albert

System design - mains and well combination.

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Posted (edited)

Hi my contract plumber is great on new build and installations but not great on thinking outside of this. I am looking to  firm up my ideas on utilizing my water options on my new build site. I have an existing well that i have tested  for water quality and supply over the past 2 years, both are good. Supply is very good, water is always clear and water tests are good other than high manganese levels.(408 ug/l)

I explored the options of filtering this water for drinking water standard and the cost was prohibitive over my £620 connection charge to the water main.  I was proposing to use the metered mains for drinking water and my free water for everything else. I am aware that manganate causes problems with pumps and copper and was proposing filling my heating system and re-pressurizing from the main when needed. I was aiming to use plastic throughout the build and run my showers baths WCs washing machines etc off the well water. I have inspected pipe work that has been in place on site for 10-15 years for signs of furring but although there is discoloration( black)  that is it. I have been running a small "log cabin" on site on this water for over 12 months with no problems with any pumps. As I have not connected to the mains as yet the UF heating and oil boiler are also running this water without problem so far.

The well water is currently pumped to a 1000 ltr tank and then gravity feeds with the assistance of a shower pump to the cabin. The shower pump achieves 1.5 bar at the boiler at it works well.  For the house I would like to pump much higher to a bigger tank (5000lts) for  some degree of storage. I understand 10m of head will only give me 1 bar so I think I will still need a pump to pressurize the water. Is there a way I can create storage and good pressure  without pumping the water twice. 

It would be easy to just connect to mains but I have a resource  that I would like to use. I also know the hot and cold pressure needs to be equal so both hot and cold non drinking water may as well be from the well.

I was planning on having a bypass valve that I can revert the whole system to mains should we have a severe drought.

Due to costs heating will initially be via an oil fire boiler , wet UF heating throughout  both floors (with log burners in kitchen living and master bedroom.) Provision  will be made for upgrading to ground source or  wood chip at a later date.

There is a possibility we may install a dark metal roof over a very large area and I was considering running a  very basic solar gain system beneath these roof sheets in order to lift the hot water temp a few degrees. Is this a silly idea  or worth a go as the cost should be minimal.

 

I would appreciate your thoughts on any of the above.

 

Many Thanks.

Edited by albert

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What's the pH of your well water?

 

Provided it's not higher than about 8, then getting the manganese out is easy, just oxidise it.  I use an ozone oxidation system to reduce both the ferrous iron and manganese in our borehole water and it's extremely effective.  Not that expensive to fit, either, and an easy DIY job.  Compared with paying ongoing water charges it was a no-brainer for us to have a borehole drilled and pay out for the parts needed to treat the water.  The running costs are a fair bit less than mains water costs here, plus we have better water quality, with no chlorination.

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Hi @albert

Ok, a bit to chew through so bear with us :) 

First thing we need to know is what pressure the pump throws out and what flow rate / for how long it can sustain it. 

Pumping into an open 'break' tank has many issues, mostly that of inadequate pressure that you've lost by dumping the water into said tank. 

Have you heard of cold mains accumulators ? These are big metal tanks ( like a giant coke can ) that have a 1/2" thick rubber ballon ( called a diaphragm ) inside. When these are filled with water, by a pump so it's forced in, a pocket of air on the other side of the diaphragm gets compressed creating stored energy in two forms. One form is the compression of that air, and the other is the starching of the diagram, like you pulling back a catapult filled with water. This setup takes the pulsed influx of pressurised water that your pump provides and holds it against its will. That usually resides at around 3bar or more if your pump can go that high and creates what is know as an "artificial cold mains" supply. It gives you a stored water system that is regulated by the pump, shunting water into the accumulator but the supply pipe doesn't suffer the 'jerks' that connecting direct to the pump would cause. 

You'd typically want a single 500L or a pair of 300L accumulators for a typical  domestic household, but you have the benefit of the cold mains too, so you could decease the stored volume ( and cost of the accumulators ) by working out how much water you use in a 24hr period. 

Forget the 5000 L tank, and get rid of the shower pumps, this is the any forward, ( if you have the budget of course) . If that's an issue then just say so and we'll help you make the most of what you've got. ?

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HI Nick that sounds like a very good plan. The 5000lts tank was to build up  storage capacity on what is relatively small well, although this was before I had resigned to make the connection to mains as back up. ( I have animals here as well  but  thinking aloud maybe best to pump to the tank for them and use gravity,)  

What sort of cost are we talking for these accumulators? The well is actually only 5 m from near the build site so these would work well as I'm sure i could pump @ 3 bar over a short distance like that. The current set up is very a heathrobinson temporary rig and in no way permanent.

 

Great info, many thanks.

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If you want any info on wells/boreholes, pumps, water treatment, pressures, filters, losses, flow rates etc, just ask.  I had a stack of problems finding companies that had a clue about how to do this in the UK.  It's commonplace in the US for household supplies to come from wells, but relatively uncommon here, where most wells/boreholes are only used for farm irrigation.

 

As a consequence, I ended up wasting a lot of time with UK companies, and ended up getting lots of really good information from a US forum that had a section on wells and water treatment.  Some of the guys there gave me a lot of help (bit like this place in many ways) and I put together a system that works very well.

 

We have two 300 litre pressure vessels (could really get away easily with one, but I needed the extra volume to back flow the sand filter - there is now a low backwash rate filter media available that would have got around this and saved needing the second pressure vessel.  The system I use is to inject ozone into the pumped water feed (a typical down hole pump will deliver over 9 bar, less head and pip losses) to cheap (less than £100) contact vessel, where the iron nd manganese, plus a bit of hydrogen sulphide, are very quickly oxidised out, with the useful side effect that the ozone disinfects the water and oxidises many other potential contaminates that could make the water smell or taste unpleasant), then the water flows to two parallel connected 300 litre pressure vessels, at a regulated pressure of between 4 bar maximum and 3 bar minimum, and then it flows to a sand filter, that filters out the oxidised iron, manganese etc particles.  Every 4 days a simple timer just backwashes the sand filter at around 2 am in the morning to flush away the small particles of iron and manganese oxides that it's trapped. 

 

Once set up it's maintenance free, and just supplies water on demand to the house at between 3 and 4 bar, with no chlorination etc to spoil the taste.

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Sorry JSH I didn't see your post earlier .  I'll check when I get home on the ph but yes water co s that I have tried all came back expensive  and not brilliant. I already have the well and the water so yes very interested in your system . I have to mole under 2 small roads to get to the main so the cost is not insignificant even doing it ourselves . Can you give me a ball park on cost to set up your treatment system. It sounds perfect. Could I set this up in a shed separate from the actual house as I need water asap and have promised the wife drinking water !! Thanks great information again.

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The magnesium levels are just about within WHO regs but not uk regs . Do you need an annual gov water test as this it appears is another cost to include.

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First off, there is no requirement for any official testing of a private water supply at all, as long as the supply is only to your own home.  If you start supplying others then there is a requirement for a LA test, at a cost of around £125.  I had an LA test just to keep building control happy, and as reassurance that what I'd made was working OK.

 

I have our system set up in a separate shed at the rear of the house, mainly because of the space taken up by the pressure vessel etc.

 

Cost depends on what you already have, as the most expensive thing is often the pump (over £600 for a decent one).  I'll put together a drawing for a basic system to remove manganese by oxidation later - I need to just re-do one of my drawings to suit what you need. 

 

Removal of manganese by oxidation only works if the water pH is low enough, so if you have very hard water it won't work well.  Ideally the pH needs to be close to 7 for it to work perfectly, although oxidation will continue to remove manganese to some extent right up to a pH above 8.

 

 

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Thankyou for this JSH I'm not on site today but will check my PH as soon as I'm back. No doubt you have already saved me much research and time already.  

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One more question, what do you think your water demand is likely to be?  The size (and cost) of the treatment system is disproportionately affected by this, as high demand systems need bigger pumps, bigger pressure vessels, bigger treatment systems and filters etc, and doubling the demand can easily quadruple the cost.

 

For example, how many showers a day, or baths, as that's probably where most water goes?

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It's a 5 bed but only 2 of us maybe 3/4 in future. We're not wastful with water . There's 3 bathrooms and a shower room. Most of the water usage will be on the horses but that's not needing treatment and best run as a seperate system I think.

if you allowed 1-2 baths / showers a day that would cover our personal needs I think. 

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Thanks, I'm trying to work out the simplest system to reduce the manganese level in your water, that won't cost and arm and a leg and which can be easily DIY installed.  If you already have a well pump, then I'm assuming this is a downhole submersible pump that can deliver a fairly high pressure, is that the case? 

 

Assuming it is, then the pump will be controlled by a pressure switch usually, although as you are using a storage cistern at the moment you may have the pump running with float switch control.  It's possible to have both, if you still want to use the open storage cistern for irrigation etc.

 

There is one very good supplier of US made well water treatment kit here in the UK that I've found, and with whom I've had very good service.  There are other companies around, but frankly none that I approached came close to being as competent or keenly priced as GAPS Water in Rochdale (http://gapswater.co.uk/ )  They sell the Aquamandix aerated manganese sand filter system that we have, and which works well, but there are some potential gotchas in both selecting the model needed.  The smallest model will deliver 600 litres per hour, and although that would seem to mean it only delivers 10 litres per minute, that isn't the case at all, because of the pressure vessel.  The problem I found is that if you go for a bigger model you need a lot more backwash flow to clean the filter, and that then pushes up the size of everything.  I made the mistake of buying too big a unit, which is how I found this out!

 

I'll do a drawing later, but given your marginally high manganese level, with no other notable contaminants to take up oxygenation capacity, I would opt for their smallest Aquamandix unit, with the air draw kit (which is £27 extra and will be needed as manganese oxidises more slowly than iron).  This is the unit and it comes complete with media, timer, etc: http://gapswater.co.uk/acatalog/Aquamandix---sand-mix-Simplex-system-with-Autotrol-Logix-263-740-digital-TIME-controller-2968.html#SID=241

 

You have two choices as to where to fit this unit.  If your pump can deliver at least 1100 litres per hour (just over 18 litres/minute) at around 2 bar or more, for at least 8 minutes, then fit it immediately after the pump, and before the pressure vessel.  A single 300 litre pressure vessel should be OK, but if building a shed for this stuff then leave room to add a second one if you later find you need it (it's easy to add a second one later).  A 300 litre vessel will usually be around the biggest that will fit through a standard door opening, which is part of the reason for suggesting this size.  It also gives you around 150 litres of high pressure water available even with the pump off, which is a pretty sizeable buffer.

 

If your pump cannot manage 18 litres per minute at a couple of bar, at the point where you want to build the pump house (taking account of head loss) then we can have a re-think, as the second option is a bit more complex (and is what I have had to do).

 

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Ah yes PH is 5.6!! I will test again as this was 12 months ago now. It was a while ago I looked in to things, I now recall that I may need to correct this, but I don't think was a big problem.

 

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The existing pump is not for keeping as its just a standard submersible. I am happy to pay for a good quality pump Grunfoss??I think i have used before. In answer to your post no I don't have suitable pump in place currently.

 

PS .I regularly travel to the US with big suitcase( usually  for dirtbike parts) so US parts are easy to source for me.

 

Thanks G

Edited by albert

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1 minute ago, albert said:

Ah yes PH is 5.6!! I will test again as this was 12 months ago now. It was a while ago I looked in to things, I now recall that I may need to correct this, but I don't think was a big problem.

 

 

 

pH of 5.6 is pretty low, which is why there is so much dissolved manganese in the water, but at least your pipes are never going to fur up with water that acidic!

 

You can correct the pH cheaply, just an empty pressure vessel like this: http://gapswater.co.uk/acatalog/PWG-composite-vessel-complete-with-head--riser-and-screens--3-4--BSPF-ports-5629.html#SID=489 filled with some cheap calcium carbonate (limestone) chippings.  Basically, the taller the vessel the longer the chippings last (they last a few years usually) and the wider the vessel the greater the effect it has on increasing the pH.  My inclination would be to not try and increase the pH too high, no higher than around 6.5, and to do the pH adjustment after the manganese removal.  The really good news is that the small Aquamandix system mentioned before will very significantly reduce your manganese level with a pH that low.

 

If you don't have a pH meter, I could lend you mine, and also lend you a water conductivity meter as well.  I have a dissolved solids meter for measuring total hardness, but with a pH that low there won't be any dissolved solids in the water, I suspect!  Sounds like nice water for making tea.........

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OK great so its still do-able that's great. £600 ish for the Aquamandix  and air kit.  That's just  my connection fee . So my water treatment bunker rather thank shed as it will be underground could house all this kit for £1000 -1500 ish ??(for the tech kit alone)

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Achieving the correct PH is a trial and error or can this be calculated? Considering I need a  better pump is a submersible the best bet? Would I be better erecting a shed over the actual well itself? Id like the one pump to service the untreated water need /tanks and the drinking domestic water. I assume I can set up a demand type valve to do this as well.

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Remember there's no water bills for a well system, too, as that's a substantial annual saving.  Our well costs around 1/3rd of the cost of water supplied from the local water company, in terms of running costs plus a bit put away to cover replacement parts.  Overall I think we save a few hundred pounds a year by being on a borehole, but that's with me having down all the work to put the kit together.

 

Your figure sounds in the right ball park, assuming your pump is already up to the job.  Any idea what the pump is and what the resting water level (RWL) is in the well?  With the latter info plus the physical height from the ground surface to the house I can have stab at working out the total head losses, and so the pressure you'll get at the house on the top floor.

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1 minute ago, albert said:

Achieving the correct PH is a trial and error or can this be calculated? Considering I need a  better pump is a submersible the best bet? Would I be better erecting a shed over the actual well itself? Id like the one pump to service the untreated water need /tanks and the drinking domestic water. I assume I can set up a demand type valve to do this as well.

 

Yes, it's trial and error, but dead easy to do.  You have a bypass pipe around the vessel filled with limestone chippings that has a valve in it.  You measure the pH at the output, and if it's too low you close the bypass valve a bit.  If it's too high you open the bypass valve a bit.  Within half an hour you should have it set about right, and it will stay more or less the same until the chippings are almost dissolved, when adding fresh chippings will bring it back to the set value again, with no need to touch the bypass valve setting.

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 I will need to supply a new pump but not a massive cost I think. the RWL is about 1200-1400 mm below FFL of the house approximately 

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12 minutes ago, albert said:

 I will need to supply a new pump but not a massive cost I think. the RWL is about 1200-1400 mm below FFL of the house approximately 

 

 

That's more good news, as the head loss will be trivial.  There are some cheap and reasonably good Polish made pumps available.  Cheap enough that you can buy 6 of them for the price of something like a Grundfos, or even the slightly cheaper Lowara.  As replacing a pump that's only going to be a few metres down is easy, it gets to be a bit of a pain when you're hauling a pump string up from around 40 metres or so down....................

 

The cheap Polish pumps are like this one, the UK importer, Dambat, only seems to sell them on ebay, but I've bought a fair bit from this company and found their stuff to be OK for the price:  http://www.ebay.co.uk/itm/IBO-3-5-SCR-1-8-50-Borehole-Deep-Well-Submersible-Water-Pump-LONG-LIVE-CABLE/172348620898?hash=item2820c74062:g:qDsAAOSwOyJX4RPY

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Ok great as I thought. I will make up a shopping list when I get five min and a rough diagram of my understandings. Maybe you would be kind enough to add you thoughts. I will ring SW Water for a refund of my connection fee as we were going to start digging this week. !!  Could I be rude and ask, as there is a slim chance of me passing  your area later in the month whether I could take a look at your system and buy you a pint for your generous time.

 

Thanks again 

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More than welcome to show you around.  We're about halfway between Shaftesbury and Salisbury, about a mile off the A30, at the far end of a village called Fovant.  If you PM me I can send you directions and let you know when I'm around.

Edited by JSHarris

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No problems.  I had a tough time getting our borehole drilled and working, and in the process I ended up having spend the best part of a year trying to learn about everything from a bit of geology to the chemistry and practicalities of water treatment, as there seems to be a dearth of expertise on this in the UK generally, and specifically locally to me.  Luckily a couple of very helpful American guys helped me a lot by email, having contacted them via a US forum that had a lot of useful info on wells and boreholes.  If you ever have some spare time and want to read about our tales of woe about water, then these blog links may make you laugh (or weep........):

 

http://www.mayfly.eu/2013/08/part-eleven-fracking-only-kidding/

 

http://www.mayfly.eu/2013/08/part-twelve-minor-disaster-strikes/

 

http://www.mayfly.eu/2013/09/part-fourteen-things-can-only-get-better/

 

http://www.mayfly.eu/2015/08/part-thirty-seven-a-long-tale-about-water-and-life/

 

http://www.mayfly.eu/2016/07/part-forty-two-water-treatment/

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