Gauteng Smallholder December 2015-January 2016 | Page 42

WATER CRISIS fine delivery you may wish to From page 39 it take into account fluids that end up in the drain as a result of agricultural pursuits on a smallholding such as dairy, abattoir or stable-yard washdown water. Not surprisingly, the resultant liquid containing these substances, if allowed to stand for a short time soon starts to smell as the solids and organic components putrefy, giving off the familiar sulphurous odour of a blocked drain. And also, not surprisingly, if the water is not filtered the solids contained in this stew will soon clog up any form of use, including sprinklers, drip irrigators and the like. Plus, the combination of soap residue, human hair and the fats, oils and greases, combine in the cool water to form a white, semi-hard solid which will build up on the sides of storage tanks and pipework in much the same way that cholesterol clogs your arteries. Just from what it contains, it is not difficult to see that using this liquid as-is on one's garden will soon result in smelly patches, an increase in flies and other insects and, soon enough, illness among workers, children and animals using the garden. Not to mention that the “fogs” will eventually clog the soil, coating soil particles and making it impossible for the soil to absorb moisture and release nutrients. So before using grey water on the garden it is necessary, at the bare minimum, to pass it Examples of simple grease traps through a couple of rudimentary filters to take out the worst of the contaminants. To remove the solid food particles, hair and much of the fats, oils and greases, at the very least the fluid should flow through a conventional grease trap, which should be regularly emptied (you'll be surprised how quickly the grease trap fills with gunk). You can buy a simple grease trap from any good plumber's merchant and installing one is a simple case of digging a hole and plumbing it into your drain line. Next, a combination of a 40 www.sasmallholder.co.za gravel-and-sand filter, with an anaerobic digestion chamber will, hopefully, rid the water of remaining organic matter, with the anaerobic digestion taking care of much of the bacterial load as well. The dimensions of such a filter will be dictated by to the daily volume of water it is to process but, basically it should comprise a tank at the bottom with an outlet high enough up so that the tank never empties fully. The tank should be partially filled with a honeycomb of bricks (even better if the bricks are of the Continued on page 41