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To compost or not to compost - The long read


Dr Bob

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13 minutes ago, MtB said:

 

How do you know for sure the composting process worked and finished and there are no pathogens left in it?

 

Just by looking at it? That doesn't seem very reliable to me. I'd like to see a testing process. 

 

 

Bob is talking about hot composting, done properly it is very effective at killing the pathogens in the base materials.

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11 minutes ago, MtB said:

 

How do you know for sure the composting process worked and finished and there are no pathogens left in it?

 

Just by looking at it? That doesn't seem very reliable to me. I'd like to see a testing process. 

 

 

Visual assesment is a good way of seeing the quality of the compost if you have a baseline to compare against.

Have a read of the Humanmanure handbook - available free on t'internet for info on pathogens and temp/time requirements.

The OECD 208 test is done in the lab for ecotoxicity for seedlings.

 

The point I am making is that if it is done properly then the waste is fully composted in 6-9 months and no poo remains. You dont need then to test every batch. You can see if it is right. ie the material changes from a box of poo turds to a box of fine soil type material. Once you've seen it happen then you will know what I am talking about.

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21 minutes ago, mrsmelly said:

Ahhhhh, now I see. It did take me two hours to read the thread though. Whilst I would never have a shit in a bag system myself, your undoubted expertise rather than google type expertise, that certain posters use is nice to read. It has been of assistance to me in one way already. I bought this boring house thingy nearly two years ago, it had/has a large compost pile in one corner of the garden that seems to do nowt but get bigger!!.

If I bought an eco fan and mounted it at the side of the compost would it aid the bugs doing their job or not?

What's happening is cold composting, you need at least two heaps, start the new one with the uncomposted stuff from the top and used the stuff that has composted, either that or turn the heap regularly 

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53 minutes ago, magnetman said:

To be fair, a fessbook site dedicated to people who use composting lavatories is fairly unlikely to consist of people who think they are a Bad Idea. 

 

Sensible discussion includes people pointing out things like the fact that the CRT have specifically needed to ban lavatory waste from their domestic waste bins. 

 

This does seem to indicate that there is a problem and some people may not be using the equipment correctly. 

 

It doesn't mean it is a crap idea to use a separating/composting lavatory but you can't really argue that there is not a problem of sort otherwise this would not have happened. 

 

I'm sure it can work for some people but equally sure it can't work for other people. The disposal of the waste product IS a problem. It isn't a made up problem it is just a problem. 

 

Obviously lavatories on boats is a major topic so there will be polarised views but I personally think a sensible discussion involves dealing with other opinions you don't agree with. 

 

 

The fact that CaRT have banned from bins is not scientific evidence nor even evidence that anything is actually going wrong. What i9s most likely to be is evidence that the collecting contractor has imposed a restriction (or a charge aka fine). I'd much rather go with a proper scientific study such as the OP cited. That said, I suspect we will not make the change in what remains of our cruising life! But who knows.

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1 minute ago, Mike Todd said:

The fact that CaRT have banned from bins is not scientific evidence nor even evidence that anything is actually going wrong. What i9s most likely to be is evidence that the collecting contractor has imposed a restriction (or a charge aka fine). I'd much rather go with a proper scientific study such as the OP cited. That said, I suspect we will not make the change in what remains of our cruising life! But who knows.

 

Surely if the contractor (Biffa I think) have identified contents which they find objectionable then it must mean people are chucking the stuff in the bins. It seems to be obvious unless the contractor is aware of the use of these lavatories on boats and simply wanted to get in -before- the problem occurs. 

 

That is a possibility but it seems fairly obvious that people have been bagging and binning the contents of composting lavatories. Nobody is trying to hide this fact as it is, or was, normal to do this for convenience.

This defeats the whole idea of having a composting lavatory and now that the CRT have mentioned it the game changes. 

 

 

 

 

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1 hour ago, tree monkey said:

What's happening is cold composting, you need at least two heaps, start the new one with the uncomposted stuff from the top and used the stuff that has composted, either that or turn the heap regularly 

 

The correct mix of "greens" and "browns" helps too - a pile of just grass clippings is never going to give a healthy compost heap.  Try adding some plain brown cardboard - no tape and no printed shiny boxes - occasionally. 

 

 

46 minutes ago, magnetman said:

it seems fairly obvious that people have been bagging and binning the contents of composting lavatories. Nobody is trying to hide this fact as it is, or was, normal to do this for convenience.

 

That was official CRT advice for a while which is why some people started doing it. 

 

The excrement really hit the air conditioning when CRT said everyone had to stop doing this at three day's notice!

 

 

 

Edited by TheBiscuits
clarity
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Thanks, Dr Bob, that explained a lot of the "mystery" of composting on a boat. 

I have a couple of questions. You use 3 similar sized boxes and always put the turds into box 1 then later transfer them to box 2 or 3.  Why not just use the three boxes in sequence? Ie when box 1 is full, start putting the turds straight into box 2 until that is full then start on box 3?  

My other question (from someone who can be squeamish) is do you wash out the boxes between use and if so how and where on a boat do you do that? 

That sort of raises another question (sorry!) about the cleaning of the turd box in the loo where the contents (before being moved to another box) will be more turd like and uncomposted? 

 

Haggis 

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1 minute ago, haggis said:

Thanks, Dr Bob, that explained a lot of the "mystery" of composting on a boat. 

I have a couple of questions. You use 3 similar sized boxes and always put the turds into box 1 then later transfer them to box 2 or 3.  Why not just use the three boxes in sequence? Ie when box 1 is full, start putting the turds straight into box 2 until that is full then start on box 3?  

My other question (from someone who can be squeamish) is do you wash out the boxes between use and if so how and where on a boat do you do that? 

That sort of raises another question (sorry!) about the cleaning of the turd box in the loo where the contents (before being moved to another box) will be more turd like and uncomposted? 

 

Haggis 

 

Oh such awkward questions! 

 

Like mine about how to field the questions form passers-by about what's in the boxes....

 

 

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6 minutes ago, haggis said:

Thanks, Dr Bob, that explained a lot of the "mystery" of composting on a boat. 

I have a couple of questions. You use 3 similar sized boxes and always put the turds into box 1 then later transfer them to box 2 or 3.  Why not just use the three boxes in sequence? Ie when box 1 is full, start putting the turds straight into box 2 until that is full then start on box 3?  

My other question (from someone who can be squeamish) is do you wash out the boxes between use and if so how and where on a boat do you do that? 

That sort of raises another question (sorry!) about the cleaning of the turd box in the loo where the contents (before being moved to another box) will be more turd like and uncomposted? 

 

Haggis 

 

I suspect the answer relates to the need to re-oxygenate the material, much like turning a compost heap or the windrows the commercial outfits use.

 

Why is there a need to clean the box as long a sit does not smell or have maggots in it? The residue should "inoculate" the new stuff with the bugs to help get a quick start to the process.

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I'm really interested in the visual inspection as a way to monitor progress. 

 

Presumably this means perspex, or even better glass boxes with some sort of anti glare lighting. LED is a bit bright for this although one can get filters. 

 

I imagine also that there are reference diagrams or colour charts which one uses to judge the status of the product during the decomposition stages. 

 

I really want one of these things now !

Data logging thermometer. Imagine the graphs one could produce !

 

Logging is definitely important here. 

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1 hour ago, Alan de Enfield said:

Dr Bob won't read this, but I wonder if he remembers posting this 'little gem' where he says he will be bagging & putting his 'composting toilet contents' in the Bins when out cruising, and tipping the Urine in nearby woodland.

 

 

 

Screenshot (209).png

 

😲

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1 hour ago, mrsmelly said:

Ahhhhh, now I see. It did take me two hours to read the thread though. Whilst I would never have a shit in a bag system myself, your undoubted expertise rather than google type expertise, that certain posters use is nice to read. It has been of assistance to me in one way already. I bought this boring house thingy nearly two years ago, it had/has a large compost pile in one corner of the garden that seems to do nowt but get bigger!!.

If I bought an eco fan and mounted it at the side of the compost would it aid the bugs doing their job or not?

You need to turn the heap over. When we had our allotments we had three compost bins on them. The 1st was the add t0 bin, the 2nd was maturing, the 3rd was the in use, i.e use this on the plot. When the 3rd was empty, the 2nd bin was turned into it with a garden fork and the first into the second. Surprising how the volume decreased as the process went on. Usually took 9 - 12 months.

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So, what you're saying is that composting needs to be an industrial managed process - chuck it in a bin and forget about it doesn't work.

 

Personally I don't spend sufficient time on-board to make the change from the existing system and since I have absolutely no interest in gardening whatsoever it's no great loss to me.

 

Good to read your report but is there usually an 'h' in coir?

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12 minutes ago, George and Dragon said:

So, what you're saying is that composting needs to be an industrial managed process - chuck it in a bin and forget about it doesn't work.

 

Personally I don't spend sufficient time on-board to make the change from the existing system and since I have absolutely no interest in gardening whatsoever it's no great loss to me.

 

Good to read your report but is there usually an 'h' in coir?

There is if it is singing

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1 hour ago, haggis said:

Thanks, Dr Bob, that explained a lot of the "mystery" of composting on a boat. 

I have a couple of questions. You use 3 similar sized boxes and always put the turds into box 1 then later transfer them to box 2 or 3.  Why not just use the three boxes in sequence? Ie when box 1 is full, start putting the turds straight into box 2 until that is full then start on box 3?  

My other question (from someone who can be squeamish) is do you wash out the boxes between use and if so how and where on a boat do you do that? 

That sort of raises another question (sorry!) about the cleaning of the turd box in the loo where the contents (before being moved to another box) will be more turd like and uncomposted? 

 

Haggis 

Thanks Haggis.

 

I have a 40 litre on the cruiser stern. A heavy duty HDPE box from B&Q.  That gets moved into 2 cheapo 20L boxes on the roof. Moving the stuff mixes it up. Remember the oxygen? You do need to mix the boxes occasionally so transferring it helps. I dont usuallly wash box 1 as the residue has all the good bugs in it. Ditto the 20L boxes. These are small to get a bit more surface area on the roof to get more heat in in the summer. Box 3 which does get the final 3 months of composting I do wash out when I am near a tap as that has essentially finished composting.

The turd box in the loo hasnt ever been washed out in 2 years. I scrape out the solids with a trowel. It doesnt smell.

I probably spend no more than 10 mins a week managing it. With our pump out I used to have to strip the vacuuflush unit twice a year when it broke - an hour each time, plus the time taken to do pump outs etc. Its a lot less time consuming than pump outs or cassettes.

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2 hours ago, mrsmelly said:

Ahhhhh, now I see. It did take me two hours to read the thread though. Whilst I would never have a shit in a bag system myself, your undoubted expertise rather than google type expertise, that certain posters use is nice to read. It has been of assistance to me in one way already. I bought this boring house thingy nearly two years ago, it had/has a large compost pile in one corner of the garden that seems to do nowt but get bigger!!.

If I bought an eco fan and mounted it at the side of the compost would it aid the bugs doing their job or not?

Alternatively turn it over occasionally Tim with a garden fork

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I have two questions.

 

1.  You say you used the compost for pots twice a year.  This implies that at times the pots are emptied to be filled with new compost.  So what do you do with the "old" compost from the pots.

 

2.  I think organic must mean something different to you than it does to me.  You said "i think the key here is that the 'highly organic waste' is no longer highly organic after composting."   Are you implying the material somehow changes state from having organic origins to not have organic origins?

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Well Dr Bob, your findings pretty much mirror mine, I have 3 black composting bins at my new allotment, they are in full sun for most of the day. The poo and other vegetables waste plus allotment waste start of in bin 1, 3 months on I lift the bin and shovel it into bin 2, 3 months on it goes into bin 3 then onto the garden. Since starting with the black bins composting has speeded up massively, I have always used coconut coir unless I have loads of sawdust :lol:

On the allotment we have mostly raised beds and winter time we cardboard them over and put compost on top ready for digging in, in the spring.

I have to say your essay was well written and I loved how you added all the science, of course the knockers will still knock it 

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3 minutes ago, peterboat said:

... in full sun for most of the day. The poo and other vegetables waste.....

 

This raises an interesting question. 

 

Are these systems suitable for non vegetarians who sometimes moor in shaded areas?

 

Is it going to be like the old "is there a signal on the telly?" or "are the solar panels going to be shaded?" or "What is the 4G signal like" situation where the onboard systems rule where one can moor. 

 

I don"t think I'd like the lavatory to rule choice of mooring locations and I definitely wouldn't like the lavatory to rule what I choose to eat. 

 

The vegetarian/vegan/animal killer side of it needs to be explored more I think. 

 

 

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1 hour ago, Dr Bob said:

I probably spend no more than 10 mins a week managing it. With our pump out I used to have to strip the vacuuflush unit twice a year when it broke - an hour each time, plus the time taken to do pump outs etc. Its a lot less time consuming than pump outs or cassettes.

 

Does that 10 minutes include walking the urine to the nearest facilities or woods? I don't want to poo poo your figures but two hours per year fixing your pumpout = 2.3 minutes/week. Say 30 minutes every 6 weeks to pump out = 5 minutes/week. So a Total of just over 7 minutes/week on the pump out. 

Edited by booke23
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