Contact on This email address is being protected from spambots. You need JavaScript enabled to view it.

I can design a bioreactor cum filter.
It's better than a vermi-filter.
Joy

Thanks for the comments Dean!

Best,
Bogdan

Dear Dean

For vermi-remediation waste, be it be solid or liquid, it is needed to be part remedied and brought in pre-cooked condition for worms to sustain !

As it is an aerobic process, O2 is required (V beds to be devoid of cocktail of swgas - CH4. H2S. CO. CO2. N2. HCs. )

In the initial stages of treatmnt process follow usual path ie. prmry ( sptc tks ). scndry ( coarse fltrs ). trtry ( fine fltrs + phto r )

For the last stage - finishing & polishing include vermi beds with effluent flowing in and out.

Effluent water is re cycled for watering farms, secondary uses and the priced worms dealt with separately.

Due tests are done to ensure that both water and worms are safe for consumption or corrections are done

Communities specialise in producing worms to be nurtured and reared for commercial benefts,

Worms are used in poultry , fish - feed and many others.

A vibrant cum lively eco - system is evolved with ideal assets in form of flora. fauna. avians too.

Well wishes
Prof Ajit Seshadri.

Hi Bogdan, certainly a primary vermifilter would eventually get a buildup of solids, which is why there should always be twin vermifilters to rotate and allow full decomposition/sterilisation to take place over sufficient time before removing the humus.

But you are asking about secondary vermifiltration. Yes, the bacteria and worms are making solids in the process of reducing the oxygen demand and filtering out the suspended fine solids. This will happen even without worms being present. The worms, however, are the caretakers of the media and actively tunnel, thus ensuring the media remains porous. The humus they create also inherently has good drainage. Compare vermicompost with sludge or mud. Then the media itself might decompose if it is organic, for example sawdust decays much faster than bark, so would need regular additions of more. But it's not so much a volume thing, but porosity. "Humus" is a stable media because it cannot decompose further. The carbon is stable, so eventually no more sawdust would be added, but some humus would need to be removed. I doubt humus would ever have insufficient porosity for use as media

I suppose it is possible that in the long term the media might end up with an excessive retention time, but I haven't seen it yet. The key being that hydraulic loading should not exceed retention. If it does then maybe there is a capacity issue rather than a media porosity issue. Maybe it will end up good practice to renew the media every 15 years or so...
cheers
Dean

Hi Dean!

I was asked today about the possibility of vermifilter eventually clogging by worm castings as basically they would turn dissolved organics into solids. Could you please comment on that?
Best,
Bogdan

Hi Dean!

Thank you!

I am involved with developing these kind of public toilets and surge loads is quite challenge for any kind of system (dry or water based) Just wanted to see how in your view vemifiltration could possibly overcome it. Looks like it is also complicated issue.

Regards,
Bogdan

Hi Bogdan,

What about scaling a single digester to the number of users? There would be no problem with high weekend use and then no use during the week.... the worms don't care, that is no different from the same quantity evenly over the week. 300 uses per week is maybe like 30-40 people using it constantly... so 10 x the capacity of a domestic vermifilter... maybe (I'm guessing) 2m high and a diameter of 3m? However, the key would be getting digestion underway rapidly to keep pace with the inflow. On a domestic system one can add a small handful of worms a few weeks after commissioning and it might take months for the population to build, which isn't a problem because there is additional capacity. With a larger system the buffer might not be so large, so the pressure would be to get digestion to keep up with inflow as soon as possible. Could you describe in more detail what you have in mind in terms of a modular system?

cheers
Dean

Hi Dean!

Do you think it is would be technically possible to develop primary vermidigester for public toilet with high number of week-end visitors (say 300 per point of use per day) , long idle period with none of few visitors? The modular system when several vermifilters cells got linked in on demand is what comes to my mind. Having one big vermidegester designed for peak loads doesn't look like a right option. Or what do you think?
Best,
Bogdan

Hi Bogdan, I have to say I prefer settling tanks in series rather than cartridge filters, because filters don't tend to be maintained by users and can affect the reliability of the whole system. Maintenance of settling tanks is minimal, perhaps 5 yearly intervals pumping sediment back to the primary vermidigester.

Also keep in mind that with vermifilters the worms maintain the filter! Settling tanks can also be built cheaply out of used 40 gallon drums. I'll upload some photos some time of a low cost domestic system made entirely out of 40 gallon drums...

Perhaps think about designing systems that malfunction at the source when not maintained... i.e. the toilet overflows because maintenance is required! These are wonderfully foolproof...

cheers
Dean

Hi Dean!

Thank you! This very valuable that you are willing to share your experince here including trials record. It is only through these experiments we can develop new systems "out of septic box")))).

Now I understand much more about your design and why did you put several setlling tanks after the primary digester. This really makes sense. I wonder if there are any very small low wattage small flow sludge pumps produced capable of passing bigger partickles. and run on 12 volts. I haven't seen any here less than 500 watts so far.
Some cartridge type rough filter serviced from outside like septic tank effluent filter is what what comes to my mind when I think of the ways to make things working with the pump. Probably also control system that warns of level raise in the sump when the filter got clogged.

Best,
Bogdan

Bogdan

Hi Bogdan, yes blockage of these small cheap pumps has always been a concern. Indeed they can block with silt building up in the inlet. The pump itself doesn't block, but the buildup of fine particles can stop the water from flowing into the pump which can burn them out. How I've got around that is to use a series of sedimentation drums between the primary and secondary vermifilters. These remove most of the suspended solids. Also, the intake for the pump is below the surface but not too far below. The solids themselves are never big enough to block the pump, with reliability being the key concern.

I'm sure there would be a thousand different ways to design the system... if there were fall then the secondary filter could be directly under the primary filter and thus avoid any need for settling and recirculation. That is not always possible, however. I'm also interested in hearing others solutions to the problem!

With this system, every 5 years (when I rotate primary vermidigesters) I pump the sediment from the settling drums back into the primary vermidigester. Depending on how well your primary vermifilter removes suspended solids, the buildup of sediment should be quite slow. I don't try and achieve high levels of removal at the primary stage, and with settling drums the secondary vermifilter is not primarily for removing suspended solids, but more to aerate the wastewater and remove BOD, pathogens and smell for subsequent surface discharge.

cheers
Dean