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Development Fiasco in Jamaica Greywater System

Subject: Greywater development fiasco in Jamaica
Date: Sun, 09 Apr 2000
From: Art Ludwig <Oasis Design>
To: Sherman White <shroomw©yahoo.com>

Sherman White wrote:
> Hello Gentlemen,
>
> I just wanted to drop you a line and tell you how much
> I like your web site. I am US Peace Corps Volunteer
> in Jamaica with an education in Civil/Environmental
> Engineering. Recently I have been getting very
> interested in greywater systems and found your site
> quite interesting and informative. My interest was
> sparked a few months ago when I got partly involved
> with a system at a beach park here in Negril. The
> system was funded by an environmental NGO and designed
> by a very prominent and respected engineer on the
> Island. Well, the thing is nearing completion and it
> doesn’t work. It is, in my mind, a very bad design.
> See what you think of this:
>
> First, the system is only designed for the water from
> the outdoor showers that people use to rinse off the
> sand and salt from the beach. The site for the
> treatment is uphill from this so it must be pumped.
> This pump is in the bottom of a big plastic water tank
> (they use these all over the island for above ground
> drinking water storage) that is buried in the ground
> and used as a sump. Naturally the pressure from the
> sand is collapsing the tank. The sandy, salty water
> is pumped up to an above ground plastic tank that is
> supposed to be a sand trap, and then it goes to
> another tank that is supposed to be the grease trap.
> Why are there two separate tanks for this? And
> shouldn’t the trap be before the pump and under
> ground? Hmmm, wonder how long that impeller is going
> to last, and how much energy is wasted creating that
> extra 6 feet of head.
>
> Anyway, after that the water goes into a reed bed,
> which I like the idea of, then into a fishpond and
> then into, of all things, a sand filter. This whole
> thing is built by mounds of earth covered with a thick
> plastic that I suspect will soon be getting ripped
> apart. Why not just use concrete and be done with it?
>
> The water then drains back into another buried plastic
> tank (which they installed the same way even after
> they saw what happened to the other one) for holding,
> only this one has pipes going in and out of it, the
> seals of which were of course broken as soon as the
> earth began collapsing the tank. Then there is a pump
> that will pump the water from this holding tank to
> either the football field or the aloe vera garden or
> another above ground storage tank. Oh, you’ll love
> this. The irrigation system for the field consists of
> underground PVC pipes with holes drilled in them.
> Well, what they did was just randomly drill holes down
> the length of the pipe and ended up with a big puddle
> at the beginning of the pipe. C’mon, even I, with my
> zero experience in this area, know that there must be
> more of a science to it than that, at least some sort
> of equation for the spacing of the holes starting far
> apart in the beginning and ending up close together at
> the end—or something.
>
> My question was: “If you are using this water for
> irrigation, why are you taking so much of the nutrient
> material out?” Answer: “Because the water must be
> stored for the dry time of the year since the shower
> water won’t be adequate during that time.” Okay, fair
> enough, but check this out. There is also a big
> bathroom and kitchen facility very close to the
> system. Apparently, the owner didn’t want to connect
> those because of the expense. Well, here’s my
> postulate. If you took in all the greywater from
> those then surely you would have enough to water the
> fields even in the dry months. Remember, this
> football field has not been watered in all its years
> of existence. Now you don’t have to store the water
> in those tanks so you can forget about the sand filter
> (which I don’t even think was necessary in the first
> place) and maybe you can have a smaller reed bed. Or
> maybe you don’t even treat it at all but send it
> straight from the grease trap to the fields! All this
> for the price of some extra pipe to the bathroom and
> kitchen.
>
> I’ve asked most of the people involved in the project
> including several engineers (but not the designer) and
> no one can explain the designers rational for the
> whole thing. They didn’t even do anything to get a
> good estimate of the water output of the showers and
> ended up, apparently, overestimating it. At any rate,
> I’m not looking for a free consultation, just thought
> you’d like to hear the story.
>
> Sherman White, PCV

Dear Sherman:
Thanks a lot for the story. It is appalling how often this sort of
expensive "green waste" happens in development projects. FYI, the only
system that is CAPABLE of watering turf is described in the greywater
mistakes: greywater on lawns section. I think there's a maybe 10%
chance of getting such a high tech, sensitive system to work under third
world conditions beyond the first 5 years, so this project was basically
doomed from the outset.
A potentially applicable design is to plant bananas all around the
showers, with the concrete shower floors themselves designed to
distribute the water over a large area; and the bananas in large,
mulch-filled basins; i.e., no drain piping AT ALL.
Yours,
Art

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