The 'Permachar Wicking Module' (PWM)

If I can get a small production line happening, I could make the 'Permachar Wicking Module' (PWM) made from biochar-epoxy resin biocomposite panels and pipes. Epoxidized Canola oil or even better but double the cost, linseed oil, may be used as a base for producing potentially solid water-free and VOC-free epoxy resin.


I'm hoping to use Pinus radiata (pine) for the biochar aquifer and biochar filler in the biochar-epoxy resin biocomposite module panels. As with the PWP, I hope to use sea kelp biochar for the Permafert as it contains minerals and trace elements which would be slowly released. All the biochar would also be made in the Kon-Tiki 'Rolls' biochar kiln.


Inititally, I would have to prototype the modules in order to assess the durability, water resistance/breathability (probably won't need as much breathability as ceramic terracotta), and UV resistance. Some of this testing can also be done in Mauro's lab.


The module panels could be made with basic formwork or molds. 2" PVC pipes could be used as molds (possibly used in conjunction with a DIY injection molding machine) for the vertical standpipes/2 way valves with slots.


The biocomposite panels might need a wood or steel exoskeleton to keep them in place, or possibly just a steel exoskeleton base using 3mm 'steel angle', which would also allow welding of plates that would attach to the castors. If the biocomposite panels are, say, 5mm thick, they could be attached together with angle brackets and screws . Biochar silicon (another new material) could be applied on the inside of the module at the panel joins to prevent water leakage.


Multiple 2" pipes (with slots) would be spaced out vertically along the centreline of the module and positioned on the base and locked into position by the surrounding aquifer/permafert layers. The pipes can be 'capped' with a 2" cap after filling in order to reduce evaporation from the pipe.


The modules could be on heavy duty swivel castors with brakes (like on the Kon-Tiki 'Rolls' biochar kiln). The wheels allow easy moving of the modules to the right place (over flat or uneven ground) which may vary over a year due to changing climate/micro-climates.  The wheels also allow transport on trailers. Rubber, in the wheels, can also use biochar as a filler which is a whole new area of research.  Until that happens it is easier to buy off-the-shelf wheels from eBay.


After R & D stages, with the right training, resources and infrastructure the PWM could be built locally and sold locally either as kits of all the components eg. the panels could be flatpacked OR as a complete unit. The seedlings could be offered as optional since some people might want to grow/supply their own seedlings.


Any punters or collaborators please get in touch on the 'Contact form'!

Other wicking module options

The PWM could be made with welded steel.
The PWM could be made with welded steel.

Or, if function and cost overrides aesthetics, you could cut a new or used IBC in half horizontally (with an angle grinder +/- jigsaw) and weld 4 castor wheels onto the base, with one in each corner. A couple of spaced out vertical 2" pipes with slots would probably do the job. If using a used IBC, you will need to check it's history and find out what it previously contained, which needs to be non-toxic.


If using longitudinally cut 200L polyethylene barrels, I would recommend reinforcing the top with wood screwed in, as they will deform over time which is what happened in the 'Permachar Kitchen Garden (PKG)' (see on a separate page - this system successfully prototyped biochar aquifers/Permafert/mulch). As with the IBCs, used barrels need to have a history of non-toxic liquids eg. ethanol.


Potentially animal feed troughs, water troughs, bath tubs, 20L ss/galv/recycled plastic buckets, large trugs etc. could be retrofitted too. Also, see the 'Permachar Wicking Pot (PWP)' page for pot-based wicking pot systems. In theory, any vessel that can hold water and is ergonomic for growing could be used.

Here's an alternate module/panel design using the key/slot system developed for the Flat-Tiki 'Carbon' V3 biochar kiln
Here's an alternate module/panel design using the key/slot system developed for the Flat-Tiki 'Carbon' V3 biochar kiln
Here's a side view of the PWM design using interlocking 1.6mm HW350 corten panels and vertical standpipes.
Here's a side view of the PWM design using interlocking 1.6mm HW350 corten panels and vertical standpipes.

I can use off the shelf components for this. I will need to use 200um black plastic for the aquifer with underwater Gorilla tape. I have just read that bioplastic that biodegrades in the ocean has been invented at Osaka University. Maybe one day we could manufacture it in Australia with no fossil fuels needed for the production and material! It's also possible to use hemp pellets as a substrate for 30% hemp content bioplastic rolls ( - no one has done it yet but I don't think we are very far off. I'm going to prototype the first module with 90mm PVC stormwater pipes with push on caps. This will increase the size of the overflow reservoir which is probably needed for the larger module size, compared to the 50/65mm PVC pipe used in the Permachar Wicking Pot/Trug/Bucket.

This gives you a 3D model for the PWM using interlocking Corten steel and PVC pipes
Can be viewed in 'Meshlab'
Permachar Wicking Module with
exe File 285.4 KB

Another option could be a new natural building experiment I will be experimenting with over the year. I call it 'CharEarth', which would be a blend of eg.20-40% biochar (filler, which could be pounded then soaked in water beforehand, making a 'biochar slurry'), ?10% straw, ?10% sand, 60% clayey loam. This would be a different recipe than for biochar briquettes used for cooking in some places but using the same principle of pounding/compression to make the blocks. I would fill up a 20 litre stainless steel bucket, using it as a mold, fill it with the ingredients and ram it with a 310mm diameter 3mm mild steel disk welded onto a sledgehammer head for vertical pounding. The idea is that the blocks would be a combination of rammed earth (pounding) and mud brick (recipe) with biochar filler in order to reduce the Carbon footprint of the design (along with the biochar in the aquifer and Permafert layer).


Note that the soaked biochar (slurry) can hold more water for a comparable volume compared to all if not many clay types due to its abundant mesopores which can adsorb liquids such as water.  A simple experiment could be done comparing Water Holding Capacity (WHC) of different biochars with different clays.  If I am right, then loam with lower clay percentages would need higher percentages of biochar slurry in the recipe in order to bind the ingredients together.  This would expand the possibilities of making the material in more places around the globe, assuming you can access sustainable biomass to make the biochar in a kiln, such as the Kon-Tiki (Rolls) and access clayey loam of variable clay content.


I would then carry the bucket to a solar drying site, preferably near or at the site of the PWM, and empty the bucket laying out the blocks on a tarp for solar drying and covering the blocks with a tarp overnight and on rainy days. An important learning issue is, can it be built without formwork eg. wooden frame traditionally used for mud bricks? If not, then would adobe/cob be a better option? Or, a bunch of plant pots could be used rather than 1 bucket, which could also be repurposed for growing trees.  Undoubtedly, this is a more labor-intensive option than the Corten design above but cost a lot less if there were multiple PWMs to build in order to justify buying or producing modest quantities of the ingredients.  The  CharEarthBuckets would provide more thermal mass for the PWM walls therefore insulating and regulating/buffering the temperature of the biochar aquifer and Permafert.

A 3 litre olive oil container turned into a mud brick mold - this could be used too!
A 3 litre olive oil container turned into a mud brick mold - this could be used too!

A smaller block/brick could be made in a angle grinded olive oil container eg. 3-5 litres. This will dry faster than a bucket sized block. The ingredients would still be rammed in this scenario. Also, once again formwork might not be needed.


I may have to consider an exterior water-resistant render such as a Silicon-based one but ideally I can track down an earth render, perhaps similar to that used on Earth Ships. However, if I can max out the biochar content in the recipe, there may not need to be a render at all - the biochar will breathe naturally while maintaining it's structure.


Or, you could possibly use a manual brick making machine from Alibaba:


F**king brilliant design! You could probably add 30% moderately crushed biochar (without water) to 70% loam since it's 'rammed' - I call it 'RammedCharEarthBricks'. Handy if you want to build PWMs all around your garden or other useful structures too eg. Chook house, Humanure toilet etc,! No render probably needed, unless you were using it to build inhabited structures.


Can't wait to try out the different options and compare!!

So here's another option. On the left is the PWP and on the right is the 'Tuff box' ($20) 100 litre box. In Oz, these can be found at Stratco. Bunnings doesn't seem to offer an altervative for the price. Cheap as Chips has 'Ecorecycled heavy duty storage tubs', 100 litre, made from recycled plastic for $25. 


In the top left are my original wicking pots that used a tray underneath which had pretty average performance and took more care to water but still using the 50% biochar bottom aquifer/50% permafert top layer. The PWMs are sitting on top of my Permafert Swale system, which has been highly successful with Sunchokes but need watering every couple of days.  I'm hoping the Tuff box PWM system will only need watering every 3-4 days - just need to prototype it. Also note that the 'Tuff box' lid could be used as a flooded microgreens tray for seed propagation.


So, I've checked the 'Tuff Box' after heavy rainfall and confirmed that the PVC pipe/2-way valve is working i.e. the water level rose in the pipe as a consequence of the permafert and aquifer reaching maximum saturation with excess water needing somewhere to go.  The only issue is that after heavy rainfall waterlogging of the Permafert was an issue.  During the wetter months, this design should probably be kept undercover with access to sunlight. If that's not possible then an overflow pipe could be inserted slightly above half way up the side of the box. During the drier months, the PWM can be left outside as waterlogging won't be a problem.


I've worked out (26/10/21) the optimum watering technique. When the water level goes down to 1/4 of the way up in the pipe, do a manual touch test of the topsoil to see if it's still moist. If dry, it's time to top up the pipe with more water since the aquifer (and permafert) is starting to dry out.


Using a 10 litre watering can, water the pipe 10L, wait 15 minutes, next 10L, wait 15 minutes etc until the water level is half way in the pipe for 10 seconds. If there is no time interval in between watering, the biochar and Permafert don't have enough time to soak in most of the water and if the Permafert is dry, it will 'float' on top of the aquifer - not good. The idea is not to waterlog the permafert but provide enough water for a few days of wicking or even longer which will depend on the rainfall/evaporation ratio too.


Seedling system with Tuff Box in the perfect place - sunlight and bricks radiating heat on the North face
Seedling system with Tuff Box in the perfect place - sunlight and bricks radiating heat on the North face