Sustainably boosting carbon dioxide fixation for growing micro-algae

A system for sustainably boosting CO2 fixation into organic acids and using the organic acids for boosting the growing of micro-algae, comprising:

• a Trickle Bed Reactor (TBR), configured as at least one plug flow pro-current reactor for growing Volatile Fatty Acids (VFA)-producing microbes, wherein the TBR comprises (a) a non-porous packing material configured as floatable particles of high surface-to-volume ratio which when packed form gaps between the particles for allowing a moistening liquid to pass, suitable for use in acidic environments, and for moistening with the moistening liquid, (b) a liquid distribution device connected at an input at a first upper point of the TBR and configured for introducing into the TBR at least one of nutrients, VFA-producing microbes, and the moistening liquid, (c) a CO2 input device connected at a second upper point of the TBR and configured for introducing CO2 into the TBR from a CO2 source external to the system;
• (d) a H2 input device connected at a third upper point of the TBR and configured for introducing H2 into the TBR from an H2 source external to the system, (e) a backflush input device connected at a first bottom point of the TBR and configured for at least one of unclogging and cleaning the packing material by reversing flow in the TBR, and (f) an output connected at a first bottom point of the TBR and configured for outputting a liquid comprising VFA;
• a microalgae cultivation module for pro-current mixotrophic micro-algae cultivation, wherein the micro-algae uses VFA as a carbon source, the microalgae cultivation module comprising (g) an input at an upper point of the microalgae cultivation module and connected to the output of the TBR, the microalgae cultivation module being configured as at least one tube-like structure, (h) a sensory module configured for detecting at least one of a concentration of CO2, temperature, and pH in the microalgae cultivation module, and for adjusting the flow into the microalgae cultivation module of the liquid comprising VFA to at least one of the concentration of CO2, temperature, and pH in the microalgae cultivation module, and (j) an output at a bottom point of the microalgae cultivation module configured for outputting a first aqueous solution comprising micro-algae;
• a biomass harvester comprising an input connected to the output of the microalgae cultivation module, and an output, wherein the output is configured for outputting a second aqueous solution that remains after the algae has been harvested from the first aqueous solution;
• a feedback module connected to the output of the biomass harvester via a first valve, wherein (k) the first valve is also connected to a second valve and to the liquid distribution device, and (l) the second valve is also connected to an output of the system and to a backflush input connected to a second bottom point of the TBR;
• and
• at least one controller module connected to at least the first and the second valve, wherein the at least one controller module is configured for one of (m) controlling the second valve to feed at least part of the second aqueous solution from the output of the system to the liquid distribution device, and the first valve to feed all the second aqueous solution from the output of the biomass harvester to the second valve, and (n) controlling the second valve to stop feeding the second aqueous solution to any of the output of the system and the liquid distribution device, and the first valve to feed all the second aqueous solution from the output of the biomass harvester to the backflush input.