The GreenHouse Project's Adventures + Lessons in - ELLEN ...

Chapter 5:Water saving technologies at the GHCThe adoption of the conservation principlefor water is of particular importanceto South Africa, where it is a limitingresource for development.Examples include – roof-top rain-water harvesting foroutdoor watering; water efficiency in buildings throughthe specification of conserving fixtures such as lowflowshowerheads, tap aerators and water conservingtoilets; and indigenous, drought resistant plants forlandscaping. Indigenous planting also reduces the needfor potentially polluting pesticides, herbicides, andfertilisers.The GHC demonstrates the following radical butpractical water saving technologies and alternativesewage systems.Many of the water-saving innovations at theGHC were as a result of Thomas Linders of LindrosConsulting. This permaculturist helped establish thegardens and select plants for the sod roof and ramp.He trained the first garden manager at the GHP, anddesigned the water cleansing systems.EnviroLoo composting toiletToilets can consume up toone third of all the waterused in a household. Eventhough it is possible tomake great water savingswith more efficient flushtoilets, the GreenHouseProject went for a toiletthat doesn’t use water atall and needs none of theusual expensive sewagetreatment infrastructure.The composting toiletis a self-contained sanitationsystem that uses verylittle energy to operate anddoes not pollute. It recycleshuman waste into usefulfertiliser for trees and ornamentalplants; a costeffective, ecological solution (our faeces are only 3%solid matter – the rest is all water!).The EnviroLoo was chosen because installation is relativelyinexpensive and it requires minimal maintenance.A system of baffles inside the toilet separates liquidsand solids. Heat and draughts created by the system dryliquids, and aerobic microbes decompose the solids. Theunique whirlybird and chimney ventilation system aidedby the increased internal temperature causes a negativepressure within the container, which ensures no backdraftinto the toilet pan, and therefore no odour.LessonsThe chimney length is designed for a normal househeight, but our toilets were dug down and inbetween quite a tall building and hothouses. Theproblem wasn’t lifting the smells away so much asthe fact that given the position they were not tallenough for the whirlybirds to catch the breezes.The tall hedge was also preventing especially thenorth toilet from getting the breeze that helps thewhirlybird to turn and therefore create the vacuumneeded to pull the smell out of the bathroom andbring air into the toilet. The other way our locationmade it difficult is that the composting toilet issupposed to be positioned facing maximum sun sothat the chimney heats up also creating a vacuum.Again as there was no other place to put thetoilets the chimney and chamber are only heated inthe afternoon a little and therefore are not gettingthe vacuum build up in the morning. Contrary towhat one might think, the bad smell that resultedwas a strong ammonia smell from urine that was notdrying out fast enough. The original toilets also hada lever that one used to ‘flush’ the toilet – actuallyit lifted a tray that emptied the faeces into anothersection of the toilet.It is best to avoid a system with any mechanicalparts as GHP discovered. A visitor ‘flushed’ thecomposting toilet rather too enthusiastically, andbroke the lever. This has now been replaced with amoving belt system connected to the lever whichis now pushed down instead of being wiggled backand forth. The chimneys have also been lengthenedand now the system works beautifully.An interesting cultural complication arose witha Muslim employee. Muslims need to wash afterusing the toilet and the fact that EnviroLoos cannottolerate the addition of water caused our poorcolleague to walk to the other side of the Centrewhere he could use a conventional flush toiletinstead.22The GreenHouse Project