Treatment plant without power. Biorock- clearfox etc

[albert]

Firstly great news this site is back....  Fantastic resource for all.!

 

I am a  builder and we build 1 house a year on average  but I am about to start my own project this year and its a very different site from our norm.

We have a 20 acre site with Class Q for 1 house. The site is remote and has no mains drainage I wanted to go down the non electric route for the treatment plant as Id like to locate it far away from my house and near a watercourse (all year Flow). I am leaning toward the clearfox  as as a trout fisherman i want to do my bit and achieve high water quality but once you start researching there is so much conflicting info out there is is somewhat confusing. I want to do it right first time with the ability to add a possible holiday cabin at a later date. Does anyone have experience with any of these non electric plants. I have read previous posts but with no direct reference to the clearfox other than its price. My father used to build his own septic tanks in blockwork on large sites with 20 beds plus, I assume this is not  cost effective to put in front of a plant nowadays. my max capacity is 10-12 beds.

Any advice much appreciated.

A

 

 

 

[ProDave]

Hi and welcome. How about making a post in the Introduce Yourself section to tell us a bit about you and your project?

 

Are you planning to discharge into the watercourse or into a soakaway?  Building control have limits on how close a treatment plant and soakaway can be to a watercourse.

 

I briefly looked at non powered plants but space was limited for us, and all the one I looked at were 2 stage systems and took up a lot more space than a simple air blower type treatment plant.

 

Is it the energy saving that bothers you with a powered unit?

 

If you later want to add a second property, make sure the system you installed is designed for the total occupancy you expect.

 

If you use the search facility and search for "clearfox" it has been discussed before and I am pretty sure at least one member ha installed one.

[Ferdinand]

Welcome.

 

I think your single most important step, if you have not already done it, is to go and look at one for your ultimate size of application installed in a site as similar as your requirement as possible which has been there for 5 years, and have an in depth conversation without the presence of a rep, particularly about the reliability, ongoing maintenance, and install costs on top of the supply of the unit itself. And about space requirements, since the 16 person Clearfox seems to be a bit of a chunk once assembled.

 

I would be interested to hear the Clearfox price, as it does not seem to be widely advertised.

 

We had a normal Aquatron at my parents home for up to 4 bedrooms, and that did fine for decades with zero maintenance except a once a year minor dig-out for compost.

 

I am not clear why you are thinking about the stream - if it is as good as you say it is and you are on 20 acres, then a leach field or land drains should probably be good enough.

 

I think simple septic tanks are now ruled out by regulations on output quality.

 

On the electrics, the Clearfox EW16 Nature (is that the one?) technical data seems to talk about a "dirty water pump 230V", which is far better summarised by the German word  "- Schmutzwasserpumpe 230V". "Ew" seems an excellent model name for such a device. Not sure what that is about. Check the datasheet section on this page:

https://clearfox.com/en/domestic-wastewater-treatment/ .

 

One question that some here have prioritised is whether you have to get down and dirty when doing maintenance.

 

We have some threads which touch on this and some questions around sewerage treatment, regulations etc - I have linked a couple below, but you will need to explore if you have not done so already. The old Ebuild checklist has links to regulations.

 

Ferdinand

 

http://www.ebuild.co.uk/topic/18509-checklist-in-preparation-off-mains-drainage/

 

 

Edited January 5, 2018 by Ferdinand

[Jeremy Harris]

Welcome,

 

There used to be a solar power option for the unit we have, the Bio Pure, that they only stopped producing because the batteries and solar panels were vulnerable to theft (or that's what they told me at the time).  This means that it is possible to use the very good blower aeration technology without mains power.  It might be worth ringing Bio Pure (they are only a small company) as asking if they can till supply the solar system, if you think that in your location theft might not be a significant risk.

 

I've had an in-depth look at the amount of power an aeration system really needs and it is a LOT lower than that used by the majority of the pump systems that these companies use.  The bottom line is that the aerated treatment plant companies are using pumps that are designed and manufactured for aerating large fish ponds (most are made for Koi carp ponds) and just re-purposing them.  The fact that they massively over-aerate a treatment plant is only really being addressed by one or two companies, and even then they only use pretty crude timers to reduce the amount of time a standard fish pond pump is on. 

 

There is definitely scope for a system that measures the biological oxygen demand (BOD) in the final discharge chamber and then intelligently adjust the aeration level to maintain that.  This would allow for periods when the house is not occupied as well as periods when there are guests staying, all the time maintaining exactly the right amount of aeration to avoid the need for tertiary treatment.  Sadly I know of no company that makes such a system, but AFAICS it would not be hard to do.  One of my long-term projects is to add some form of BOD measurement sensor to the effluent chamber on our system and see if I can come up with a way to run the air pump more intelligently.

 

Although pumped aeration is far an away the best system, because is both aerates and stirs up settling sediments for digestion, passive systems can be made to work, although some have had mixed reviews.  One system that works extremely well if you have the space, is a settlement tank followed by a reed bed treatment system.  Reeds are exceptionally good at providing the aerobic final treatment stage, as well as removing pretty much all the nitrates etc, so will usually give a very clean discharge.  The down side is that the settlement tank (nothing more than a conventional septic tank, really) will probably need emptying more often than with a pumped air system, as there is no mechanism to circulate and digest sediment.

 

There are some really quite poor designs around, but the key thing is that to work well the main treatment stage must have adequate aeration, and this aeration depends on the usage.  Conventional septic tanks relied on aeration from the land drains and aerobic soil bacteria, but this is inherently poor, as within 10 years those land drains will have grown biofilms and have become anaerobic and septic.  The easy check for this is to dig next to one and check the soil colour.  If it's turned grey or black then it's septic and no longer treating the effluent, whatever drains away will have a high pathogen count and a high BOD, without a doubt.  Both are bad news for watercourses nearby, as well as livestock and wildlife.

[albert]

Thanks for your reply's, I will do some more research as you suggest and then reply.  I need to make a decision fairly swiftly as we are now living on site any I have a temporary fully contained tank system in place but this need emptying every month!! We have unlimited space and I had initially wanted to put a reed bed in but was put off by the maintenance involved. The soil is solid clay over rock and a perc test would show virtually zero peculation.   I will do some reading up and report back. Many Thanks

[Jeremy Harris]

I believe there are reed bed systems around that need little more than regularly trimming back the reeds, now.  We looked at fitting a vertical reed bed system, but couldn't quite get it into the space available, and, IIRC, the maintenance was too onerous.

 

Discharge to the watercourse will be a doddle if you use an approved treatment plant.  Although the EA messed us about with flood risk assessments and adding clauses  to our planning permission to make sure that no mud or rain run off from our site reached the adjacent stream, they approved my application to discharge the treatment plant into the stream within a few minutes!

 

This may rule out a reed bed, as you may find that you have to argue with the EA as to whether it provides good enough tertiary treatment.  All the evidence suggests that reed beds are far better than treatment plants at doing this, but that doesn't wash with the bureaucrats at the EA, who would rather see a certificate than proper evidence................

 

We're on clay, too, so a discharge to the stream was our only option.

 

Whatever treatment plant you go for, look carefully at the location where you are planning to put it and how easy it's going to be to access it.  They generally need de-sludging once every two or three years and some of the unpowered ones need a vertical differential between the vents, to get enough natural aeration through whatever media they use.  Look carefully at the internal mechanical design of any non-electrical design, too, as the media does need replacing periodically and the arrangement to fitting it in some units makes access a bit awkward (and messy).  Most use something like coir as the aerated media, perhaps on some sort of rocking tray arrangement, so that it gets regularly tipped over towards the fresh air vent.  All of the unpowered units use natural convention to pull enough air over the media, hence the need for the exhaust vent to work as a chimney. 

 

Sadly there is some pretty poor engineering in some of these units.  One I looked at, as a cutaway at the Swindon self build place, had an electric motor, shafts, bearings and a toothed drive belt inside the tank.  I hate to think what a job fixing any of that stuff would be.

[joe90]

Well I too am on solid clay with zero water permeability and can only discharge to a ditch ( which runs 10 months a year) I went for a vortex which is the only system that can manually regulate the air pump to the amount of people using it, as I have read that not balancing the input with usage can lead to problems ( Jeremy, I would be keen to hear of your self modulating experiment). We have to have a 6 person unit because we have a three bedroom house but most of the time there will only be 2 of us. One local treatment plant dealer says they no longer sell Reed beds as a previous customer died as a result of sepsis when cutting back his reeds!!!!. However I still fancy a reed bed or wet location for wildlife around the ditch we will be discharging too. I did have a hankering to be “ off grid” and considered a wind driven air pump, like the Wild West water pumps you see in westerns ( we are in a windy location) .?

[Jeremy Harris]

Aeration doesn't need a lot of air at all to be effective.  It's hard to get hard facts, as it seems pretty much all the treatment plant designs around were designed empirically.  The designers just thought something up, built it, tested it, then tweaked it a bit to make sure it passed the testing under EN 12566-3.  In every one I've looked at, assuming some figures for the biological oxygen demand (BOD) of the incoming effluent and then looking at the efficiency of getting oxygen into it (not air - there's a difference, as solubility varies a great deal with bubble size and temperature) it seems that all the pumps I've seen are massively over-sized for the actual oxygen requirement. 

 

That's safe, in that too much oxygen eliminates all possibility of the tank becoming anaerobic (a bad thing, as it will tend to kill the aerobic bacteria that do what we want in terms of treatment), but it's both wasteful of power and runs the risk that the start up time after a period of low utilisation might be too long, risking effluent with a higher BOD than allowed being discharged until such time as the aerobic bacteria have multiplied up to the right level again.

 

I reckon that it is perfectly possible, with the efficiency of easily available pumps, to get the electrical power demand to below 15 W for a typical 4 person unit.  That's roughly equivalent to around 7 or 8 watts of actual air pumping power, something even a very small wind driven air pump could deliver.

 

The key is finding a way to reliably measure the BOD in the effluent discharge section of the tank and then using that to control the aeration process.  If that can be cracked then the benefits are significant; a responsive system that will tend to maintain the aerobic bacterial colony at around the optimum level all the time, a more consistent effluent discharge quality and a much reduced power demand.  My target is to convert our system so that a single standard size solar panel on the roof of the small stone pump housing I've built will be more than enough to run the treatment plant and it's alarm system all year around.

[joe90]

I forgot to say the Vortex also has multiple bubble sizes to ensure maximum oxygen delivery. 

[ProDave]

I would only add that as above, if you choose an electric plant, you choose one that uses the aeration principle.  I have seen the ones that have mechanical rotating parts, motors, gearboxes and pulleys in the "works" of the plant and thought I would not want to be the one replacing any of those parts WHEN they fail.  I also saw one where the infiltration field had blocked and the tank had over filled completely submerging the motor.

[Gone West]

3 hours ago, albert said:

We have unlimited space and I had initially wanted to put a reed bed in but was put off by the maintenance involved.

I installed a WPL Diamond DMS2 electrically aerated system nearly eight years ago. There wasn't room on the site for a leachfield so I installed Kingspan Klargester reed bed system. I soon found out just how fast and tall (2.5m) the reeds grow. After two years I replaced the reeds with iris plants which do the same job but are much more manageable. The reeds take a lot of maintenance as they need thinning out every couple of years.

[Onoff]

5 minutes ago, PeterStarck said:

I installed a WPL Diamond DMS2 electrically aerated system nearly eight years ago. There wasn't room on the site for a leachfield so I installed Kingspan Klargester reed bed system. I soon found out just how fast and tall (2.5m) the reeds grow. After two years I replaced the reeds with iris plants which do the same job but are much more manageable. The reeds take a lot of maintenance as they need thinning out every couple of years.

 

Didn't a guy nearly die thinnng his reed bed out? BAD enough that the company stopped doing them?

[ProDave]

If you wave the watercourse and can get a discharge permit (a LOT easier in England than in Scotland) I would do that without hesitation.

 

We were directed to use a partial soakaway system, and I have to say it works well.  This is a small infiltration field, very much smaller than you would normally use, and the far end of it discharges to the burn.  What happens in practice is the partial soakaway absorbs a lot of the discharge, particularly in summer when hardly anything goes into the burn. Even in winter, it has the effect of acting a bit like a sponge so there is no sudden discharge when you let a lot of water go, rather a steady but slow (barely ever any faster than you can pee) but more constant discharge.

[joe90]

8 minutes ago, ProDave said:

If you wave the watercourse and can get a discharge permit (a LOT easier in England than in Scotland) I would do that without hesitation.

 

We were directed to use a partial soakaway system, and I have to say it works well.  This is a small infiltration field, very much smaller than you would normally use, and the far end of it discharges to the burn.  What happens in practice is the partial soakaway absorbs a lot of the discharge, particularly in summer when hardly anything goes into the burn. Even in winter, it has the effect of acting a bit like a sponge so there is no sudden discharge when you let a lot of water go, rather a steady but slow (barely ever any faster than you can pee) but more constant discharge.

Yes, I think we will have to have the same, any link to exactly how this is done, dimensions, volumes etc?

[albert]

Thanks again,

I would love to build my own plant as a "farmyard engineer" but as mentioned its all about the right paperwork.

My initial idea was to go down the no power route on the  basis of cost not only Kws but getting the power to the site and the noise issue. I am aware its just a humming but the site enjoys total silence and zero light pollution and i would like to keep it that way.

I was thinking of running a vent stack underground and then up in flexi pipe into the crown of a high tree in the hedge line maybe with a vent cowl to draw air. We are in a very rural windy location.

The location is important as i need to achieve acceptable fall from the potential cabin sites. 

I have potential for wind or better a small hydro generator from the stream but i think I will try a well designed  chimney first. I plan to test this with smoke at different heights and setups.

I have tractors etc  and the tank will have a hard access track so this is not a problem. I don't like the designs with small tanks as they will surely require desluging at shorter intervals. I have considered building my own large 4 chamber tank ( septic tank style) and using a clearfox or similar to effectively treat the primary treated  effluent and thus prolonging its life. Am I right in this assumption.?

 Again my father use to claim he would throw some road kill or similar in a newly build tank(very large  concrete multi chamber) to get the bacteria going with a head start. I can confirm that with good air circulation and the multiple chambers he achieve good results with low odour clear effluent. The tanks were often rarely cleaned out .( sometimes 10 Years ) 

I'm going back a few years but feel the system worked well as a primary  treatment system much better than the off the shelf" onions" my generation have subsequently  installed.

If i used this multi-chamber vented  system prior the the plant I could discharge the the steam using the plant documentation and reduce maintenance buy having a larger / more efficient pre tank than whats on offer. I think it would work?

I will now take a look at the tanks mentioned in the posts above.

 

 

 

 

 

[albert]

I will try and introduce myself as suggested if i get time as well.

 

[Stones]

I fitted a Biorock at my last house.  Not a great experience. You can read my review on the old forum:

 

http://www.ebuild.co.uk/topic/13972-user-review-of-biorock-sewage-treatment-system/

 

I think the biggest problem with the non electric plants is if the set up us is not spot on, they are far less forgiving than an electric aeration plant. 

 

Cost is also an issue, or at least was. The Biorock system I fitted was around £3K IIRC eight years ago, over £1K more than the aeration plant installed at our current house.

[Jeremy Harris]

There's a big difference between a septic tank, that was designed to run as it's name implies, as an anaerobic septic (and hence toxic) settling tank, that did nothing more than break down solids, and a treatment plant, that is designed to significantly reduce the level of organic sludge (by aerobic digestion) and run in aerobic mode, which means that it's essentially non-septic, clean-smelling and produces fairly clear effluent that has a low BOD.

 

To some extent there was an "out of sight, out of mind" approach to effluent disposal, and few worried about leach fields that had stopped working or any pollution they were creating, as long as they couldn't see it. 

[albert]

OK I've had a look at your suggestions and thanks all for your input.  I've looked at every system I think .To summarize these are my understandings :

 

-Powered  pumped  aerated  system is the most effective but regulation of airflow is desirable no know automated system available . 

This system could be run via solar or hydro at additional cost to install.

Tank will need desludging/ pump replacing/ power to site or solar.

 

-Passive systems no power but harder to get set up,  media will need replacing and tank desludging.

 

-installing a multi-chamber tank  pre any treatment plant will serve no advantage other than increase storage and may upset the aerobic operation of the plant?

 

 

[Jeremy Harris]

Pretty good summary.  The conical single tank systems have an advantage that the air flow blows the sediment up from the bottom and recirculates it so that it has multiple passes through the high oxygenation zone.  This tends to reduce the volume of sludge, by aerobic digestion into liquid effluent for some of it.

[ProDave]

2 hours ago, joe90 said:

Yes, I think we will have to have the same, any link to exactly how this is done, dimensions, volumes etc?

In my case I was very limited for space. We have a road at the front and a burn in the middle of the plot. It was a recent change to building regs up here that increased the minimum distance from a road to a soakaway up to 10 metres (it was already 10 metres from a watercourse) That only left me with a thin strip of land that was "available" for use as a soakaway. That's why I had such a problem finding a solution and it was only then, when I had run out of options that SEPA agreed to permit me to discharge into the burn, but with a partial soakaway.

 

So I dd the best I can. The effluent comes out of the treatment plant (which only needs to be 5 metres away from the road) across the plot a little to the "available strip"  There is then a linear section of sokaway (perforated pipe set on stones and covered with stones), adhering to the other limits of 5 metres from a building and 5 metres from a boundary. It then goes back to solid pipe and out to the burn.

 

It always struck me as completely bonkers that the soakaway must be 10 metres from the burn, yet it is allowed to discharge into the burn. It would have made more sense to me to install a larger soakaway area going closer to the burn and that would have resulted in even less being discharged. But rules are rules.

[joe90]

Thank Dave, what volume of stone did you use for your partial soakaway?

[ProDave]

1 hour ago, joe90 said:

Thank Dave, what volume of stone did you use for your partial soakaway?

I just fug a trench 1 bucket wide (2ft) about 300mm deeper than the pipe, filled it with stones, laid the perforated pipe, more stones around it and over it, some plastic sheeting then the soil. Npthing over complicated.

[readiescards]

I have a Clearfox, 6 months in and all seems ok.

Its great for being silent and zero power - we likewise have no light or sound pollution so this was important to me plus at the time I was considering being off grid

However it was jolly expensive probably £5k by the time I paid for the unit, the massive hole needed, the tons of gravel needed around it, the long drain to the dyke but no electric costs and only rarely will it need desludging - I went for the 9 person unit - to allow future expansion of my property

 

Remember the settlement tank is full of water/sludge but the Clearfox tank is effectively full of air so you need to think about drainage of any surface water that gets in the hole tanks are sitting in so that the tank full of air does not float up if the hole fills with water.

 

I've yet to finish making it look pretty so it is still a few random pipes sticking out of the ground.

 

 

[albert]

Thanks for that readiescards

Im still to make a final decision.