Thanx for the info i was reading they removed 99.9 percent of all the bad stuff. I may of read some bad info.
It's not bad info, just misleading.
99.9% is 3 log removal. By federal standards that's not enough. That.1% is still enough to make you very sick, if not dead. The Saywer removes 7log (99.99999%). Most of the ceramic filters get it down below the 4log (99.99) federal requirement.
http://www.aquarain.com/testing.htm
Crypto is only 99.9% but they are fairly large organisms. Most filtration systems can achieve that. It's the bacteria and viruses that are a problem since many are very small. That why, except for the Sawyer (maybe some others) they all need post filter disinfection. Even then I'd still like to know that the last little bits are dead too, so I'd still disinfect.
I don't work in the Lab at work. The numbers we use to maintain good water is the NTU number. That's both inline and manual testing. Somehow, it correlates to the 6log removal requirements. Our lab does those tests and I've never heard of us violating out permit. It's impossible for the average person to afford this level of testing, NTU meters cost big money and need calibration too.
Lab testing for all the microbes just isn't possible on the individual house level. For now, while things aren't SHTF I always suggest folks, even with wells to have their water tested yearly by a local lab. Your county extension service should be able to provide you with a source.)
But if TSHTF that's all gone. Better to have a backup system that's been thoroughly tested and exceeds all standards for potable water. Ceramic filters with <8 microns will do that as long as disinfection is used.
Most of the water I ran through was water that had algae in it and a small amount of sediment. I was considering using it to refilter grey water from showering and clothes washing to use for irrigation. Any ideas? I'm trying to recycle as much as possible but don't want to harm the raised beds that I was planning on irrigating.
I'm not sure a biosand filter could handle grey water either. The soaps could have a drastic effect on the biofilm layer. It really is a sensitive ecosystem that doesn't seem well suited for but the cleanest water. From what I've read they have a hard time with heavy algea loads too. Try killing the algea with chlorine and the chlorine kills the biofilm.
There's another thread in the DIY subforum with lots of links and plenty to read. Some of it I found alarming and downright unsafe.
http://www.survivalistboards.com/showthread.php?t=145631
Even the test run by using rainwater seemed unsafe to me. In that test half the victims didn't even get a filter. But the rate of illness was about equal. So did the filter actually kill enough? I'd have thought they folks with 'real' filters wouldn't get as sick as those that got a fake filter.
http://www.sciencedaily.com/releases/2009/11/091104091728.htm
The way a biosand filter works and how unstable they are is something that's hard to control perfectly. Reading some of the links it appears that science doesn't understand what happens fully. Maybe in the biolayer but down in the sand is more a mystery. To think that people without labs could consistently produce potable water from unknown sources seems highly unlikely.
It's not something I'd trust with the life of me and my family.
For grey water and using on your food supply I'd think it might work, or might not. The soaps could kill the biolayer. I'd want at least a layer of activated carbon in there just to play it safe.
This link is what scared me;
Please, anyone wanting to use this method should read this and try and understand all that goes into getting this to work and how just small changes can have drastic effects of the filtered water.
http://www.who.int/water_sanitation_health/publications/ssf3.pdf
"Indeed, there is still a need for considerable research before interaction all these processes is fully understood."
" the smallest pores are 20 microns and unable to intercept colloidal particles 1 micron or less and bacteria up to 15 microns."
Believe me there are lots of bacteria that are smaller then 15 microns.
" Sudden changes in filtration rates tend to upset this equilibrium, resulting in deterioration of effluent quality "
"In a similar way the various bacterial populations are adapted to the type and amount of food supplied by the passing water, and sudden changes in raw water quality should be avoided."
"For satisfactory biological oxidation of organic matter, sufficient time should be allowed, enough oxygen must be available and the temperature of the water must not be allowed to fall to low."
Sounds highly technical and not something to experiment with to me.
That whole pdf should scare anyone away from thinking of just pouring water in the top and clean water coming out the bottom.
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