|
Post by blackox on Mar 29, 2015 8:33:08 GMT -5
|
|
|
Post by oldmobie on Mar 29, 2015 10:59:40 GMT -5
Here's the idea - can agricultural terraces somehow be adapted or utilized to filter polluted water? Maybe lay down old pvc pipes down the terraces at an angle and fill with a mixture of charcoal and sand? (This would also act as a sort of drainage system. It'll probably be important to know what type of contaminants, and to specify the goal. Utilizing free/ convenient water from a dirty source, vs cleaning up the source and outputting clean water. There are a lot of variations on aquaponics that use a similar concept. Water with fish waste and maybe algae runs over a bed of sand and gravel with plants in it. The plants filter out the waste and use it. The plants and agitation aerate it. The output is nothing I'd want to drink, but it should be safe if boiled.? Are you looking for a scaled up version of that?
|
|
|
Post by flowerweaver on Mar 29, 2015 12:06:53 GMT -5
Currently there are ways of making terraced ponds that convert effluent (sewerage) into clean water by using aeration and various sets of plants in each pond to do the filtering. I have a friend who built a passive solar house that put one in (with a permit) instead of a septic tank. His house was featured in Mother Earth News, Southern Living, and Solar Today many years ago. Look up biological wastewater ponds for home sewerage and you'll likely pull up info on the subject. I'm not sure you can plant food plants in them if you live where a permit is needed. But you know the best looking tomatoes are always found on the plants growing around the ponds at city sewerage plants!
|
|
|
Post by philagardener on Mar 29, 2015 12:21:07 GMT -5
Interesting ideas, blackox ! There is a pretty good literature on using wetland systems at various scales for waste water treatment as flowerweaver described. Yes, if you are trying to clean up "dirty" water you need to know your contaminants and test the inflow and outflow for effect (and safety, if the dream is to get potable water; usually the outflow is used as greywater, not for drinking). Sometimes these water treatment systems are setup as a series of large tanks in a greenhouse so biofiltration can continue to operate in the winter in cold climates. Your idea also doesn't sound too different from hydroponic set-ups using gutter material. Just Google hydroponics + gutter + gardening and you will find lots of good info! If you are setting up a recirculating system like oldmobie suggested, you will need to watch water losses from evapo/transpiration that can concentrate salts in your system.
|
|
|
Post by mskrieger on Mar 29, 2015 13:07:18 GMT -5
Yeah, that's a cool idea. I'd say if you're working with purely biological (bacterial/viral/sewage-type) contaminants, or even hydrocarbons, such a set up works well. Less so if you have radioactive or chemically stable contaminants, stuff that is impossible or difficult for fungi, bacteria and plants to degrade.
Although I did hear of a group in New Orleans using certain types of plants and fungi to "mop up" seriously bad stuff after Hurricane Katrina. Sadly, I don't remember where I saw that. I'd assume you'd need to harvest those plants and sequester them as toxic waste, though I may be wrong. (Certain plants such as tobacco preferentially absorb uranium, just as an example...that's one of the many reasons why smoking is bad for you.)
|
|
|
Post by flowerweaver on Mar 29, 2015 13:18:52 GMT -5
What mskrieger is speaking of is called phytoremediation, or more specifically phytoextraction or phytomining. It's a pretty interesting field for botanists these days. Too bad when I was in college the career path for most of us environmental designers/botanists was limited to residential and corporate landscaping with imported plants.
|
|
|
Post by walnuttr on Sept 1, 2015 4:09:03 GMT -5
oldmobie says: " It'll probably be important to know what type of contaminants, and to specify the goal. " Absolutely agree; Over here, terraces like that with saturated soils would just fall off the hills unless with major engineering expenses.
Couple of suggestions: A base layer of impermeable (clay? ), with recovery drain pipes laid on that , set into a whole layer of permeable sandy soil; Some ideal depth of undisturbed filtering soil between the drain layer and the cultivated depth of Agri. production soil. Certainly the incoming nutrient needs to be balanced by outgoing crop nutrient load,as beef, spuds or timber... Some allowance for "permanent but limited" adsorbtion of some contaminants by the soil itself....usually onto the clays. Regular measurement of the critical qualities of the "clean" drain water coming out-- which depend on the 'goal'.whether that is pathogens, colour, particles, nutrients or toxics. Almost absolutely need to ensure that fully saturated then anaerobic soil conditions never happen, so background rainfall / snowmelt needs to be allowed for. In dryland areas it might only work for 20 years before the buildup of "irrigation salts" become toxic ; but if these can be flushed out as part of the filtered water, it may work 'forever'. If filtering out lots of nutrient, perhaps add ( an annual?) layer of sawdust / shavings / woodchips as much as a foot deep to balance the diet of the bugs doing the job ?
Would love to give it a try, W
|
|
|
Post by reed on Sept 1, 2015 5:41:53 GMT -5
Plants can definitely clean water. I have a little artificial pond with a small artificial stream that runs by a pump. When I first put it in I planted things in pots of soil and set them in the edges and also ran a filter system. I learned over the years to leave out soil and no longer need the filter. I now plant in clean gravel. Big masses of roots from mint and miniature cat tails fill the gravel in the stream part. Water lilies just tied to a rock to sink them grow in the pond part. Every three of four years I drain it and clean out the rotted leaves that build up in the bottom and divide the lilies. It says crystal clear all the time except for about a week or so each spring when it turns pea soup green. I think the cause of that is the fish poo and rotten leaves build up over the winter and when it warms up in the spring the algae kicks in. Then the plants wake up and take over and all of a sudden it it clear again.
I'v experimented with growing various things in what I guess would be called hydroponics and about anything seems to grow that way. Set something in a pot of clean gravel in the stream part it and it grows. When I used soil it would rot and stink. If I had a natural flowing stream and didn't need the electric pump I'd expand on this but needing electricity isn't sustainable I don't think, so it is just for decoration and curiosity.
|
|
|
Post by steev on Sept 4, 2015 20:16:47 GMT -5
There is a puny "hill" on my farm by the ravine down which my back ten drains to the neighbor's stock-pond; I've long thought of damming and excavating that area for a pond, the soil being very clay-ish (can't drive there in normal Winter without mudding in). Figured I'd have a little island for duck nesting and fish in the pond. This thread has me thinking I could solar-pump pond water to the hilltop, letting it return to the pond through terraces or some installation. I'm liking the self-containedness and productivity of which this may be capable, not to mention the possibility of a pond clean enough, thanks to fertilizer-sucking plants, for a swimming hole in the heat of Summer.
|
|
|
Post by philagardener on Sept 5, 2015 5:11:59 GMT -5
Interesting project! A broad and shallow pond will suffer more evaporation in your ever-increasing dry spells, but is the easiest to create.
|
|
|
Post by reed on Sept 5, 2015 5:14:04 GMT -5
Mine is totally artificial, the pond is a 300 gallon rubbermaid stock tank, the stream is lined with (FDA approved) pond liner, whatever that means. I could easily harvest frog legs if I wanted but instead I relocate the bigger ones so they don't eat the little ones. Blue gills are easy to grow so in a bigger set up you could have them or a California counterpart for tasty protein. Add solar lighting for awhile each night to attract bugs and you don't have to feed anything. Ours is right by the kitchen windows so got that covered by happy accident. Toads use it for breeding each spring, don't know where the frogs come from. Had a baby snapping turtle named Carl one time. We sitting eating breakfast one day when and a Great Blue Heron landed three feet away on the other side of the window. We were amazed to see a heron so close, then it swallowed poor little Carl and flew away. One night a big owl slid past my head close enough to feel a breeze but not a sound did it make and made a very brief stop, don't know what it snatched.
Oh, whine, whine, whine I want a place with much bigger water.
|
|
|
Post by steev on Sept 5, 2015 15:25:01 GMT -5
The county agent says even the best-clayed pond will lose ~7' per year to seepage and evaporation; that's why the Sites Reservoir they want to construct in the wide, shallow valley east of mine is such a piss-poor idea (well, one of several reasons why).
|
|
|
Post by blackox on Sept 5, 2015 15:27:21 GMT -5
There are definitely some interesting ways in which water systems can be tied in with horticulture/agriculture/whatever. This thread is getting me excited about it all.
As far as the terraces go, maybe it would be a smart idea starting out with several models before moving onto something of a larger scale.
|
|
|
Post by RpR on Sept 22, 2015 11:37:29 GMT -5
Around here, some while back, quite a few made ponds, or a water hole in a solid vegetation slough,with x bags of fertilizer and a detonator.
Can that still be done?
|
|
|
Post by walnuttr on Oct 3, 2015 3:52:23 GMT -5
Around here, some while back, quite a few made ponds, or a water hole in a solid vegetation slough,with x bags of fertilizer and a detonator. Can that still be done? Detonation cord laid on the swamp surface cuts the first line of drain about a foot deep; second run is three lines of det cord into the base of the first trench. Keep on with triple the power for double the depth. much simpler than round spots with home-brew. As always, check with your local authority and neighbours before playing in the mud. At some stage it's cheaper and less irritating to hire an excavator and scoop the trench. Ah, sorry;you wanted a nice round water-hole; try a ring of the mix at 1/3 the depth and 1/3 the diameter of the pond you want; perhaps someone else can give an idea of the weight of mix needed per cubic yard of swamp to be moved. Somewhere around one sausage of power-gel for each two yards, methinks. ( the NZ farm engineering textbook was a long time ago, now) Keep your circuits closed and earthed until ready to fire; and never reopen a dud shot. Enjoy.
|
|