Using Woodchips for Solids Mineralisation, Nitrate Reduction & Filtering

[mattyoga 163]

With all this talk of off line mineralisation tanks etc, I started wondering about a low energy/lower capital solution....composting and/or vermiposting the solids out of the RFF.   

 

Conceptually what I am thinking is having a bathtub with wood shavings/cardboard etc that I deposit the solids into (with water)., any excess liquid will be drained into my grey water surge tank, that will then get sent to the fruit trees every time I take a shower

 

What I'm hoping will happen is that as long as I keep adding enough carbon (woodchips), that the solids will be broken into a high value fertilizer that I can use on my earthan beds/wicking beds/fruit trees etc.

 

Has anyone tried this setup?  I may be able to install a small pump at the bottom of the RFF that will come on once a day for a minute to auto empty the RFF into the vermiposting bath.  I think vermiposting will be better as it should be able to handle wetter conditions than just straight composting.  What I'll be essentially doing is dumping all my solids into a big worm farm.

 

I'm hoping the solids will be mineralised into a stable form that can then be used in the soil based garden.  Another bonus may be worms as fish food. 

 

Other option I was considering was just pumping solids directly out to garden beds, though this would require a more extensive retic grid.

 

It seems that my system(s) always have high nitrates, so hopefully with solids removal I may be able to lower them sufficiently to get better performance from fruiting plants.  K would still need supplementing (due to ammonia directly excreted and nitrified )so I'm hoping I would get a better N:K ratio.   and if I find P lacking I'll supplement with a dash of MPK... 

 

Ultimately I'm thinking convert all fish systems to RAS, then run the growbeds as pseudo hydro /AP systems - and get lots more good fertiliser for the soil based systems.

 

 

Edited March 9, 2015 by Gary Donaldson
Thread Renamed at Request of Mattyoga (see edit history)

[mattyoga 163]

http://researchrepository.murdoch.edu.au/16000/1/vermicomposting_of_aquaculture_solid_waste.pdf

[Rotaco 10]

Hi Matt

I have been placing my RFF solids (with water, as I siphon the waste out of the bottom) into the worm farm at least once a week. It is difficult to tell if it's increased the number of worms, however it has not had a negative impact as the worms are present and still breeding. I also add a small lot of old lawn clippings each time. The worm farm is also not just dedicated to RFF solids and clippings (I add the usual veg based kitchen scraps).

The small (20 litre) RFF gets emptied (siphoned for solids) once a day, with the waste going onto the soil beds, 6 days a week. I observed almost twice the growth rate on targeted corn and zucchini plants receiving the RFF solids. The same beds also receives a combo pellet fertilizer (named organic extra), monthly, without bias to the targeted plants.

The above process costs me about 5 mins of time per day.

My only solids removal from my separate inside tank (800 litres, no AP loop) occurs daily via gravel cleaner/syphon (other than weekly sponge filter clean and monthly canister filter clean). This goes straight into a 200 litre blue barrel on a trolley, and then siphoned out from the barrel to fruit trees and soil beds as the next step.

The above process costs me 200 litres of water and about 40 mins of time per day but takes 1.5 hours in total. The 200 litres was also a way of rationing my water to the gardens and lowering my nitrates in the tank. (No town water available on my property). This part of greater Brisbane (Samford) did not receive any tank filling rain until late December.

I have not fertilized 3 fruit trees (pawpaw, mulberry, nectarine) targeted in the above process with anything other than the blue barrel water (and potassium added directly to soil in the form of sulphate of potash) and received impressive fruit crops from all 3 trees last year.

Apologies for sounding so low tech (it's like this while I'm setting up something better ... I am taking my time though), but I hope this info helps.

Rob

[ande 826]

Hi m

 

With all this talk of off line mineralisation tanks etc, I started wondering about a low energy/lower capital solution....composting and/or vermiposting the solids out of the RFF.   

 

Conceptually what I am thinking is having a bathtub with wood shavings/cardboard etc that I deposit the solids into (with water)., any excess liquid will be drained into my grey water surge tank, that will then get sent to the fruit trees every time I take a shower

 

What I'm hoping will happen is that as long as I keep adding enough carbon (woodchips), that the solids will be broken into a high value fertilizer that I can use on my earthan beds/wicking beds/fruit trees etc.

 

Has anyone tried this setup?  I may be able to install a small pump at the bottom of the RFF that will come on once a day for a minute to auto empty the RFF into the vermiposting bath.  I think vermiposting will be better as it should be able to handle wetter conditions than just straight composting.  What I'll be essentially doing is dumping all my solids into a big worm farm.

 

I'm hoping the solids will be mineralised into a stable form that can then be used in the soil based garden.  Another bonus may be worms as fish food. 

 

Other option I was considering was just pumping solids directly out to garden beds, though this would require a more extensive retic grid.

 

It seems that my system(s) always have high nitrates, so hopefully with solids removal I may be able to lower them sufficiently to get better performance from fruiting plants.  K would still need supplementing (due to ammonia directly excreted and nitrified )so I'm hoping I would get a better N:K ratio.   and if I find P lacking I'll supplement with a dash of MPK... 

 

Ultimately I'm thinking convert all fish systems to RAS, then run the growbeds as pseudo hydro /AP systems - and get lots more good fertiliser for the soil based systems.

 

I love the thinkering and playing with mineralization etc. , makes one understand "the process" , how to influence speed up/down (help along) to achive "no polution" in the efluents.

Preferably making a "profit" (read harwest) on the excess fertilizers "waste" , to use, in my imedate suroundings.

I'm trying to produce enoughf compost/fertelizers to cover my own needs, minimizing having to buy suplementals.

 

RAS/PRAS is it, for me, given my location, easy and/or free access, to soil/peat/clay/etc & space available, I'd be ignorant to go "high-tech"  and not make use of the resources I have, with wich, I can achive the same (maybe even better )

 

This Lennon song lyrics poped up in my head, reading your reflections enjoy

 

 

cheers

Edited February 19, 2015 by ande (see edit history)

[ande 826]

Hi again

 

In our eagernes to perfectionate, a singel component, within the RAS/PRAS, we all tend loose sight, of the overall big pic, now and then

At least for me that happens  " all the time" 

Cut this quote from here "Recirculating Aquaculture Tank Production Systems A Review of Current Design Practice"  http://appliedecology.cals.ncsu.edu/wp-content/uploads/453.pdf  It gets lost   or some how, gets much less (if any?) attention, than the headings, on singel components, within the system yet it probably contain/holds, some of, the most valuble advice in the hole PDF/doc (KISS) IMO

cut/paste ;

Integrated Treatment

To the novice, RAS design can appear complicated.

Yet, robust RAS designs can be as simple as a tank, a pump, a few spray heads, and a bioclarifier.

All the technologies described here have proven track records and can be combined in a variety of ways to form a viable RAS.

Always be sure that the five core processes: 1) circulation, 2) clarification, 3) biofiltration, 4) aeration, and 5) carbon dioxide stripping are addressed.

All components in an RAS must be sized to handle the same fish (feed) loading.

Table 1 (see link above) presents just a few of the large variety of RAS configurations that have worked successfully.

In a typical design exercise, the holding capacity of the system (pounds of fish) is defined, the peak daily feed ration is calculated, and then all components are sized to support the peak daily feed load.

A prudent designer will then multiple a uniform safety factor (for example 1.5) across all the major component sizing calculations.

With a little knowledge, it is relatively easy to develop an RAS system that will produce fish.

 

It is considerably more difficult to configure a RAS business that makes money.

When you make the transition from hobby or bench scale to commercial, seek professionals for help or review of your RAS design. Cost effectiveness between RAS design varies widely

 

cheers

Edited February 19, 2015 by ande (see edit history)

[TheDictator 346]

http://scholar.lib.vt.edu/theses/available/etd-10162003-205902/unrestricted/Final_Submitted_Thesis1.01.pdf

Don't know if you have already read this Matt but I think it's an interesting paper.

[mattyoga 163]

Thanks Swede.

 

The resource I have at hand is woodchips - lots of them, some 1-2 inches, other stuff fine.  From what I have read woodchips are not great in that they do not absorb much moisture and their carbon is 'hard' to access.

 

Anyway I might try it and see if I end with a stinking mess - I'll be adding other more softer carbon sources (kitchen scraps, tea bags etc).  I like the idea of have plenty of wood in there as even if it ends up in the garden, it will be a useful source of fungal food.  plus I've got 10 m3 of it on my front verge

 

@Rob, thanks for the info - good to know its working for some one else.  I agree with Ande .... IMO if low tech works, why use high tech  Probably one of our greatest challenges is system design is not over complicating things!

Edited February 24, 2015 by mattyoga (see edit history)

[TheDictator 346]

Do a search for a movie called Garden of Eden. It's about a guy growing veggies and fruit trees using wood chips as a mulch to maintain moisture in the soil. Interesting if you live with the fact that the guy is super religious and references God in every other thing he talks about.

[TheDictator 346]

It was back to Eden. That's the movie right there in that link.

[mattyoga 163]

Cool - will check it out.

[yahoo2 215]

I've had a few days to think about it, a low mounded row of woodchips mixed with something finer and perhaps some green waste to hold moisture should handle the same volume of sediment. It might take 5 years to break down and work its way into the garden soil completely. I know it looks a bit scruffy but cold composting is very energy efficient

 

Pumping a slurry directly onto the ground will probably overload it if there is not a heavy layer of vigorously growing plants.

[mattyoga 163]

I agree Yahoo - If there is no need to remove pathogens or seeds, cold composting is the go. Its generally how nature does it, though in this instance the worms should help.  I might try chucking some coffee grounds in the mix - Can get these from a coffee shop and they will help absorb moisture and add a bit more 'green' to the mix.

 

Will also try sifting the woodchips with a course sieve - save the big chunks for mulching ornamental beds and use the finer stuff for the RFF worm farm slurry grey water feeder.

[yahoo2 215]

One of the projects that is in the wings for me is a charcoal retort, the version I will build is a super efficient modified rocket stove, mine will be for blacksmithing charcoal but it would turn big woodchips into biochar very easily. Best of all it would do it with no smoke, the major downside of traditional charcoal kilns.

 

the massive surface area of bio-char would really kick things along in difficult weather conditions.

 

I will have to take some photos of the built when I get started.

[GaryD 1054]

It was back to Eden. That's the movie right there in that link.

 

Hi Swede,

 

The "Back to Eden" video to which you linked is very interesting…..notwithstanding the constant sermonising.  

 

The core non-religious message delivered many times is that you can create soil out of tree mulch and that, with tree waste, you can build a garden almost anywhere.

 

I used to believe that tree mulch would rob the soil of nitrogen but that only becomes an issue if you bury the wood.  Anecdotal evidence from other threads suggests that, even where you do bury the wood, the nitrogen deficiency only last the first season or two. 

 

We're planning to fill the trenches that result from digging the swales in our backyard with tree mulch.  It will act as a sponge when it rains and the water will accelerate the degradation of the tree mulch….in to healthy soil.

 

Gary

[GaryD 1054]

Hi Matt,

 

With all this talk of off line mineralisation tanks etc, I started wondering about a low energy/lower capital solution....composting and/or vermiposting the solids out of the RFF.   

 

Conceptually what I am thinking is having a bathtub with wood shavings/cardboard etc that I deposit the solids into (with water)., any excess liquid will be drained into my grey water surge tank, that will then get sent to the fruit trees every time I take a shower

 

What I'm hoping will happen is that as long as I keep adding enough carbon (woodchips), that the solids will be broken into a high value fertilizer that I can use on my earthan beds/wicking beds/fruit trees etc.

 

Why not add a bit more nitrogen and pee in it, too……directly or while you're in the shower.

 

Has anyone tried this setup?  I may be able to install a small pump at the bottom of the RFF that will come on once a day for a minute to auto empty the RFF into the vermiposting bath.  I think vermiposting will be better as it should be able to handle wetter conditions than just straight composting.  What I'll be essentially doing is dumping all my solids into a big worm farm.

 

​Don't over think this.  A timed pump won't remove most of the solid waste.  I've found that it won't all gravitate to the bottom of a cone-shaped container even - it's pretty sticky stuff.  

 

I'm hoping the solids will be mineralised into a stable form that can then be used in the soil based garden.  Another bonus may be worms as fish food. 

 

You'll achieve more effective mineralisation if you put the solids into a drum and bubble air through it….although your idea is going to require less handling.

 

Other option I was considering was just pumping solids directly out to garden beds, though this would require a more extensive retic grid.

 

That would work, too.  

 

It seems that my system(s) always have high nitrates, so hopefully with solids removal I may be able to lower them sufficiently to get better performance from fruiting plants.  K would still need supplementing (due to ammonia directly excreted and nitrified )so I'm hoping I would get a better N:K ratio.   and if I find P lacking I'll supplement with a dash of MPK... 

 

The simplest solution is to water your gardens out of your fish tank.  That way, the nitrate-rich water goes directly to your plants and the biological oxygen demand on your system is reduced.  You're still getting two crops for the same quantity of water.

 

Ultimately I'm thinking convert all fish systems to RAS, then run the growbeds as pseudo hydro /AP systems - and get lots more good fertiliser for the soil based systems.

 

RAS/wicking bed combinations are great.  They serve each other no less than any aquaponics system…..and its a great way to take the load off your fish system.

 

 

Gary

Edited March 1, 2015 by Gary Donaldson (see edit history)

[TheDictator 346]

Hi Gary,

When using the wood chips remember that it takes a long time for them to break down. You still need composted organic matter to grow in. Just add wood chips on top. Don't plant in the wood chips but in the organic matter below. Wood chips on top keeps moisture at a good level reducing the need for constant watering.

With time wood chips breaks down too of course and adds a very much needed fungal food for the microbes.. This is especially good for growing trees.

[mattyoga 163]

I agree - I've been amazed at the woodchip conversion around the trees where the grey water currently runs.  Its only been there 6 months but is already good earthy blackness at the bottom layer with worms.  I'm expecting the break down process to accelerate in winter when more of the woodchips will be moist from winter rains.  I know of some people that use just woodchips and rock dust to develop their soil and they do very well (100mm depth of wood chips added twice yearly)

 

I do pee in the shower now, happy in the knowledge all the nutrient content is feeding the trees/mulch breakdown.

 

One concern I have with using fish water to water the garden week in week out is nitrate leaching, though I think in summer this would be minimal, it could be significant in winter.  I also wonder about excess nutrient build up in wicking beds.  Currently my AP system EC can be as high as 5 ms/cm, which I think is too strong for seedlings and some plants, so I'd need way more planted area to utilise all the nutrients within the AP system.  What would be the effects of excess nutrient build up in wicking beds?  salt burn on the leaf tips?  

[GaryD 1054]

Hi Gary,

When using the wood chips remember that it takes a long time for them to break down. You still need composted organic matter to grow in. Just add wood chips on top. Don't plant in the wood chips but in the organic matter below. Wood chips on top keeps moisture at a good level reducing the need for constant watering.

With time wood chips breaks down too of course and adds a very much needed fungal food for the microbes.. This is especially good for growing trees.

 

Yeah, the message about the need to plant into the soil (rather than into the tree mulch) was reinforced by another bloke in Paul Gautschi's video.  Actually, that video could have been a lovely little three minute job if you removed all of the religious stuff out of it.  The core messages were simple and the evidence that his methods work was very clear.  I was glued to the bloody thing for the entire hour and a half - afraid that I'd miss some key point.

 

 

I agree - I've been amazed at the woodchip conversion around the trees where the grey water currently runs.  Its only been there 6 months but is already good earthy blackness at the bottom layer with worms.  I'm expecting the break down process to accelerate in winter when more of the woodchips will be moist from winter rains.  I know of some people that use just woodchips and rock dust to develop their soil and they do very well (100mm depth of wood chips added twice yearly)

 

I do pee in the shower now, happy in the knowledge all the nutrient content is feeding the trees/mulch breakdown.

 

One concern I have with using fish water to water the garden week in week out is nitrate leaching, though I think in summer this would be minimal, it could be significant in winter.  I also wonder about excess nutrient build up in wicking beds.  Currently my AP system EC can be as high as 5 ms/cm, which I think is too strong for seedlings and some plants, so I'd need way more planted area to utilise all the nutrients within the AP system.  What would be the effects of excess nutrient build up in wicking beds?  salt burn on the leaf tips?  

 

When I was in the Navy (many years ago), we were encouraged to pee on our feet in the shower to help prevent tinea - a nasty ailment to contract if you're in the tropics.  Then I became a submariner and the showers stopped.

 

I'm about to start harvesting my own urine again.  It's a low cost nutrient package that will help to break down the wood chips, too.

 

Matt….if you think that there's a risk of excess nutrients, plant some gross feeders like tomatoes, cucumbers and beans.  They'll soak them up.

[mattyoga 163]

I wish it were that easy Gary - I find when I do that (plant heavy feeders)  I end up with potassium deficiency and still excess nitrates, then nothing grows productively well.  Hence my reference to pseudo hydro AP as I've taken to supplementing potassium (in addition to buffering with potassium bicarb) to get enough in the system.

 

Other than those on medicines, it seems a crime almost that we don't all harvest our urine, and for that matter our solids, though that is a bit more involved with more risks to manage.

 

Did you find the tinea cure worked?  Not convinced urine has anti fungal properties.

[ande 826]

Hi

IMO use it if you can

Practical Guidance on the Use of Urine in Crop Production
http://www.susana.org/_resources/documents/default/2-757-5-ecosan-urine-in-crops-100824-web1.pdf

and this

Guidelines for the Safe Use of Urine and Faeces in Ecological Sanitation Systems
http://conference2005.ecosan.org/presentations/schonning.pdf

 

 

cheers

Edited March 4, 2015 by ande (see edit history)

[GaryD 1054]

I wish it were that easy Gary - I find when I do that (plant heavy feeders)  I end up with potassium deficiency and still excess nitrates, then nothing grows productively well.  Hence my reference to pseudo hydro AP as I've taken to supplementing potassium (in addition to buffering with potassium bicarb) to get enough in the system.

 

Other than those on medicines, it seems a crime almost that we don't all harvest our urine, and for that matter our solids, though that is a bit more involved with more risks to manage.

 

Did you find the tinea cure worked?  Not convinced urine has anti fungal properties.

 

I never had tinea. 

 

if you want to burn off excess nitrates you could do worse than to produce duckweed.  It's a magic little plant.  It will use up nitrogen (it actually prefers unionised ammonia) and will give you a high protein product that can be fed directly to livestock…..or it can be fed to BSF larvae and, in the process, converted to animal protein.  Mixed with BSF larvae, duckweed becomes a salad for chickens, ducks and quail.

[mattyoga 163]

Good point Gary - whats the minimum depth required for a duckweed tank?  I'm assuming you have them as flow through.

 

Ande, thanks for the links - can't get the first one to work.

[ande 826]

Hi

should work now I made a new to the same doc

 

http://www.susana.org/_resources/documents/default/2-757-5-ecosan-urine-in-crops-100824-web1.pdf

 

Ande, thanks for the links - can't get the first one to work.

 

[mattyoga 163]

Cool - good to see a lady using urine on the cover-

 

On a facebook gardening forum recently someone stated that only men can wee on citrus trees, and only the first wee of the morning!  

[GaryD 1054]

Good point Gary - whats the minimum depth required for a duckweed tank?  I'm assuming you have them as flow through.

 

Ande, thanks for the links - can't get the first one to work.

 

Any depth from 100mm (4") upwards…….deeper is better if you experience very hot conditions because, as with everything else to do with aquaponics, theres an optimal water temperature range…..of 20^oC to 32^oC…..and much above that - or much below that - will stall its growth and eventually kill it off.

 

Gary