Pumping greywater

[Stefan (S.T.E.F.)]

Hi all,
been rather busy so haven't contributed for a while.
Just ran into trouble with building control and have to totally rethink my greywater system. There is no black water due to composting toilets being used.
The greywater / urine now needs to go into a holding tank similar to a septic tank. However, from there it can't drain away, so I need to either pump it into a header tank so it can slowly drain through a biofilter or I need to pump it into the biofilter directly which means it needs to have a very small flow rate.
Either way it then drains through the filter into a small soakaway surrounded by loads of willow and alder which will take up the water as the ground isn't suitable for a soakaway.
My problem is to find a solar powered or even mains powered pump that will shut off when either a) the header tank is full or b) the holding tank is below a certain level, or if I don't use a header tank it needs to have a very slow flowrate (5L/h) and shut off when the holding tank is below a certain level.
Been searching the internet but haven't really found anything that will work out of the box. Either I am looking in the wrong place or I need a custom solution....
Any help greatly appreciated.

[Justme]

Use a standard pump with two float / level switches.

One in the lower tank set to stop when the level is low & the other to stop when the tank is full. Wired so both switches need to be on for the pump to run.

[clockmanFR]

I use 12v DC bilge pumps designed for boats, (shurflo, model Piranha, flow rates to suit) some come with float valves attached, or attach the float valve accordingly.

Mine have been in constant use for well over 5 years, i use solar panels to power 4.

Only drawback is their head (lift height) max, depends on model, is only 3 meters.   

[Stefan (S.T.E.F.)]

Bilge pump sounds good, 12V is certainly preferred over 240V. Do I need a controller of some sort ? I am not sure how to wire it so that it not only stops when the holding tank gets low but also when the header tank (15L) is full and then restarts when the header tank gets lower and the holding tank is not empty....
Seems like one of those logical things I can't get my head round...
What kind of pipe would be best for the pump bearing in mind it needs to comply with building regs and go from inside the holding tank under ground to the header tank....

[billi]

I guess i would built a bigger  reed bed idea and forget about flow rates and regulations


Billi

[Stefan (S.T.E.F.)]

I would too but the water table is above surface when it rains a lot.... soakaway and reed beds are not a financially viable option.....

[billi]

Our "official" septic tank is 2 metres  higher than our toilet  and we pump  

We just got all  the gear to meet the regulations ....  but .....

[Justme]

Most float switches come with 3 wires. NO & NC (Normally Open & Normally Closed).

On the lower tank you want it so that when its above the minimum level its using the NC wires & then the upper tank wants it so it's using the NO when its full. Then the pump can only run if both the tanks are in the NC position. If either changes to NO then the pump will stop.

[EccentricAnomaly]

Picture of what Justme said, assuming the switches float into the upper position when immersed and drop to the lower position in air. I guess for NO and NC for a float switch "normally" means in air. Which is which might just depend on which way up you mount the switch.

[profp]

I would too but the water table is above surface when it rains a lot.... soakaway and reed beds are not a financially viable option.....

Are you sure?

Our reedbed is based on old water tanks - so the sides are impervious. Any old containers of a similar ilk would do (e.g. old baths). The don't even have to be buried, so long as the water still runs downhilll (depends on your site layout as to whether this work for you).  Once the water runs off from the reed bed, it's supposed to be clean enough to be returned to the watercourse.

The whole exercise is inexpensive: ReedsFromSeeds will sell you reeds - they are cheap, the delivery costs more than the reeds. The reed bed substrate is just sand and aggregate. Digging holes saves on gym membership :-) It is all DIY-able.

Regarding pumping grey water - be sure to get adequate filters. Grey water from the kitchen sink and bath will inevitably have a light scum, which over time will accumulate and block pipes. I haven't yet found the ideal filter for my inlet pipes and through-flow pipes, but I have a 12V caravan pump (a FlowSure) used for rainwater which has an optional filter which works really well at removing the silt from the bottom of the water butt. If you don't use a filter on a diaphragm pump and there are particulates in the water they soon fail, as I found out to my cost :-(

You may also want to consider separating urine from the reed beds. Envirolet (boo, hiss), for example, recommend using a simple lime pit for the drainoff. Their recommendations are in the installation manuals which are on the web.

P.

[clockmanFR]

Profp

The shurflo your using is very different to the shurflo bilge pumps.

The bilge pumps are designed to be constantly immersed and will pump absolute anything, (oily water, water snails, mud etc) there cheap about £40 and use any bilge pump float valve, Shurflo, Rule etc. Shurflo do an electronic one that attaches direct to the side of the pump body and shuts the pump down when the water is to low/high. I also use a DPDT 12v relay that controls a relay to switch on/off at a set height.  

I use 25mm MDPE pipe and fittings, but from the pump itself you will need to use 3/4inch hose adapter to 25mm MDPE.

For info Try;-  http://www.marinemegastore.com/find.asp?cid=XROME9YI9SQVUVTG9S7HDQFJSGZDP5FY  

[clockmanFR]

sorry!

Put in PIRANHA as model name, then SHURFLO for manufacturer.

You will need to bury the 25mm pipe at least a meter to stop it freezing in winter, but MDPE pipe is brill at not splitting when frozen.

[Stefan (S.T.E.F.)]

At what temperature does moving water freeze ?
Inline pump without the header tank is what I submitted to building control. I don't think they will even consider freezing conditions....after all they approved my first application of a treatment plant for grey water/urine. Only problem is those treatment plants don't work without solids.... surely building control should have flagged that up

[clockmanFR]

Does this help.

In my humble experience water will freeze even when running.
Depends on:- 1.  Pipe exposure distance to the frost. 2. Rate of flow to diameter.  Basically how long has the water in the pipe been exposed to the cold.

Regards in line pump. I have my bilge pumps in small header tanks, Screwfix do a fully insulated 4 gallon tank for £70, 500mm x 350mm x 350mm. Put it in a manhole.
Build a base of concrete, and brick sides so the whole lot can take a manhole cover. (its a suprise after a few years what moles and earth worms can do to reclaim the hole if it's not solid). Its best to connect up first once the base concrete is in and build around. I use 25mm MDPE single (one end is screw up clamp to pipe the other is threaded), I then use a threaded plastic nut (cut from another connector, their cheap), to tighten the connector to the tank. On the pump output side i then attach a female converter that threads on inside but converts to a 3/4 inch hose fitting (get from garden centre). Then flexible h/duty 3/4 inch pipe to pump, each end has Stainless worm drive clips. I attach the pump base to stainless plate to keep the pump vertical, ( or thick ceramic tile would do but you need to drill a couple of holes in it).  I use half house bricks that i drill and plug for attaching the float valve. Remember the pump does not want to run dry.

Your urine/water flows in to the tank, the float valve rises and switches the pump on, the urine/water level drops and the pump switches off.  You now have a in-line pump,  Simple-sss!

[Stefan (S.T.E.F.)]

Clever !

The thing is it wouldn't bother me if the water would freeze for a few days, the holding tank will just get fuller for a change... however, if it's below 0°C for more than 10 days I presume my holding tank would overflow...
And of course I would have to be careful that no pipes/filter/pump get damaged during freezing conditions.