Warp knitted spacer microfiber biomass carrier for wastewater treatment

Abstract

The development of novel biomass carriers is an option for increasing the efficiency of processes at wastewater treatment plants (WWTPs). Biomass carriers support the adhesion of specific bacteria and the subsequent biofilm formation. As part of this work, a new type of microfibrous biomass carrier with a unique sandwich structure was developed. Technologically, the structure of the biomass carrier is based on warp knitted spacer fabric created on a double-needle bar machine. Commercially available microfiber materials were used to achieve a large specific surface area (SSA) and internal porosity of the carrier to ensure high microorganism capture. A yarn combination was chosen to reach a final carrier density slightly lower than water to float in an aqueous environment. As the first, was developed and described a three-dimensional warp knitted microfiber biomass carrier. Next, were evaluated the properties of this carrier for post nitrification on WWTPs and compared with commercially available biomass carriers. Testing biofilm (using respirometry, real-time polymerase chain reaction, and next-generation sequencing) growing on the developed carrier in a post-nitrification laboratory reactor showed excellent adhesion, stability, and abundance of microorganisms. A high rate (more than 95%) of ammonia nitrogen removal was achieved in post-nitrification, and molecular genetics methods confirmed the high concentration of nitrifying bacteria in the biofilm. The developed three-dimensional microfiber biomass carriers have proven their functionality and can be considered an advance in biofilm processes.