Simultaneous control of sulfide and methane in sewers achieved by a physical approach targeting dominant active zone in sediments

March 9, 2022

CRAES, Tsinghua University uses EasySensor DGT to publish the article as below:


• It only takes 0.06 N/m2 to erode the sediment surface to a depth of 2.3 cm.•

• Surface sediments (1.5 cm) contribute ∼70% of sulfide and methane production.•

• Surface sediments flushing effectively reduces sulfide and methane production.•

• Intermittent surface sediment flushing is a cost-effective operation strategy.


Sewer sediments not only induce sewer blockages, but also contributes to significant sulfide and methane productions in gravity sewer systems. Chemical control of sulfide and methane production is extremely expensive. This study aims to propose a novel physical control approach—intermittent surface sediment flushing to synchronously address sediment-induced multiple issues. The proposed approach was established investigating the suppression and recovery characteristics of sulfidogenic and methanogenic activities of sediments including the in-situ activity analysis by using the diffusive gradients in thin films (DGT). The results showed that ∼70% of total sulfide and methane production in sediments was contributed by surface sediments (0–1.5 cm), which could be easily flushed away by a low shear stress (<0.1 N/m2). Surface sediment flushing resulted in an immediate reduction in sulfidogenic and methanogenic activities, which both required about one week to recover to 50% of the maximum. These novel insights hopefully provide a feasible approach, i.e., intermittent surface sediment flushing, to effectively reduce sulfide and methane production in sewers. Compared with chemical dosing methods, the proposed approach, which has no chemical input, greatly reduces operating cost and environment impact. Moreover, intermittent surface flushing is expected to keep sediment thickness within a certain range to alleviate sewer blockage.

Sulfide(A) and methane(B)production rates of R4 relative to the corresponding R1 rates, prior to and after being scraped off 15 cm surface sediment on Day 0(vertical arrows). The dashed lines are regressions with the Gompertz growth equation.
Two-dimensional distribution of sulfide production in the sediment measured by DGT in controlRR4 after flushing,and R4 after recovery(c).

Writers: Daheng Ren, Zhiqiang Zuo, Yaxin Xing, Penghui Ji, Tong Yu, David Zhu, Yanchen Liu, Xia Huang,