DOS septic tanks

[eyecatcher]

Does anyone have any comments or advice about these hand grenades.

Is a 1000litre tank too big for two persons?

Is the filtrate already inside the sectioned off part or is are still bucketfuls of chemical to add.

Should they ever need maintenance?

Or should i be looking at the wave brand or elephant brand?

Thanks

[Crossy]

You can never have a septic that's too big

We have two of the 1m³ units for our 3 bed home although there's usually just the two of us resident.

They will normally self-start but you can get bags of 'starter culture' to flush down the loo (some recommend dropping a dead animal in).

Maintenance, if the septic is working correctly, is a pump out of the sludge every few years (when the loo starts getting slow to flush).

[IMHO]

Generally speaking 1000L is plenty for a single toilet, and 1600 plenty for 2 toilets. If you have big parties you might want to consider 1600L per toilet though

[T_Dog]

We used a 1600 liter Hero tank feeding a 4 ring tank open at the bottom for three people. The output of that went to a drainage field which was about 80 cm of 1 inch round stone with a plastic sheet cover and earth on top of that. Never had a problem in six years. The drainage field was probably overkill but it was easier to put it in at the early stage rather than later. PM me if you want photos.

[IMHO]

We used a 1600 liter Hero tank feeding a 4 ring tank open at the bottom for three people. The output of that went to a drainage field which was about 80 cm of 1 inch round stone with a plastic sheet cover and earth on top of that. Never had a problem in six years. The drainage field was probably overkill but it was easier to put it in at the early stage rather than later. PM me if you want photos.

We do the same sort of thing when the septic tank is in a confined space (e.g. when there's only a couple of meters between the house and the fence) - except we run the septic output into a bottomless concrete ring "tank" at least 3M down. No further overspill/outlet.

[eyecatcher]

Generally speaking 1000L is plenty for a single toilet, and 1600 plenty for 2 toilets. If you have big parties you might want to consider 1600L per toilet though

Are you suggesting I am a party pooper

[eyecatcher]

(some recommend dropping a dead animal in).

Any suggestions; or should I ask Global if they can supply.

Thats got to be the most bizarre piece of advice you......or anyone else has ever given?

Anyone beat that?

[canopy]

It's easy to see that Thai's are happy to pump their cesspits frequently so when they choose a septic tank, they just get a small one that in turn needs pumped frequently and the trucks dump it all in an environmentally insensitive way. Thai's also don't care about groundwater contamination so the outlet from these undersized tanks that aren't as effective as big tanks for treating waste usually goes to a pit rather than getting biological treatment in a drain field. In the 21st century it's just not necessary to make up a system that clogs easily and pollutes the environment when the rest of the world has developed simple rules that solved these problems for generations. It may be of interest to note the smallest legal size of a septic tank in the state of Florida, which has a similar climate, is 3400 liters. And in many cases they need to be, and are much larger than that. Moral of the story is if you want a system that is long lasting and good for the environment to boot, don't choose septic tank size arbitrarily by just putting a finger up in the air or looking at what other incompetent people around you are doing. Look it up. If you are smart enough to post here, then you are smart enough to look it up. Also it's a good idea to opt for a multi-chambered unit. Some building codes require 2 or even 3 chambers to maximize treatment.

Edited June 4, 2015 by canopy

[kamalabob2]

Canopy has some very good observations. The OP posted a photo of a low end DOS septic tank, when in fact DOS offers multi chamber septic tanks that any full line DOS dealer could offer in Thailand. I installed three of the 1000 liter DOS septic tanks that have dimples in 2008. One septic tank is fed by two toilets and one urinal each. I would have purchased larger DOS septic tanks for my home but there was a mix up where a lot line was "changed" and a fence put in place where it was not expected. The slope from the bathroom toilets to the actual septic tank played a major role in how many septic tanks we installed. Once a year we put a bag of the "starter' in the septic tank and in 7 years there has never been a need to call out the honey bucket. The DOS ST-20/BK is far superior to cement rings and if that is the 1000 liter tank offered where the OP lives he would be wise to buy that septic tank at Global House if they offer free delivery. SAFE is a popular brand of water tank in Buriram and they offer at least two series of septic tanks that are worthwhile for the OP to consider. Elephant brand is not in the same specs of water tanks as DOS or SAFE if you check the printed brochures. Most any builders merchants can offer good quality septic tanks including DOS and SAFE brand tanks, but the delivery options might make one store a better source than a chain store. I see the exact same DOS septic tank for sale for 200 baht less and no charge for delivery at a family owned builders merchant store in Buriram. There might be a similar lower overhead store for the OP to consider where he might receive customer service in English from the owner of the store in his part of Thailand.

[Retdent]

Post #7

Common in rural Australia to start your system off by dumping a dead cat into it. Cats maybe have the correct bacteria in their gut systems. I have noticed a few road kills, just have a bag handy next time you see one.

[canopy]

My guess is...

And in the 21st century why guess? There is absolutely no need to do that when the answers are online free and easy. Just choose a reliable source to your liking and you have chosen a solid system size. Be forewarned 1000 liters sometimes doesn't work. Numerous people have had problems with that size. So it would be stupid to listen to a single observation that says "it worked for me" and flat out ignore the rest of the people's experiences. And studies have been done, calculations performed, and easy to read material released to help your decision. It shouldn't take even 2 minutes to look up the right septic size for your purposes. It may be less than 1000 liters. Or more. Or equal. You could end up saving some money. Regardless it means you've made a large step in assuring your system has a chance of performing great.

One other note. It is short sighted to calculate based on how many people are currently reside a dwelling. It can fluctuate over time and if it's ever more than that, then what. Again there are easy to follow guidelines to help.

[eyecatcher]

Likewise I could have looked it up also.

Does your car actually do 36mpg?

I want advice and real experiences from westerners who have tanks or whatever the topic is.

I will take that advice every time over some hyped up piece of wiki junk every time.

I will check tank volumes or pump presures as a final check.

Keep the anecdotes coming guys.

[T_Dog]

A lot of the info on the exalted internet comes from the west where grey water is put in the same tank as human waste, which does not apply to Thailand. The Thai system of having separate systems for human waste and grey water is very efficient as it gives the human waste much more "dwell time" to decompose. Those plastic tanks with two chambers are designed to optimize that process. Eyecatcher.... Is your shower water and sink water going to a separate system? Would be wise to follow the Thai convention as it works well.

[canopy]

where grey water is put in the same tank as human waste

Exactly right. And so if separating blackwater from greywater, which you probably are, that's an excellent factor to take into account when choosing your source since it reduces the size needed. Typically a size that yields 4 days retention time is considered to be very good.

I will take that advice every time over some hyped up piece of wiki junk every time.

Simple solution: if you don't like wiki junk, then don't read it. Simple as that. There are plenty of sources of reliable information to choose from. If you can't be bothered to look anything up, you'll simply be repeating the mistakes of the past which in the 21st century is completely avoidable and ludicrous.

Hey Arjen, your research stinks haha. Sorry, couldn't resist.

[eyecatcher]

Yes of course there are plenty of good info websites and my reference to wiki junk was an arbitrary all in one not actually that particular site.

TDog. At the moment my house grey water, waters the neighbouring longan orchards which was naughty of the previous house builder but my builder here had suggested that the grey is piped into the drain system which appears to be a pipe outflowing into the khlong but not entirely sure on that.

[passingas]

(some recommend dropping a dead animal in).

Any suggestions; or should I ask Global if they can supply.

Thats got to be the most bizarre piece of advice you......or anyone else has ever given?

Anyone beat that?

If two different people are using the system, the different bacteria from the two different people's excrement is enough to get the bacteria going. It is all about anaerobic bacteria and if you want to make sure...you can use milk dumped into the toilet and flush into the system (milk has bacteria that will fortify the other ones). My dad was a plumber for 40 years and told me about this. Not sure why one individual using the system wouldn't kick start it, but he always said two or more. I sure as hell wouldn't throw an animal carcass into it. But...if you're in Rome....do it as they would. pg

[passingas]

I use two of these plastic type anaerobic septic tanks for three toilets. The larger one (1200 lt) takes the two and the single is going into a 1000 lt one. Then...the effluent from both go to secondary settling tanks (two)....just the concrete rings with the bottom one actually having a bottom in it...then the output of these both go to a single tertiary aerator tank (concrete rings again) where I have designed and made my aerobic septic system to treat the liquid effluent with continuous air bubbling via a large aquarium pump (last one went 24/7/5 years before I had to replace it) and it dumps via a submersible sump pump with a float switch...out into the naa, after intense aeration. I could not put in a leach field as we live in a hard pan clay area which is primo for rice farming. It works wonderfully. I was able to see for myself as the system filled...it took a month almost for all the tanks to fill (water in-water out) before it filled the secondary settling tanks and then make its way to the last aerator tank. There it took almost a week before the sump pump kicked in and I was able to see (with all the lids off the three tanks, not the plastic ones, as they were already in the ground and covered up). The final effluent coming into the aerator tank was black as could be and had a distinct oder with it, as to be expected. Within 24 hours of aeration, the color had changed to a weak tea brownish color and absolutely, no oder. After a few days, I tripped the float switch to make sure all was working and then put all the concrete lids on. By the way...make sure you fill the plastic tanks with water after they have been backfilled...or they can dislodge after a bit rain event and float up out of your back fill and you'll have to redig it again...I've seen his happen before. Keep in mind....the water (some solids in the initial phase)in-water out. The solids sink where the healthy anaerobic bacteria eats it all away and the flush water in....goes out. So when all is said and done...you can flush the toilet and then hear water going into the last tertiary aerator tank a few minutes later. Happy digestion! pg

[Netease]

One thing hasn't been mentioned in this thread. People taking Antibiotics' and using your toilet can kill the good bacteria in your septic tank, I also believe surface area in your tank is most important for the decomposing of the waste, I would often open the small inspection opening and see the crust being munched by the bugs and listen and you will hear the bugs going to town. If no noise or movement in the crust means your bugs are dead and you should clean your tank out and fill with non chlorinated water again. I have never had to add bugs to get the systems working again. These are my experiences.

[Naam]

One thing hasn't been mentioned in this thread. People taking Antibiotics' and using your toilet can kill the good bacteria in your septic tank, I also believe surface area in your tank is most important for the decomposing of the waste, I would often open the small inspection opening and see the crust being munched by the bugs and listen and you will hear the bugs going to town. If no noise or movement in the crust means your bugs are dead and you should clean your tank out and fill with non chlorinated water again. I have never had to add bugs to get the systems working again. These are my experiences.

-there is no "crust" forming in a properly working septic tank,

-nobody can hear bacteria munching,

-have you ever tried writing science fiction novels?

[Netease]

Little you know

[eyecatcher]

Little you know

I just wonder if you are confused between septic tank and cesspit; which does have some rapid activity on the surface if you ever decide to pull out the concrete plug.

Not sure i would describe it as a crust though.

My favourite part of bread.......and you just ruined my chicken baguette sarny.

[Netease]

I am only putting forward my experience with septic tanks on 3 properties I have owned over a 30 year period, I have installed tanks and evaporation trenches to council regulation in Queensland

[Netease]

https://en.m.wikipedia.org/wiki/Septic_tank

[Netease]

Read the description section of this article where it talks about the crust

[Netease]

Apologies will be accepted

[Naam]

It's easy to see that Thai's are happy to pump their cesspits frequently so when they choose a septic tank, they just get a small one that in turn needs pumped frequently and the trucks dump it all in an environmentally insensitive way. Thai's also don't care about groundwater contamination so the outlet from these undersized tanks that aren't as effective as big tanks for treating waste usually goes to a pit rather than getting biological treatment in a drain field. In the 21st century it's just not necessary to make up a system that clogs easily and pollutes the environment when the rest of the world has developed simple rules that solved these problems for generations. It may be of interest to note the smallest legal size of a septic tank in the state of Florida, which has a similar climate, is 3400 liters. And in many cases they need to be, and are much larger than that. Moral of the story is if you want a system that is long lasting and good for the environment to boot, don't choose septic tank size arbitrarily by just putting a finger up in the air or looking at what other incompetent people around you are doing. Look it up. If you are smart enough to post here, then you are smart enough to look it up. Also it's a good idea to opt for a multi-chambered unit. Some building codes require 2 or even 3 chambers to maximize treatment.

Volusia County Florida requirements based on my last home with four bathrooms (occupants irrelevant!) 3-chamber tank each chamber minimum 1,000 gallons plus drainfield of 2,400 sqf (225m²) if natural slope drain or 1,600 sqf (150m²) if forced drainage by pump.

[Naam]

Apologies will be accepted

no apologies because the definition of "crust" is "hardened layer". a working septic system has no hardened layers anywhere and definitely no "bugs" who's "noise" one can "hear munching that crust".

by the way, the quoted wiki site starts with:

Septic tankThis page has some issues

it sure has!

[kamalabob2]

I bought three DOS brand septic tanks for a six bathroom home located in a Buriram Province small town. For a new lower cost village two car garage granny unit apartment unit, I bought a DOS septic tank for the one bathroom. It was delivered and installed by a local builders merchants store that also provided the water pumps, water filter and DOS water storage tanks for the village modest house. Delivery was free as my new home is only 55 kilo from the Buriram Store where I bought the DOS Septic tanks and DOS water tanks. Installation of the septic tank and installation of the water pumps was an agreed upon fee in advance paid to the store owner. There were no moonlighting employees and I have a guarantee on all the installations. Same store did the Franklin Schaefer well pump installation, but not the well drilling. The large truck in the photo dropped off the tank at the road and men carted it onto the property with no damage. I bought the same DOS water tanks that are installed at a friends home building site in Buriram.