August 2009 

Left: tomatoes sown in mini greenhouses 
below: Silke transplants tagasaste 
right: the mini greenhouses have moved from our house into the greenhouse

Right: the first chicks of the season. The brown ones on the left are Welsummers, the black ones are Plymouth Rock hen and Welsummer rooster crosses. These are the first generation crosses of our Welbar breeding trial. The barring gene is sex linked. Barred birds are males (they also show the white mark on the top of their heads). The females are black without barring. 

A winter project: our new council-approved greywater system
When we planned our house we chose a composting toilet to keep toilet waste separate from the greywater. We wanted to use the greywater in the garden to be water efficient, but we didn't know how to do it with council approval. In the end our plumber built a standard septic system with septic tanks and trenches. It never worked very well and there was no way to make use of the water. Our local council recently changed its policy regarding greywater systems. A greywater system engineer-designed for an individual location will now be approved. We looked at our options and had a system designed for us.

The system uses the existing septic tanks. Only one tank is required, but we already had two 2400 litre tanks and kept them. After passing through an effluent filter at the outlet of the second tank the water is gravity-fed to a sand filter. It seeps through the sand in the sand filter and is gravity-fed into a 550 litre sump tank. From the sump tank the water is pressure-fed into the drip-lines of the irrigation field.

The water that collects in the pump pit is filtered clear water. We planted green manure in the irrigation area and  later in the year the chickens can feed on the green manure. The pump in the pump pit makes it possible for us to water other areas with the treated greywater. The pump isn't really necessary for the operation of the system. The irrigation area could be gravity-fed from the pit but council insisted on the pump.

A sand filter for the treatment of greywater

	Left: this is the filter box. We built it from treated pine boards and lined it with old carpet from the tip shop. The soft carpet protects the plastic liner against damage. Right: the next layer is a .6mm polypropylene liner. A 100mm slotted pipe collects the water at the bottom of the box.
	Left: 20mm aggregate to a height of 150mm Right: this is the filter sand. It must have a particle size of less than .6mm and more than .25mm. The height of this layer is 750mm. Slotted 90mm pipes distribute the untreated greywater over the full area of the filter sand
	Left: 20mm aggregate covers the 90mm pipes which are connected to the septic tank. Greywater is gravity-fed from the septic tank to the sand filter.  Right: treated water is gravity-fed into the 550l pump pit from the sand filter
The finished project: the irrigation area is fenced. The chook house is next to it and the chooks will have access to the cover crops we will grow here. Finally we can use all our greywater to grow food for the chooks and the system has council approval