TH Forums Highlights: Water Conservation, Eating Out + More
by Collin Dunn, Corvallis, OR, USA on 10.22.07
1) With widespread droughts and water conservation high on the list of hot topics these days, Forums user Wayneburg wants to know how to save the water that goes down the drain while waiting for the water to get hot. "In the past I've put a pot or bucket under the tap until the water has gotten to the right temperature. I plan to build my own home and I would like to know if there are products or ways of setting up the plumbing in my new home that will prevent this loss of water?" Shorter distance from heater to tap and insulated pipes have been suggested; anyone else?
2) User Wayneburg is back, hoping to save lots more water with an anaerobic digestion system instead of toilets. "Anaerobic who-what? It's a waste disposal system that is similar to a composting toilet, but it traps all the gases that are created when the sun heats up the holding tank and bacteria breaks down the organic waste...that gas can be bottled up and sold as 'BioGas,' an alternative to natural gas or methane." Interesting idea, but talking about it is a lot easier than implementing it, unfortunately, and Wayneburg is having a tough time finding more info or plans to get it done. Can anyone help?
3) Lastly, Forums user Wai wants to talk about the green pros and cons of eating out. "Is there any reason that eating out might be more green than cooking and eating at home? Suppose I can walk to a local restaurant, can I assume that the way a restaurant cooks is almost more efficent and thus more green? Or are restaurants almost always more wasteful overall?" Lots of "what ifs" here, and answers that come down on both sides of the debate, so far. Where do you stand?
Not sure about a billion Chinese using these anaerobic digestion system throughout china. I've been cycling my recumbent trike around China for over a year now. www.chinawheelie.com I've cut through about 15 provinces and have never seen one. The system they appear to use is quite simple. Poop in a hole, or pit. Thats it. No trapping of gas, no parp powered stoves. I may have missed something though, but most of rural China functions more simply than this system. I am very intrigued now. I thought there were few mysteries surrounding toilets in China.... it seems that I may have been terribly wrong.
http://www.cityfarmer.org/biogasPaul.html
According to the above website, 5 million people use them throughout rural China. Thats about 0.4% of the population.
The way I think that it could go into a tank, is that you go to the toilet that has a 60 degree slope and IT slowly makes its way towards the bottom. Above this is the capture dome. These slopes are standard issue in many public toilets so perhaps behind these walls are collection units. I doubt it though. They may well be more prevalent in the west of china.. I have yet to see. A lot of untreated waste goes straight out as fertilizer.
Going to the toilet and toilets themselves in China do not have the same stigma or embarrassment attached as they do in the west. It is simply a function, one that can be harvested a little (or a lot). Toilets are very public and no one seems to care about another person seeing them. No doors, no divisions. Hence the no mysteries. A real horror story for many readers, but with no flush function or sewage systems it saves a hell of a lot on water wastage. It could do with a few improvements though, but essentially its very back to basics and good for nature.
China may well be an ecological nightmare on many fronts, but naturally people in China do not like to waste anything at home. They are natural born recyclers, stemming from an ingrained necessity. They are an amazingly practical and pragmatic people. For example there are Solar water heaters on almost every family home. Electric bikes are everywhere in cities.
China is now experiencing the infinite repercussions from its fast development, but it is also changing incredibly fast to cope with it. When things change in China they happen on a mammoth scale. When something takes off it takes off everywhere. Things that take 10 years to do in the west can be done in 1 year in China. Giant construction projects to enforced government policies. If directed in the right way it is an incredible opportunity to go very green.
Eating out is a "good thing" in terms of driving innovation because it centralizes the waste production and energy use. Because the electric bill or gas bill for a restaurant is astronomically higher than the one I have at home, they'll benefit more from reducing said bill (and see faster break-even on technologies to do so).
Also, it's easier for a municipality to regulate restaurant waste (and Seattle does) than to regulate personal waste.
I have a refrigerator again, but used to simply leave mine unplugged. It's likely I'll do so again in the future. At that point the benefit to eating out (although likely only if I walk there) is clear.
Incorporating a methane digester into a single residence will likely be quite difficult from a regulatory standpoint, but it's worth pursuing.
The Mother Earth News had numerous articles on this about 30-35 years ago. They even published a book around it. A lot of the work was being done in India. One of their designs involved using recycled nesting propane tanks in a water bath to serve as the gas accumulator. I built a 1 gallon proof of concept version and it worked fine.
Getting waste from the house to the digester is likely the most problematic aspect of the project. You need to minimize flushing and transport water. You also must eliminate the possibility of smells and gasses from backing up into the house. People die from methane asphyxiation in manure pits on farms every year.
Functioning plumbing traps are essential. But these are only meant to restrict unpressurized gasses. So you need to separate fully the biodigestion side of things.
Methane is obviously quite explosive, so system design that ensures adequate safety is critical.
Fertilizer produced as a byproduct from biodigestion is self sterilized and will have fewer pathogens than raw waste. It will have heavy metals and other materials that are concentrated in humans and not broken down anaerobically. However, it should not be used where people will come into direct contact with it or eat food grown directly from it.
A sewage grinder/ejector pump may work for the transport aspects. Or to use a Clivus-like toilet and then batch transport the waste periodically to the digester may be the simpler solution.
You should do the calcs to see just how much gas is likely to be produced by your family's contributions. It may not be enough to justify the effort involved. Biodigestion could be very useful on a multi-family or neighborhood level. It would also be ideal for feed lots and hog farms, where waste lagoons are one of the most egregious environmental problems.
Good luck, and send updates on what you find, please!
Saving water at the tap is pretty easy, and hard at the same time. On-demand instant water heaters only produce heat when the water is running, but cannot usually provide hot water to an entire house so houses usually have several installed close to the bathrooms reducing the distance traveled and reducing wasted heat.
Downside, even a single instant heater can be hundreds more expensive than a conventional tank water heater, and you'll likely need more than one. Consider it a long-term investment.
Alternatively, when pluming the house, you can plumb it so that hot water slowly circulates the house in insulated pipes. The water starting from the tank, traveling from one sink/shower to the next before returning to the tank. This could be powered by a small pump, possibly even solar/battery powered. It would give you instant heat, minimal energy loss, and with potentially significant equipment savings.
Downside: Recirculating hot water really has to be built into a new home, as retrofitting would not be fun.