A microbial fuel cell–membrane bioreactor integrated system for cost-effective
wastewater treatment
Yong-Peng Wang
a
, Xian-Wei Liu
a
, Wen-Wei Li
b,
⇑
, Feng Li
b
, Yun-Kun Wang
b
, Guo-Ping Sheng
b
,
Raymond J. Zeng
b
, Han-Qing Yu
b
a
School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China
b
Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
article info
Article history:
Received 9 January 2012
Received in revised form 9 March 2012
Accepted 12 March 2012
Available online 28 April 2012
Keywords:
Microbial fuel cell (MFC)
Membrane bioreactor (MBR)
Wastewater treatment
Bio-cathode
Low-cost
abstract
Microbial fuel cell (MFC) and membrane bioreactor (MBR) are both promising technologies for wastewa-
ter treatment, but both with limitations. In this study, a novel MFC–MBR integrated system, which com-
bines the advantages of the individual systems, was proposed for simultaneous wastewater treatment
and energy recovery. The system favored a better utilization of the oxygen in the aeration tank of MBR
by the MFC biocathode, and enabled a high effluent quality. Continuous and stable electricity generation,
with the average current of 1.9 ± 0.4 mA, was achieved over a long period of about 40 days. The maximum
power density reached 6.0 W m
À3
. Moreover, low-cost materials were used for the reactor construction.
This integrated system shows great promise for practical wastewater treatment application.
Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction
Microbial fuel cells (MFCs) are devices that use bacteria as cat-
alysts to oxidize various substrates and recover electricity [1,2].
MFCs are promising for wastewater treatment processes, but to
achieve practical application there are still many technical and cost
obstacles to overcome [3]. One approach to reduce the barriers and
improve its applicability is to incorporate MFC into existing waste-
water treatment processes [4,5]. In this respect, a continuous-flow
mode of operation is usually adopted, which is regarded as more
suitable for practical wastewater treatment and MFC application
[6]. An integration of MFC with conventional activated sludge pro-
cess was first reported by Cha et al. [7]. In this system, an aeration
tank was directly used as the cathode chamber, where the aerobic
biofilm developed on the cathode serve as low-cost and self-sus-
tainable catalyst. To support a continuous-flow operation, the aer-
ation tank was followed by a clarifier, and settled sludge was
continuously returned. However, this setup incurs additional cost
for the clarifier construction and sludge pumping. Compared with
this design, a MFC–membrane bioreactor (MBR) integrated design
appeared to be more attractive in terms of costs and footprint [8].
MBRs present a high-efficient technology for wastewater treat-
ment, and recently the development of coarse filter MBRs have sig-
nificantly lowered the operating cost and promoted its widespread
application [9–14]. A novel bioelectrochemical membrane reactor,
which makes advantage of both a MBR and a MFC process, was re-
cently reported to achieve a maximum power density of
4.35 W m
À3
and good pollutant removal performance attributed
to the high biomass retention and solid rejection [8]. Nevertheless,
that system has a unique and complex reactor design. Specifically,
a stainless steel mesh was used, which played a dual function of fil-
ter and MFC cathode. Thus, the application of other less-conductive
coarse materials would be limited in that system. In addition, there
might be difficulties for the integrated system in keeping an appro-
priate and balanced biofilm, which serve as both the biocatalyst of
MFC and the filtration/fouling layer of MBR. All these make it dif-
ficult to be directly incorporated into the existing MBR facilities
and its practical application might be limited.
Therefore, in this study we develop a more practical MFC–MBR
integrated process, in which the aeration tank of a MBR was di-
rectly used as the cathode chamber. Carbon felt was used as the
cathode to favor biofilm development. In order to further reduce
the investment and operating cost, low-cost nylon mesh were
adopted here as the filter material. The suitability of such materials
as MBR filter have been demonstrated in several previous studies
[8,14,15]. This work aims to investigate the feasibility of applying
a relatively simple MFC–MBR integrated system for continuous
wastewater treatment and power generation.
0306-2619/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.apenergy.2012.03.029
⇑
Corresponding author. Tel.: +86 551 3607592; fax: +86 551 3601592.
E-mail address: wwli@ustc.edu.cn (W.-W. Li).
Applied Energy 98 (2012) 230–235
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