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Ling T.,Jiangnan University | Huang B.,CAS Shenyang Institute of Applied Ecology | Zhao M.,Jiangnan University | Yan Q.,Jiangnan University | And 2 more authors.
Bioresource Technology | Year: 2016

Composite Fe2O3/ACF electrode facilitated methyl orange (MO) oxidative degradation using bio-electro-Fenton in bioelectrochemical system (BES) was investigated. Characterized by both XPS and FT-IR techniques, it was found that the composite Fe2O3/ACF electrode with highest Fe loading capacity of 11.02% could be prepared after the carbon felt was oxidized with nitric acid. Moreover, hydrogen peroxide production reached steadily at 88.63μmol/L with the external resistance as 100Ω, cathodic aeration rate at 750mL/min, and the pH of the bio-electro-Fenton system adjusted to 2. Significantly, not only the electrochemical profiles of the BES reactor as electrochemical impedance spectroscopy (EIS) was bettered, but the MO oxidative degradation could be accomplished for eight repeated batches, with the MO removal efficiency varied slightly from 73.9% to 86.7%. It indicated that the bio-electro-Fenton might be a promising eco-friendly AOP method for Azo-dye wastewater treatment. © 2015 Elsevier Ltd. Source

Yang N.,Jiangsu Key Laboratory of Anaerobic Biotechnology | Ren Y.,Jiangsu Key Laboratory of Anaerobic Biotechnology | Li X.,Jiangsu Key Laboratory of Anaerobic Biotechnology | Shi Y.,Food Safety Key Laboratory of Zhejiang Province | And 2 more authors.
Environmental Progress and Sustainable Energy | Year: 2015

Sediment microbial fuel cell (SMFC) is a novel technology that oxidizes organics in sludge or river/lake sediment to generate electricity using microorganisms as the biocatalyst. The electricity production performance of the SMFC was obviously enhanced by mixing conductive graphite fibers into the anodic sludge. The output voltages and the maximum power densities (Pmax) of the SMFCs increased with the increase in the added graphite fibers from 0.5 to 5 g L-1. Ultimately, the SMFC with 5 g L-1 graphite fibers (SMFC-5) exhibited the uppermost output voltage (154 mV) and Pmax (12.48 mW m-2), whereas that of the blank SMFC were 65 mV and 4.68 mW m-2, respectively. Moreover, the phospholipid concentrations on the anode surfaces of the SMFCs augmented with the increase of graphite fibers and the charge-transfer resistance (Rct) of the corresponding anodes evidently decreased when the amount of graphite fibers was increased. Furthermore, with the increase of graphite fibers, chemical oxygen demand removal efficiencies increased from 12.72% of the blank SMFC to 44.64% of the SMFC-5. However, the SMFC with 0.5 g L-1 graphite fibers (SMFC-0.5) provided the highest coulombic efficiency (CE%), 2.46%. © 2015 American Institute of Chemical Engineers Environ Prog. Source

Chen Y.,Jiangnan University | Chen Y.,Jiangsu Key Laboratory of Anaerobic Biotechnology | Ren H.,Jiangnan University | Ren H.,Jiangsu Key Laboratory of Anaerobic Biotechnology | And 2 more authors.
Chinese Journal of Environmental Engineering | Year: 2015

The anaerobic (circular-lift reactor, CLR)-aerobic(high dissolved reactor, HDR)process was adopted to treat the leachate from incineration plant, achieving stable operation after 180 days of debugging. Anaerobic system successively went through twice loading-increasing: the first promotion via 120 days (normal temperature), the COD removal efficiency was more than 85% when the volumetric loading rate reached to 8 kg/(m3·d), and the maximum biogas yield could be maintained about 2 500 m3/d; the second raising via 20 days (steam heating), the COD removal efficiency was more than 90% when the volumetric loading rate reached to 9.2 kg/(m3·d), and the maximum biogas yield could be maintained about 2 909 m3/d. The relationship between the biogas production rate and the volumetric loading rate or the amount of COD removal was analyzed, it revealed that biogas could increase about 0.28 m3 when the volumetric loading rate rose by 1 kg/(m3·d). Meanwhile, 0.32 m3 biogas was generated when CLR anaerobic reaction consumed 1 kg COD. 87.5% of the influent COD was used to form biogas, and the rest of 12.5% COD was mainly used for microbial growth and the remaining in effluent. Simultaneous oxidation of COD and ammonia nitrogen could be realized in the underlying of the aerobic tank, and denitrification in the upper by controlling the dissolved oxygen, which could remove COD and ammonia nitrogen and reduce total nitrogen of the effluent. © 2015, Science Press. All right reserved. Source

Ma H.,Jiangnan University | Chen X.,Jiangnan University | Liu H.,Jiangnan University | Liu H.,Jiangsu Key Laboratory of Anaerobic Biotechnology | And 2 more authors.
Waste Management | Year: 2016

In this study, the anaerobic fermentation was carried out for volatile fatty acids (VFAs) production at different pH (between 7.0 and 10.0) conditions with untreated sludge and heat-alkaline pretreated waste activated sludge. In the fermentation with untreated sludge, the extent of hydrolysis of organic matters and extent of acidification at alkaline pH are 54.37% and 30.37%, respectively, resulting in the highest VFAs yield at 235.46 mg COD/g VS of three pH conditions. In the fermentation with heat-alkaline pretreated sludge, the acidification rate and VFAs yield at neutral pH are 30.98% and 240.14 mg COD/g VS, respectively, which are higher than that at other pH conditions. With the glucose or bovine serum albumin as substrate for VFAs production, the neutral pH showed a higher VFAs concentration than the alkaline pH condition. The results of terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that the alkaline pH caused low microbial richness. Based on the results in this study, we demonstrated that the alkaline pH is favor of hydrolysis of organic matter in sludge while neutral pH improved the acidogenesis for the VFAs production from sludge. Our finding is obvious different to the previous research and helpful for the understanding of how heat-alkaline pretreatment and alkaline fermentation influence the VFAs production, and beneficial to the development of VFAs production process. © 2015 Elsevier Ltd. Source

Yin B.,Jiangnan University | Liu H.,Jiangnan University | Liu H.,Jiangsu Key Laboratory of Anaerobic Biotechnology | Wang Y.,Jiangnan University | And 3 more authors.
Bioresource Technology | Year: 2016

The real cause to the low yield of volatile fatty acids (VFAs), from inhibition or low biodegradation, is uncertain in sludge anaerobic fermentation. In this study, poor biodegradability of proteins and fast decrease of the indigenous hydrolase activity in the residual post-fermented sludge were found to be the major reasons. With the addition of trypsin or alkaline protease in residual post-fermented sludge after primary alkaline fermentation, degradation efficiency of refractory protein increased by 33.6% and 34.8%, respectively. Accordingly, the VFAs yields were improved by 69.7% and 106.1%, respectively. Furthermore, the activities of added trypsin and alkaline protease could maintain at 13.52 U/mL and 19.11 U/mL in the alkaline fermentation process. This study demonstrated that exploiting the refractory proteins in residual post-fermented sludge by protease addition seems to be a very promising way for improving VFAs yield of conventional alkaline fermentations with waste activated sludge. © 2015 Elsevier Ltd. Source

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