cksantos wrote:jsbiff wrote:Pardon my ignorance - what is backflow, and what does that have to do with the EPA?
backflow occurs when i flush a fire hydrant line outside your home and your line sucks water/air into the system, think venturi. Now imagine if that open line sucked in wastewater, or some other contaminant.
-snip-
I thought we were talking about people disconnecting from municipal/regional water pipes? If they completely disconnect, there'd be no backflow possible, right? So, wouldn't EPA regs go away?
Although it does raise the problem that Fire Departments still need hydrants, which currently, are subsidized (I think?) by the fact that you have all these customers helping to pay for the cost of a water network. Although it might be a bit smaller and cheaper to build/maintain for just fire hydrant usage, wouldn't it be at least close to the same overall cost to maintain a water network for fire hydrants, but since you have no customers (theoretically), or substantially fewer customers, doesn't it suddenly become much more expensive for the municipality to provide fire service?
cksantos wrote:
jsbiff wrote: For more suburban and rural areas, your 'storage' could be a pond in the backyard that you also swim and fish in. Or a large underground tank.
That would never pass county permitting backflow issues. Remember that you have to DRINK this water.
I wasn't proposing you drink the water untreated. Like I said, I thought I had suggested an in-home water treatment device (filtration + something to kill pathogens [chlorine, pasteurization, boiling - something; I'm no expert on water treatment, but I know there's ways to clean it up]).
I mean, obviously it would be bad if your water got contaminated by heavy metals, industrial chemicals, pesticides, etc, which might pass right through a filter, and wouldn't be affected by heat or chlorine, so that might be a valid reason to not use a pond, if there were a chance of that. In that case, go back to the cistern + underground tank (where the tank is completely sealed to prevent chemical contamination).
As for backflow, again, if you are disconnected from the muni network, shouldn't that issue go away?
cksantos wrote:
jsbiff wrote: I think the cost of piping the water around becomes small on a per-capita basis - I.E. running a pipe to an apartment building with 500-1000 people living in it doesn't cost much more than running a pipe to a house with 1-8 people living in it.
Not true, a pipe running to a building with 500-1000 people would not just be "a pipe", first off it requires huge backflow preventers >10,000$ 4"-6" ductile iron piping (several hundred $ per section), and when it breaks (not if, when) you have to pay union workers to tear up huge sections of pavement for up to days at a time. Where with a single family home the service lateral is simply 3/4 copper line that is usually in their yard and can be fixed with a shovel and a clamp. I think most people have no idea how expensive water transmission systems are, its insane. This is not even getting into the cost of running booster pumps that can push water up a skyscraper.
O.K. I stand corrected. I'll defer to you since it sounds like this is your area of expertise. I figured the costs would increase for a big apartment building, I just figured they would scale non-linearly - i.e. if it costs $x for a single-family home, it would cost less than 500*$x for a 500 family apartment building. Sounds like that is not the case?
A question, however, about that 3/4 copper line you mentioned - My limited understanding of muni water networks is that while you might have a small copper line that runs from your house to the street, that there is a water main at the street which is substantially larger, designed to accomodate all the water necessary for all the houses in your neighborhood?
So, if that water main is providing water to 500 houses in a neighborhood, wouldn't it be substantially the same cost for that water main, as for running such a water main to the apartment building?
cksantos wrote:
jsbiff wrote:Trying to condense water on a scale to ensure adequate water for the needs of a city is, I think, probably not reliable enough - on humid days, you'd have plenty of water, but what about if you get a stretch of pretty dry days in a row, and suddenly everyone in the city doesn't have enough water to shower, water their plants, cook, make drinks, etc. That's not even considering commercial and industrial water needs.
UAE uses AWG and its fairly dry there so the variability would be marginal and only consume more energy.
Alright. I wasn't really sure how effective they are, I haven't had time to research them. Just the idea of condensing water out of the air didn't seem like it would be very effective from my past experience (which, admittedly, might not be germaine to this discussion) - when I was in high-school, my family got a small dehumidifier for our basement. I don't remember exactly, but it seemed like we had to empty the approx 5 gallon holding tank every 2 or 3 days of operation, so it didn't seem like it pulled that much water out of the air (and the basement was pretty humid at that).
However, that thing was small, and running off 120V household power (it didn't even use the big appliance-grade plugs and cables like you might use for a stove or dryer), so I suppose it's reasonable that they could make a similar device which was a bit more efficient and used a lot more power, to get a lot more water.
cksantos wrote:
jsbiff wrote:Plus, the first time some family gets sick or someone dies because of an improperly maintained AWG which got contaminated, it'll be all over the news. . . (that applies to a cistern/pond system equally, by the way, so as not to play favorites. . . I'm just trying to think this through better).
AGW is more potentially more pure than any other water source.(although I wonder about air pollutions affect)
Oh, I agree. What I meant wasn't that the water didn't start pure when it was condensed, but I was thinking more along the lines of water sitting in a storage tank, getting contaminated somehow (maybe just from the water being stagnant too long), and not properly purified on-site (which, in principle, it should be purified, but system failures seem to happen with any tech).
I'm still not sure I see how some of the critiques you applied to the cistern idea (backflow issues in particular), don't also apply to an AWG-source of water? If you are hooked up to the muni network, wouldn't backflow still be an issue for AWG?