Monday, October 12, 2009

"First Flush" System: designed, built, and installed!

So, here come the rains, and I wanted the whole rainwater cachement system up and running. The tanks are in place, the tubes are place, and finally, I had to get a 'first flush' system in place.

A first flush system is a way to take that first batch of water that hits the roof and dispose of it before it gets into the tanks. That's where most of the crud is: bird poop, pollen, dust, air pollution, etc.

I did some reading on the inter-tubes here, and decided I could make one myself.

Here's me, waiting for Melissa's help to install the thing (there's one for each tank):

It's 4" PVC, with rubber pipe reducers to a 3" pvc pipe, creating a bottleneck near the top. There's a screw off cap at the bottom, to allow me to let the crud out. Later, I'll make a slow drip system for that, so the whole thing will be automatic.

The above and the below pictures explain best how it works. You can see in the above picture, you can see I've cut holes in the top of the pipe (above the bottleneck) for the insertion fittings to enter the PVC. (the inlet is slightly higher than the exit) Those gray fittings attach to the black hdpe pipe that has the rainwater flowing in it.

The rain pours in, filling the pipe, and raising the float to to the "bottleneck" get it? the plastic water bottle is a float that cuts off the flow to the pipe after the first 5 gallons or so , and then the rest of the water just flows over the top of the bottle, and on into the tank.

Here it is attached into the whole system. Hope all goes well!

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Little birdie

Won't stop coming up onto the patio.