gray water storage and reuse for flushing

[vas]

hello,

still not completed the purchase, and I'm designing the rebuilt...

One of the issues that I'm trying to address is the multi-holed wooden hull for all sorts of unnecessary (IMHO) reasons:
So two heads + one crew cabin with a toilet and washbasin that will be removed altogether.
That means a lot of holes and seacocks to bring sea water for flushing, and remove washbasin/ shower gray water.

From the building con background I'm coming, it makes sense (enough to me anyway) to store washbasin/shower waste + aircon condensation in a tank (120-180lt should do for our family of four + two extra kids/teens) and reuse it for flushing the toilets.
Ideally some treatment to the water (to kill it as they say) has to be done with some enzymes and such. Furthermore, when full this gray water tank must be flushable to sea at will (but not fully to keep some water for the heads + enzyme built-up or whatever/however this thing works). Haven't found anything small in that respect, only house installations utilising big upright PVC barrels of 1ton each!

The black water will be stored in obviously another dedicated tank flushable with normal terms. Thinking on something around 200lt as well.

Boat currently has 500lt fresh water tank (2X250 aft to the gearboxes) no holding tank, so nothing to reuse, both heads will be moved so starting afresh so to speak and easy for me to decide and implement.

Q:

does it make sense or for the fear of the smelly head issue (topics that appear every month or so) I'm getting into more problems?

if I fail to treat the grey water, am I up to more odour related issues than the cleaning of algae from seacocks and piping to the heads?

placing these two 200lt tanks is easily done in the reorganised space under two beds or one under the bed and the other one halfway under the deck and inside a cupboard/storage space midship. Makes sense, or should I keep the gray water under a bed close to the heads and move the black water one aft and out of the way?

cheers

V.

 

[jfm]

Imho the plan does not make sense. Grey water will be dirty, goes smelly after a while, and is full of hairs. By all means use a grey tank if you want to dump it offshore (generally not necessary) but do not re-use the grey water

Instead i suggest you use the 200l space for an additional potable water tank

Think about it: if you do what i say, you can have 700litres potable at start of a trip. If you do the grey tank idea, you have 500 litres potable. With the grey tank, you will keep the shower water but not the kitchen sink water or the WC flushwater or the water you drink. Out of the 500litres at start of your trip, you might re-use say 200 litres. So you are no better off than if you had 700litres of potable to begin with. Get my drift?

 

[MapisM]

placing these two 200lt tanks is easily done in the reorganised space under two beds

Aside from agreeing with jfm suggestion, I'm surprised to read that you can easily fit biggish grey water tanks.
Which boat are we talking about?
Normally, you would want grey waters to flow to the tank just by gravity, and since the shower floor is typically very low, it's hard to find an even lower location. I can't imagine how any beds can be that low.
You can always fit pump(s), of course, but you might wish you didn't, when (mind, not IF) it/they will stop working...

 

[vas]

jfm, I see your point clearly, thanks for the input. However, I was never considering dumping and keeping soapy water just like that. There are proper systems for neutralising, disinfecting water that simply I've not come across a boat friendly solution, hence my asking. I'll probably forget about it altogether.

MapisM, it's this Versilcraft Mystere 43 we were discussing the Italian labels on the main el. dash and of course I was contemplating plumbing the two washbasins and two showers into one dedicated pump with auto start (or whatever you call it) so as to do the job shifting the gray water under a bed placed tank Elevation difference is around 50cm so not a problem but I cannot seem to find the treating system.

I get your points though, so the flatish 80lt or so tanks may just fit under the floor but wont be enough if daughter and/or wife go for a shower i'm afraid...

Actually based on the points made, I'm better off with the following combo:

A. gray water tank as big as I can get that works with no pumping about for the two showers + aircon condensation + possibly small front bilge pumps (it's a wooden hull, so seems that one frontal pump is not an option with the framework as it stands).
B. two washbasins dump straight to sea
C. two heads + kitchen sink to a holding tank aft
(D. a water maker in the place of the one of the two 250lt fresh water tanks the rest of the space occupied by the holding tank on C. )

In either case, I'd convert the heads to fresh water flushing rather than sea water (at 2lt or so a flush it's not a big deal...)

Since I'll be often anchored in 10-20m depth and 20-40m from the shore on deserted islands/bays, I'm not so keen on dumping my waste were I'll be spending my days hence my idea of keeping everything and have enough storage for 4-5days at a time.

thanks

V.

 

[rafiki_]

Unless you are inland, why do you want to store the grey water, or even black water? This sounds like a solution to problem that does not exist. What is wrong with sea water to flush the heads?

Even you achieve what you are setting out to do here, my gut feel is that you will continually be chasing blockages/odours/pumps etc.

Unless you are putting to sea for weeks at a time, in which case you need a desalination system, you top up in port like everyone else.

Unless I've missed the plot here.

As a general rule in boats, keep it simple. If it can go wrong, it will. Usually at the most inappropriate moment.

 

[henryf]

I agree with JFM.

We store grey water in our motorhome and it does get a bit smelly. We use it to clean the pipes after dropping the black tank.

I hear what you are saying about treating it somehow but why bother. It's not as though fresh water from the marina tap costs you anything and you can never have too much, so an additional tank and the ability to fresh water flush sounds ideal. Do you need a separate tank for fresh water flushing or can you fit a 1 way valve by the toilets and then balance the two tanks or possibly even better have a switch over and two separate fill points. That way a diesel in the water tank moment wouldn't be such a disaster.

Henry

 

[vas]

OK, I can see the KISS concept coming up strongly from all contributors on this thread.

I've minimal experience on such systems, I can see why you all want to have simple solutions, so I'll explain my concerns:

A. in the areas I'll be settling and spending up to a week at a time, will be well protected bays (sometimes 30-50m across...) on nice clean shallow water. It simply doesn't feel right to me to dump my waste or flush the heads while the kids maybe swimming around - water temps are in upper mid 20s and kids tend to spend 3-4h in the water at a time playing fooling around with inflatable mattresses and all sorts of things.
B. Don't like the idea of smelling heads as explained on a current thread all due to stagnating seawater in the piping before the heads. Hence the freshwater flushing which should be dead easy with a one way valve or a small 20lt tank elevated in the bathroom furniture I'm designing at the moment. Don't really need a pressurised system before the head for flushing, right?
C. as I mentioned both women in the family are exceptional water wasters. I've not measured it but I doubt they can have a shower with less than 50lt each. When I'm off for a week I'll be annoyed to travel to a marina 10+nm away just to get water... I understand this last one goes for jfm's suggestiong for an extra tank, will look around for a s/h watermaker if they come cheap.
D. also want to reduce the number of holes in the hull to single digit numbers if possible with less seacocks and intakes (2 for engines, 1 for gen, 1 for aircon, 1 for anchor and deck washing should be enough)

any other ideas/points welcomed!
thanks

V.

 

[jfm]

OK, I can see the KISS concept coming up strongly from all contributors on this thread.

I've minimal experience on such systems, I can see why you all want to have simple solutions, so I'll explain my concerns:

A. in the areas I'll be settling and spending up to a week at a time, will be well protected bays (sometimes 30-50m across...) on nice clean shallow water. It simply doesn't feel right to me to dump my waste or flush the heads while the kids maybe swimming around - water temps are in upper mid 20s and kids tend to spend 3-4h in the water at a time playing fooling around with inflatable mattresses and all sorts of things.
B. Don't like the idea of smelling heads as explained on a current thread all due to stagnating seawater in the piping before the heads. Hence the freshwater flushing which should be dead easy with a one way valve or a small 20lt tank elevated in the bathroom furniture I'm designing at the moment. Don't really need a pressurised system before the head for flushing, right?
C. as I mentioned both women in the family are exceptional water wasters. I've not measured it but I doubt they can have a shower with less than 50lt each. When I'm off for a week I'll be annoyed to travel to a marina 10+nm away just to get water... I understand this last one goes for jfm's suggestiong for an extra tank, will look around for a s/h watermaker if they come cheap.
D. also want to reduce the number of holes in the hull to single digit numbers if possible with less seacocks and intakes (2 for engines, 1 for gen, 1 for aircon, 1 for anchor and deck washing should be enough)

any other ideas/points welcomed!
thanks

V.

V, all sounds like you have some nice vacations ahead!

I honestly do not think you can spend a week as you describe. You'll need loads of food, and there is no way a 43er will have enough fridge space. No way at all. Next problem is trash. Unless you fit a trash compactor (and you wont really have space on a 43er - the space would be better used for another fridge) you will have so much stinking black bags full of trash that you will not be able to move. And even a trash compactor will give you only a few days

I cruised 6 years in squadron 58s and I never could have spent a week isolated. I touched into a marina every 2 days, sometimes just for an hour, to get fresh water and get rid of the trash, and sometimes stock up on food

I know that you can get food and take rubbish ashore in a tender, but only if you are near to a town or a port. And you will have a very small tender on a 43er, not capable to go say 3 miles each way to do these chores

You really would be better planning to touch into port every 2-3 days imho, and empty your black+grey tanks on the trip to the port. Best wishes

 

[MrB]

What is stopping you from pulling up the hook,cruising half a mile away to empty the tanks and return ?
I kinda feel you are trying to get "green and efficient" land based architecture into a small maritime platform, while i applaud it, i feel you just won't have the room to play with. I love projects like this and will follow your plans to the end result. Good luck

 

[henryf]

I don't think anyone disagrees with you in wanting to keep your poo away from the kids as they are swimming. But I don't think the shower's expulsion is going to do them any harm.

Rather than trying to somehow fill a header tank which in turn feeds the toilet just pressurise the whole system with an expansion tank thrown in to save the pump running every time someone goes to brush their teeth.

If you're not careful it'll be like a scene from Wallace & Grommit in there

Surely if you don't want to be running for the marina then extra fresh water storage would be more beneficial than carting round your old shower water.

Henry

 

[MapisM]

MapisM, it's this Versilcraft Mystere 43...

Doh! For some reason, when in your OP you mentioned a wooden hull, I ruled out the Versilcraft because I thought it was plastic...

I see your point re. spending a whole week anchored in the middle of nowhere. The difficulties jfm mentioned are real, but manageable.
In fact - even if my boat is not much bigger - when I cruised the Croatian coast it was pretty normal to spend a week without touching a marina.
Actually, my personal record was almost 2 whole weeks. But in that occasion, only myself and swmbo were onboard, and we had to manage water with some care, in spite of the 1.5 tons tank.

That said, we never bothered using grey nor black water tanks.
If in the bay where you're anchored the water is stagnating, you don't want to stay there anyhow.
In fact, you normally wish to anchor in bays where the prevailing wind blows from the land. Which means that the water surface is by definition always clean.
Though of course the toilet usage should be somewhat restricted at least while someone's swimming...

 

[jfm]

Yes Mapis I can see you could stay out with just 2 people for a week or more, if you were careful

The main problem is still trash I think, esp in warm places where it smells. On current boat we have an insinkerator and all food scraps go in there and then into the sea, where the fish eat the gunk within about 3 minutes. If you use the insinkerator every time and put almost no food into your trash you can substantially reduce the smell of a 4 day old bag of trash and I'd recommned an insinkerator to Virtuvas. Catch is, they are 230v so we have to start a 3.3litre diesel genset to power it, sometimes!

 

[Nick_H]

OK, I can see the KISS concept coming up strongly from all contributors on this thread.

I've minimal experience on such systems, I can see why you all want to have simple solutions, so I'll explain my concerns:

A. in the areas I'll be settling and spending up to a week at a time, will be well protected bays (sometimes 30-50m across...) on nice clean shallow water. It simply doesn't feel right to me to dump my waste or flush the heads while the kids maybe swimming around - water temps are in upper mid 20s and kids tend to spend 3-4h in the water at a time playing fooling around with inflatable mattresses and all sorts of things.
B. Don't like the idea of smelling heads as explained on a current thread all due to stagnating seawater in the piping before the heads. Hence the freshwater flushing which should be dead easy with a one way valve or a small 20lt tank elevated in the bathroom furniture I'm designing at the moment. Don't really need a pressurised system before the head for flushing, right?
C. as I mentioned both women in the family are exceptional water wasters. I've not measured it but I doubt they can have a shower with less than 50lt each. When I'm off for a week I'll be annoyed to travel to a marina 10+nm away just to get water... I understand this last one goes for jfm's suggestiong for an extra tank, will look around for a s/h watermaker if they come cheap.
D. also want to reduce the number of holes in the hull to single digit numbers if possible with less seacocks and intakes (2 for engines, 1 for gen, 1 for aircon, 1 for anchor and deck washing should be enough)

any other ideas/points welcomed!
thanks

V.

A. You seem to be considering the black and grey water as the same, which obviously they're not. For sure you need a black tank, as its extremenly unsociable to flush heads to sea in an anchorage, but IMO you don't need a grey water tank (at least not for storage/recycling). The worst you are going to put in the sea is small amounts of soap/shampoo etc. which will quickly dissipate and no health hazard for swimmers

B. The sea water flush wont stagnate whilst you're using the boat, so its only a problem when you first arrive after a spell away. Just flush the toilets through when you first reach the boat. Anyway, if your cruising area is crystal clear water as you describe, its unlikely to be an issue anyway. We don't get any pong from the flush water in the med.

C. Tell the women to save more water, or fit the extra water tank as jfm's suggestion

D. You can fit a small grey water tank to receive more than one feed from multiple showers/sinks, then discharge through a single sea cock, either with a pump on a float switch , or possibly gravity fed depending on routings for pipes. This is standard practice on many boats.

I agree with the others on here, I can't see why you would want to capture and treat grey water for flushing the heads, when you have an endless supply of flushing water under the hull.

 

[prv]

The main problem is still trash I think, esp in warm places where it smells.

Should be alright with decent quality bags tied in a knot (not just handles tied together).

I sail occasionally as a volunteer deckhand with the Tall Ships Youth Trust, and one of the deckhands' less salubrious jobs is managing the garbage. Admittedly we dump most food waste overboard on long ocean trips, but the plastic waste that has to be kept is usually contaminated with food (wrappers, plates scraped into the wrong bin, etc) and there's always a bag or two of mixed waste collected while still close to shore before the segregated bins are in use. That then has to be kept until the end of the voyage because of the plastic among it.

I've done voyages of nearly three weeks before, and emptying the garbage locker into the skip at the destination is just a job of work, not a disgusting smelly experience as you might imagine. Deckhands often hang oilies and harnesses in the garbage locker as it's near our cabin and the fo'c'sle where our work is based, and we avoid it getting mixed up with the voyage crew's stuff. We wouldn't do that if the garbage locker stank.

Pete

 

[vas]

thanks, some very interesting points, especially the food waste disposers that I'd forgoten about since no-one uses them in houses anymore (at least down here) and they are not expensive either... With around 250euro you get a 1/2hp (or 350-400w) 220V one from TEKA, Franke, GE, etc. Pretty sure I can run it off the batteries though. Thinking about it, timing for it is just right to turn the gen on for a few espressos so at the same time while waiting you can dump/process the food remains and feed the fish

As for our diet being a bit lighter than the typical british one, wont be using lots of plastic wrappings and messy pots/foam dishes and such. Have an extra 60+lt toploading 12V fridge for the lazarette (sp?) so I can keep enough meet, veg, milk, coke and wine. Cooking pasta, beans, lentils, fish we hopefully catch (most likely soups due to son's low patience threshold) produces little waste and few things for the black rubbish bag. At least our free camping experience says so, not too worried.

So modified plan is:

A. gray water underfloor tank under the corridor to the cabins that hopefully works with no pumping about for the two showers + aircon condensation + possibly small front bilge pumps (it's a wooden hull, so seems that one frontal pump is not an option with the frame and keel as it stands). No treatment, just dumps overboard when full with a pump on a float switch.
B. two washbasins dump straight to sea preferably from one hole as the two washbasins are 10cm apart.
C. two heads to a holding tank aft flushed using seawater hopefully with one seacock only as they are also very close
D. kitchen sink fitted with food waste disposer and straight out to sea using existing routing
E. keep the 2X250lt inox fresh water tanks aft and at a later stage (and when I wont be as skint as I'll be by easter when project is going to be ready) add a watermaker

Hope it makes more sense now (although it looks quite simple and normal and I do love Nick Park's twisted mind )

any more comments welcomed (should be starting another thread/Q soon on more constructional issues)

cheers

V.

 

[jfm]

.
B. two washbasins dump straight to sea preferably from one hole as the two washbasins are 10cm apart.
C. two heads to a holding tank aft flushed using seawater hopefully with one seacock only as they are also very close

Beware: if sink #1 is full and you pull the plug, the used water might go into sink #2. I suppose you could fit n/retrun valves but I wouldn't do that in a sink waste. Much better to have two holes in the hull.

Likewise the heads flushing might not prime right if fed to a pipe that will have air in it (as will be the case in your shared-seacock system). It should be possible to avoid that with careful plumbing, bit it's a possibility. I still think seawater flushing of heads is a big mistake and I would have always nice clean freshwater flush every time, but each to their own on that .

 

[Nick_H]

You could plumb the outlets from the heads direct to the holding tank (ie. no option to divert stright to sea), then you'd have one sea cock instead of three. I think it's then important to have a back up manual pump for the holding tank, in case the elec pump fails.

I'll have to agree to disagree with jfm on the sea water flush, I can't think of a single downside with having sea water flush in clear water areas, where you don't get smells from the inlet water.

 

[BartW]

I'll have to agree to disagree with jfm on the sea water flush, I can't think of a single downside with having sea water flush in clear water areas, where you don't get smells from the inlet water.

I can confirm that the heads in Blue Angel flush with sea water without any issue.
swmbo could not believe they were, as they are still so clean (she insisted to taste the water )

most of the time they are used in a marina (not cristal clear water), but even so the heads appear clean.

I did expect that they were flushed with fresh water in what used to be a super yacht, but now don't see a disadvantage of using sea water

 

[jfm]

Okay okay I give in . I cannot think of a rational argument not to have sea-water flush, at least in clean seas. I still don't like the idea though, and will stick with my freshwater flushing, but I accept that the reasons for this are capriciousness not science!

 

[MapisM]

Well, when I fitted Tecma WCs and black water tank (which the boat originally didn't have), I also got rid of sea water flush, fwiw. And I'm glad I did.
I accept it's not a compelling reason, but not a caprice, either.
My WCs, T-valves, pumps, tank are now in MUCH better shape, after almost 10 years, compared to how the original equipment looked like after just 4.
If I would/could spec my dream boat, I would get rid of ANY sea water:
1) just two sea chests, interconnected for redundancy;
2) engines, gensets, a/c, anchor chains wash - all feeded from the chests;
3) some mean of deviating the chests intakes (electric valves?), in order to fill them from the fresh water tanks rather than from the sea;
4) upon arrival in a marina, just switch the chests intakes, and run every equipment for a minute.
Job done, the boat when not used would have ZERO sea water inside her.