(117d) New Odor and Corrosion Control Technologies for Concrete Stormwater Drainage and Sewer System

Hydrogen Sulfide gas and Sulfuric Acid are the two materials that coexist together inside the sewer or drainage system because of the metabolic digestion of sulfur-containing materials inside the foul water or contaminated stormwater. The former would cause the odor nuisance to the surrounding neighborhood whereas the latter would corrode the water pipe that was constructed using the basic concrete materials through acid-base reactions. This study is aimed to develop a sustainable and durable solution to tackle the long-lasting issues in both drainage and sewer systems. The proposed approach is with the application of malodor-control (MOC) hydrogel that encapsulates metabolic inhibitors to curtail both Sulfur-Oxidizing bacteria (SOB) and Sulfur-Reducing bacteria (SRB) and capsulize the concrete façade from the biogenic sulfuric acid.

Laboratory research study demonstrated that MOC hydrogel is capable of reducing both SRB and SOB by approximately 90% throughout the 25 days of the measurement along with the release profile test of the metabolic inhibitors. In the practical experimentation in one of the drainage channels, the result indicated a 90% curtailment of the hydrogen sulfide gas with 82% of the reduction in SRB population. For the corrosion prevention, two types of epoxy coating were employed in the study, which are the commercial epoxy coating and the epoxy coating that is modified with anti-microbial ingredients that equipped the epoxy coating with self-sanitizing capabilities. Utilization of the commercial epoxy coating inside the severely corroded sewer manhole was capable to curtail 50% (90 days) and 71% (180 days) of the corrosion rate compared with the uncoated concrete. On the other hand, the modified epoxy coating exhibits a higher curtailment rate, with 67% and 78% respectively.