High rate electrochemical sulfide removal from synthetic feed and real domestic wastewater

The microbial reduction of sulfate to hydrogen sulfide causes sewer pipe corrosion, one of the major issues in the water infrastructure [1]. Oxygen injection is presently considered as an attractive option for sulfide abatement in sewer systems. Oxygen can both inhibit the activity of sulfate reducing bacteria (SRB) and oxidize the sulfide that has been produced [2]. It is less expensive than most other chemicals and can target rising mains where the SRB activity is the highest [3]. Unfortunately, oxygen injection in sewer systems has some disadvantages, such as inefficiencies during dosing (i.e., coarse bubbles, which results in a significant loss of undissolved gas to the air in gas release valves downstream). In addition, the transport and storage of pure oxygen carries serious safety issues and precise control of dosing is not straightforward [4]. Here we propose an electrochemical system that can generate the oxygen in-situ. Compared to traditional methods for oxygen supply, the advantages of this in-situ oxygen generation are the high transfer efficiency, fine dispersion, high controllability (i.e. oxygen addition is directly related to current input) and no requirement for transport and storage. IrOx coated titanium anodes were used to perform the electrochemical oxidation from synthetic feed and real domestic wastewater [5].