An anecdotal approach to SEPTIC TANKS (illustrated)

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An anecdotal approach to SEPTIC TANKS (illustrated)

Postby jazzman » Fri Dec 08, 2006 9:59 pm

I'm starting a new thread here, because although several posters have provided some useful tips, the original (see link at the end) thread got a bit confused to say the least, and some readers may not yet be aware of the article on thecoolthaihouse.com site (see link in the text), and I wasn't either, so here are my two satangs worth:

Britain is one of the few countries
in the world where the arrival and departure of essential services (water, electricity, gas) is taken for granted and done by a piped system provided and installed by the state over 100 years ago and all located neatly underground.
However, one only needs to cross the English Channel to find a very different state of affairs. People there routinely buy their drinking water and cooking gas in bottles, telephone and electricity cables are an eyesore, and with the exception of the cities and large towns, they live very successfully with their septic tanks and without the intrusion of bad smells.

If you are going to install one, what you have to remember, is that contrary to the Thai philosophy which in all aspects is completely alien to anything we are used to, physics has proven (and you don't need a PhD to understand it) that water does not in fact flow up hill (at least not without a pump behind it); apparently it's got something to do with a phenomenon called gravity - but as a previous poster mentioned, try explaining this to a Thai plumber.

I know of three farangs
who all within the last 12 months have had to rip up their expensive, imported, Pattaya patio tiles, and practically put a bomb under the far-too-thick concrete floor to get at their blocked 4" bog pipes and replace them with a downhill route. (Thais do not generally understand how to mix good concrete, so they over compensate by laying a floor which is thick enough to withstand the impact of the most frustrated homeowner banging his head on it).

With a septic tank as close to the bathroom
as possible, it's just possible to get away with a fall angle of 2% - that means 2 centimeters for every metre or 2 inches for every 100 inches, but any further away than a metre or so and the angle needs to be significantly greater because the water content of one flush will not be enough to push the semi-solid matter you dumped all the way to a septic tank that is miles away in your rice field, and you will be living with one of those snaky wire things as a regular accessory in your toolbox. The best solution is a vertical fall pipe, but if yours is a single storey house, this may not be practical. It's not for cultural reasons that in many countries (not only Thailand), a receptacle is provided for used bum paper. In ideal situations, for toilets connected to septic tanks, paper is not provided at all; a far more hygienic system is in use in Thailand that most Western civilizations still have to hear about.

If you don't want to wade through technical stuff
to find out whatever angle the British bullsh... sorry, BUROCRACY, dictates for bog pipe tilt, and if you don't want to wade through sticky, stinking backed up brown stuff, you can work it out yourself:
Buy a short length (about 1 metre) of 4" (100mm) blue PVC pipe, and pour substances of various sluggish constitutions down it (have you got a dog? or better still, a buffalo...) at different angles of tilt until you are satisfied that it will slide all the way through. Actually, cold Heinz Baked Beanz have about the right consistency for this experiment, just add a little water or lukewarm coffee in varying degrees, so you need not be afraid to enlist the help of your Thai wife as a lab assistant.

A properly constructed
home sewage system can be close to the house and any evil smell will almost certainly be due to misuse rather than faulty construction. The usual cause is using proprietary disinfectants to clean your 'klo'; they will kill off the very bacteria that the system depends on for correct, 'pong-free' function. Also, to avoid diluting the bacteria, you must build separate systems for your raw toilet waste (black water) and your kitchen / shower water (gey water). It won't cost a fortune, and a grease trap is an essential addition to the kitchen water system if you care about the quality of your leach water.

Years ago I copied the design of a ready made 1,200 litre fibreglass septic tank on sale at Leroy Merlin in Avignon and built the same kind of double chamber system, but in concrete, for my house in the Provence. In the 12 years I lived there I never had any blockages or bad odours. We were running a busy Bed 'n Breakfast and had 12 toilets connected to it. I did the same thing here for my house nd the motel and instead of paying 8,000 baht or more for a fibreglass or plastic tank from HomePro or Global Home, it will cost me precisely 540 baht.- doing it the way described here http://www.coolthaihouse.com/infobathroom.htm - each concrete ring costs 90 baht. I'm using TWO interconnected holes for the solid waste silos (See photo below), to ensure that no grey water goes into the black water tank, and that no solid waste at all can escape to the leach pipe, whatever happens, including a serious flood after heavy rain, civil war or a military coup. My ground is solid clay so the seepage system won't work. I distribute my leach through a 4" perforated PVC leach pipe buried under my banana hedge.
The concrete rings were painted inside and outside with bitumen, and for added safety the pits were lined with PVC sheeting. The lids were tiled over to blend in with the patio and should never need removing. They have access for pumping out and are vented.

I have never heard of wax seals for toilet pans, (I have heard of paper rings you can put on toilet seats if you are worried who used it before you) but here you can buy a thick 4" diameter silicone rubber compression seal which is the same as what millions of klos are connected with all over Continental Europe. Based on an ancient Roman system, my toilets each have their own individual pipe to the septic tank, but as a previous poster mentioned, it is ESSENTIAL that you have a vented system if you are connecting several bog pans together. Otherwise, when you flush one, the suction created in the system will just drag the water out of the U-bends of the other bogs, leaving you without a stink trap. The vent should be as close to one of the toilets as possible, preferably at the back of the house, and the pipe should rise high enough for its opening to be above the head height of any passers by, because it WILL emit a foul smell if the system in your septic tank has been ruined by an overdose of Domestos.

Now go ahead and read this valuable thread - at your peril because it certainly stinks in places
:twisted: http://coolthaihouse.com/forum/viewtopic.php?t=468
Attachments
soak away.gif
X-section of a soak-away trench with its perforated pipe.
Jazzman's archives: source/artist unknown.
septic tank.gif
X-section of a septic tank. For the two chambers, Jazzman used three silos (see concrete rings above) joined by a piece of 4" PVC pipe.
drawing credit: Northern Arizona University
septic tank.gif (9.86 KiB) Viewed 5658 times
septic_system.jpg
Overview of septic system with a leech field.
Jazzman's archives: source/artist unknown.
Concrete rings.jpg
Various sizes. These are 75cm inside dia., 50cm deep, hold 220 litres each and cost 90 baht each. Calculate π x radius² x depth, to get the volume. We use two silos of three of these rings, one for heavy waste and one for greywater.
Last edited by jazzman on Tue Feb 24, 2009 6:49 am, edited 8 times in total.
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Postby jazzman » Tue Mar 20, 2007 9:04 pm

I should have mentioned that the concrete lids for some strange reason are more expensive than the rings. They cost 140 baht each.
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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby BillyBobThai » Mon Feb 23, 2009 12:46 am

Being from the rural portion of America, I have lived with septic systems all my life. I am no expert on septic tanks, but have had four systems installed when I built houses. Everything that you said seemed to me to be correct. The differences are as follows:

1. For the riser from the tank I used a 6 inch PVC pipe with a removable cap.The tank was fully covered with 18 inches of dirt.

2. A distribution box was not allowed. The leach field was one continous run. Length determined by the tank size. Last one I put in was 1,500 gallons with 500 feet of drain pipe.

3. You mentioned pumping a tank every 2 years. It is my understanding that as long as the biology is working correctly, you do not need to pump it out. In my 60 years, the only time I had to pump out a tank was when my propane delivery truck drove over the tank with a full load of gas and sank into the tank. :roll:

I love the site as it will help many of us here in the LOS.

Thanks
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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby jazzman » Mon Feb 23, 2009 12:30 pm

I mentioned pumping out every two years as a recommendation because 99% of all septic tanks in Thailand are either the wrong type, incorrectly installed, or just bad ad hoc designs without consideration for the soil type and processes involved.
The tank I constructed in Avignon was first emptied and cleaned after 7 years - prior to an enlargement for the extra guest rooms that were built.

I have seen septic tanks constructed for luxury homes here in Thailand that were completed in April. As soon as the first rainscame and the water table rose, the interior of the houses were covered with a strange, dark brown, evil smelling, slimmy substance...

I have rarely seen a tank constructed with anti-vacuum vents, adequate aeration, and an overflow pipe.
How to build a $20,000 / £14,000 house and a $???? MOTEL Updated 21 March 09 - with BOQ and costs
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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby tung » Mon Feb 23, 2009 11:51 pm

I thought you could buy these ready made, therefore eliminatiing problems?
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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby jazzman » Tue Feb 24, 2009 6:34 am

tung wrote:I thought you could buy these ready made, therefore eliminatiing problems?

I have already mentioned in many places on this board that these can be purchased ready-made. Member Apetly used one and had considerable problems with it: It broke and needed replacing, and it was also not installed correctly. They are far more expensive than a traditional concrete septic tank, which if designed and installed correctly will work perfectly. Please refer to to the dedicated septic tank postings above, and the details on my album.
How to build a $20,000 / £14,000 house and a $???? MOTEL Updated 21 March 09 - with BOQ and costs
Don't let this happen in YOUR house.
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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby gliffaes » Mon Mar 12, 2012 4:06 pm

If I have only one toilet waste pipe maximum 2 metres to septic tank,do I need to install an airvent or not in the pipeline apart from the one which will already be in the septic?
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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby fredlk » Mon Mar 12, 2012 4:53 pm

gliffaes wrote:If I have only one toilet waste pipe maximum 2 metres to septic tank,do I need to install an airvent or not in the pipeline apart from the one which will already be in the septic?

I have no extra air vents apart from the one on the tank and everything works well.
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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby thailazer » Mon Mar 12, 2012 5:47 pm

Regarding venting, the premium option is to run the vent from your septic system up through the roof with 2 inch pipe, letting it stick out 30 cm above the roof. Ground level vents tend to be "smellable" if you know what I mean. If you have a vertical run from your toilet, put in a 45 degree three-way fitting from your toilet and run a "stack" vertically to your roof vent. No need to vent your tank as it will vent through the sewage line to your house.
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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby MGV12 » Mon Mar 12, 2012 6:51 pm

The only vent I have is directly from my sewage tank and that terminates just above ground level. My reasoning is that if the tanks emits a smell I want to know about it as there is something wrong. A correctly installed and functioning propriety tank or concrete ring system will not emit smells. Mine hasn't in two years of use ... we don't allow chemicals to be used when cleaning the toilet .... and I don't expect it to in the future as none of my previous installations have.

We have three toilets discharging into one 1200L septic tank. One is on the second floor and the pipe runs directly to the tank ... the other two ground floor toilet outlets branch into that pipe. There is no need for a vacuum vent as they are not close to each other [the only time I have seen this 'suck back' condition occurring] and when you do a full flush on the upper toilet there is no affect on the other two. A 4" pipe will never be filled from a single toilet flush and so as the water drops towards the tank there is plenty of space for the air negating any potential vacuum to flow in reverse over the water.

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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby gliffaes » Mon Mar 12, 2012 10:34 pm

MGV12 wrote:The only vent I have is directly from my sewage tank and that terminates just above ground level. My reasoning is that if the tanks emits a smell I want to know about it as there is something wrong. A correctly installed and functioning propriety tank or concrete ring system will not emit smells. Mine hasn't in two years of use ... we don't allow chemicals to be used when cleaning the toilet .... and I don't expect it to in the future as none of my previous installations have.

We have three toilets discharging into one 1200L septic tank. One is on the second floor and the pipe runs directly to the tank ... the other two ground floor toilet outlets branch into that pipe. There is no need for a vacuum vent as they are not close to each other [the only time I have seen this 'suck back' condition occurring] and when you do a full flush on the upper toilet there is no affect on the other two. A 4" pipe will never be filled from a single toilet flush and so as the water drops towards the tank there is plenty of space for the air negating any potential vacuum to flow in reverse over the water.

Thanks MGV it did seem a bit OTT for ONE toilet so it will be removed from the build.
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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby geordie » Tue Mar 13, 2012 9:00 am

gliffaes wrote:

Thanks MGV it did seem a bit OTT for ONE toilet so it will be removed from the build.[/quote]

Another £1-25 saved :lol: :lol: :lol:
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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby gliffaes » Tue Mar 13, 2012 10:28 am

geordie wrote:
gliffaes wrote:

Thanks MGV it did seem a bit OTT for ONE toilet so it will be removed from the build.


Another £1-25 saved :lol: :lol: :lol:[/quote]
Yep gets me one step nearer that windsor upvc guttering Im trying to squeeze into this build hahahah.
Ive bought some of those special roof vent tiles at 800 baht a pop ( pricey) I want to get a cowl to go over them , probably get something made up so hot air can vent straight out of those but rain cant get in.
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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby gliffaes » Sat Mar 17, 2012 2:22 am

Ive actually posted this on "my build thread" but it may be better here, the bitumen paint? does anyone have a Thai name for this type of paint?? I have seen some bitumen type paint at Thai watsadu ( photo) but it seems pricey for 2.5 litres at 1750 baht, I mean the rings are now 300 baht each here ( not 90 baht) so add up 6 rings = 1800 baht + 1750 for paint for the 1st black septic and thats about 3550 baht already for 2 tanks when plastic tanks can now be had for 3k each. Ok so its still about half the cost but its not the cheap price it used to be.
Bitumen paint anyone??
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Re: An anecdotal approach to SEPTIC TANKS (illustrated)

Postby gliffaes » Sun Mar 18, 2012 7:53 pm

gliffaes wrote:Ive actually posted this on "my build thread" but it may be better here, the bitumen paint? does anyone have a Thai name for this type of paint?? I have seen some bitumen type paint at Thai watsadu ( photo) but it seems pricey for 2.5 litres at 1750 baht, I mean the rings are now 300 baht each here ( not 90 baht) so add up 6 rings = 1800 baht + 1750 for paint for the 1st black septic and thats about 3550 baht already for 2 tanks when plastic tanks can now be had for 3k each. Ok so its still about half the cost but its not the cheap price it used to be.
Bitumen paint anyone??

Ive quoted a price of 300baht for 80cm rings but in fact they are 130baht the ones that are 300b are the one ring which has base built into it of which I only need one.
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