Re ECF Project: 2014-72

Project Title: Multi-functional gel materials for malodor treatment

Applicant: Dr. HAN Wei, The Hong Kong University of Science and Technology

Total Approved Grant: $480,000 (ECF & WWGF: 50/50)

Duration: 2/3/2015 to 1/9/2016

Project Status/Remarks: Completed

Malodor is one of the main air pollutants affecting life quality and may cause psychological stress and psychosomatic symptoms. Hydrogen sulfide and ammonia are two major malodors from anaerobic decomposition of organic matter containing sulfur and nitrogen in household and industrial wastes. This project aims to develop an effective technology for removing hydrogen sulfide and ammonia and inhibiting their generation from the source in sewer systems by utilizing new multi-functional gel materials to controlledly release active components which can reactively absorb the two malodors and suppress the activities of malodor-causing microbes.

Summary of the Findings/Outcomes:
In this project, new multi-functional gels are formulated and optimized for reactively absorbing malodors and inhibiting bioactivity of malodour-causing microorganisms by incorporating reactive and antimicrobial reagents into silica gel matrix. The obtained multi-functional gels are capable of reducing the concentration of hydrogen sulfide from 3 ppm to below 10 ppb, reducing the concentration of ammonia from 10 ppm to below 1 ppm, and suppressing 95% of sulfate-reducing and denitrifying bacteria within 5 minutes. The multi-functional gels exhibit excellent malodor treatment performances to completely remove 3 ppm of hydrogen sulphide, and reduce above 85% anaerobic and aerobic bacteria during 3-month field testing in the sewer system located at Jordan Valley. Low cost and monolithic macroscopic morphology of the multi-functional gels make them applicable facilely in the practical conditions. Two hundred grams of multi-functional gels are able to suppress H2S in the sewer system with water flow of 120 m3/h, treating totally 90000 m3 of drainage water.