Final Report: Development of 3D-printed surfaces for ultra-high surface area trickling biofilters for water pollution remediation

EPA Grant Number: SU836122
Title: Development of 3D-printed surfaces for ultra-high surface area trickling biofilters for water pollution remediation
Investigators: Carrano, Andres
Institution: Auburn University Main Campus
EPA Project Officer: Page, Angela
Phase: I
Project Period: September 1, 2015 through August 31, 2016
Project Amount: $14,903
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2015) RFA Text |  Recipients Lists
Research Category: P3 Challenge Area - Water , P3 Awards , Pollution Prevention/Sustainable Development , Sustainability

Objective:

Water pollution is a global problem and exists wherever there is human activity. Every 20 seconds a child dies from a preventable illness caused by unsafe drinking water, poor hygiene and inadequate sanitation [1]. Although the United Nations Millennium Development Goals (MDGs) for water access have been met ahead of schedule, the world is not on track to meet goals for access to sanitation by 2015 [2]. Nearly half of the people living in developing regions still lack improved sanitation [3]. In addition, the Natural Resources Defense Council states that dirty water is the world’s biggest health risk and threatens quality of life as well as public health [4]. Water is considered polluted when impaired by anthropogenic contaminants and thereby rendered unusable as drinking water. Wastewater typically contains a combination of organic and inorganic substances, and different remediation methods exist for various pollutants. One method that addresses water pollution recovery is through biofilters that involve the cultivation of complex microbial biofilms that can grow rapidly and with high metabolic rates. Biofilms colonize a surface substratum and capture pollutants that are subsequently removed from the water by harvesting or sloughing processes. While reliably high metabolism of biofilms in these two systems has been proven in many applications related to pollution remediation, the efficiency of the operation is currently limited by design of the effective colonization surface (i.e., biofilter media). Recent advances in 3D printing technologies allow for a precise fabrication of complex shapes that can provide an ultra‐high surface area for a complex of bacteria and algae to colonize, thus potentially increasing the pollution recovery rate of the biofilter. The goal of this Phase I project is to design, develop and evaluate new media for biofiltration of water by using complex shapes and geometries achieved with 3D printing.

Summary/Accomplishments (Outputs/Outcomes):

Most commercial biofilter media provide a specific surface area that is less than 1,000 m2/m3 (with the most popular media ranging between 200‐500 m2/m3). The findings in Phase I produced a spherical Gyroid media design that achieved 1168 m2/m3, almost a 12% improvement over standard commercial media. This was proved feasible via fabrication and testing in bioreactors with wastewater from agricultural (fisheries) effluents. The new designs outperform existing commercial media not only in specific surface area but also on sinking velocity as well as other factors. Furthermore, preliminary mathematical refinement of the media design has shown that this area can be modulated and further improved significantly.  

Conclusions:

This Phase I effort successfully challenged the existing paradigms in media design for biofilters. It proved the concept that ultra‐high surface area media designs can be realized and produced with advanced manufacturing approaches such as 3D printing. This effort also aimed at fabricating and testing these designs in pilot‐scale bioreactors on agricultural wastewaters and compared them to commercially available media. This novel idea opens a wide array of possibilities that point towards a significant increase in efficiency in next‐generation biofilter technologies. These novel ideas have generated IP/invention disclosures and may likely produce patent application to lead the way towards product commercialization.

Supplemental Keywords:

Biofilm, biofilters, Moving Bed biofilter, 3D printing, additive manufacturing

P3 Phase II:

Development of 3D-printed surfaces for ultra-high surface area biofilters for water pollution remediation  | 2017 Progress Report