Rain water harvesting for garden irrigation tank size?

ispookie666

The RO will not work for the whole house, but might be useful for drinking water.  
Have a look at the Troptronic. I do know people who run huge fish tanks with a few in series  and the throughput is definitely more than 30. Definitely not the cheapest way.  

JSHarris

ispookie666 said:

The RO will not work for the whole house, but might be useful for drinking water.  
Have a look at the Troptronic. I do know people who run huge fish tanks with a few in series  and the throughput is definitely more than 30. Definitely not the cheapest way.  

Unfortunately the solution has to work for the whole house, as there is no option other than this (won't pass the local EH testing without).  The assumption with new private water supplies is that they must supply potable water to all outlets, especially showers and any tap that may be used for drinking water.  The EH testing is to the same standards as used by the DWI for the water companies, although done by the local public health lab in our case.  The odd thing is that legacy private supplies don't have to comply.  As our US cousins might say, "go figure".

Cost is a big factor, although at the moment the cost is modest, just that of replacing the 5µ filter and the UV tube every year.  That comes to around £40/year in total, so not a massive cost when compared with the cost of mains water locally (not that mains water was an option for us).  I can't justify spending hundreds of pounds on a system to save £40/year, really, even given my wish to try and avoid the hazardous waste issue with disposing of the mercury vapour lamps.

Grandad2b

Reed_Richards said:

JSHarris said:

Our UV unit uses a mercury vapour lamp, inside a stainless steel tube, to zap the (non-existent) bugs.  This uses around 30W, and has to run 24/7, so uses a fair bit of energy.  Also, the UV light needs replacing every year, and isn't cheap (the tubes cost around £30 each when bought in bulk - more if bought one-off each year).

Have you looked to see if there is an LED alternative?  If so that should use a lot less energy.

Funnily enough there was a episode of 'Sliced Bread' on R4 yesterday [15/6/23] lunchtime looking at UV-C sterilisers for another purpose (baby bottles, I think, I wasn't really paying attention). Anyway my ears pricked up when someone mentioned that the only ones that worked effectively used mercury lamps since I'd rather hoped that LEDs would soon be offering a realistic alternative. It seems we may have some time to wait.
However, 30W is 720Wh per day which is not a huge amount of either energy or money even if you're paying SVT of 33p/unit.