication that there has been a failure that will result in unsafe, unsanitary leakage of urine and feces into a living space where children and pets could come in contact with it.
For that reason, the design of the Sun-Mar Excel (and many/all of their other toilets) is unacceptable. I am shocked that it received and still has NSF certification. It makes me wonder how seriously to take the NSF. I have to wonder if their “certification” can be bought.
My wife and I are now considering an Eco-let toilet, but I don’t know enough about them to recommend them just yet.
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