Effects of piecewise electric field operation on sludge dewatering

2 hours ago - Electro-dewatering (EDW) is an energy-efficient method for sludge dewatering. In this study, effects of piecewise electric field operati...
1 downloads 0 Views 1MB Size
Subscriber access provided by Miami University Libraries

Separations

Effects of piecewise electric field operation on sludge dewatering: phenomena and mathematical model Hang Lv, Fang Wang, Daoguang Liu, Yanlin Zhang, Yueyuan Gu, Du Yuan, Siqi Xing, Xu Wu, Jiakuan Yang, Wenbiao Zhang, and Keith Scott Ind. Eng. Chem. Res., Just Accepted Manuscript • Publication Date (Web): 04 Jun 2018 Downloaded from http://pubs.acs.org on June 4, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Industrial & Engineering Chemistry Research

Effects of piecewise electric field operation on sludge dewatering: phenomena and mathematical model Hang Lv1#, Fang Wang1#, Daoguang Liu2, Yanlin Zhang1, Yueyuan Gu1, Du Yuan1, Siqi Xing1, Xu Wu1,*, Jiakuan Yang1, Wenbiao Zhang2, Keith Scott3 1, School of Environmental Science and Engineering, Huazhong Unviersity of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, China 2, Shanghai Techase Environment Protection Co., Ltd. 1121 North Zhongshan No. 2 Road, Shanghai, 200092, China 3, School of Chemical Engineering and Advanced Materials, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom Abstract: Electro-dewatering (EDW) is an energy-efficient method for sludge dewatering. In this study, effects of piecewise electric field operation on EDW were investigated by experiments and simulation. Operational parameters were studied mainly in terms of sludge resistance variation during electro-dewatering process, which were evaluated by linear sweep voltammetry (LSV) analysis. Simulation of the sludge cake electro-dewatering processes was developed and validated, based upon time-dependent experimental data of electric currents and filtrate weights. The modeling results were in good agreement with experiments. It was proved by experimental and modelling results that the piecewise operation has positive effects on key performances of EDW devices, i.e. limited water content, space-time yield, and mass specific energy consumption. Keywords: Sewage Sludge, Electro-dewatering, Model Simulation, Piecewise Electric Field strength.

1

ACS Paragon Plus Environment

Industrial & Engineering Chemistry Research 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1. INTRODUCTION Over the last decades, municipal and industrial wastewater purification activities have been increasing, which confronts with a dramatically increasing flow of sewage sludge 1, 2. Sewage sludge usually contain high water contents, gelatinous structures of hydrophilic substances, organic pollutants, pathogens, heavy metals and other toxic and hazardous substances, making them rather ill-defined systems with difficulties in solid-liquid separation. If not properly disposed, sewage sludge will lead to serious secondary environmental pollution 3. Sludge dewatering is an important process in the sludge treatment project and such projects in many areas often account for approximately 50% of all costs in wastewater treatment 3. Currently in China, sewage sludge with moisture content higher than 60 wt. % is not allowed for further disposal, for example after traditional mechanical solid-liquid separation 4. EDW is a highly efficient technique for sludge deep dewatering, which may reduce the water content of sludge cakes to