Influence of sulfate reduction on fraction and regeneration of phosphorus at sediment–water interface of urban malodorous river

The effective control of the release of endogenous phosphorus is an urgent problem in the management of urban malodorous rivers. This research explored the fraction and regeneration of phosphorus of urban malodorous river in the context of sulfate reduction. It was found that sulfate reduction could promote sediment phosphorus release. The contents of total phosphorus (TP) and soluble reactive phosphorus (SRP) in the overlying water presented a decreasing trend after the initial increase during the operation of 120 days. The phosphorus release was positively related to the input of sulfate, and the maximum values of TP and SRP (14.01 mg/L and 12.27 mg/L, respectively) in the overlying water were observed when 8 mM Na₂SO₄ was added. Moreover, the addition of sulfate could significantly affect the distribution of phosphorus fraction in the sediment and promote the transformation of moderately active phosphorus (NaOH-P, D. HCI-P) to more active phosphorus Resin-P), which resulted in more release of phosphorus to the overlying water. In addition, it was observed that sulfate input could increase the relative abundance of phosphate solubilizing bacteria (PSB) and sulfate-reducing bacteria (SRB) from 0.69 to 1.1% and 4.92 to 9.03%, respectively.