Busy Again

I managed to do a little work in the van today. A final coat of masonry paint on the end wall (inside and outside the facilities) and some minor tidying up. Most of my day today was spent on remedial work on the digger. The last time Eco used it, the 'dozer blade was very reluctant to operate so we had a quick look on Tuesday and I'd worked out a game plan which I decided to have a go at today.

The problem boiled down to stiffness in the linkages from the blade control lever to the hydraulic valvegear. The swivels on the rotating linkages were pretty rusty and the lateral linkages weren't in the best of shape either. A good soaking with penetrating oil then some beasting with a hammer and the linkages are now free, if a little stiff. Before lunch the 'dozer was working.

I needed to make a small reinforcing plate for the top pivot bracket. The bracket itself was a nice thick 'U' bracket, but it was bolted through a very thin steel plate and this steel was flexing rather than the effort travelling down the linkage.

All reassembled, plate fitted and I went to start the engine, and it wasn't having any of it. The chap over the road had borrowed it and returned it pretty empty so our first thought was fuel starvation. We filled the diesel tank, and tried again, but after a minute or so of coughing and hunting, it gave up again then completely refused to even try firing. Eco had a spare fuel filter kit, so we purged the fuel lines, fitted new filters and a complete main filter housing and put everything back together again. Still it refused to play ball. There wasn't a lot of fuel showing in the filter glasses, and we'd noticed that we couldn't hear any 'ticking' from the electric fuel pump, so I looked into the cause of that. Turns out I had slightly dislodged a multi-way connector on the control panel during my ferreting around in the mechanics, and as soon as I waggled it a little, the fuel pump kicked in. One more try of the starter button and she roared into life.

New filters, fuel system as per manufacturers setup (rather than retro-fit inline filters) and all is as it should be. The 'dozer blade works fine now and we're back in operation. The linkages are still a little stiff, but a combination of use and more lubrication should ease them back to normal feel, we hope.

Now the toilet floor is dry and traffic-ready, I cleared out all the gubbins in there and you can now get a better view of the slow sand column filter and the plumbing.

A close-up of the electricals. The main incoming feed (6mm) from the external 16A connector runs up a length of mini-trunking and into the digital kWh meter. The 'tails' from the meter are again 6mm cable and feed the RCCD main breaker. A 16A MCB protects the sockets and a 6A MCB protects the lighting circuits. You can just see the earth cable coming in to the bottom of the consumer unit from the TT earth bonding system, and the 2.5mm grey cable runs down to the weatherproof 13A socket which is our temporary feed (via an extension drum) to the other van bodies. Ultimately, each body will have it's own independent power supply and this extra temporary) socket will be removed.

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Just a random photo looking out of the office window and across the Goat Field. The Landrover has now had a major oil-leak repaired (the oil feed pipe to the turbocharger had broken) and is now ready to go off and get an MOT. 

Some More Photos Of Progress

Just a few photos of the office by way of an update. Ewww....the lens on my camera really is a bit fish-eye, isn't it? It's not the van that's warped - trust me! Another coat of stain and varnish on the external woodwork. You can see the guttering running around the perimeter of the roof. We've not had much rain in the last few days so the ground outside the van is quite firm now.

The guttering goes round the van in a complete loop, so has a surface area of around 2 square metres.

Here you can see the 21.5mm PVC pipe that channels the water into the filter unit. The overflow pipe prevents the storage tank from overfilling.

Looking good now. We really must turn our attention to the woodwork and metalwork shops next now that we have some good weather.

Internally, the second coat is finished on the kitchen floor, I've swept up most of the sawdust, cut the architrave to trim along the front wall once it is clad and the loo has had it's first bucket-change so it's all smelling sweet and freshly painted. I also put a couple of screws up near the top of the partition wall to hang the speakers on. Less shelf-space taken up and more room for stuff.

Shot taken through the front window, hence some reflection and smearing. I still have the compound mitre saw in the office area, but other than that, the floor is pretty clear now. I need to get some more floor paint to do the main office area although the edges have already been cut in.

Trimming and Tatting

Today I took down a pack of rounded architrave and used the compound mitre saw to chop some angles and bevels. The door to the loo is now trimmed in and the 'skirting' is now in place. A second coat of paint on the loo wall and the first coat on the main loo floor is now done and drying, and I got a second coat of floor paint on the section of floor outside the loo.

The partition wall between the kitchenette and office now has it's edging trim and is looking much more finished now, Just another coat of Sandtex and it's done.

Architrave and trimming finished around the door-frame and the end wall and all the woodwork now ready for a final rub down with a fine emery paper and then a coat of gloss paint.

Apart from the final decoration and trimming out, the loo and water supply is now finished. The new slow sand filter is in place and water is running nicely. 

The guttering feeds in using a couple of sections of solvent-weld 21.5mm waste pipe and this has been terminated with a tank connector. The 3/4" plastic thread usually passes through a tank body and is secured with a backnut and a couple of rubber washers to produce a watertight seal, but you can see in the image above I have used a 3/4" appliance hose (washing machine cold fill hose) to make the inlet and outlet hoses for the filter. The outlet hose acts as the weir to the storage tank and the outlet height has been set to leave a 5cm layer of supernatent water on the surface of the filter so it always maintains a wet layer above the filter media and prevents the bio-film from drying out. So far, no leaks!

The bucket is left over from my initial purging and run-through...it doesn't need to be there, but as I'd just painted the floor, I couldn't retrieve it!

Close-up of the filter showing the inlet and outlet hoses. There is just enough space to open the threaded cap on the top of the filter to remove and clean the foam biofilter as needed, and the whole unit can be removed for more serious cleaning or maintenance as required. The filter can be drained by removing the outlet hose from the storage tank and draining it down into a bucket, the inlet can be disconnected and the whole filter column removed and worked on. For now, the column is just supported by the stand at the bottom, but ultimately I may fit a 110mm drain collar bracket just for additional support.

Filter Mk2 - We have lift-off!

No pictures today - my camera-phone had a completely flat battery and I didn't have a charger with me, but I can finally report a stunning success on the filter front.

More research into the finer points of slow sand filtering eventually led me to throw away the rule-book (which is mostly American) to some extent, and to pick up on some research conducted here in the UK. Several factors have come to light as a result of my web trawling.

The sand - forget common or garden builder's sand. What I needed was a fairly specialist type of sand called 16/30 silica sand. This is very clean and has a carefully graded particle size of 0.5mm to 1mm. It's much coarser than builder's sand, but has a very uniform spread of particle sizes and is the 'right stuff for the job'. Used in swimming pool filters and aquarium filters, it has exactly the right properties. Builder's sand was fine in my larger butt, and it had been well flushed and was filtering ok, but the much larger surface area allowed a reasonable flow. In my 4" filter, there was nowhere near enough surface area to allow more than half a cup an hour of flow, and the almost clay-like minute silt particles just clogged the outlet up.

Depth of sand - conventional wisdom, he say a minimum of 40-60cm of media depth...more if you can afford the space, and a good 50cm or more of head at the inlet. My new findings say I can get away with much less...as low as 15cm potentially. I settled for 25-30cm of sand as that works well in my filter column. With a proviso...and here is the real deviation from the rules.

Reticulated PE foam - filter foam in other words. A very low resistance to flow, but a large surface area on which the active biolayer (schmutzdecke) can form, without forming a homogenous layer on the surface of the sand and slowing the filter down too much and causing head loss.

Apparently, 25mm-50mm of foam sat on top of the sand media does exactly the same job as an extra foot of sand and a schmutzdecke. It also means that the effective run-time of the filter is increased several-fold, the head loss is reduced to almost nothing, and the sand only has to act as a mechanical filter, rather than a mechanical and biological filter. Foam filters have been used for some time in the fish-keeping game. I once had tropical fish and used a bio-foam filter in my aquarium, and this foam on the top of the sand media works in exactly the same way. The bioactive layer forms on the foam, rather than the sand itself....it has a much larger surface area because of the many walls between the pores of the foam, and better still, the foam just needs to be removed and cleaned gently under the tap every so often to wash out any sediment, leaving behind the majority of the active biolayer.

I've read the in-depth analysis, reports of field trials and results of water quality tests on the system, and I'm totally swayed to the new concept. So, a couple of purchases on ebay...one sheet of 50cm x 50cm x 2.5cm reticulated PE filter foam, and one 25kg bag of 16/30 silica pool filter sand.

As luck would have it, today was not only a nice day and I managed to get a bit more painting done, but both my deliveries turned up by mid-afternoon.

I rebuilt the filter and output hose (with washed gravel over the collector tube), set the output hose at about 20cm from the top of the filter column and flushed through three buckets of water. With the hose blocked off so the water stayed in the pipe, I then slowly added the silica sand to the right final level. I ran the three buckets through again, catching the outfall in an empty bucket, and passing it back through the system. The silica sand was pretty clean and dry to start with, but this flushing through was designed to rinse out any 'dust' and to ensure the sand bedded in and formed a nice air-free column. After several runs, and pretty fast runs too, the water was coming out almost clear. 

Compared to the original sand butt which produced a very small trickle, dying back to a few drops as the head in the butt got lower, this new filter runs at something like a half a litre to a litre a minute. A little too 'fast' for a slow filter, but with zero head loss and no bio-layer, I'm rather pleased at the speed. The filter was then replaced in the facilities and the outlet pipe coupled back up to the clearwell tank. With a circular piece of the new PE foam in place on top of the sand media, I then filled the column with fresh water (pre-filtered through the Pozanni) to the point where it just began to flow (head height=outlet height). At the point it stopped, the height of the water (supernatent water) above the foam filter (soon-to-be 'schmutzdecke') was checked and found to be a sliver under 5cm, which is apparently the optimum height to allow oxygenation of the biolayer through the water, and to prevent the biolayer drying out. To be fair, I had already marked the heights I wanted to be at, and this was close enough for me. A centimetre or so either way, and I could have added or removed a little sand from the column to optimise my supernatent water level. As it turned out, it was almost spot-on at the first attempt. Sometimes it's luck...sometimes it's luck!

Now, in theory, I should have no leaks, a well-proportioned and effective filter and a rapidly establishing biological filter and a unit that will require a lot less maintenance. Perhaps a weekly or fortnightly inspection and rinse of the foam filter, and then a media (or possibly even a complete column) change perhaps as infrequently as 3-6 months or so. 

All I need now is some rain to check that it can cope with the flow-rate from the gutter without complaining to much. I think it will handsomely.

I think I'll let the system establish itself over the next week or so, drain off some of the existing clearwell stock and run it back through the gutter a few times, and then get a chemical/biological test kit and analyse the water produced. If the tests look really good, I may even be able to bypass the Pozanni cartridge altogether and improve the overall flow rate from the storage tank. For now I'll accept a trickle from the tap knowing that my as yet 'unknown quality' of water is going through a triple stage ion-exchange and activated carbon 'backup'.

I did make three cups of coffee today with water from the tap. As yet...no ill effects :o)

More Progress

A bit of a disaster on the filter front after a night of heavy rain. Flow through the filter just isn't happening and the guttering had backed up to the point of overflowing. With the dimensions of the new filter, compared to the proportions of the butt filter, it seems that the builder's sand I used just isn't cutting it. The outlet pipe/weir was seriously clogged with fine sand silt and the filter was leaking from the inlet hose due to the sheer weight of water. I've now stripped the filter, connected the guttering directly to the storage barrel (which is now full!) and removed all the sand and rinsed the gravel. I'm going to get a bag of sharp sand which should have a larger grit size and better filtering properties. The fine builder's sand just seemed to turn to a slimy mud. I'm wondering now exactly how effective the butt filter was. The larger surface area would have helped, but there is always the chance that any water filtering through the butt was travelling down the walls between the butt and the sand itself, rather than filtering through the sand bed. One lives and learns...

A first coat of floor paint on the floor in the kitchenette. 

Another sheet of OSB fitted to the partition between the kitchenette and the office proper. This is now pretty much the finished wall, bar a final coat of paint and the skirting. 

The floor will need a couple of coats at least to fully cover and seal the phenolic board floor and to give a reasonably hard-wearing surface finish. I'm going to put down some rubber-backed mats to prevent the floor getting too shabby too quickly.

Leakier Than A Leaky Thing

Grrrr! Two afternoons pretty much wasted down in the van. I decided that I needed to get the slow sand filter system in and running as we were expecting rain and it would be a shame to waste it.

With a little hassle with delivery, I finally got all my guttering together and have fitted it to the van body. I'm not necessarily collecting water off the roof yet. If I decide to do that, I need to think about flashing the roof to the gutter. Right now, the gutter itself is my rainwater collector. With 18m of length and a width of about 114mm, that equates to a surface harvesting area of just over 2 square metres of collector - Enough to be getting on with.

I dragged the sand filter from the Toy Shed up to the van body, and with some heaving and grunting and lumps behind the ears, I got it located and set into position. A few modifications to change right handed to left handed plumbing and I was ready for a wet test.

Slow filter on the left - water tank on the right. From top to bottom, inlet pipe carrying rainwater in from gutter, overflow pipe for filter barrel and weir pipe (filter outlet to tank inlet).

It rained on Thursday, but not enough to get things rolling at any speed, so I hurried things along with a hosepipe. Stood on a stepladder outside, I could hear the water running into the tank through the guttering takeoff, and all seemed to be going well. Then, to  my dismay, I heard the unmistakable sound of water dripping onto the phenolic ply floor. Not good.

The collector pipe union with the outlet at the bottom of the filter butt was leaking like a leaky thing...so fast that the height of the water in the filter wasn't going up much. By the time the level reached the top of the weir pipe and started filling the clearwell tank, I figured I would have about 40 litres sloshing around on the loo floor. Despite my attempts to weld the union to the butt, I couldn't slow the leak down enough to conclude any testing, so I decided to drain the whole lot back out again (the tap on the side of the filter is there for that reason).

There is clearly some leakage involved with the water butts. My initial testing was carried out outdoors back in 2013 and a few leaks made no odds. Indoors, in the dry, this is going to be a real problem, so time to rethink the filter system. I think I can get away with the clearwell (storage tank). There is the slightest of weep around the copper tank connector, but nothing major to worry about.

Plan B, after a bit of discussion with Eco on the subject, is to make a thinner cylindrical filter out of PVC soil pipe and some solvent weld components and give that a go. There are two advantages to going down that road. Firstly, the filter unit is still about 1m tall (it's the height, not the volume that governs the working 'head pressure') but is only 110mm diameter so contains less gravel, sand and water. This makes for a much less heavy unit, and one that can be maintained much easier. Secondly, by using flexy couplings, it is possible to make the unit like a 'cartridge', so at end of run (3-6 months or so), the filter unit can be swapped for another and the first one taken down for maintenance and cleaning. If tests on the new Mk 2 system go according to plan, then I'm going to make a couple of spare units to allow for 'one on, one off and one in the wash'. Simples.

It may even be possible to double up the filter units, to increase the available water harvest if necessary. Two identical filter units running in parallel means the volume of water filtered is doubled.

Another advantage to using a much smaller diameter filter is that the working height will increase significantly for a much smaller volume of inlet water. In order to fill the butt filter from sand level to weir height the input volume needs to be some 60-70 litres. With a 110mm filter unit, the volume required is only 6 litres.

The new filter is made from a 110mm grey PVC soil pipe, a push fit access cap on the top end and a solvent weld blanking plug on the bottom. 21.5mm solvent-weld tank connectors will allow connection to the top and bottom of the filter housing using 3/4" nut flexy hoses (washing machine fill hoses). 

The lower outlet hose also becomes the weir pipe and will be connected to the threaded part of the tank connector on the clearwell. In order to carry out maintenance, this hose can be detatched from the clearwell inlet and drained into a bucket before the filter is then removed. 

The inlet pipe will again be flexy, allowing the top of the filter to be disconnected. With a screw-on access cap, the filter can be inspected and wet-harrowed in situ, or removed for complete overhaul and backflush as necessary.

If tests prove successful, I may even modify the inlet pipework to allow two filters to be connected. These can be operated individually or in tandem if necessary with a pair of inline valves (appliance valves). An individual filter can then be taken out if need be, leaving the other in place.

The collector pipe is a 20cm length of 21.5mm solvent-weld overflow pipe, drilled with an array of 3mm holes. This is welded to the inside of the lower tank connector and remains in place in the lower tube. The gravel needs to cover this tube, plus a few cm, and then there is a 40cm layer of sand over this as the main filter construction. A 20cm water level over the active 'schmutzdeck' provides the supernatent water for the filter unit. Oxygenation should be provided by the aeration of the inlet water as it flows from the gutter. The misshapen grey 'lump' on the end of the collector pipe is the dimple cut off the access plug during fitting the inlet connector. It has been heat-welded to the collector pipe with a soldering iron to prevent any of the filter media clogging up the tube.

All in all, a much better scheme than the original system. Lighter, faster, more compact and easier to maintain. To be fair, the prototype proved the principle a couple of years ago, so no harm - no foul.

Kitchen Progress

Cracking on a-pace now.

The copper pipework is now in place and soldered up for the feed (via the cartridge filter) to the kitchen sink. 

I did have an 'oh shit' moment today in the facilities. When I developed and trialled the slow sand filter in 2013, I obviously set it up in such a way that the filter unit was on the right and my clearwell was on the left. There was no real reason for this other than I was pumping water from the drainage ditch to the right of me and draining off clean water to the left of me.

In the van, the water will be coming in from the left hand side and exiting to the right. No problem...reverse the plumbing to the butts. The inlet and outlet are mirror image. The connectors are plastic overflow tank/cistern connectors. No worries. 

Until, revisiting my connections, I realised I couldn't loosen any of them off as I solvent-welded all the threads for added watertightness. Doh! New 21.5mm connectors and tube to be re-fettled to reverse the tankage. I also have a drain off tap for the supernatent water in the filter unit that might just be in completely the wrong place...

On a more positive note, I managed to frame the second partition wall using some 2" x 2" timber. Not only that but stuffed and mounted it, painted it and anchored it to the ceiling tie. All looking (bar the cladding on this side) like the final structural layout now.

A little trimming required to sit neatly around the cable conduits and the skirting and all securely screwed into position.

Just some final tweaking to do, but the kitchenette is almost finished. Tiling of the splashback, final seating of the sink, the siliconing and floor finish to be done, doors to fit and we're good to go. Note the 5 litre bottle of water for brewing up. The company teaboat that I take to and from Portishead is now earning it's keep in here.

Just ignore all the random tools. Kettle, sink, mini-fridge for the milk and coffee makings are all in place and brewing up is happening. If I drink too much coffee, on the job, the loo is just next door.