EAPSI: Silica Removal from Industrial Waste Water to Facilitate Water Reuse

Baca Ehren, Albuquerque NM

Investigators

Abstract

Water shortage is a problem facing many parts of the world today. Water reuse offers relief to this problem by decreasing the need for fresh water withdrawals. However, silica scale is a major inhibiting factor in the application of reuse technology. Industries such as Integrated Circuit (IC) manufacture discharge millions of gallons of water per day with silica content. This substantial water source must be purified before it can be reused, and in doing so, costly and debilitating silica scale results. Taiwan has a high density of IC manufacture and presents itself as a strategic location to study effective silica removal from industrial waste water. Dr. Chihpin Huang, a distinguished researcher and Vice President of National Chiao Tung University (NCTU) in Hsinchu Taiwan, will provide mentorship for this work. Research will be in conjunction with Dr. Huang's previous studies in silica removal, thereby leveraging his expertise and laboratory equipment. NCTU's close proximity to Hsinchu's renowned technology park will allow unique and consistent access to waste water from a variety of IC manufacturers. Silica speciation is variable and exists as a monomeric (H4SiO4), polymerized (<5nm), and colloidal (>5nm) constituent in water. Silica presents no known health effects, but leads to process hindering scale when present in reverse osmosis (RO), cooling tower, and boiler operations. The integrated circuit (IC) industry produces copious amounts of waste water containing colloidal silica. In order for this water to be reused, it must be purified by RO, which is inherently hindered by silica scale. Taiwan has a high density of IC manufacture and presents itself as a strategic location to study effective silica removal from industrial waste water. This work will evaluate adsorption, co-precipitation, and coagulation mechanisms in their effectiveness for silica removal from IC waste water. Research will proceed under the expertise of Dr. Chihpin Huang, distinguished water purification researcher and Vice President of National Chiao Tung University (NCTU) located in Hsinchu, Taiwan. Dr. Huang's previous studies implementing coagulation and filtration for colloidal silica removal will serve as the foundation for this work. NCTU?s close proximity to an abundance of IC manufactures in Hsinchu will provide advantageous access to a variety of silica waste streams for evaluation. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Ministry of Science and Technology of Taiwan.