Pozo negro

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edna
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Pozo negro

Postby edna » Thu Sep 15, 2005 8:49 pm

Does anyone have any info about starting off a new pozo negro, I have heard that you cannot use any bleach cleaning products to start with, but that when the bacteria is established you can. Is this correct and what sort of time period are we talking about, not too long I hope! Any other info gratefully received.
Many Thanks.

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hillybilly
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Postby hillybilly » Thu Sep 15, 2005 9:56 pm

Nothing special needed, just start using it. Not even necessary to fill up with water before use (but add hot water to the system initially as often as possible esp if starting up in winter when it's cold). The bacterial process of breakdown and digestion will start naturally as the solids start to accumulate in the tank. There are products on the market for "seeding" the tank with bacteria but really shouldn't be necessary.
Household bleach products are OK if you don't go over the top with them. Yes, they'll kill off some bacteria but your system should be able to cope as long as it's in permanent use. Avoid putting any grease or fats into the tank and all the other nasties which I'm sure you know about. Be aware that some medications (in one end, ahem, out the other..) can have an adverse effect on your tank!

nevada smith

Postby nevada smith » Thu Sep 15, 2005 9:56 pm

edna,
i posted something on this about 3 years ago... same forum...
so, let's start with the basics:
1. then, as now - pozo negros are illegal!
(they may be being built, but they are still illegal)
2. describe your 'pozo negro' - i.e. how it is built, how it's supposed to work, where it is... etc)
3. do you have a 'septic tank' between your waste water and your 'pozo negro'? - if so, describe your 'septic tank' - (same as your pozo negro)
with this information - we can open this for discussion...

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silver
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Postby silver » Fri Sep 16, 2005 7:38 am

A pozo negro..is just a hole bricked in a special way to act as filter...and are not allowed any more.
No muerdes la mano que te da de comer.

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jpinks
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Postby jpinks » Fri Sep 16, 2005 9:25 am

If you actually mean a Septic Tank, that is a good way of dealing with sewerage. The tank needs to be a good size, about half a cubic metre per person in the house, so a three bedroomed house would have a 6cubic metre tank. You can reduce this if the bedrooms are not in continuous use - proportional to the time people are there. Better too big than too small though.
Make sure the outflow goes into a reedbed to completely clean the outflow. You might want to build a small reedbed tank especially for that purpose, and then the authorities test the ouflow after the reedbed, and it will always pass.
A small quantity of some chemicals will not harm a well-established septic tank, but during the start-up phase they are very delicate. Better to use products like ecover detergents which are non-chemical. Do not dspose of any medications through either the tank or the reedbed, antibiotics will kill a large amount of the bacteria which you need in there.
Do not put all your waste through the septic tank - only the sewerage. Use your grey-water waste for irrigation, or put it through a large reedbed.
I had a septic tank (in Scotland admittedly) for many years, and it gave no trouble, no smell and didn't need emptying. The normal action of the bacteria will break up the solids to be water soluble and the reed-bed does the rest.
If a septic tank is needing emptied it is because it does not have enough bacteria, has had too much water through it (probably the washing machine, etc) and is possibly not big enough.
There is the choice of a composting toilet - no water at all. Many people around here use those, especially as they are on private water supplies which are limited.
Slainte,
JohnP.

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country boy
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Postby country boy » Fri Sep 16, 2005 7:00 pm

:D Edna...are we talking "Pozo Negro" or "Septic Tank"? Pozo Negro is just a hole in the ground and requires no consideration other than when it gets full!
Septic Tanks get everything they need from the first "flush"!...think of them as a liquid compost heap, the bugs love food bits, sour milk and human waste, they can cope with moderate amounts of bleach and cleaning materials but not brine . do not let your water softner back-flush discharge into it ( if you have one) , the bugs will not survive that. Otherwise treat them as friends, any chemical you wouldn't like being poured on you extensively...they won't :lol: :lol:

edna
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Postby edna » Fri Sep 16, 2005 8:22 pm

Country Boy,
The builder has put a pozo negro in. Very common in the rural parts here, its a hole in the ground away from the house which is brick lined, concrete beams and blocks for the roof, with concrete layer over the top. There is an access hole, but unlike a septic tank I dont think its for emptying only if there is a problem inside. The builders contract states the building of the pozo negro as part and parcel of the other renovations.
Many thanks
Edna

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kevin77
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Postby kevin77 » Fri Sep 16, 2005 8:32 pm

A pozo negro is not a septic tank as we know it but a cesspit - basically a hole in the ground which your *beep* flows into - popular in medieval times I believe.

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country boy
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Postby country boy » Fri Sep 16, 2005 8:37 pm

:) Yes that is very common in rural Spain and you have no problems, even though the purists will tell you it has been illegal since 2002 (which it is!) but the old ways prevail in rural Spain ...God Bless Them!!
Basically you have a huge hole in the ground into which you can pour anything you choose...don't even begin to think about the water table !!!!!!!
It's highly unlikely that you will ever need to remember you have a Black Pozo during your lifetime as they are very capacious and some bacterial degradation does go on . The only real problem is if you live on the irrigation levels where the water table is higher, then in a wet year you may find it overflowing (NOT NICE): Also it is Illegal and if you want to sell that might cause a problem, but you are in good company as the Spanish are still building them and most people don't give a fig!! Enjoy the sun and forget it!!

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kevin77
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Postby kevin77 » Fri Sep 16, 2005 9:47 pm

Thats right Country Boy, open another bottle of Cruzcampo as you sit on the patio and live the dream!
It doesnt get much better than this.
Wait a minute - whats that smell? and the flies!

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Postby Nikvin » Fri Sep 16, 2005 9:59 pm

I was told that one of the best ways to get one going, and (apparently what the locals do) is to throw a dead dog/sheep/goat or similar in there when you finish buiding it!
actually more eco friendly than chemicals!!

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hillybilly
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Postby hillybilly » Fri Sep 16, 2005 10:10 pm

Yes, that's one of the old wives' tales associated with septic tanks.
Dead livestock or not avoid using antibacterial soaps, washing up liquids etc for obvious reasons.

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kevin77
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Postby kevin77 » Fri Sep 16, 2005 11:38 pm

Why not install a modern plastic septic tank? With proper vents there will be no smell. But you have to empty it when its full.
Surely there are companies who will pump it out every few months?
There must be a market for this in Andalucia?

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Postby k » Fri Sep 16, 2005 11:48 pm

Without wishing to hijack Edna's thread, Can some of the answers be expanded on.
I have two farmhouses, semi's that have (at the moment, as far as I am aware) seperate pozo negros, and have been discussing putting in a shared or individual septic tank. Based on what has been said so far, I will be speaking to my fabulous builder friend about the possibility of just using the septic tank for waste and keeping the pozo for grey water. The first two questions relates to the legality. The house (one house originally) is older than I feel at the end of the working week, so at one point was the norm.
1. Does this mean that I must replace as it is now illegal, or, does it just relate to new buildings ?
2. Dependant on above, if I do as I am now thinking of doing, by putting in a septic tank for waste and seperating grey water, will this solve any legal issue and poss problems if I ever sell ?
Secondly as a generall question, I think (?) we are within range of mains sewerage, has anyone had experiance of applying for connection and likely costs.
Thirdly, it has been said the tank should be half cubic metre per person, is this based on just waste matter ?
Finally, Is the reed bed a further recomendation to assist in the cleaning process of a septic tank or is it essential. (where do you get the reeds?)

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kevin77
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Postby kevin77 » Sat Sep 17, 2005 12:00 am

the tank should be half cubic metre per person

Depends on your diet. Are you drinking any Guinness?

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silver
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Postby silver » Sat Sep 17, 2005 6:34 am

k
Tourist
we are within range of mains sewerage, has anyone had experiance of applying for connection and likely costs.
This is your best solution.
No muerdes la mano que te da de comer.

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jpinks
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Postby jpinks » Sat Sep 17, 2005 9:04 am

kevin77 wrote:
the tank should be half cubic metre per person

Depends on your diet. Are you drinking any Guinness?

Guinness is good for septic tanks :)
Slainte,

JohnP.

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jpinks
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Postby jpinks » Sat Sep 17, 2005 9:41 am

k wrote:......
Thirdly, it has been said the tank should be half cubic metre per person, is this based on just waste matter ?
Finally, Is the reed bed a further recomendation to assist in the cleaning process of a septic tank or is it essential. (where do you get the reeds?)

The half cubic meter per person is for a long-term septic tank which will not need emptying because the bacteria have time to deal with everything in there.
The reed-bed is simply some reeds which you buy in any viveros, planted in the outflow or in a small open tank which catches the outflow. Almost any of the water reeds will do the job, and papyrus will grow well in it too, but be ready for it to be 3 metres tall.
Slainte,

JohnP.

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country boy
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Postby country boy » Sat Sep 17, 2005 10:19 am

K....
1.Shared Septic Tank or Pozo is a definate no-no...fraught with hazards :shock:
2. Septic Tank Regulations only apply to new build; but are most desirable on re-forms in my opinion.
3. Use of grey water in the garden is very necessary if you are a gardener, there are those however who wouldn't want it, a thought if you are re-forming to sell .
4.Septic tanks are happy to have only Black Water so grey water can go elsewhere
Other questions have been answered elsewhere and are good advice in my opinion. ( I used to build Septic Tanks and maintain 'em...luvverly!) :(

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jpinks
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Postby jpinks » Sat Sep 17, 2005 10:36 am

country boy wrote:3. Use of grey water in the garden is very necessary if you are a gardener, there are those however who wouldn't want it, a thought if you are re-forming to sell

Good point - just make the reed bed much bigger. If you use the grey water for irrigation, fine, if not, put it straight into the reedbed.
Slainte,

JohnP.


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