Elemental sulfur (S0) reduction process has been demonstrated as an attractive approach for metal-laden wastewater treatment in lab-scale studies. However, the performance may significantly vary from lab-scale system to pilot- or large-scale systems using real domestic sewage as carbon source. In this study, a pilot-scale S0-based system was newly developed and applied for the treatment of Cu-laden electroplating wastewaters using domestic sewage as carbon source. During the 175-d operation, &gt;99.9% of Cu2+ in real electroplating wastewater (up to ~6000 mg Cu/L) was efficiently removed by the biogenic sulfide that produced through S0 reduction. Relatively high level of sulfide production (200 mg S/L) was achieved by utilizing organics in the sewage. The long-term feeding of domestic sewage significantly re-shaped the microbial community in S0-based bioreactors. Compared to the reported lab-scale bioreactors, higher microbial community diversity was found in our pilot-scale bioreactors. The presence of hydrolytic, fermentative and sulfur-reducing bacteria was the critical factor for system stability: biodegradable particulate organic carbon (BPOC) was firstly degraded to dissolved organic carbon (DOC) by the hydrolytic and fermentative bacteria. Then, sulfur-reducing bacteria utilized the DOC (both DOC degraded from BPOC and the original DOC present in sewage) as electron donor and reduced S0 to sulfide. Afterwards, the sulfide precipitated Cu2+ in the post sedimentation tank. Compared with other reported technologies, the S0-based treatment system remarkable reduced the total chemical cost by 87.5-99.6%. This pilot-scale study demonstrated that S0 reduction process can be a sustainable technology to generate sulfide for the co-treatment of Cu-laden electroplating wastewater and domestic sewage, achieving higher Cu2+ removal and higher cost-effectiveness than the conventional technologies.

Pilot-scale sulfur-based sulfidogenic system for the treatment of Cu-laden electroplating wastewater using real domestic sewage as electron donor

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.