AKA Sullage
Greywater Gray water

By now most people have heard of grey water recycling. It means reusing water that you've used once, and there are all sorts of new technologies coming out, and it saves water... And that's about all most people know. It's easier to buy a composting toilet than a toilet that recycles grey water. It easy to save rainwater running off your roof to water your garden, but much harder to find information on how to use water running down the drain for the same purpose. Grey water recycling is a great idea that has completely failed to take off. Maybe a writeup on Everything2 will help...

First off, grey water is dirty water. Not really dirty water; grey water comes from shower drains, kitchen drains, and washing machines. Water from toilets and water containing toxic chemicals are black water, and are not as useful as grey water. While grey water is too dirty to use for cleaning or drinking, it is still uncontaminated enough to be useful for some household or industrial purposes. Grey water can be used for gardening, irrigation, and flushing toilets, often with little or no treatment.

One of the biggest challenges in reusing grey water is avoiding bacterial growth. Most grey water has some bacterial contamination, some sort of nutritional content, and it is often warm; perfect for growing bacteria. This makes grey water a potential health hazard, and also stinky. If you are releasing the grey water directly (for example, draining it directly into your garden) you are probably fine, as long as the water is absorbed completely into the soil (it should not be left to pool). It should not be used to water plants that will be eaten raw, especially root vegetables and herbs. You might also have to worry about local regulations dictating the disposal of wastewater, which may restrict both acceptable sources and uses of grey water.

If you are storing the grey water for more than 24 hours you will need to filter and/or treat it in some way. This can involve some fancy equipment, but it doesn't need to. You can disinfect grey water with chlorine, iodine, or bleach. None of these are really good for the environment or your garden, but you don't want to be spreading giardia and other nasties. Chemically treated water is often used to flush toilets. You can also build your own filter; you may wish to do this even if you are using the water immediately, as grey water can contain bits of food, hair, and grease that may do your irrigation system / toilet / plants harm. These filters can be anything from an old sock to a homemade sand filter, but even the best homemade filter will leave some bacteria in the water.

Toilets: Your toilet uses a lot of clean, drinkable water just to empty itself. Unfortunately, there is no neat and cheap way to use grey water for flushing. You don't want to pump grey water into the toilet tank if it is also connected to the house water supply, as it may contaminate your water supply. You also don't want to leave grey water in your tank for very long, lest the bacteria start to stink. (On the plus side, you can chemically treat the water in the tank all you want).

If you are rich and environmentally conscious (great combination!), you may want to simply buy a high-end composting toilet; these are not connected the the house's drainage system, so if you are careful in the soaps you use for dish- and clothes-washing, you can then convert your house's entire wastewater output to grey water. But good composting toilets are both big and expensive. You can also filter and treat all your grey water, and then use it to flush your toilet, but this requires extra plumbing and more expensive filters.

If you are earthy but not rich, you can keep using your standard toilet, but use grey water to flush by simply dumping a bucketful of grey water into your toilet bowl whenever you wish to flush. Not high tech, but effective. You may have to clean your toilet more frequently to keep the grey water residue from growing something unpleasant.

Gardens: Using grey water for gardening is a complex subject; every gardener will have to judge for themselves how clean they want their grey water to be. You can simply drain your sink/shower/washer into your garden, and let the water soak into the ground. This is rather unsanitary, and should not be done if you are eating any of the plants raw or selling them to be eaten. It's fine for flower gardens and landscaping, but still should not be applied by spraying, as airborne droplets may carry bacteria. You can introduce any level of filtering from an old sock over the drain that filters out food particles to a thousand dollar water purification system that will render your water cleaner than the municipal water.

All of the chemicals used to treat grey water are potentially harmful to your plants, although not necessarily deadly. If you are on municipal water you probably have some chlorine in it; this hasn't killed off your plants, but they might do a little better if you filtered out the chlorine. You can get a good chlorine-removing filter for about US$70, but you can't feed raw grey water into this filter. You'll need yet another filter to catch food and grease particles.

Your best bet for watering your garden with grey water is to filter it though a sand filter (you can build it yourself), and then run it under your garden through a modified French drain; bury a perforated pipe in a shallow trench, and cover it with mulch. This water won't be drinkably fresh, but it will be reasonably sanitary, and because it stays underground it won't allow spray to contaminate leaves and fruit. It should not be used to water root vegetables. If you are willing to go to a little (or lot) more expense, you can build a grey water septic tank. A septic tank will clean grey water the same way it cleans the black (toilet) water, and this water can then be used on your garden. (But do not use the same septic tank for grey water and black water!)

Also be warned -- grey water is alkaline, so do not use it on plants that need acidic soils.

Choosing your poisons: Grey water has all kinds of nasty stuff in it. Triclosan is found in many soaps, and breaks down into dioxins and chlorine gas. Some cleaners use boron (borax), which kills plants, or sodium, which is bad both for plants and for soil. You can limit yourself to biodegradable, biocompatible, and natural soaps and detergents, which will not harm any plants (or toilet bowls, for that matter). These are slowly becoming more available, but are still often hard to find, more expensive, or less effective then traditional cleaners. If you don't want to go the rainforest-herb route, you can still adjust your soap usage to be kinder to your soil.

• Laundry Detergents: Avoid detergents that include sodium and borax. Liquid detergents are usually better than powdered, as sodium is used as a filler in many powdered detergents.
• Bleach: chlorine bleach or bleach using sodium perborate aren't good for your plants. Use liquid hydrogen peroxide when possible.
• Hand and Dish Soaps: Most of these are okay. (Shampoo too.) Don't use more than you need to, and avoid those that include triclosan (it will say somewhere on the back label). Remember, you don't need antibacterial soap to wash the dishes or take a shower.
• Chemicals: Life is full of chemicals, from nail polish remover to used motor oil. Use common sense, and when possible avoid putting anything odd into your grey water.

Heat recovery: Water isn't the only thing going down the drain. When you take a hot shower a lot of heat is lost down the drain, and even if you aren't recycling the water you can still recycle the heat. For a few hundred dollars you can buy a spiffy little section of copper pipe that will transfer heat from the wastewater to the water heater, saving energy and increasing the amount of hot water you can get from the hot water heater at one go. This is essentially a smaller copper pipe wrapped in a spiral around a central, straight shaft. This shaft feeds into the hot water heater, and the shower drains through the spiraling pipe; heat from the wastewater passes through the walls of the pipe and reduces the amount of heat that the hot water heater will need to add to the water to get it up to full temperature.

Gee, Tem, that didn't help me at all! Well, yes. Unless you live in a rather arid climate, you probably aren't going to be recycling your grey water, especially if you don't have a yard. It just takes too much time, planning, and money, and water is still insanely cheap. While your city planners may wish that there was some way to reduce the amount of sewage coming down the pipe, and farmers in your area may dearly wish that all the water wasn't being gobbled up by the cities, the fact is that no one has yet figured out a good and inexpensive way to use grey water recycling in the average household. In the meantime, we should all work on our water conservation.

I would love to see some examples of good grey water usage posted here. You can also /msg me with tips and ideas, and I'll add them to my node.

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rootbeer277 reports a toilet top sink from Japan that drains directly into the toilet. It is an excellent invention, and not too expensive either, at US$89 (before shipping). It is a little unergonomic, as you have to reach over the toilet bowl to wash your hands, and it may be of more use in public restrooms than in your home (it would be awkward to brush your teeth or dye your hair in it). It would be perfect for that little half-bath that never has enough room.

http://www.gaiam.com/product/eco-home-outdoor/energy-efficient-climate-control/energy-saving-tools/toilet+lid+sink.do

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Here are some sites to give you ideas for DIY water filters. Do it, I dare you!

http://www.uas.coop/node/175
http://www.reuk.co.uk/Sand-Filters-for-Greywater.htm
http://www.instructables.com/id/Water-Recycler-Grey-Water/
http://hurricanecandice.wordpress.com/2007/12/04/diy-grey-water-system/
Thanks to Oolong for the bathtub-filter ideas!

Gravity got you down?

Does the existence of gravity weigh heavily upon you? Does the incessant pulling of planet earth on your shoes get you down? Are you frustrated by your inability to fall towards the ground at high speeds and miss? Perhaps you are beginning to believe that gravity has you trapped like a rat; a flightless rat, with neither a Saturn V, nor a space shuttle to boot.

 

Fear not, dear reader. For I am about to teach you how to defy the Earth's heavy handed grip on you and your possessions.

Find a balloon. This may be the most difficult part of your task, as balloons are skittish creatures; they are known to explode with little or no notice. Beware.

Inflate the balloon using ordinary air. Using helium would clearly be cheating; you don't want to lie to yourself about this sort of thing.

Rub the balloon in your hair, or in the hair of a nearby dog or child.

Continue doing so until the balloon has accumulated sufficient static charge. Try to avoid accidentally discharging the static electricity by touching metallic objects, or other people.

Now for the moment of truth: take the balloon, and stick it onto the wall. Bask in your own amazing abilities and the wonder of the natural world as it sticks there, defying gravity for the entire world to see.

 

So, why does it work?

There are two forces acting on the balloon. The first is gravitational force, which is pulling the balloon towards the center of the earth. But, there are clearly other forces at work here, since the balloon isn't falling. When the balloon rubs through your hair, electrons jump from your hairs to the surface of the balloon; this gives the balloon a negative charge since there are now more electrons in the balloon than there are protons (the number was equal before the hair rubbing).

It is a well known fact that opposite charges attract while like charges repel. When you bring the balloon near the wall, the electrons in the wall are repelled by the negatively charged balloon, leaving that area of the wall with a positive charge. The end result is that the negatively charged balloon is attracted to the positively charged wall with more force than gravity can possibly muster.

Both electrical and gravitational force vary inversely with the square of the distance between the two objects/charges; to find the force you simply take the product of the masses or charges, divide by the square of the distance (taken from the centers of the two objects) between them, and multiply by a constant. The mass of the earth is 5.9743 x 10²⁴ kg, and its radius is 6,377.83027 km, which is the approximate distance from the balloon to the earth’s center. Let’s say that your average balloon is four grams (.004 kg), and that the charge on the balloon courtesy of your hair is 5*10^-7 C (coulombs)*. For the sake of argument, assume that the balloon has a radius of .1m, and that the charge induced in the wall by the balloon is also 5*10^-7 coulombs. Thus:

F_g = G(Mm/r_e²) and F_e=k(Q₁Q₂/r_b²) where G is the universal gravitation constant, 6.670 x 10^-11 Nm²/kg² and k is Coulomb’s constant, 8.99 x 10⁹ Nm²/C².

Plugging the above numbers into our respective equations and consulting google tells us that:

F_g= 0.0490040801 newtons

and F_e=.22475 newtons.

So in this instance, the gravitational force is five times weaker than the electrical force--and you can keep adding charge to the balloon! In fact, the only thing that keeps the balloon from accumulating an infinite amount of charge is the electrical repulsion between the charged balloon and the new electrons that you're trying to put on its surface.

Balloons: Two. Earth: Zero. Gravity is truly weak.

*Values for mass, charge, and radius of a balloon were lifted from "Back of the Envolope Physics" and are very approximate. Values for mass and radius of earth from E2 node earth.

For those that care, a more in depth explanation of the mechanics of the situation (beware, physics ahead!): There are four forces acting on the balloon

Fs

/\

N <<<<O|w|>>>Fe W is the location of the wall, included for reference.

\/

mg (mass times gravity, g, which is 9.8m/s² on earth)

Mg is the gravitational force, Fe we are already familiar with, Fs is the force of static friction caused by the balloon "sticking" to the wall, and N is the normal force, or the force that the wall exerts on the balloon; it is equal and opposite to the electrical force.

Since the balloon is not moving in the X or y direction, the net force on it is zero (max and may = 0). Thus:

Fs--mg = ma_y = 0

Fs=mg The balloon is actually held in place by the force of friction, which resists its motion down the wall.

The force of friction is equal to the normal force times the coefficient of friction (Us), which varies depending on what two surfaces are being moved across one another.

Fs= Us*N

N=Fe Recall that the normal force is, in this instance, equal to the electrical force.

Fs=Us*Fe

Us*(k(Q1Q2/r²)=mg Substitution of Coulomb's law.

Us=mg/(k(Q1Q2/r²)) Solve for Us. When we crunch the numbers, we find that for our example balloon, the minimum coeficcient of static friction necessary to keep the balloon in place is .174.

Of course, for any given coefficient of friction and mass of the balloon, you can easily determine the charge necessary to hold the balloon to the wall:

Us*(k(Q1Q2/r²)=mg

Q1Q2=mgr²/(Us*k) If we remember our assumption that the charge induced in the wall is equal to the charge of the balloon, Q1=Q2, ergo Q1*Q2 = Q1². So:

Q_balloon=√(mgr²/(Us*k))

TADA!

Delayed Non-Match to Sample (DNMS) is a research protocol for testing object recognition memory in experimental animals - typically monkeys or rats.

Obviously, you can't find out what the animals remember by asking them. Tying recognition to rewards such as food or intracerebral cocaine injection confuses spontaneous recognition and operant conditioning which involves distinct neuronal pathways.

The test therefore relies on the innate preference of all animals for novelty and consists of 3 phases.

SAMPLE - The subject is shown 2 identical objects.

DELAY - ...

CHOICE - The subject is shown 2 objects, one of which was shown in the sample phase and one of which is novel. The time the subject spends with the new and the old object is recorded.

The ratio of time spent with the new object : time spent with both objects is used as an index of successful recognition.

The effects of various neurophysiological challenges - typically pre-sample or in the delay phase - can thus be gauged. Examples of such fiddling might include lesion of distinct brain areas in the hippocampal formation or directed intracerebral infusion of neurotransmitter agonists or antagonists.

Our understanding of the processes of memory encoding, consolidation and retrieval is rudimentary. Such experiments, though crude, provide a means of breaking down and studying these 3 phases of memory. A better understanding of the processes of memory may allow us ultimately to improve or manipulate it.

A condition characterized by a collapsed tolerance to auditory stimuli. Hyperacusis sufferers may experience ambient noises (e.g. the purr of a dishwasher, the rustle of a newspaper, a dog’s staccato barking) as inner ear pain or pressure. The most common form of hyperacusis, Cochlear Hyperacusis (CH), is caused by damage to the inner ear or the auditory nerve. In certain cases this condition occurs as a cerebral processing disorder, the result of brain damage. The presentation of this disorder is measured by Johnson's Hyperacusis Quotient.

Developed by Dr. Marsha Johnson, an audiologist and hyperacusis researcher from Oregon, Johnson's Hyperacusis Quotient is derived by first comparing a person’s threshold of discomfort, the decibel level at which a person can no longer listen, at different frequencies. This is then compared with the same person’s Loudness Discomfort Level, the level at which sound is merely uncomfortable. Mild hyperacusis patients experience pain at a range of 75-90 decibels; profound victims can be shattered by a sound above 30 decibels.

Hyperacusis often develops gradually, but can be triggered suddenly by exposure to high levels of sound. Temporomandibular Joint Disease (TMJ), Ménière's disease, and Lyme disease have all been indicated as factors affecting the onset of Hyperacusis. Sufferers of Williams Syndrome are more likely to be susceptible to Hyperacusis.

Hyperacusis is often comorbid with tinnitus, an experience of ringing in the ears. The introduction of loud or even ambient sounds that accompany a routine hearing test can increase an individual’s perception of the ringing, and lead to phonophobia, a fear of sound. This may induce the individual to retreat into the protection of ear plugs, leading to a further collapse of tolerance levels.

There is no cure for Cochlear Hyperacusis. A treatment involving a regimen of desensitization to a form of sound known as pink noise is commonly used to stabilize auditory perception.

Much rarer is Vestibular Hyperacusis (VH), in which sounds are incorrectly interpreted as motion and balance cues. A person that suffers from VH might feel as if they are falling in response to exposure to loud, jarring sounds. Nausea, the sensation of spinning, and severe disorientation present in much the same manner as motion sickness, but in response to sounds about the 85 decibel level. Comorbidity with tinnitus is much less prevalent with VH.

Notable Hyperacusis sufferers include Stephin Merritt, of The Magnetic Fields.

A somatoform disorder prevalent in India, also known as Jiryan in the Northern regions of the country. This disorder is characterized by a marked and consistent fear that the passage of semen (Dhat) in the urine is causing some form of illness. Individuals may present with several related symptoms including, but not limited to, headaches, pains, insomnia, loss of appetite, psychogenic impotence, or loss of libido. This disorder seems to be comorbid with anxiety, and treatment may necessitate the prescription of antidepressants or anti-anxiety medication.

This disorder is tied to the cultural belief in India that semen is precious, and that the expenditure thereof causes a man to be weakened. Men with this disorder tend to be of average socioeconomic status, who live in rural areas. Heavy feelings of guilt are associated with this disorder, the individual believing that his symptoms are due to excess masturbation, nocturnal emissions, or sexual intercourse.

Most often the symptoms diminish when the individual is given correct information on the physiological workings of the endocrine system, and reassured that the situation is not making him ill.

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_{Barlow, D. H. and Durand, V. M. Abnormal Psychology: An Integrative Approach; Fourth Edition. Thomson - Wadsworth, 2005. Pg. 171
http://www.laramededucation.com/sexo_ds.html
http://www.ijponline.org/oct2001/indIJPCaseRep3.html}