I said I’d get to it. To follow this section we need to define some terms. Potable water is fit to drink. Black water is sewage, effectively used toilet water. Grey water is waste water without excrement or urine in it. Examples are used shower and bath water, dishwashing water, used laundry water, and the like.
We flush a huge amount of grey water down the drain every day. This places excess strain on sewage treatment plants and generally overloads the drainage systems of our cities and towns. It also puts added strain on our clean water treatment plants and pumping facilities because it all has to be supplied to our homes and we are squandering fully potable water for things like watering our lawns.
Grey water is no longer drinkable, although it would be considered clean by the standards in much of the world. This doesn’t mean it should go to waste. Grey water is ideal for watering the garden. Doing a soap wash on the car followed by a clean water rinse, hosing off the deck and a variety of other uses. By using it for these purposes we reduce our draw on the water treatment and pumping stations and lower the shear volume of water going through the sewers. This saves energy, money and means that existing facilities can supply a larger number of homes before they have to expand.
How it works.
In brief, a collection tank is put in the basement of the home and diversion pipes are placed on the drain lines between the appliances, sink, laundry, dishwasher, what have you, and the waste water collection stack. The diversion pipes may have a valve placed close to where they connect to the drain line. More on that later. The diversion pipes all lead into the collection tank. A pipe comes from the top of the storage tank and links into the vent stack system so the air that is displaced when the tank fills is vented outside the house. The collection tank has a valve and drain at its base that empties into the sewer system. This is so that the contents of the tank can be flushed occasionally to carry away any solid residue that may accumulate in the collection tank. The collection tank also has an over flow that can either drain into the sewer or, depending on height of the over flow, how damp the soil is and ease of access, outside the house into the garden. The overflow from the rain collection tank could also flow into the grey water tank.
All pipes, except the large line with the dump valve in it at the bottom of the tank, leaving the grey water tank have coarse filters on them to prevent large particulate matter leaving the tank. The main line from the grey water tank is the supply line with a pump on it that goes outside the house so that it can be attached to sprinklers and the like.
Now for the reason for the inline valves on some fixtures. There are appliances that at times you may wish to run directly into the sewer. Examples of these might be a washing machine doing diapers. A shower, after you’ve spent the day under your pickup truck putting in a new clutch and having a transmission fall on you cracking several ribs because some demented gorilla of a mechanic couldn’t be bothered to restart a cross threaded nut and you had to snap it off then re-drill the mount and.... Deep breath, wipe away the rabid drool. If you are covered in a variety of petrochemical products and metal shavings, you will probably want your wash water to go directly into the sewer. In short, some times you might feel the grey water is sufficiently polluted it should be disposed of. On those rare occasions, a turn of the valve and the water will go straight into the sewer. Most of the time though you get to water your lawn for free.
Objector. That soap and stuff will hurt my plants.
Answer. As long as some care is taken to use bio-degradable soaps and the like, they will form a low grade fertiliser enriching your soil. Also, spraying plants with soapy water is an excellent way to discourage pests.
Objector. Someone might drink it.
Answer. Believe it or not, this is the excuse my city gave me for grey water tanks being illegal in my area. This is despite the fact that they are actively encouraged in a nearby community. The answer is simple. The water will only flow out of the hose when the pump is on. Put the pumps on off switch in the house.
Objector. What good will it do? The water still needs to be pumped.
Answer. It takes a lot less energy to pump a litre or water thirty metres than three thousand metres. Oh heck, because from past experience I know someone will call me up on it. Metre = base unit, about a man’s stride in length. Kilometre, Kilo = 1,000 so 1,000 metres. Centimetre centi = 100 so centimetre = 1/100 of a metre Milli = 1/1,000 so a millimetre is 1/1000 of a metre.
I’m not going to try to convert because that’s where it gets confusing and stupid. Metric is a great system just don’t try to mate it to imperial. I can work in both but the only place I use imperial is when I’m working on my house. It was built in the 1940s and it’s easer to stay consistent. Now back to my scheduled rant.
Objector. Suppose you want to water your lawn but the collection tank is empty.
Answer. Using tap water is still an option.
One interesting thing with grey water is that while retrofitting an apartment building would be harder than a house, the potential collection capacity is so much greater that you could move it to the next level and water city parks and the like with water gleaned from nearby high rises.
Another advantage with grey water reclamation is that you can add a heat pump to the collection tank and use waste heat in the waste water to supply your hot water needs at a fraction of the cost in energy and money that other methods would require.
So folks, let’s annoy some of those over paid fat cat politicians who do nothing but call each other names, vote themselves raises and suck up your tax dollars, to change some plumbing codes to at least let people do the right thing for themselves. Maybe even change the building codes so new structures and major retrofits will be obliged to include grey water tanks. What do you say?
Causes Stephen Pearl Supports
World Wildlife Fund, SPCA, Farley foundation, CNIB,