Membrane Bioreactor (MBR) Technology – a Promising Approach for Industrial Water Reuse

TLDR

Membrane bioreactor (MBR) technology combines activated sludge with micro‑ and ultrafiltration, offering high‑quality product water and a low footprint, and submerged systems are increasingly favored for their robustness and flexibility. This paper presents two industrial case studies—one in a commercial laundry and another in a textile factory—and outlines a new EC‑funded project aimed at developing novel membrane materials for a nanofiltration MBR reactor to improve rejection of low‑molecular‑weight organics. The authors designed a 200 m³ d⁻¹ integrated MBR+RO reuse system for a German laundry, achieving ~80 % reuse and operating economically since 2007, and tested a 0.4 m³ d⁻¹ MBR in a Chinese textile factory, while a new EC project is developing NF‑MBR membranes. The large‑scale system achieved an ~80 % reuse ratio and has operated reliably since 2007, while the small‑scale MBR removed ~90 % COD but produced permeate with colored dyestuff, necessitating further nanofiltration or reverse osmosis to raise the reuse proportion.

Abstract

Membrane bioreactor technology (MBR) a combination of the activated sludge process with micro- and ultrafiltration is widely regarded as an effective tool for industrial water treatment and water reuse due to its high product water quality and low footprint. Due to their robustness and flexibility submerged MBR systems are more and more preferred. This paper highlights two case studies for industrial application in a commercial laundry and in a textile factory. A large-scale integrated water reuse process based on MBR+RO technology (capacity 200 m3/d) has been designed and established in a German laundry within an EC funded project eventually resulting in a reuse ratio of around 80% of the total wastewater. The process was in full operation at the beginning of 2007 and has been operated economically since that time without any failure. Within another EC funded project a small-scale MBR (capacity up to 0.4 m3/d) has been successfully tested in a Chinese textile factory. Despite high concentration of low biodegradable chemical in the wastewater, the COD removal rate achieved around 90%. However, the MBR permeate quality was not as high as in the laundry due to remaining colored dyestuff what makes an additional treatment step such as nanofiltration or reverse osmosis necessary in order to increase the proportion of reused water. In order to improve rejection of low molecular weight organics Karlsruhe University of Applied Sciences and the Institute of Membrane Technology have started a new EC funded project within a consortium of 11 partners in total which aims at developing novel membrane materials providing a basis for the development of a NF MBR reactor.