Recycling

Biography

Biography: Chuan Chen

Abstract

Denitrifying Sulfide Removal (DSR), which simultaneously degrades sulfide, nitrate and organic carbon, has increasingly gained attention as the key unit in industrial wastewater treatment. Its stable operation depends by autotrophic and heterotrophic bacteria close cooperation. The low treatment efficiency with high C/N molar ratio, which cause heterotrophic denitrifiers more vigorous, was seen as a burden on DSR engineering application and a problem to be solved. In this artical, 12 groups of batch tests were conducted with different C/N molar ratios (1.26/1, 2/1 and 3/1) and two S/N molar ratios (5/6 and 5/8) under anaerobic or micro-aerobic condition. Less than 50% sulfide was removed from the anaerobic bottles and no sulfur transformation was observed at the end, because high C/N molar ratios can enhance the activity of sulfur reducer, resulting in the sulfur produced from sulfide oxidation reduced to sulfide again. This phenomena didn’t get much better with the use of different S/N molar ratios. Nevertheless, 100% sulfide removal was gained under micro-aerobic condition (DO<0.2) in which sulfide chemical oxidation only accouted for less than 5%. Whereafter, continuous expanded granular bed reactor was employed to further vertify the enhancing effect of micro-aerobic condition. Results showed that sulfide removal efficiency reached peak performance at 70% and 55% of total sulfur was recoverd . This performance was nearly twice as much as anaerobic environment overall. We speculated that applying micro-aeration can inhibit herterotrophic denitrifiers’ activity and make DSR technology handle industrial wastewaters with high C/N ratios