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Sewage TratementSubmitted by fyl on 4 April, 2008 - 09:05.
We have been asked by MARENA to come up with a "bio-filter" for sewage treatment. This seems to translate to the equivalent of secondary treatment. We have initially planned to separate black from gray water so that the volume of "real sewage" would be relatively small. So much for that solution. Now, unlike the U.S. government, it sounds like we actually need to follow the environmental guidelines. :-) We have been doing a bit of research and it is looking like there is a good alternative to the traditional sewage treatment systems that municipalities use. The goal is to create an aerobic environment with lots of surface area for the bacteria to act on the sewage. There are now passive systems that do with a system of plastic mesh. But, beyond some web pages, we have no first-hand knowledge. Anyone know about these systems? It would appear that we can build our own tanks and just purchase the "filters" (the plastic material that the sludge collects on). But, we really could use some contacts. ( categories: )
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PollIn Nicaragua, my income will come from Job in Nicaragua 4% Run business in Nicaragua 35% Pension/investments/savings 35% External work (e.g., on-line) 20% No clue 7% Total votes: 46 A ThoughtHe was often wrong, but never in doubt. |
There must be hundreds of resources available
One resource I just found may or may not be any good, but you can get ideas from looking at the pictures. From the home page of Biolytix Sewerage Systems:
"Use 90% less energy than most competing systems. Of the 16 competitors we researched, Biolytix® uses at least 90% less energy than all of them. This is because the most common sewage treatment systems, aquatic systems, rely on energy-consuming blowers and mechanical parts to aerate and clean the wastewater.
"Our visionary 'ecosystem in a tank' cleverly uses nature (worms and micro-organisms) to turn sewage into clear irrigation water for your garden. Biolytix® emulates the ingenious way nature breaks down waste - using minimal fossil fuels and no chemicals."
See http://www.biolytix.com/detail.php?ID=69
Competitor comparison: http://www.biolytix.com/detail.php?ID=76
They even have a Poo-Cam: http://www.biolytix.com/php/videos/quirky.html
(Labeled as PG for "pretty gruesome", and takes a long time to fire up, but not that bad if you can handle the sight of poop "rusting".)
You might check for resources available in Africa, or through various aid programs in poor parts of the world in general (simple, low tech, and effective because they have to be).
-- Dave Sailer
Ask Marena to hum a few notes...
and give you an idea, oficially or unofficially, of what they are looking for. Stateside 2000 gpd would be handled by a "package plant", ie a small plant delivered in one piece. It's a glorified septic tank that will give terciary treatment.
I have a hunch thats not what Marena wants and probably isn't avialable in Nic, anyway.
Another type of biological filtration involves wastewater flowing over a porous surface or crushed rock or specially made plasctic cubes. "Zooglial mass" aka "good bugs" living on the surface in an aerobic environment consume the waste. Think of a biological aquarium or pond "biological filter" and you get the idea. In the trade these are reffered to as "tricking filters" or possibly "rotating biological contactors", both of which sound like much overkill for your little project.
This has nothing to do with a "filter-filter" or membrane filter. This is another type of technology usued in wastewater treatment. (like an RO filter) but would not usually be referred to as "biological". It's a pricey up upcoming technology, possibly not availably not available in Nic., more likely in Euro.
Bug Marena, ask them what they want of if they know where one is that you can look at.
Chao, I'm in a freezing public library in bullhead city az and gotta go!
¨pata de perro¨
If they only knew
Gixia asked. The MARENA dude at first said he had no idea. Then, he said someone working on a project in Jinotega was doing one.
She has since talked to that guy and he knows about as little as we do. All in all, I feel like we are in a new delay loop. The feeling I get is if we can point him at something and say "we will use an XYZ-39 system like this or equivalent" we can probably move forward while we are looking for the real answer.
The closest I have come to one is http://www.ecofluid.com/ who I wrote to but no answer yet.
good subject...
pictures to follow?
when government grows, liberty yields, thomas jefferson
You Know
Sarcasim is the lowest form of wit. I am still laughing. That was really funny.
I
I will pass on that....my 5 year old thinks potty humor is the highest form of wit....i am definitely undecided...
when government grows, liberty yields, thomas jefferson
How much volume do expect
Max daily, weekly and monthly and "average" for each?
What percent will be grey water?
ATZ
Volumes
The current numbers we have are:
Average depends on all too many things. Initially it will be much lower because of lower occupancy rates. (I mainly state this because I know some systems need a minimum to actually work right.)
Don't you just multiply daily to get weekly and monthly? That gives me 14,000 gallons/week or 60,000/month max, 3500 gallons/week or 15,000 gallons/month average.
averages...
One thing you have to look at is occupancy when deliberating averages. You may have days when volumes are heavier... like on Saturday or Sunday, but say on a Tuesday it is well below the weekend mark. To ensure a system is adequate and capable of handling output, it is best to take the higher volume and use this as the daily volume. Then the figures you used (simply multiplying by 7 or 30)would give you definite maximums. To get true weekly/ monthly numbers you would need to gather information over a long period to determine actual averages. I would say that to take the highest volume per day and do the simple multiplication for weekly/ monthly averages errs on the side of caution, but you would know it could handle it.
As far as MARENA is concerned, I would suggest putting together a system that uses the "pond filter" type system utilizing micro organisms and very little power. Show them what it is capable of and that should satisfy them. They have indicated they don't know what you should have so you have to "sell" them the system you want. Hopefully they will adopt something along those lines for other users. You have an opportunity here to set guidelines for them and others. You have indicated you have a good relationship with them, use that to everyones benefit.
I think that 's a helpful response
and reeks of common sense. From what I gather you are also saying that the Manager(?) of Marena has no precedent to gather from. In other words can't offer guidlines or point to an existing structure/system, close to home that already complies with requirements. That's too bad if true.
MARENA "stuff"
The reality is, no, he doesn't. But, he does know there is this thing called a bio-filter that should make sense. The traditional answer is that you hire a consultant that writes some BS that makes everyone happy (particularly the consultant).
That said, this is not unique to Nicaragua. Having worked for state government in the US and for a subcontractor to the federal government, this seems to be the all too typical approach. If an "outsider" said it, then it is ok.
After talking to some friends/Geek Ranch co-conspiritors, we decided to come up with a useful answer that, hopefully, will be useful to others as well. It is being designed to be low cost, low tech, self-monitoring and use appropriate (for here) materials.
We are still scribbling but the basic spec will be on the Linux Journal site soon. It should offer a reasonable solution for anyone here needing a bio-filter system where the word reasonable applies both the appropriate and to cost.
Note that we had intended to do gray water treatment with plants and, the reality is that it could be used to treat the output of the septic tank as well. There are two reasons we decided on this different approach: