Anaerobic membrane bioreactors for sludge digestion: Current status and future perspectives

Abstract

Excess sewage sludge in wastewater treatment plants (WWTPs) is regarded the key energy source for achieving energy neutral WWTPs. The anaerobic digestion process transforms sludge-organic matter into methane, which subsequently can be used for heat and electricity production. Conventional anaerobic digesters (ADs) have been used for sludge treatment for many decades, requiring high energy and providing poor effluent quality. Anaerobic membrane bioreactor (AnMBR) technology exhibits a promising option for treatment of high solids concentration streams including sludge. AnMBRs result in an increase in digestion efficiency and enhancement in effluent quality at small footprints. AnMBRs have the potential to reduce capital and operational costs, and produce more energy in comparison to conventional ADs. Thus, energy neutral or positive operation can be achieved with AnMBRs. Besides, nutrient recovery or direct use of permeate will become more feasible in AnMBRs compared to use of sludge supernatant in ADs. However, membrane fouling can limit the feasibility of AnMBRs for sludge treatment, which requires further research. This review paper critically evaluates the current status of AnMBR technology for municipal sludge treatment discussing the effect of different factors on treatment and membrane filtration performances. Furthermore, future research opportunities to enhance applicability of this technology are addressed.

Phosphorus Recovery by Adsorption from the Membrane Permeate of an Anaerobic Membrane Bioreactor Digesting Waste-Activated Sludge

“…The first reason is that the reactor configuration incorporated external cross-flow. There are two types of AnMBR configurations: external cross-flow and submerged configurations [13]. In external cross-flow configurations, the membrane unit is outside the digester, whereas in the submerged configurations, the membranes are immersed in the digester or external sludge tank.…”

“…In addition, the quality of the effluent is generally poor because of the washout of the suspended solids (SS), including anaerobic microbes. To solve these problems, anaerobic membrane bioreactors (AnMBRs) have been applied to sludge digestion [13]. An AnMBR comprises a system that couples membrane filtration with anaerobic treatment.…”

Impact of food waste addition in energy efficient municipal wastewater treatment by aerobic granular sludge process

“…The most preferred approach for enhancing the energy self-sufficiency of wastewater treatment plants (WWTPs) is the anaerobic digestion of excess sludge (Ersahin 2018 ). There are several applications in order to enhance methane production from excess sludge (Silvestre et al 2015 ; Guven et al 2019 ; Abdelrahman et al 2021 ). For example, anaerobic co-digestion can be described as an instantaneous digestion of two or more substrates.…”

Primary and A-sludge treatment by anaerobic membrane bioreactors in view of energy-positive wastewater treatment plants

“…By using microfiltration or ultrafiltration (UF) membranes, a higher quality of permeate can be produced in comparison with the supernatant of conventional anaerobic digesters. Furthermore, nutrients recovery using physicochemical treatment can be more feasible, since the permeate is almost free of solids (Abdelrahman et al, 2021).…”

“…The application of AnMBR for sludge treatment has received increased attention over the last few decades (Abdelrahman et al, 2021). Liew Abdullah et al (2005) studied the effect of OLR on AnMBR treatment performance treating sewage sludge.…”