Specific energy consumption of membrane bioreactor (MBR) for sewage treatment

Abstract

This paper provides an overview of current electric energy consumption of full-scale municipal MBR installations based on literature review and case studies. Energy requirements of several MBRs were linked to operational parameters and reactor performance. Total and specific energy consumption data were analysed on a long-term basis with special attention given to treated flow, design capacity, membrane area and effluent quality. The specific energy consumption of an MBR system is dependent on many factors, such as system design and layout, volume of treated flow, membrane utilization and operational strategy. Operation at optimal flow conditions results in a low specific energy consumption and energy efficient process. Energy consumption of membrane related modules was in the range of 0.5-0.7 kWh/m(3) and specific energy consumption for membrane aeration in flat sheet (FS) was 33-37% higher than in a hollow fibre (HF) system. Aeration is a major energy consumer, often exceeding 50% share of total energy consumption. In consequence, coarse bubble aeration applied for continuous membrane cleaning remains the main target for energy saving actions. Also, a certain potential for energy optimization without immediate danger of affecting the quality of the produced effluent was observed.

Application of hybrid coagulation microfiltration with air backflushing to direct sewage concentration for organic matter recovery

“…Visvanathan et al [14] also demonstrated that periodical air backflushing could improve the flux by up to 371% compared to the continuous operation. Furthermore, on account of more than 60% of the energy consumption of aerobic MBR process coming from aeration [15], low frequency AB would save a lot of organic matter and energy by avoiding continuous aeration and vibrating as to reduce a great part of the energy consumption of the membrane process in sewage treatment. As far as the inevitable microbial activity in sewage is concerned, low frequency AB in concentration process rather than continuous aeration can prevent the rapid growth of aerobic microbes and hence conserve as much organic matters in the recoverable form as possible.…”

Green technology in wastewater treatment technologies: Integration of membrane bioreactor with various wastewater treatment systems

“…Energy consumption of membrane related modules was in the range of 0.5-0.7 kWh m -3 and specific energy consumption for membrane aeration in flat sheet was 33-37% which was higher than in a hollow fibre system. While submerged membranes in MBR reduces the pumping energy requirement to 0.007 kWh m -3 of permeate compared with side-stream membrane (3.0 kWh m -3 ) [92].…”

Full-Scale Implementation of a Vertical Membrane Bioreactor for Simultaneous Removal of Organic Matter and Nutrients from Municipal Wastewater

“…However, despite these developments and applications of MBRs, energy demand together with frequent membrane cleaning remain a challenge in terms of energy consumption and optimization of MBRs [9]. Energy demand of full-scale CAS processes for municipal wastewater treatment, expressed per volume of treated wastewater was reported to be in the range of 0.1-0.6 kWh/m 3 [18]. However, energy consumption of MBRs was generally higher due to intensive membrane aeration rates required to mitigate membrane fouling and clogging than that of CAS systems.…”

“…However, energy consumption of MBRs was generally higher due to intensive membrane aeration rates required to mitigate membrane fouling and clogging than that of CAS systems. Typical energy demand values for full-scale MBR systems are reported to be in the range of 0.4-2.0 kWh/m 3 [11,18] . This is slightly higher than that of the CAS systems and some MBRs mainly due to addition of FeCl3 for enhanced phosphorus removal.…”