Elemental sulfur biorecovery from phosphogypsum using oxygen-membrane biofilm reactor: Bioreactor parameters optimization, metagenomic analysis and metabolic prediction of the biofilm activity.

This work investigated elemental sulfur (S) biorecovery from Phosphogypsum (PG) using sulfur-oxidizing bacteria in an O-based membrane biofilm reactor (MBfR). The system was first optimized using synthetic sulfide medium (SSM) as influent, then switched to biogenic sulfide medium (BSM) generated by biological reduction of PG alkaline leachate. The results using SSM had high sulfide-oxidation efficiency (98 %), sulfide to S conversion (∼90 %), and S production rate up to 2.

Optimizing Autotrophic Sulfide Oxidation in the Oxygen-Based Membrane Biofilm Reactor to Recover Elemental Sulfur.

Biological sulfide oxidation is an efficient means to recover elemental sulfur (S) as a valuable resource from sulfide-bearing wastewater. This work evaluated the autotrophic sulfide oxidation to S in the O-based membrane biofilm reactor (O-MBfR). High recovery of S (80-90% of influent S) and high sulfide oxidation (∼100%) were simultaneously achieved when the ratio of O-delivery capacity to sulfide-to S surface loading (SL) (O/S → S ratio) was around 1.

Effect of alkaline leaching of phosphogypsum on sulfate reduction activity and bacterial community composition using different sources of anaerobic microbial inoculum.

Phosphogypsum (PG), a by-product of the phosphate industry, is high in sulfate, (SO), which makes it an excellent substrate for sulfate-reducing bacteria (SRB) to produce hydrogen sulfide. This work aimed to optimize SO leaching from PG to achieve a high biological reduction of SO and generate high sulfide concentrations for subsequent use in the biological recovery of elemental sulfur. Five SRB consortia were isolated and enriched from: IS (Industrial sludges), MS (Marine sediments), WC (Winogradsky column), SNV (petroleum industry sediments) and PG (stored Phosphogypsum).

Microbial transformations by sulfur bacteria can recover value from phosphogypsum: A global problem and a possible solution.

Rising global population and affluence are increasing demands for food production and the phosphorus (P) fertilizers needed to grow that food. Essential are new approaches for managing the growing amount of phosphogypsum (PG) that is a by-product of phosphoric-acid production from phosphate rock. Today, only ~15% of the worldwide production of PG is recycled, mainly for agriculture and road construction.