Gravity-Driven Membrane Reactor for Decentralized Wastewater Treatment: Effect of Reactor Configuration and Cleaning Protocol.

Ihtisham Ul Haq Shami,Bing Wu

doi:10.3390/membranes11060388

Abstract

In this study, three gravity-driven membrane (GDM) reactors with flat sheet membrane modules and various biocarriers (synthetic fibers, lava stones, and sands) were operated for municipal wastewater treatment. The effects of water head, periodically cleaning protocol, and operation temperature on the GDM reactor performance were illustrated in terms of membrane performance and water quality. The results indicated that: (1) the cake layer fouling was predominant (>~85%), regardless of reactor configuration and operation conditions; (2) under lower water head, variable water head benefited in achieving higher permeate fluxes due to effective relaxation of the compacted cake layers; (3) the short-term chemical cleaning (30–60 min per 3–4 days) improved membrane performance, especially when additional physical shear force was implemented; (4) the lower temperature had negligible effect on the GDM reactors packed with Icelandic lava stones and sands. Furthermore, the wastewater treatment costs of the three GDM reactors were estimated, ranging between 0.31 and 0.37 EUR/m3, which was greatly lower than that of conventional membrane bioreactors under lower population scenarios. This sheds light on the technical and economic feasibility of biocarrier-facilitated GDM systems for decentralized wastewater treatment in Iceland.

Highlights

The annual wastewater production is estimated to be at 359.4 × 109 m3, of which ~48% of the total produced wastewater is released into the environment without any treatment [1]
The three gravity-driven membrane (GDM) reactors were continuously operated for 80 days
4b), configwhich urations and operation in turn led to lowerfibers, membrane cost

Summary

Introduction

The annual wastewater production is estimated to be at 359.4 × 109 m3 , of which ~48% of the total produced wastewater is released into the environment without any treatment [1]. The conventional activated sludge process (CAS) and membrane bioreactor (MBR) have been widely applied as efficient wastewater treatment processes. Both treatment processes require high utility, maintenance, and operation costs, which are considered to be major challenges for their application in developing countries or in decentralized regions. Both treatment processes are based on biodegradation of organics/nutrients in wastewater, which generally display lower treatment efficiency at lower temperatures. CAS and MBR are not favorable wastewater treatment processes in cold climate regions [3,4]

Methods

Results

Conclusion