Dear researchers,
I’m currently running a dry anaerobic digestion (AD) experiment treating FOGO (food and garden organics) with a total solids (TS) content of 15% inside CSTR. One major challenge I’m facing is the management of solid retention time (SRT).
The biogas production is not improving with time which makes me suspect that the SRT is either not well controlled or not optimal for this system.
I’d appreciate any guidance on:
Effective strategies to maintain or adjust SRT independently of HRT in high-solids AD systems. .
- How to effectively maintain or adjust SRT in high-solids AD systems? At the moment, I am taking out more solids from the reactor as effluent to reduce SRT. Do I need to take out particular solids in single time and dilute the reactor content to make up to the desired working volume? I am not sure which strategy I should adopt to maintain SRT.
- Common methods to recirculate digestate in dry AD to retain active biomass
- Any benchmarks or ranges for SRT that have worked well in similar setups
Any suggestions, references, or shared experiences would be incredibly helpful.
Thank you in advance for your time and support.
Best regards, Ayesha Rafique (PhD Researcher – Anaerobic Digestion of FOGO)
Dry AD of FOGO at 150-400 gDS/L would make little sense in CSTR because the complete stirring/mixing would consume a huge amount of energy aside from mechanical issues on such mixers resulting in high wear and tear and frequent maintanance at a short lifecycle. That's why dry AD is applied in plug-flow or in batch mode.
I don't know too much about FOGO however, since can anairobic system is desire, the moment the ferment iscset up with initialixing to distribute the nutrients and fermenting organisms very well. The moment anaerobic condition is achieved, there may be little or my need for agitation or mixing. For a batch system, as nutrients are used, products are made at the same time and location once the starter cultures are evenly distributed. When production is assured, process ends. Then product recovery and another batch.
The scientist may contact me for furthervl discussion.