Biological Desulfurization of Tannery Effluent Using Hybrid Linear Flow Channel Reactors

Abstract

The tanning process generates a saline effluent with high residual organics, sulfate and sulfide concentrations. The transition from a linear to circular economy requires reimagining of waste streams as potential resources. The organics in tannery effluent have the potential to be converted to renewable energy in the form of biogas if inhibitors to anaerobic digestion are removed. Hybrid linear flow channel reactors inoculated with culture-enriched halophilic sulfate reducing bacteria from saline environments were evaluated as a novel pretreatment step prior to anaerobic digestion for the concurrent removal of sulfur species and resource recovery (elemental sulfur and biogas). During continuous operation of a 4-day hydraulic retention time, the reactors were capable of near-complete sulfide oxidation (>97%) and a sulfate reduction efficiency of 60–80% with the formation of a floating sulfur biofilm containing elemental sulfur. Batch anaerobic digestion tests showed no activity on untreated tannery effluent, while the pretreated effluent yielded 130 mL methane per gram COD consumed.

Microwave-Hydrogen Peroxide Assisted Anaerobic Treatment as an Effective Method for Short-Chain Fatty Acids Production from Tannery Sludge

“…As underlined by Zhai and colleagues, the tannery sludge is rich in proteins and macromolecular organic matters, so a mild oxidative treatment was considered a viable option to support the hydrolysis of the organic compound and improve the SCFA production performance. Additionally, partial oxidation is desirable as it reduces the concentration of the S species [20], which are abundant in tannery sludge. Hydrogen peroxide (H 2 O 2 ) is an oxidizing agent that is similar to oxygen in effect but is significantly stronger.…”