So, I've previously written about my windowfarm that I'm building. I'm also currently working on a 105 gallon system for my friend +Evgeny Pogorelov's apartment. It's going to be a basic flood and drain on a timer. We have a 55 gallon aquarium, which will feed into our 50 gallon stock tank grow bed. We're currently planning to have about 5-6 tilapia, and grow all kinds of veggies. I'll update with pictures soon.
Right now, we're constructing the frame that will hold the system. We've cut all the wood, and painted it all white, and now we need to assemble and put it on wheels for easy mobility. The next step is plumbing; we'll use a 200 GPH pump. We're hoping to stay away from using PVC due to conflicting reports about PVC leaching chemicals into water over time. However, this may only apply to soft PVC, not hard PVC. We need to do a little more research before we buy pipes.
Here's what Pogo wrote to me about PVC in farming systems:
Found some resources that cite PVC as leeching dioxin, pthalates, and other toxins into water / food. Definitely want to avoid PVC piping in any operation we start. The safer alternative is biodegradable EVA plastic.
"See: www.aaa.dk/pvc PVC plastic is an environmental and public health hazard because dioxin and other persistent organic pollutants can be emitted into the air, water and land during its manufacture and incineration.
In addition, PVC products can leach toxic additives during use, and thus may harm patients receiving certain medical treatments.
PVC has come under scrutiny by the European Commission since 1997 resulting in the release of the Green Paper in July 2001 that highlights the dangers associated with its disposal, and in April 2001 the European Parliament adopted a resolution calling on the Commission "to introduce rapidly a policy on the replacement of softPVC, in so far as the current risk analysis of phthalates indicates that it is desirable to reduce the exposure of people and the environment".
These concerns have led increasing numbers of health care providers to search for alternatives. Grenaa Central Hospital, Denmark, substituted 95 percent of its PVC-products with safer alternatives without compromising safety and care, and found many of the alternatives to be more cost effective."
http://www.annieappleseedproject.org/nonalforplas.html
In addition, PVC products can leach toxic additives during use, and thus may harm patients receiving certain medical treatments.
PVC has come under scrutiny by the European Commission since 1997 resulting in the release of the Green Paper in July 2001 that highlights the dangers associated with its disposal, and in April 2001 the European Parliament adopted a resolution calling on the Commission "to introduce rapidly a policy on the replacement of softPVC, in so far as the current risk analysis of phthalates indicates that it is desirable to reduce the exposure of people and the environment".
These concerns have led increasing numbers of health care providers to search for alternatives. Grenaa Central Hospital, Denmark, substituted 95 percent of its PVC-products with safer alternatives without compromising safety and care, and found many of the alternatives to be more cost effective."
http://www.annieappleseedproject.org/nonalforplas.html
Here's a company that sells EVA piping: http://dir.indiamart.com/impcat/eva-pipe.html
Looks like theres some duplicate copying and pasting there! One thing i realized is that this relates specifically to "soft" medical PVC and may not apply to the hard white PVC we would use. However, i know PVC flakes off and i am unsure whether have the same risk profile in terms of toxicity (soft vs hard). People use PVC for plumbing in their houses, if its that much of a risk, why would they do that? The question becomes, if its safe, is it safe enough to pass organic certification? I don't have the answer to that question yet.
ReplyDeleteNice post!
I'd lean towards agreeing with Pogo here. I didn't even see any hard EVA pipes on that site (I just did a quick glance), only the soft tubes. I've seen pvc used in both gardening and home plumbing, as Pogo mentioned. I'm sure there is a risk, as with most plastics, but I think those risks would be minimal/nonexistent in this setup where the pipes would be inside a climate controlled environment, getting minmal direct sunlight, and not running chemical fertilizer through them.
ReplyDeleteThis is just my two cents without any further research though. Just stirring the pot a little more. Sweet blog, Dirkwell!