can anyone suggest the best anaerobic digester pilot structure wherby we can easily calculate sludge properties during experiment with highly limited laboratorial equipment?
Perhaps our study on Anaerobic Digestion might be helpful?
https://www.researchgate.net/publication/269874743_Anaerobic_Digestion_Assessment_for_Contingency_Base_Waste
Technical Report Anaerobic Digestion Assessment for Contingency Base Waste
I add you two pictures.
- Bauart Reusch, is an old construction built on farms in the 50's. There are no pumps and the steering system could be operated manually.
- Image_0003 is a lab-scale biogas plant we built 10 years ago. Most components are standard construction materials. You can easily cut holes in the plastik and bond the pipes. The heating system was realized with electrial heaters, but could also be done with water pipes in the fermenter. The steering is done with magnetic steerers (expensive). For the gas collection you will need special bags (impermeability).
- try to place the penetrations of the shell (e.g. pipes) in the liquid level, not the gaseous level. This way it is easier to get the system tight.
- good steering systems are expensive, therefore I suggest manual steering (if possible)
first of all thanks for your comments, i mean how we can sample the sludge without allowing oxygen can penetrate to our semi-continuous or batch digester(in pilot scale)?furthermore how we can feed the sludge without penetration of oxygen? these challenges should be taken into account and addressed prior to design our pilot.
You cannot avoid oxygen by 100%, but that does not matter. A little bit of oxygen, e.g. when feeding solids, is no problem.
You can fill in the sludge with a pipe (from top) which is connected via a valve to the digester (2nd picture, left digester). Fill in the sludge in the pipe (valve closed), wait a moment so the air can get out of the sludge, open the valve an let the sludge run into the digester, close the valve before air can get into the digester.
You will need a scale (volume) on the pipe to measure the filled in volume. You will loose an aquivalent volume of biogas when filling with this method.
yes i see, by the way, have you utilized impeller mixer or magnetic stirrer in your experiment for mixing sludge in your digester?what was your approach for measuring biogas? from your perspective, which reactor is more efficient, batch or semi-continuous?
We are using both kinds of stirring systems, magnetic stirring is limited by the size of the digester and the thickness of the sludge. If possible use an impeller st. with an external drive. We are measuring the biogas continously with flow meters (e.g. http://www.ritter.de/de/produkte/trommel-gaszaehler/) or we collect the gas and measure it regularly (24 h rhythm). Most continous measuring devices need gas flow rates, you cannot get in a lab scale system
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