Simultaneous phase operated anaerobic sequential batch reaction system with batch degassing unit and semi-continuous settling unit

A process for treating an aqueous fluid comprising a biodegradable organic substance in an installation comprising:

• a bioreactor unit, wherein the aqueous fluid is anaerobically microbiologically treated, whereby a biogas is produced from the biodegradable organic substance;
• a batch degassing unit, wherein an aqueous suspension withdrawn from the bioreactor, said aqueous suspension comprising aqueous liquid, biogas and biomass, is subjected to batch degassing;
• and
• a semi-continuously operated biomass separator unit, wherein the degassed suspension withdrawn from the degassing unit is subjected to separation into a sludge enriched in biomass and an aqueous fluid having reduced biomass content compared to said degassed aqueous suspension fed into the biomass separator unit,
• the process comprising:
• a bioreactor unit batch feeding stage (A), wherein the aqueous fluid that is to be treated is fed into the bioreactor unit;
• a batch reaction stage (B), wherein the aqueous fluid is microbiologically treated under anaerobic conditions and biogas is produced in the bioreactor unit;
• a semi-continuous biomass separator unit feeding stage (C), wherein the degassed aqueous suspension is withdrawn from the batch degassing unit and fed into the semi-continuous biomass separator, wherein the semi-continuous biomass separator unit feeding stage comprises an initial phase without withdrawal of aqueous fluid having reduced biomass content followed by a continuous phase wherein feeding and withdrawal take place continuously;
• and
• a degassing unit feeding stage (E), wherein an aqueous suspension comprising microbiologically treated aqueous fluid and biomass is withdrawn from the bioreactor unit and fed batch-wise into the degassing unit.