Major organic foulants in ultrafiltration of treateddomestic wastewater and their removal by bio-filtration as pre-treatment [Elektronische Ressource] / vorgelegt von Xing Zheng

Xing Zheng

Informations

• Publié par: technische_universitat_berlin
• Publié le: 01 janvier 2010
• Nombre de lectures: 27
• Langue: English
• Poids de l'ouvrage: 3 Mo

Extrait

Major Organic Foulants in Ultrafiltration of
Treated Domestic Wastewater and their Removal
by Bio-filtration as Pre-treatment


vorgelegt von
Master of Science
Xing Zheng

an der Fakultät III – Prozesswissenschaften
der Technischen Universität Berlin
zur Erlangung des akademischen Grades


Doktor der Ingenieurwissenschaften
– Dr. Ing. –
genehmigte Dissertation

Promotionsausschuss
Vorsitzender: Prof. Dr. Ing. Sven-Uwe Geißen (Technische Universität Berlin)
Gutachter: Prof. Dr. Ing. Martin Jekel (Technische Universität Berlin)
Gutachter: Prof. Dr. Peter M. Huck (University of Waterloo/Ontario, Kanada)
Gutachter: Dr. Ing. Mathias Ernst (Technische Universität Berlin)

Tag der wissenschaftlichen Aussprache: 09.04.2010

Berlin 2010
D 83Acknowledgements I
Acknowledgements
I would like to thank my two advisers Prof. M. Jekel and Dr. M. Ernst for providing me the
opportunity to conduct my research under their guidance in different projects. Several years
ago as I began to work on the Technical University of Berlin, the dissertation was so remote
to me that I doubted if I could finish it. Thanks to their suggestive advices, to their patient
corrections of my papers and presentations, and also to their inspirations, I could make some
progress in my work and enjoy the research as well. Thank you so much, Herr Jekel and
Mathias. Simultaneously, the finance agencies of the projects which are the Federal Ministry
thfor Education (BMBF, Germany) and the European Commission under the 6 Framework
Programme are gratefully acknowledged for the financial supports.

I would also give my thanks to Prof. Peter M. Huck for his suggestion to the writing of my
dissertation and the attendance of my examination. Prof. S. Geissen is acknowledged for be-
ing the chairman of my examination committee. My acknowlegement is also given to Prof.
Gary Amy for his suggestive advices each time when we met together and the coordination of
fluorescence measurement.

And of course I would like to thank all of my colleges at the Department of Water Quality
Control. This is a warm and creative research group. Either at the beginning of my work, or in
the difficult times during the research, I have got always kind helps from them. Especially, I
would acknowledge Alexander Sperlich for his kind help, and also the membrane group –
Jens Haberkamp and Renata Mehrez – for the discussions and introductions of the measuring
methods. Thanks also to Carsten Bahr, Steffen Grünheid, Uwe Hübner, Hendrik Paar, Ulf
Miehe, Andreas Albers, Michael Stieber, Arne Hein, Aki Sabastian Ruhl and Christian Peters
for their help.

The research work is based on experiments. Without the supports from lab assistances and the
factory of the institute would it be impossible to be finished. I would like to acknowledge Dr.
Anke Putschew for her always presence when the LC-OCD was defect, Angelika Kersten and
Katrin Noack for their maintenance of the instrument, Ulrike Förster for the DOC and protein
measurement, Jutta Jakobs, Gisela Sosna, Elke Profft, Hella Schmeisser for their patient helps
in the laboratory. All of my sand filter systems were set up by Thomas Thele and Hans Riet-
dorf. It was my luck to get their help. Finally, thanks also to Karin von Nordheim and Han-
nelore Meingast our secretary for all the help in practical things.

Besides the lab works, the pilot tests were carried out in different wastewater treatment plants.
The cooperation and help from Mr. S. Foth, Ms A. Krug and Mr. M. Kempf from the WWTP
Ruhleben in Berlin, Ms Yiping Gan, Mr. Jun Hu, Dr. Jun Zhou, Mr. Jinhua Gao from the Bei-
jing Drainage Group (BDG) and Dr. Xuzhou Cheng, Dr. Futai Chen from the Tsinghua Uni-
versity in Beijing, Mr. Jianhong Chen and Mr. Renyang Hong from the Industrial Technology
Research Institute (ITRI) in Taipei are sincerely acknowledged.

In different projects, the involved students attributed a lot to water quality measurement, lab
experiments, operation and maintenance of the pilot plants. Their efforts released me to a
large extent, either in Beijing or in Berlin. I would like to thank Jiahui Kang from the Univer-II Acknowledgements
sity of Geology China, Tanja Ratuzny, Benito Martin, Nadin Drescher, Blanca Hernández
García, Zhichao Liang, Adriana González Tomaskovich, Florian Härtl, Stephan Plume and
Christopher Gabler from the Technical University of Berlin for their efforts.

I would thank Mr. Sun Kyu Maeng from TU Delft, Dr. S. Huber, Dr. M. Abert and Mr. A.
Balz from DOC Labor (DOC Labor Dr Huber, Germany) for their kind assistance in fluores-
cence and LC-OCD measurement. Special thanks to Martin Meingast from the ABU Consult
Berlin GmbH for commenting on the English grammar of this dissertation.

And finally thanks to my friends and family. The encouragement and help of my friends, es-
pecially from Dr. Weihua Peng in the United Water, Dr. Thomas Ludwig and Yongjun Zhang
from the Technical University of Berlin are sincerely acknowledged. In the past several years
the warm telephone communications with my parents in China inspired me to work forward.
Last but not least, I would like to express my love and gratefulness to my wife Bingxin for her
love, patience and support. It is her smile and insistence helping me to overcome the difficul-
ties and also enjoy the life. The past several years were also tough for you, Bingxin. We have
experienced a lot, sometimes maybe too much. But your patience and optimism gave me
courage to continue my research processes.







Abstract III
Abstract
Ultrafiltration (UF) membranes can be used after conventional wastewater treatment to pro-
duce particle free and hygienically safe water for reuse. However, membrane fouling affects
UF performance to a large extent. Without suitable pre-treatment and optimized operational
conditions, the membrane can loose its permeability quickly. Althogh hydraulic backwashing
is periodically used to remove the foulants, the accumulation of hydraulically irremovable
fouling reduces the efficiency of the membrane permanently. Thus, qualitative and quantita-
tive identification of the major foulants is necessary to understand and control fouling.

This research investigated the variation of fouling potential of domestic wastewater applying
bio-filtration as a pre-treatment process. The aim is to identify and quantify the major foulants
and understand fouling control effects using bio-filtration. Pilot-scale bio-filtration processes
were used to treat secondary effluent prior to UF. The fouling potential of various water sam-
ples was assessed by lab-scale stirred cell experiments. An UF pilot plant was used to verify
the correlation between the feedwater characteristics and membrane fouling.

The lab-scale stirred cell experiments demonstrated that the dissolved substances larger than
or comparable to the UF pore size are major foulants, in either secondary effluent or in bio-
filtrate. These substances were detected as biopolymers using liquid chromatography with
online organic carbon detection, UV absorption and organic nitrogen detection (LC-OCD-
UV-OND) which were characterized as macromolecular protein-like and polysaccharide-like
substances. The content of biopolymers influenced the filterability of water samples in UF
proportionally. It affected the reversibility of formed fouling crucially. The correlation be-
tween the biopolymer content in feedwater and the performance of UF was verified to be re-
producible by pilot-scale UF experiments.

Bio-filtration was demonstrated to be able to improve the performance of the downstream
connected UF due to the removal of particles, colloids and especially biopolymers from the
secondary effluent. The elimination of biopolymers was observed mainly within the upper
active filter layer and was revealed to be relevant to biological processes. The operational
conditions of bio-filtration, e.g. temperature, biopolymer concentration in feedwater and fil-
tration rate, influenced biopolymer removal efficiency.

After bio-filtraton, although the fouling potential of secondary effluent could be significantly
reduced, operational conditions of UF plant affected fouling development to a large extent.
Backwash interval and filtration flux were identified as the most important operational pa-
rameters affecting the severity of fouling. Severe fouling can appear due to the extension of
filtration time and/or the increase of filtration flux. To control fouling development under
these critical conditions, different chemicals were used to perform chemically enhanced
backwash. The results showed that NaClO and H O were effective reagents in controlling 2 2
irreversible fouling. Chemical cleaning was carried out to restore the permeability of a fouled
UF membrane. In the present study, the combination of NaOH and NaClO as cleaning reagent
was identified as an effective choice. IV Zusammenfassung
Zusammenfassung
In der weitergehenden Aufbereitung von Kläranlagenablauf bietet der Einsatz von Ul