Septic Tank Installation

[cmsally]

Any pointers as to advantages/disadvantages on plastic septic tanks , also the concrete tubing variety.

Any info on cost, installation, advice gratefully received.

PS New house not old house ie starting from scratch

Tried a search but mainly about emptying them!

[necronx99]

There is a goodly discussion about them in this thread.

http://www.thaivisa.com/forum/topic/494413-bojangles-budget-bungalow-in-the-boonies/page__hl__septic%20tank__st__100

[Naam]

cmsally,

more info required to advise you. what size plot, what size built-up area, how many people will sh** and shower, define "concrete tubing", do you have space for a drainfield, space for separate gray water soaking tank and separate septic tank?

if possible forget ridiculous Thai style ready made plastic tanks, they are expensive and good for nothing except polluting the ground water and making money for the companies which empties them!

[transam]

Do you have government grey water sewer pipes to connect too ?, if yes then the fiberglass ones work great, filled with bio matter to break down your poo. Had mine 5 years and no probs. The concrete round type just drain the water into the ground and get bunged up so require regular pump outs.

[cmsally]

cmsally,

more info required to advise you. what size plot, what size built-up area, how many people will sh** and shower, define "concrete tubing", do you have space for a drainfield, space for separate gray water soaking tank and separate septic tank?

if possible forget ridiculous Thai style ready made plastic tanks, they are expensive and good for nothing except polluting the ground water and making money for the companies which empties them!

Basically - 2 rai of land with one average size house. Mostly only 2-3 people using but could be up to 10 for short periods (holidays). No local drain pipes as far as I can see. Last resort can be drained out of back into local waterway at the side of the rice field, but would obviously want it to be clean first!

Sorry by concrete tubing mean those concrete cylinders they stack in 3-4 deep to make tanks.

[slapout]

With the land area you describe, a plastic or concrete septic tank, which is divided, for solids with fluid overflow going out via perforated pipe into a soaker field. for soak away and evaporation. The basics, soil type, trench depth rock size/ fill, size of pipe/trench, depth should be known for the area as well as expertise of those supplying material and doing the job.

[T_Dog]

cmsally... We are going through this as well, and the majority of the advice we have gotten is use the plastic tanks with the fluid discharge from that going to a drainage field of perforated pipe over rock. The main advantage of the plastic tanks is that the bacteria stays very active digesting the, er, stuff, and ground water will not fill the tank during rains. For your size of house and occupants, a 1000 liter tank should be adequate. (We are putting in a 1600 liter unit.) Put it just below ground level and drop a 4 inch pipe with a screw on cap for clean out.

Also, you can use the rings for the grey water and kitchen drains which you want to keep separate from the toilet septic system.

Here is a link for more info:

http://www.coolthaihouse.com/forum/viewtopic.php?f=14&t=640

[Naam]

a 1000 liter tank should be adequate

i'm outta here

[necronx99]

a 1000 liter tank should be adequate

i'm outta here

1 cubic meter septic tank?

[expatmakmak]

Please consider moving to another, more relevant, forum. Yes we have septic tanks in Chiang Mai, too many some may say. But this is not really the place to be discussing them.

[Naam]

a 1000 liter tank should be adequate

i'm outta here

1 cubic meter septic tank?

the average Thai clown builder installs a 1.6m³ septic tank, septic eggsburts recommend 1m³ plastic tanks because in these the bacteria are very active

Edited January 25, 2012 by Naam

[Lite Beer]

Moved to do It Yourself Forum

[cmsally]

Bed time reading for me

http://www.epa.gov/owm/septic/pubs/homeowner_guide_long.pdf

[haveaniceday]

Right or Wrong, I am not sure, we ended up from the clue less builder with a set of rings for each toilet, and some grey water ones.

My question, the rings were not sealed, nor was the walls rendered, is this going to be a total night mare?

[sezze]

Right or Wrong, I am not sure, we ended up from the clue less builder with a set of rings for each toilet, and some grey water ones.

My question, the rings were not sealed, nor was the walls rendered, is this going to be a total night mare?

No , it is no problem since the water will be leaching out ... which normally would be the setup after all ( septic to leach ) . It is a problem if it is not supposed to leach out and you have a well next to it .

The "clueless "builder uses the system that by far the most Thai houses use , and there is nothing wrong with the system .

[slapout]

The use of the rings as a reservoir for waste/water is/was probably a makeshift solution before the proper plastic/cement ones were avaliable. Since running water, washing machines, flush tolets etc have come into common use, this system is overloaded rather quickly. The small lot size seen in many areas is too small for a proper leach field system, the plastic tanks need a fluid discharge method to work properly, so this system has been adopted by many builders as its also cheap and they use more than one in sequence. On a scale of 1 to 5, I would rate it a 2 with the old outhouse system a 1.

[Naam]

The use of the rings as a reservoir for waste/water is/was probably a makeshift solution before the proper plastic/cement ones were avaliable. Since running water, washing machines, flush tolets etc have come into common use, this system is overloaded rather quickly. The small lot size seen in many areas is too small for a proper leach field system, the plastic tanks need a fluid discharge method to work properly, so this system has been adopted by many builders as its also cheap and they use more than one in sequence. On a scale of 1 to 5, I would rate it a 2 with the old outhouse system a 1.

a fluid discharge doesn't make a plastic tank a "properly working system". any system where the discharged fluid does not drain into a minimum area that mother nature and her bacteria have space and time to do a proper job is polluting the environment.

besides, the ready made tanks available here have a flaw if used as they are used. the overflow/discharge section is much to small in comparison to the first section plus the tanks are meant for a drain field/drainage area! of course nobody, neither builder nor client, cares a sh*t because it involves spending an additonal few thousand Baht. that this money is well invested is unknown to ignorants. they prefer to have their sh*t tanks pumped out once in a while, not knowing that an initially properly planned system will save them a lot of hassle for years to come. although forbidden in my home country, i am quite familiar with septic systems since more than 35 years. have never lived in a home (designed by me) where a tank had to be pumped out.

edited because of typos

Edited January 27, 2012 by Naam

[Naam]

Right or Wrong, I am not sure, we ended up from the clue less builder with a set of rings for each toilet, and some grey water ones.

My question, the rings were not sealed, nor was the walls rendered, is this going to be a total night mare?

No , it is no problem since the water will be leaching out ... which normally would be the setup after all ( septic to leach ) . It is a problem if it is not supposed to leach out and you have a well next to it .

The "clueless "builder uses the system that by far the most Thai houses use , and there is nothing wrong with the system .

basically you are right because the concrete ring system is any day better than the black plastic tank without a drainage area except if the ground is too hard that fluids cannot seep in.

[slapout]

Anyone who knows sh/t about septic systems knows that the design of the septic system has more to do with the number of people using the system, system used/chosen/proven, etc, than the house design. Throw in the lot size, soil type, rainfall, average dry season temp., etc and then you can approach the problem of safe desposal of waste material. The plastic tanks are normally smaller than the cement units poured on site in another world, but I would hazard a wild extimate if both were the same size in physical construction, maintaned/sized properly, neither would need a pump out. Granted there are some parts of the world where the inexperienced builder may find both will foat out of the ground during the heavy rain season but that is another reason for anchors.

[bankruatsteve]

I don't know for sure what the diff between plastic/concrete but if you want a septic SYSTEM then you need a leach field/pit. Or, you need the purple trucks come several times a year. Given that, I doubt there is much difference. Anyway... no matter what you use, separate the container for black/grey. eg: the poop doesn't need any detergents (like from washing) to kill the bacteria that it needs.

[ozzydom]

I spent many hours of the first couple of years of my plumbing and drainage apprenticeship up to my armpits in septic tanks and sewers so I can speak with some authority on the subject.

My first piece of advise is do it right the first time as its not an easy chore to change later.

A septic system comprises two compartments, the primary is where the effluent from your toilet is flushed to and where most of the bacterial action takes place,this is separated from the secondary chamber by a partition with a hole low down, this is where the grey water moves to this secondary chamber and exits high up to the soakage trench(french drain in Ozzy speak ).

Early french drains were simply a length of trench filled with medium size crushed metal ,covered in heavy duty plastic sheet and back filled.

The french drain is just a repository for the grey water while it soaks away into the surrounding soil.

Note... always ensure you have enough soakage pit to retain the grey water on your own property.

I built my own septic system which emits no odours and has not needed pumping for 6 years.

It is simply two stacks of 4x1 metre rings,about 60cm apart joined by a 4 inch PVC pipe at the bottom and a 4 inch outlet pipe close to the top of the second stack going to the soakage drain.

The first stack works on the principle that most poo floats while it is broken down by bacterial action. The level in both tanks is equal and grey water enters the second chamber via the low connection and when the fluid level reaches the outlet pipe ,away it goes.

The amount of fluids exitting to the soakage trench is equal to the quantity that is flushed and the longer the poo can remain in the first chamber the more broken down it is ,so bigger is always better.

[sirineou]

I spent many hours of the first couple of years of my plumbing and drainage apprenticeship up to my armpits in septic tanks and sewers so I can speak with some authority on the subject.

My first piece of advise is do it right the first time as its not an easy chore to change later.

A septic system comprises two compartments, the primary is where the effluent from your toilet is flushed to and where most of the bacterial action takes place,this is separated from the secondary chamber by a partition with a hole low down, this is where the grey water moves to this secondary chamber and exits high up to the soakage trench(french drain in Ozzy speak ).

Early french drains were simply a length of trench filled with medium size crushed metal ,covered in heavy duty plastic sheet and back filled.

The french drain is just a repository for the grey water while it soaks away into the surrounding soil.

Note... always ensure you have enough soakage pit to retain the grey water on your own property.

I built my own septic system which emits no odours and has not needed pumping for 6 years.

It is simply two stacks of 4x1 metre rings,about 60cm apart joined by a 4 inch PVC pipe at the bottom and a 4 inch outlet pipe close to the top of the second stack going to the soakage drain.

The first stack works on the principle that most poo floats while it is broken down by bacterial action. The level in both tanks is equal and grey water enters the second chamber via the low connection and when the fluid level reaches the outlet pipe ,away it goes.

The amount of fluids exitting to the soakage trench is equal to the quantity that is flushed and the longer the poo can remain in the first chamber the more broken down it is ,so bigger is always better.

Interesting design.Thank you for sharing.

A little more information would be appreciated as I will be building soon and was thinking along the same lines as you.

How many rings in each stack is adequate for an average house?

Did you seal the bottom and the rings to prevent discharge to the ground from the stacks and water entering the holding stacks from ground water?

How high from the bottom is the connecting 4" pipe?

How high from the top is the discharge pipe?

at what angle decline did you set your soakage (leach field) to enhance discharge and to prevent ground water from entering your holding tanks?

Did you use perforated pipe in your leach field?

Did you use gravel in your leach field?

[ozzydom]

I spent many hours of the first couple of years of my plumbing and drainage apprenticeship up to my armpits in septic tanks and sewers so I can speak with some authority on the subject.

My first piece of advise is do it right the first time as its not an easy chore to change later.

A septic system comprises two compartments, the primary is where the effluent from your toilet is flushed to and where most of the bacterial action takes place,this is separated from the secondary chamber by a partition with a hole low down, this is where the grey water moves to this secondary chamber and exits high up to the soakage trench(french drain in Ozzy speak ).

Early french drains were simply a length of trench filled with medium size crushed metal ,covered in heavy duty plastic sheet and back filled.

The french drain is just a repository for the grey water while it soaks away into the surrounding soil.

Note... always ensure you have enough soakage pit to retain the grey water on your own property.

I built my own septic system which emits no odours and has not needed pumping for 6 years.

It is simply two stacks of 4x1 metre rings,about 60cm apart joined by a 4 inch PVC pipe at the bottom and a 4 inch outlet pipe close to the top of the second stack going to the soakage drain.

The first stack works on the principle that most poo floats while it is broken down by bacterial action. The level in both tanks is equal and grey water enters the second chamber via the low connection and when the fluid level reaches the outlet pipe ,away it goes.

The amount of fluids exitting to the soakage trench is equal to the quantity that is flushed and the longer the poo can remain in the first chamber the more broken down it is ,so bigger is always better.

Interesting design.Thank you for sharing.

A little more information would be appreciated as I will be building soon and was thinking along the same lines as you.

How many rings in each stack is adequate for an average house?

Did you seal the bottom and the rings to prevent discharge to the ground from the stacks and water entering the holding stacks from ground water?

How high from the bottom is the connecting 4" pipe?

How high from the top is the discharge pipe?

at what angle decline did you set your soakage (leach field) to enhance discharge and to prevent ground water from entering your holding tanks?

Did you use perforated pipe in your leach field?

Did you use gravel in your leach field?

sirineou,Three rings is the norm hereabouts so I went one more and it has worked well ,so that is what I would recommend .

Both stacks were placed on 2 inch precast concrete slabs and all joints were sealed with Sikaflex FC.

The top sealing slabs are sealed likewise with a 3/4 inch pvc vent on each stack.

The connecting pipe is 6 inches centre from the base, I gave more clearance so that the ring did not crumble while I made the holes, I picked the hole out the old fashioned way with a jointing chisel ground to a point and rehardened,

I sealed the inside joint with Sikaflex and boxed the pipe in concrete between the stacks,you dont want it to come adrift down there once its installed.

The discharge is the same 6 inch centre from the top,the discharge pipe (5 foot in length) is virtually level with a downwards facing elbow into the soakage trench (note... the tops of my stacks are about 2 inches above ground level )

The french drain is 2 foot wide and 30 inches deep, it is filled with 1-2 inch crushed rock to 2 foot depth then 3 layers of heavy black plastic sheeting (from Global; House,the top layer is cut wider to turn it up the side of the trench,this helps stop sand getting down the sides when you backfill.

It may not be a Rolls Royce but it was a matter of making do with the materials available in our small town.

In our village ,all sullage (water from showers sinks etc )goes direct to the street drains so I built a grease trap to the same principal only much smaller ,the top of the primary ring slides off to scoop out the set grease about once a month.

Edited January 30, 2012 by ozzydom

[sirineou]

I spent many hours of the first couple of years of my plumbing and drainage apprenticeship up to my armpits in septic tanks and sewers so I can speak with some authority on the subject.

My first piece of advise is do it right the first time as its not an easy chore to change later.

A septic system comprises two compartments, the primary is where the effluent from your toilet is flushed to and where most of the bacterial action takes place,this is separated from the secondary chamber by a partition with a hole low down, this is where the grey water moves to this secondary chamber and exits high up to the soakage trench(french drain in Ozzy speak ).

Early french drains were simply a length of trench filled with medium size crushed metal ,covered in heavy duty plastic sheet and back filled.

The french drain is just a repository for the grey water while it soaks away into the surrounding soil.

Note... always ensure you have enough soakage pit to retain the grey water on your own property.

I built my own septic system which emits no odours and has not needed pumping for 6 years.

It is simply two stacks of 4x1 metre rings,about 60cm apart joined by a 4 inch PVC pipe at the bottom and a 4 inch outlet pipe close to the top of the second stack going to the soakage drain.

The first stack works on the principle that most poo floats while it is broken down by bacterial action. The level in both tanks is equal and grey water enters the second chamber via the low connection and when the fluid level reaches the outlet pipe ,away it goes.

The amount of fluids exitting to the soakage trench is equal to the quantity that is flushed and the longer the poo can remain in the first chamber the more broken down it is ,so bigger is always better.

Interesting design.Thank you for sharing.

A little more information would be appreciated as I will be building soon and was thinking along the same lines as you.

How many rings in each stack is adequate for an average house?

Did you seal the bottom and the rings to prevent discharge to the ground from the stacks and water entering the holding stacks from ground water?

How high from the bottom is the connecting 4" pipe?

How high from the top is the discharge pipe?

at what angle decline did you set your soakage (leach field) to enhance discharge and to prevent ground water from entering your holding tanks?

Did you use perforated pipe in your leach field?

Did you use gravel in your leach field?

sirineou,Three rings is the norm hereabouts so I went one more and it has worked well ,so that is what I would recommend .

Both stacks were placed on 2 inch precast concrete slabs and all joints were sealed with Sikaflex FC.

The top sealing slabs are sealed likewise with a 3/4 inch pvc vent on each stack.

The connecting pipe is 6 inches centre from the base, I gave more clearance so that the ring did not crumble while I made the holes, I picked the hole out the old fashioned way with a jointing chisel ground to a point and rehardened,

I sealed the inside joint with Sikaflex and boxed the pipe in concrete between the stacks,you dont want it to come adrift down there once its installed.

The discharge is the same 6 inch centre from the top,the discharge pipe (5 foot in length) is virtually level with a downwards facing elbow into the soakage trench (note... the tops of my stacks are about 2 inches above ground level )

The french drain is 2 foot wide and 30 inches deep, it is filled with 1-2 inch crushed rock to 2 foot depth then 3 layers of heavy black plastic sheeting (from Global; House,the top layer is cut wider to turn it up the side of the trench,this helps stop sand getting down the sides when you backfill.

It may not be a Rolls Royce but it was a matter of making do with the materials available in our small town.

In our village ,all sullage (water from showers sinks etc )goes direct to the street drains so I built a grease trap to the same principal only much smaller ,the top of the primary ring slides off to scoop out the set grease about once a month.

Thank you for taking the time to answer my questions, I will design a similar system for my house, the only thing I might do a little different would be to install the connecting pipe a little higher from the bottom allowing more room for the sludge to accumulate .