Smart control for micro-aeration toward sulfide removal in sewer systems at low costs

Sulfide control is a critical subject to guarantee the operational safety and process conditions in sewage treatment works. It can be related to the areas of biogas utilization, corrosion control, and odor management. This study introduces a simple low-cost approach to remove H₂ S in wastewater headspace, and hence recover the elemental sulfur by micro-aeration. Lab-scale experiments were carried out to establish a simulation model to enhance aeration control, and predict the performance of a pilot-scale twin scrubber treating biogas generated from 1 m³ anaerobic digester. The model successfully described the changing pH in the two systems. Experiment results from residual gases showed higher than 99% hydrogen sulfide removal. A real-time off-gas monitoring algorithm is developed to control the flow rates of gases going in the twin scrubber system for optimizing the sulfide removal and micro-aeration. The new process differs from other scrubber techniques with MDEA or biofilter media and may be particularly useful for decentralized sewer treatment units or nature water as it can be operated without the needs of harmful chemicals or process control of bioreactions.