Gray water is usually used for watering the garden directly, but it can also be purified for use in ponds and other water features. The best known way to do this is with a gray water treatment marsh. This consists of a shallow (12\u201d18\u201d) pond filled with gravel (to prevent mosquitoes breeding) and planted with marsh plants, such as Cattail, Bulrush (Tule) and Reed. These plants have the ability to supply oxygen to their submerged roots, which enables various species of bacteria to grow around their roots. These are able to break down various pollutants and convert them into plant foods. These marshes don\u2019t work in winter because the plants are dormant, but this isn\u2019t usually an issue as we generally have plenty of water at this time. Another problem with such systems is that the plants use a proportion of the water for their own purposes. <\/p>\n\n\n\n
Over complexity is one of the banes of modern life and we\nshould beware of introducing it into the garden. A gray water treatment marsh\nfeeding a pond is a wonderful thing, but it is usually simpler to just use the\ngray water directly for irrigating plants (perhaps alternating with irrigation\nof fresh water). You can then use the clean water you saved to supply a pond<\/p>\n\n\n\n
Myco\ufb01ltration <\/strong><\/p>\n\n\n\n Some fungi can be grown in wood chips and the whole mycelial mass can act as a filter to purify water. This system is simpler and cheaper than a treatment marsh and doesn\u2019t consume as much water (it does require some expertise though).<\/p>\n\n\n\n Irrigating with gray water <\/strong><\/p>\n\n\n\n If you produce a lot of gray water you should reorganize your household plumbing, so that it can be more easily re-used when it comes back out. <\/p>\n\n\n\n The cleanest gray water is that wasted while waiting for the hot water tap to get hot. The next cleanest comes from the shower and bathtub, then the washing machine (make sure you use eco-friendly detergent) and finally the kitchen sink. The latter is rich in nutrients, but very dirty (from grease and oils and food particles) and has the most potential to cause problems. You could have 2 separately plumbed sinks in the kitchen, one for relatively clean tasks like washing vegetables and another for the dirty jobs. You could also wash your vegetables in the garden sink outdoors. This fairly clean water can go directly onto the garden.<\/p>\n\n\n\n An easy way to re-use gray water is to build an outdoor shower or bathtub. This allows you to reuse the water in hot weather when you need it most. Another easy way is to direct your washing machine water into the garden. You might have several perforated pipes buried in different locations and simply move the discharge hose as necessary. <\/p>\n\n\n\n Planning your gray water system<\/strong><\/p>\n\n\n\n You may want to draw up a plan of how the gray water is to be used. Draw out where you are tapping into the house plumbing, where the pipes will go and which garden areas they will supply. This isn\u2019t complicated, but it helps you to visualize what needs doing and where. How to get the pipes from A to B (through the foundation?) How to get gravity flow. Where to bury pipes so you don\u2019t trip on them or see them (and can drain them in winter). A plan may also help you find them again in a few years time.<\/p>\n\n\n\n It is very important that gray water is used immediately and not stored for any length of time, otherwise bacteria will start to grow and it will smell bad.<\/p>\n\n\n\n I have found two useful books on using gray water for\nirrigation, written by two inspired individuals, Art Ludwig (Branched Drain\nGreywater Systems: A Supplement to Create an Oasis with Gray water, Oasis\nDesign 2000) and Robert Kourik (Gray Water Use in the Landscape, Metamorphic\npress 1988). Both systems start with a diverter valve that allows you to run\nwater either into the septic tank (in winter when you don\u2019t want it in the\ngarden) or out to the gray water system in summer. <\/p>\n\n\n\n Surge tank and hose <\/strong><\/p>\n\n\n\n Robert Kouriks system consists of a pipe that runs the water into a surge tank (a 50 gallon polyethylene drum works well). There is a washable screen to remove any solids. The bottom of the tank has a tap connected to a hose, which runs the water to any one of a series of buried 10 foot long perforated pipes that act like mini leach fields. You could also just run the hose to mulch basins surrounding trees. <\/p>\n\n\n\n Branched drain <\/strong><\/p>\n\n\n\n Art Ludwig came up with the branched drain idea, as a foolproof no-maintenance system. This simple system relies on gravity and uses large enough pipes (1 \u00bd minimum) that they don\u2019t get clogged. The gray water is diverted through a series of branched pipes that split the flow and direct it to different areas of the garden. It then flows out into mulch basins (often around trees). The mulch keeps the gray water covered and prevents many problems. <\/p>\n\n\n\n Ludwig recommends that the discharge should be in the air,\nso solids don\u2019t accumulate and back up to block the pipe. There should also be\nclean outs where necessary, in case something does get clogged.<\/p>\n\n\n\n Assembling your gray water system <\/strong><\/p>\n\n\n\n When you are ready to assemble your system you should cut and lay all the pipes out on the ground in place and dry fit all the connections. This will help you to work out any problems. Plastic pipe is pretty easy to work with, but its still best not to glue anything until the end. Expensive fittings such as valves can be glued with silicone caulk rather than glue (this allows them to be taken apart and reused if necessary).<\/p>\n","protected":false},"excerpt":{"rendered":"![\"\"](\"https:\/\/greenmanpublishing.com\/wp-content\/uploads\/2020\/04\/graywater1.jpg\")
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