WTK: septic system

[zagie]

looking for some info on what material to use in the catchment pits of a septic system to purify effluent, heard some say wash gravel, some say blue metal, some say coals, etc want to know who used what and was effective due to position of catchment pits(2) living close to ppl and dont want that awful smell to bother anyone and myself , also the process of filling the pits (aeration) etc

[hotknights]

Interesting qstn

[Gladiator]

The material does not matter... you just need to make up as much surface area as possible. Get some Guyacara (SP??) boulders.

The spaces between the bluemetal and gravel will be too small and will create a bio mat very quickly.

Coal is a bad idea... very bad

[88sins]

Material matters, but the soil conditions at the leach pit location are more important.
If the soil in the designated area is sandy or loam, large boulders as the base would be sufficient. For clay, you'll have to dig till you hit sand, & depending on where you are, that might end up being one deeeeeep leech pit.

[rspann]

If it's too much clay, and absorption is a problem, you could use a rubble drain leading away from the soak away. There are also other systems for the removal of water. I'm doing one right now with an aeration tank, and two submersible pumps working with a timer, in another chamber which then goes to a chlorination system . The water that comes out is clear and has almost no smell.

[rspann]

The material does not matter... you just need to make up as much surface area as possible. Get some Guyacara (SP??) boulders.

The spaces between the bluemetal and gravel will be too small and will create a bio mat very quickly.

Coal is a bad idea... very bad

Long ago people used bottles.

[streetbeastINC.]

JUST DO NOT use a pump to pump effluent into the roadside drain,,,,,,

[rspann]

You know a lot of people do that. You only have to pass by the drain and you will know who they are.

[streetbeastINC.]

report it,,,,,,this puts alot of stress on water treatment and can cause a plethora of diseases...that is not allowed alot of plumbers are installing this submersible pump system....its just nasty

[adnj]

All of these answers have some truth but the real answer depends on the height of the water table, septic tank size, soil type, and percolation test results.

The best answer was gladiator's answer. You need boulders to provide as much empty volume as possible in the soak away pit. Volume and depth of the pit matters a great deal but any non-porous stone will do. The leech field should be a fish bone pattern of perforated 2 inch pipe on top of 6 inches of 3/4 inch gravel. Cover the soak away and leech field with grass or other dense vegetation and no trees nearby. Consult with a decent plumber because there is a lot that can go wrong.

[rspann]

report it,,,,,,this puts alot of stress on water treatment and can cause a plethora of diseases...that is not allowed alot of plumbers are installing this submersible pump system....its just nasty

Do they just install pumps and put it in the drains ? Or do they put it through the chlorine on or UV light system to disinfect/ purify the effluent? What Water Source does is the aerobic systems and the UV system.

[Gladiator]

This is a good technical topic for discussion. Many local "plumbers" don't know squat and give bad advice.

The purpose of the boulders or bottles is to create a large surface area for the aerobic bacteria to live and treat the sewer after the anerobic bacteria in the septic tank does the initial digestion.

The second purpose of the boulders is to prevent the chamber from collapsing. Contrary to many, the soak away needs to "breathe" in order for it to work properly. In modern countries there are specially molded plastic shapes that are designed for maximum surface area that is used in soak away systems.

The final treatment is the actual leeching into the soil that filters etc. The boulders/gravel does not do filtering as people think.

One fundamental flaw in our "local" design is that a pit is just dug and filled with boulders. This design causes silt to move into the spaces in the boulders and clog it. In modern countries they use a perforated pipe 36" or so and pack the boulders inside. This prevents silting.

[rspann]

Good info there. Another thing many plumbers don't know ,is that the septic tank has to be filled with water up to the height of the bottom of the baffle wall before it is put into use. This prevents the solids (floaters) from going over into the liquid side, and going into the soak away.

What does your plumber use for creating bacteria?

[Gladiator]

I have seen plumbers suggest and use cheese, yogurt, dahee ... I cant say if it worked or not. However Peakes has something called BACKBITE that i heard works well.

[streetbeastINC.]

It does not matter if you ru it through uv dis or chlorination, no effluent from a septic soak away sys is to run into a road side drain.....

[adnj]

It's actually very important that you use vegetation in a leech field or surround a soak away. The bacteria that lives on plant roots will break down organics and the vegetation absorbs complex molecules that would otherwise be a contaminant.

The second purpose of the boulders is to prevent the chamber from collapsing. Contrary to many, the soak away needs to "breathe" in order for it to work properly. In modern countries there are specially molded plastic shapes that are designed for maximum surface area that is used in soak away systems.

The final treatment is the actual leeching into the soil that filters etc. The boulders/gravel does not do filtering as people think.

One fundamental flaw in our "local" design is that a pit is just dug and filled with boulders. This design causes silt to move into the spaces in the boulders and clog it. In modern countries they use a perforated pipe 36" or so and pack the boulders inside. This prevents silting.

The tank should be filled to the level of the outlet and activated before use.

The best activator is decomposed horse or cow manure. You can also throw some soil from the bottom of a compost heap in there. You really need the bacteria that breaks down cellulose fiber for the toilet paper.

Good info there. Another thing many plumbers don't know ,is that the septic tank has to be filled with water up to the height of the bottom of the baffle wall before it is put into use.

What does your plumber use for creating bacteria?

I have seen plumbers suggest and use cheese, yogurt, dahee ... I cant say if it worked or not. However Peakes has something called BACKBITE that i heard works well.

You can only run effluent to a surface drain or river it has been processed by an aerobic waste treatment system with final UV treatment and WASA sign-off. But that's usually for commercial buildings.

It does not matter if you ru it through uv dis or chlorination, no effluent from a septic soak away sys is to run into a road side drain.....

[streetbeastINC.]

Wasa approval and public health inspectorate, serious fines are now attached if breached ..

[Rory Phoulorie]

Just go with the recommended design for the soakaway on page 42 of the Trinidad and Tobago Standard "Guide to the Design and Construction of Small Buildings TTS 599: 2006".

[Monkey Man]

the perfect material to line your sespit is here bro...

[adnj]

This illustration shows you that the bottom of the pit should be in a "natural sand vein" that is at least 800 mm deep. You don't get to see that every time in some places.

This illustration can probably be blamed for more than a few of the premature failures of soak aways built locally. About five different posters already said that you need porous, well-drained soil. That is simply not the case in many areas but some people build it like that anyway because it's in the handbook. .

Just go with the recommended design for the soakaway on page 42 of the Trinidad and Tobago Standard "Guide to the Design and Construction of Small Buildings TTS 599: 2006".

Soakaway.jpg

[Chimera]

allyuh fellas real know allyuh sheit

[Rory Phoulorie]

This illustration shows you that the bottom of the pit should be in a "natural sand vein" that is at least 800 mm deep. You don't get to see that every time in some places.

This illustration can probably be blamed for more than a few of the premature failures of soak aways built locally. About five different posters already said that you need porous, well-drained soil. That is simply not the case in many areas but some people build it like that anyway because it's in the handbook.

With respect to the type of sewage treatment system that you would use for a development, you should do what is called a Percolation test. This will guide you on whether you could use a soakaway, an absorption trench or whether some other type of treatment system is required.

WASA will dictate where the Percolation tests should be done and they will witness the tests being conducted. WASA will then advise you on the sewage treatment system that should be used at your site.

The natural sand vein in the illustration does not mean that there sand needs to be naturally occurring at the site. It means that you need to place a layer of naturally occurring sand (as opposed to manufactured sand) in your soakaway.

WASA is the authority that will indicate the type of sewage treatment system that should be used at a site being developed and this will be determined from the percolation rate of the soil at the site.

[silent_riot]

Is rel sheit talk on the forum these days

[rspann]

adnj or rory, what do you recommend for high volumes of effluent?

[88sins]

adnj or rory, what do you recommend for high volumes of effluent?

stick the waste outlet up imbert's but, or in rowley's mouth.
both orifices are big enough, & I feel both well qualified to handle whatever volume of waste you could give them.

[adnj]

I'm sorry to disagree but that particular illustration is for sandy soil. There are different ways to build soak aways including surrounding the pit with sand and filling it with boulders. But you still need evaporation and filtration to eliminate the discharge.

Your design, again, will depend on water table, available space, soil type, and grade. There's more to it than just an absorption/percolation test.

With respect to the type of sewage treatment system that you would use for a development, you should do what is called a Percolation test. This will guide you on whether you could use a soakaway, an absorption trench or whether some other type of treatment system is required.

WASA will dictate where the Percolation tests should be done and they will witness the tests being conducted. WASA will then advise you on the sewage treatment system that should be used at your site.

The natural sand vein in the illustration does not mean that there sand needs to be naturally occurring at the site. It means that you need to place a layer of naturally occurring sand (as opposed to manufactured sand) in your soakaway.

As I said above, it depends. If the septic tank is properly sized and you have the space, a large soak away with a leech field is typically the most effective. The soak away acts as a distribution box. Other than that you're heading into coffins, aerators and electrical cables.

adnj or rory, what do you recommend for high volumes of effluent?

[Rory Phoulorie]

adnj or rory, what do you recommend for high volumes of effluent?

If you have the space, use ponds (facultative, maturation and polishing) to treat the effluent. This is what was used at the Tamana InTech Park in Wallerfield. No mechanical equipment to breakdown or to maintain. Only maintenance is desludging of the ponds every so often.

If space is at a premium, use a package treatment plant. You can contact WaterTech Limited (673-5453) or Aquatech Engineering Limited (640-0231) to see what systems they offer.