Microbial biofilms for the removal of Cu2+ from CMP wastewater

• Published in: Journal of environmental management 2015-09, Vol.160, p.67-72
• Main Authors: Mosier, Aaron P., Behnke, Jason, Jin, Eileen T., Cady, Nathaniel C.
• Format: Article
• Language: English
• Subjects: Adsorption; Biodegradation, Environmental; Biofilm; Biomass; Biosorption; Cations - chemistry; Chemical mechanical planarization; Copper - chemistry; Humans; Industrial Waste; Lactobacillus casei; Manufactured Materials; Pichia pastoris; Silicon; Wastewater; Water Pollutants, Chemical - chemistry
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2015.05.016

The modern semiconductor industry relies heavily on a process known as chemical mechanical planarization, which uses physical and chemical processes to remove excess material from the surface of silicon wafers during microchip fabrication. This process results in large volumes of wastewater containing dissolved metals including copper (Cu2+), which must then be filtered and treated before release into municipal waste systems. We have investigated the potential use of bacterial and fungal biomass as an alternative to the currently used ion-exchange resins for the adsorption of dissolved Cu2+ from high-throughput industrial waste streams. A library of candidate microorganisms, including Lactobacillus casei and Pichia pastoris, was screened for ability to bind Cu2+ from solution and to form static biofilm communities within packed-bed adsorption columns. The binding efficiency of these biomass-based adsorption columns was assessed under various flow conditions and compared to that of industrially used ion-exchange resins. We demonstrated the potential to regenerate the biomass within the adsorption columns through the use of a hydrochloric acid wash, and subsequently reuse the columns for additional copper binding. While the binding efficiency and capacity of the developed L. casei/P. pastoris biomass filters was inferior to ion-exchange resin, the potential for repeated reuse of these filters, coupled with the advantages of a more sustainable “green” adsorption process, make this technique an attractive candidate for use in industrial-scale CMP wastewater treatment. •A library of microorganisms was screened for ability to bind Cu2+ from solution.•L. casei and P. pastoris formed biofilms within packed bed filtration columns.•Cu binding of the bioadsorbant filter was measured using mock CMP wastewater.•Bioadsorbant was found to be reusable after wash and regrowth.•Batch saturation adsorption properties of the bioadsorbant were studied.